Search

The lateral prefrontal cortex of primates (lPFC) plays a central role in complex cognitive behavior, in decision-making as well as in guiding top-down attention. However, how and where in lPFC such behaviorally relevant signals are computed is poorly understood. We analyzed neural recordings from chronic microelectrode arrays implanted in lPFC region 8Av/45 of two rhesus macaques. The animals performed a feature match-to-sample task requiring them to match both motion and color information in a test stimulus. This task allowed to separate the encoding of stimulus motion and color from their current behavioral relevance on a trial-by-trial basis. We found that upcoming motor behavior can be robustly predicted from lPFC activity. In addition, we show that 8Av/45 encodes the color of a visual stimulus, regardless of its behavioral relevance. Most notably, whether a color matches the searched-for color can be decoded independent of a trial’s motor outcome and while subjects detect unique feature conjunctions of color and motion. Thus, macaque area 8Av/45 computes, among other task-relevant information, the behavioral relevance of visual color features. Such a signal is most critical for both the selection of responses as well as the deployment of top-down modulatory signals, like feature-based attention.

Pupil size is modulated not only by the luminance at the eye position but also by that at the attended location. This study aims to examine whether pupil changes also correspond to the luminance at the spatial location to which the attention is shifted in optokinetic nystagmus. The test stimulus consisted of randomly positioned dots that moved to the left or to the right on a display screen that was bright on one side of the centerline and dark on the other. The results show that pupil size changes in accordance with the luminance at the location to which participants’ attention shifts as a result of optokinetic nystagmus (i.e., eye movements in the direction opposite to that of the motion stimulus). This study suggests that pupil size is modulated by the luminance at the location to which attention shifts through unidirectional field motion.

Laste loodud jutustusi peetakse rikkalikuks keelematerjaliks, keelearengu taseme peegeldajaks ning selle hindamise heaks vahendiks. Eesti keele alastes uuringutes ei ole testi “The Multilingual Assessment Instrument for Narratives” (MAIN) seni kasutatud. Nii puuduvad andmed selle kohta, kuivord sobib test eesti laste jutustamisoskuse uurimiseks. Artikli eesmark on selgitada, kas test eesti lastele sobib, kas ja kuivord erinevad eri vanuses laste tulemused, millised osad testist on eesti laste jaoks raskemad ja kergemad ning milline on seos laste sonavara mahu ja rikkuse ning jutustamisoskuse vahel. Uurimismaterjal on kogutud testi eelkatsega, kus osales 18 last vanuses 4−8 eluaastat. Tulemustest selgus, et test annab laialdase pildi nii narratiivi loomise kui ka moistmise kohta. Loomiskatse aluseks olnud pildi moistmine oli lastele kergem kui iseseisev jutustuse loomine. Narratiivi loomist ei alustanud lapsed tavaliselt alguspunkti signaliseerimisega (aja voi koha nimetamisega), vaid pigem kohe katse voi eesmargi sisukomponendiga, mis osutusid ka koige sagedasemateks ja seega koige kergemateks sisukomponentideks laste narratiivides. *** Using the Multilingual Assessment Instrument for Narratives test for the assessment of Estonian children’s narrative skills In the Estonian language context, the Multilingual Assessment Instrument for Narratives (MAIN) has not been used for research purposes. A total of 18 children (9 boys and 9 girls) between the ages of 4 and 8 took part in trial tests: 15 Estonian mother-tongue and 3 Estonian-Russian bilingual mother-tongue children. The article was an analysis of the suitability of the test and an analysis of the test’s preliminary results in assessing Estonian children’s narrative skills. The preliminary test showed that storytelling is difficult for children. It emerged that when producing a narrative, it was not natural for children to indicate a starting point (giving time or place), but rather storytelling began immediately with a conflict and goal as internal components. Challenges and goals also turned out to be the most common and therefore the simplest content in the children’s narratives. There was little complexity in the children’s narratives, and most presented individual goals without conflicts or outcomes. Least common was all three macrostructural components (goal-conflict-outcome) in succession in the children’s stories. Stories that achieved higher scores in production were also more complex and these displayed components and sequencing of components that show the cohesion and completeness of the work. Stories that achieved lower scores rather contain individual goals of narrative production, but with conflicts and outcomes to a lesser extent. In the Estonian children’s narratives, there were few words referring to a person’s inner feelings or reactions. The results showed that Estonian children find it difficult to use emotion words, which is evidenced by their limited use of IST words (including emotion words) as well as their null-rated understanding of the internal reactions and states of individuals. No connection emerged showing that those that narrate better also understand better. A high comprehension test result shows that the test stimulus, a series of pictures, was understood and the test turned out to be appropriate for the children. Better narrators generally have a richer vocabulary and children with a richer vocabulary express more internal reactions and conditions of individuals in their stories. By analysing the density of the vocabulary used by the children in their narratives and its relationship with points in the narrative, it became clear that a child’s more varied vocabulary is not connected to better narrative skills. For further research purposes, this test has significant added value and research focus which provides an opportunity to link narrative production skills with studies of the developmental environment.

Abstract. The present study sought to explore whether musical information is processed by the phonological loop component of the working memory model of immediate memory. Original instantiations of this model primarily focused on the processing of linguistic information. However, the model was less clear about how acoustic information lacking phonological qualities is actively processed. Although previous research has generally supported shared processing of phonological and musical information, these studies were limited as a result of a number of methodological concerns (e.g., the use of simple tones as musical stimuli). In order to further investigate this issue, an auditory interference task was employed. Specifically, participants heard an initial stimulus (musical or linguistic) followed by an intervening stimulus (musical, linguistic, or silence) and were then asked to indicate whether a final test stimulus was the same as or different from the initial stimulus. Results indicated that mismatched interference conditions (i.e., musical – linguistic; linguistic – musical) resulted in greater interference than silence conditions, with matched interference conditions producing the greatest interference. Overall, these results suggest that processing of linguistic and musical information draws on at least some of the same cognitive resources.

Grapheme-color synesthesia is a perceptual phenomenon that occurs when letters or numbers elicit an abnormal color sensation (e.g., printed black letters are perceived as colored graphemes). Grapheme-color synesthesia is typically reported following explicit presentation of graphemes. Very few studies have investigated color sensations in synesthesia in the absence of visual awareness. To address this issue, we took advantage of the dichoptic flash suppression paradigm to temporarily render a stimulus presented to one eye invisible. Synesthesic alphanumeric and non-synesthetic abstract stimuli were presented to 11 synesthete and 11 matched control participants in achromatic and chromatic experimental conditions. The test stimulus was first displayed to one eye and then masked following the sudden presentation of visual noise in the other eye. The time for an image to be perceived following the onset of the suppressive noise was calculated in each condition. Trials free of flash suppression but mimicking the perceptual suppression of the flash were also tested. Results showed that target detection by synesthetes was significantly better than by controls in the absence of flash suppression. However, no statistically significant difference was found between the groups when the test stimulus was interocularly suppressed, either for synesthetic or non-synesthetic stimuli. This study suggests that synesthesia can be associated with enhanced perception for overt recognition, but does not occur in the absence of visual awareness.

In the visual oddball paradigm, surprising inputs can seem expanded in time relative to unsurprising repeated events. A horizontal input embedded in a train of successive vertical inputs can, for instance, seem relatively protracted in time, even if all inputs are presented for an identical duration. It is unclear if this effect results from surprising events becoming apparently protracted, or from repeated events becoming apparently contracted in time. To disambiguate, we used a non-relative duration reproduction task, in which several standards preceded a test stimulus that had to be reproduced. We manipulated the predictability of test content over successive presentations. Overall, our data suggest that predictable stimuli induce a contraction of apparent duration (Experiments 1, 3, and 4). We also examine sensitivity to test content, and find that predictable stimuli elicit less uptake of visual information (Experiments 2 and 3). We discuss these findings in relation to the predictive coding framework.

Prolonged exposure to wide (thin) bodies causes a perceptual aftereffect such that subsequently viewed bodies appear thinner (wider) than they actually are. This phenomenon is known as visual adaptation. We used the adaptation paradigm to examine the gender selectivity of the neural mechanisms encoding body size and shape. Observers adjusted female and male test bodies to appear normal-sized both before and after adaptation to bodies digitally altered to appear heavier or lighter. In Experiment 1, observers adapted simultaneously to bodies of each gender distorted in opposite directions, e.g., thin females and wide males. The direction of resultant aftereffects was contingent on the gender of the test stimulus, such that in this example female test bodies appeared wider while male test bodies appeared thinner. This indicates at least some separation of the neural mechanisms processing body size and shape for the two genders. In Experiment 2, adaptation involved either wide females, thin females, wide males or thin males. Aftereffects were present in all conditions, but were stronger when test and adaptation genders were congruent, suggesting some overlap in the tuning of gender-selective neural mechanisms. Given that visual adaptation has been implicated in real-world examples of body size and shape misperception (e.g., in anorexia nervosa or obesity), these results may have implications for the development of body image therapies based on the adaptation model.

Exposure to a particular sensory stimulation for a prolonged period of time often results in changes in the associated perception of subsequent stimulation. Such changes can take the form of decreases in sensitivity and/or aftereffects. Aftereffects often result in a rebound in the perception of the associated stimulus property when presented with a novel stimulus. The current study sought to determine if such perceptual aftereffects could be experienced following tactile stimulation at a particular frequency. To this end, participants’ perception of a 5 Hz standard frequency stimulus was evaluated using an adaptive staircase psychophysical paradigm. Participants’ perception of the standard stimulus frequency was tested a second time following the adaptation to another stimulus frequency that was either lower (i.e., 2 Hz), the same (i.e., 5 Hz), or higher (i.e., 8 Hz) than the standard stimulus (i.e., 3 groups). Following adaptation, participants who received the 5 Hz or 8 Hz stimulation reported significantly lower estimates of the standard stimulus frequency relative to the 2 Hz group. Thus, the current work provides preliminary evidence that directional after-effects can be induced when the adapting stimulus is of equal or greater frequency relative to the test stimulus, but no such influence is observed when the adapting stimulus is less than the standard stimulus.

Perceptual judgements are, by nature, a product of both sensation and the cognitive processes responsible for interpreting and reporting subjective experiences. Changed perceptual judgements may thus result from changes in how the world appears (perception), or subsequent interpretation (cognition). This ambiguity has led to persistent debates about how to interpret changes in decision-making, and if cognition can change how the world looks, or sounds, or feels. Here we introduce an approach that can help resolve these ambiguities. In three motion-direction experiments, we measured perceptual judgements and subjective confidence. Sensory encoding changes (i.e. the motion-direction aftereffect) impacted each measure equally, as the perceptual evidence informing both responses had changed. However, decision changes dissociated from reports of subjective uncertainty when non-perceptual effects changed decision-making. Our findings show that subjective confidence can provide important information about the cause of aftereffects, and can help inform us about the organisation of the mind.

Many vertebrate taxa respond to heterospecific alarm calls with anti-predator behaviours. While it is unclear how apparent recognition is achieved, learned associations between the occurrence of the call and the presence of a predator are considered the most likely explanation. Conclusive evidence that this behaviour is indeed underpinned by learning, however, is scarce. This study tested whether wild black capuchin monkeys (Sapajus nigritus) learn to associate novel sounds with predators through a two-phase field experiment. During an initial training phase, three study groups were each presented with a playback of one of the three novel sounds together with a simulated felid predator on four occasions over an 8- to 12-week period. This was followed by a test phase, wherein each of the three sounds was played back to individuals in all three groups, allowing each sound to serve as both a test stimulus for individuals trained with that sound, and a control stimulus for individuals trained with another sound. Antipredator responses were significantly stronger in response to test sounds than to controls. Limited observations suggest that antipredator responses persisted for at least 2 years without reinforcement of the predator–sound link. Additionally, responses to noisier sounds were typically stronger than were those to more tonal sounds, although the effect of sound type cannot be disentangled from potential effects of group. This study provides the strongest evidence to date that learning affects the responses of primates to sounds such as heterospecific alarm calls, and supports the contention that signals provide receivers with information. Electronic supplementary material The online version of this article (10.1007/s10071-019-01264-3) contains supplementary material, which is available to authorized users.

Dogs enrolled in a previous study were assessed two years later for reliability of their local/global preference in a discrimination test with the same hierarchical stimuli used in the previous study (Experiment 1) and with a novel stimulus (Experiment 2). In Experiment 1, dogs easily re-learned to discriminate the positive stimulus; their individual global/local choices were stable compared to the previous study; and an overall clear global bias was found. In Experiment 2, dogs were slower in acquiring the initial discrimination task; the overall global bias disappeared; and, individually, dogs tended to make inverse choices compared to the original study. Spontaneous attention toward the test stimulus resembling the global features of the probe stimulus was the main factor affecting the likeliness of a global choice of our dogs, regardless of the type of experiment. However, attention to task-irrelevant elements increased at the expense of attention to the stimuli in the test phase of Experiment 2. Overall, the results suggest that the stability of global bias in dogs depends on the characteristics of the assessment contingencies, likely including the learning requirements of the tasks. Our results also clearly indicate that attention processes have a prominent role on dogs' global bias, in agreement with previous findings in humans and other species.

In two adaptation experiments we investigated the role of phonemes in speech perception. Participants repeatedly categorized an ambiguous test word that started with a blended /f/-/s/ fricative ( ?ail can be perceived as /fail/ or /sail/) or a blended /d/-/b/ stop ( ?ump can be perceived as /bump/ or /dump/) after exposure to a set of adaptor words. The adaptors all included unambiguous /f/ or /s/ fricatives, or alternatively, /d/ or /b/ stops. In Experiment 1 we manipulated the position of the adaptor phonemes so that they occurred at the start of the word (e.g., f arm ), at the start of the second syllable (e.g., to f u ), or the end of the word (e.g., lea f ). We found that adaptation effects occurred across positions: Participants were less likely to categorize the ambiguous test stimulus as if it contained the adapted phoneme. For example, after exposure to the adaptors lea f , gol f ... etc., participants were more likely to categorize the ambiguous test word ? ail as ‘sail’. In Experiment 2 we also varied the voice of the speaker: Words with unambiguous final phoneme adaptors were spoken by a female while the ambiguous initial test phonemes were spoken by a male. Again robust adaptation effects occurred. Critically, in both experiments, similar adaptation effects were obtained for the fricatives and stops despite the fact that the acoustics of stops vary more as a function of position. We take these findings to support the claim that position independent phonemes play a role in spoken word identification.

Three rhesus monkeys (Macaca mulatta) were tested in a same/different memory task for proactive interference (PI) from prior trials. PI occurs when a previous sample stimulus appears as a test stimulus on a later trial, does not match the current sample stimulus, and the wrong response "same" is made. Trial-unique pictures (scenes, objects, animals, etc.) were used on most trials, except on trials where the test stimulus matched potentially interfering sample stimulus from a prior trial (1, 2, 4, 8, or 16 trials prior). Greater interference occurred when fewer trials separated interference and test. PI functions showed a continuum of interference. Delays between sample and test stimuli and intertrial intervals were manipulated to test how PI might vary as a function of elapsed time. Contrary to a similar study with pigeons, these time manipulations had no discernable effect on the monkey's PI, as shown by compete overlap of PI functions with no statistical differences or interactions. These results suggested that interference was strictly based upon the number of intervening events (trials with other pictures) without regard to elapsed time. The monkeys' apparent event-based interference was further supported by retesting with a novel set of 1,024 pictures. PI from novel pictures 1 or 2 trials prior was greater than from familiar pictures, a familiar set of 1,024 pictures. Moreover, when potentially interfering novel stimuli were 16 trials prior, performance accuracy was actually greater than accuracy on baseline trials (no interference), suggesting that remembering stimuli from 16 trials prior was a cue that this stimulus was not the sample stimulus on the current trial-a somewhat surprising conclusion particularly given monkeys.

Exposure to a to-be-tested stimulus produces a reduction in generalization to that stimulus from another similar conditioned stimulus (e.g. Bennett et al., 1994; Symonds and Hall, 1997). Generally, this effect has been interpreted as the result of a loss of effectiveness of the common elements of the stimulus to be conditioned (e.g., latent inhibition). However, Sanjuan et al. (2006) questioned this interpretation after finding that exposing rats to either the test stimulus or to its elements had different effects when the amount of exposure to the common elements was equated. Only exposure to the test stimulus reduced generalization. In the study presented here, this effect was assessed in human participants using a videogame method and colors as stimuli. Generalization after exposure to the test stimulus, or to its elements was assessed. Results show that with people, as in rats, pre-exposure to the test stimulus leads to a greater reduction in generalization than to the elements. Therefore, latent inhibition cannot be the only mechanism responsible for this perceptual learning effect. Results are discussed in terms of current associative theories addressing perceptual-learning phenomenon.

In this study we sought to determine whether infants, like adults, utilize previous experience to guide figure/ground processing. After familiarization to a shape, 5-month-olds preferentially attended to the side of an ambiguous figure/ground test stimulus corresponding to that shape, suggesting that they were viewing that portion as the figure. Infants' failure to exhibit this preference in a control condition in which both sides of the test stimulus were displayed as figures indicated that the results in the experimental condition were not due to a preference between two figure shapes. These findings demonstrate for the first time that figure/ground processing in infancy is sensitive to top-down influence. Thus, a critical aspect of figure/ground processing is functional early in life.

The Attentional Theory of Context Processing (ATCP) states that extinction will arouse attention to contexts resulting in learning becoming contextually controlled. Participants learned to suppress responding to colored sensors in a video-game task where contexts were provided by different gameplay backgrounds. Four experiments assessed the contextual control of simple excitatory learning acquired to a test stimulus (T) after (Exp. 1) or during (Exp. 2-4) extinction of another stimulus (X). Experiment 1 produced no evidence of contextual control of T, though renewal to X was present both at the time T was trained and tested. In Experiment 2 no contextual control of T was evident when X underwent extensive conditioning and extinction. In Experiment 3 no contextual control of T was evident after extensive conditioning and extinction of X, and renewal to X was present. In Experiment 4 contextual control was evident to T, but it neither depended upon nor was enhanced by extinction of X. The results presented here appear to limit the generality of ATCP.

Whole-brain responses to sound are easily measured through auditory evoked potentials (AEP), but it is unclear how differences in experimental parameters affect these responses. The effect of varying parameters is especially unclear in fish studies, the majority of which use simple sound types and then extrapolate to natural conditions. The current study investigated AEPs in goldfish (Carassius auratus) using sounds of different durations (5, 10, and 20 ms) and frequencies (200, 500, 600 and 700 Hz) to test stimulus effects on latency and thresholds. We quantified differences in latency and threshold in comparison to a 10-ms test tone, a duration often used in AEP fish studies. Both response latency and threshold were significantly affected by stimulus duration, with latency patterning suggesting that AEP fires coincident with a decrease in stimulus strength. Response latency was also significantly affected by presentation frequency. These results show that stimulus type has important effects on AEP measures of hearing and call for clearer standards across different measures of AEP. Duration effects also suggest that AEP measures represent summed responses of duration-detecting neural circuit, but more effort is needed to understand the neural drivers of this commonly used technique.

Attention maintains task-relevant information in working memory (WM) in an active state. We investigated whether the attention-based maintenance of stimulus representations that were encoded through different modalities is flexibly controlled by top–down mechanisms that depend on behavioral goals. Distinct components of the ERP reflect the maintenance of tactile and visual information in WM. We concurrently measured tactile (tCDA) and visual contralateral delay activity (CDA) to track the attentional activation of tactile and visual information during multimodal WM. Participants simultaneously received tactile and visual sample stimuli on the left and right sides and memorized all stimuli on one task-relevant side. After 500 msec, an auditory retrocue indicated whether the sample set's tactile or visual content had to be compared with a subsequent test stimulus set. tCDA and CDA components that emerged simultaneously during the encoding phase were consistently reduced after retrocues that marked the corresponding (tactile or visual) modality as task-irrelevant. The absolute size of cue-dependent modulations was similar for the tCDA/CDA components and did not depend on the number of tactile/visual stimuli that were initially encoded into WM. Our results suggest that modality-specific maintenance processes in sensory brain regions are flexibly modulated by top–down influences that optimize multimodal WM representations for behavioral goals.

Discrimination tests are used in food companies to quantify small differences between products. Within the diversity of methods available, some are quicker to conduct, whereas others are more sensitive or statistically powerful. One class of methods includes the reminder tasks in which the reference product is given before tasting the actual test stimuli. During the task, such a 'reminder' can be compared directly to each test stimulus, or alternatively, only serve to prime the memory of the judge without being taken into account in decision-making. Previous research with trained judges provided evidence for the latter process while research with untrained consumers has provided some evidence for the former process. Two studies were conducted with untrained consumers using the A Not-AR and 2-AFCR reminder tasks. Objectives were to determine the decision strategies used in, and the relative sensitivity of the tasks. In addition, the use of an "authenticity test" was explored to see if this has a positive effect on test performance. In the first study, mayonnaise and ice tea with small stimulus differences (d'

Adaptation to the duration of a visual stimulus causes the perceived duration of a subsequently presented stimulus with a slightly different duration to be skewed away from the adapted duration. This pattern of repulsion following adaptation is similar to that observed for other visual properties, such as orientation, and is considered evidence for the involvement of duration-selective mechanisms in duration encoding. Here, we investigated whether the encoding of duration - by duration-selective mechanisms - occurs early on in the visual processing hierarchy. To this end, we investigated the spatial specificity of the duration after-effect in two experiments. We measured the duration after-effect at adapter-test distances ranging between 0 and 15° of visual angle and for within- and between- hemifield presentations. We replicated the duration after-effect: the test stimulus was perceived to have a longer duration following adaptation to a shorter duration, and a shorter duration following adaptation to a longer duration. Importantly, this duration after-effect occurred at all measured distances, with no evidence for a decrease in the magnitude of the after-effect at larger distances or across hemifields. This shows that adaptation to duration does not result from adaptation occurring early on in the visual processing hierarchy. Instead, it seems likely that duration information is a high-level stimulus property that is encoded later on in the visual processing hierarchy.

Although looking time is used to assess infant perceptual and cognitive processing, little is known about the temporal structure of infant looking. To shed light on this temporal structure, 127 three-month-olds were assessed in an infant-controlled habituation procedure and presented with a pre-recorded display of a woman addressing the infant using infant-directed speech. Previous individual look durations positively predicted subsequent look durations over a six look window, suggesting a temporal dependency between successive infant looks. The previous look duration continued to predict the subsequent look duration after accounting for habituation-linked declines in look duration, and when looks were separated by an inter-trial interval in which no stimulus was displayed. Individual differences in temporal dependency, the strength of associations between consecutive look durations, are distinct from individual differences in mean infant look duration. Nevertheless, infants with stronger temporal dependency had briefer mean look durations, a potential index of stimulus processing. Temporal dependency was evident not only between individual infant looks but between the durations of successive habituation trials (total looking within a trial). Finally, temporal dependency was evident in associations between the last look at the habituation stimulus and the first look at a novel test stimulus. Thus temporal dependency was evident across multiple timescales (individual looks and trials comprised of multiple individual looks) and persisted across conditions including brief periods of no stimulus presentation and changes from a familiar to novel stimulus. Associations between consecutive look durations over multiple timescales and stimuli suggest a temporal structure of infant attention that has been largely ignored in previous work on infant looking.

There is consensus in research that food tastiness is not only contingent on the food itself (e.g., its ingredients, colors, or its preparation) but also on context factors such as lighting while consuming the food and on the use of communication and promotional tools. Regarding the latter measures, prior research focused on the shape of food packaging and on verbal and visual advertising cues.

Definitions: Envision, your first name is Anne and you intend to order Pizza. There are two restaurants to do this service: Alfredo and Luigi. Would your choice be affected by the congruence of the initial letter of your first name and Alfredo? If you respond favorably to this commonality, your behavior is affected by the name-letter effect (Nuttin, 1985; Coulter and Grewal, 2014).

Accurate perception of sub-second tactile duration is critical for successful human-machine interaction and human daily life. However, it remains debated where the cortical processing of tactile duration takes place. Previous studies have shown that prolonged adaptation to a relatively long or short auditory or visual stimulus leads to a repulsive duration aftereffect such that the durations of subsequent test stimuli within a certain range appear to be contracted or expanded. Here, we demonstrated a robust repulsive tactile duration aftereffect with the method of single stimuli, where participants determined whether the duration of the test stimulus was shorter or longer than the internal mean formed before the adaptation (Experiment 1A). The tactile duration aftereffect was also observed when participants reproduced the duration of the test stimulus by holding down a button press (Experiment 1B). Importantly, the observed tactile duration aftereffect was tuned around the adapting duration (Experiment 1C). Moreover, the effect was confined in the adapted sensory modality (Experiment 2) and the enacted fingers within a somatotopic framework (Experiment 3). These findings suggest the early somatosensory areas with the topographic organization of hands play an essential role in sub-second tactile duration perception.

We examined the effect of temporal context on discrimination of intervals marked by auditory, visual and tactile stimuli. Subjects were asked to compare the duration of the interval immediately preceded by an irrelevant "distractor" stimulus with an interval with no distractor. For short interval durations, the presence of the distractor affected greatly the apparent duration of the test stimulus: short distractors caused the test interval to appear shorter and vice versa. For very short reference durations (≤ 100 ms), the contextual effects were large, changing perceived duration by up to a factor of two. The effect of distractors reduced steadily for longer reference durations, to zero effect for durations greater than 500 ms. We found similar results for intervals defined by visual flashes, auditory tones and brief finger vibrations, all falling to zero effect at 500 ms. Under appropriate conditions, there were strong cross-modal interactions, particularly from audition to vision. We also measured the Weber fractions for duration discrimination and showed that under the conditions of this experiment, Weber fractions decreased steadily with duration, following a square-root law, similarly for all three modalities. The magnitude of the effect of the distractors on apparent duration correlated well with Weber fraction, showing that when duration discrimination was relatively more precise, the context dependency was less. The results were well fit by a simple Bayesian model combining noisy estimates of duration with the action of a resonance-like mechanism that tended to regularize the sound sequence intervals.

When faces, objects, or voices are encountered, naming lapses can occur, but this does not preclude knowing other specific semantic information about the nameless thing. In the experiments reported here, we examined whether this is also the case for odours, using a procedure based upon the Pyramid and Palm Trees test. In Experiment 1, participants were presented with a target odour, then two pictures, and had to pick the picture semantically associated with the target. In Experiment 2, participants were presented with a target odour, then two test odours, and again had to pick the semantically associated test stimulus. In each experiment, other tests followed, including a parallel verbal-based test, an odour-naming test, and various ratings. Neither experiment found any evidence of specific semantic knowledge about a target odour, unless the target odour name (Experiment 1) or all of the odour names (Experiment 2) were known. Additional tests suggested that these effects were independent of odour familiarity and similarity. We suggest that the absence of specific semantic information in the absence of a name may reflect poor connectivity between olfactory perceptual and semantic memory systems.

Auditory evoked potentials (AEPs) to motion onset in humans are dominated by a fronto-central complex, with a change-negative deflection 1 (cN1) and a change-positive deflection 2 (cP2) component. Here the contribution of veridical motion detectors to motion-onset AEPs was investigated with the hypothesis that direction-specific adaptation effects would indicate the contribution of such motion detectors. AEPs were recorded from 33 electroencephalographic channels to the test stimulus, i.e. motion onset of horizontal virtual auditory motion (60° per s) from straight ahead to the left. AEPs were compared in two experiments for three conditions, which differed in their history prior to the motion-onset test stimulus: (i) without motion history (Baseline), (ii) with motion history in the same direction as the test stimulus (Adaptation Same), and (iii) a reference condition with auditory history. For Experiment 1, condition (iii) comprised motion in the opposite direction (Adaptation Opposite). For Experiment 2, a noise in the absence of coherent motion (Matched Noise) was used as the reference condition. In Experiment 1, the amplitude difference cP2 - cN1 obtained for Adaptation Same was significantly smaller than for Baseline and Adaptation Opposite. In Experiment 2, it was significantly smaller than for Matched Noise. Adaptation effects were absent for cN1 and cP2 latencies. These findings demonstrate direction-specific adaptation of the motion-onset AEP. This suggests that veridical auditory motion detectors contribute to the motion-onset AEP.

We recorded from middle–lateral (ML) and primary (A1) auditory cortex while macaques discriminated amplitude-modulated (AM) noise from unmodulated noise. Compared with A1, ML had a higher proportion of neurons that encoded increasing AM depth by decreasing their firing rates (“decreasing” neurons), particularly with responses that were not synchronized to the modulation. Choice probability (CP) analysis revealed that A1 and ML activity were different during the first half of the test stimulus. In A1, significant CP began before the test stimulus, remained relatively constant (or increased slightly) during the stimulus, and increased greatly within 200 ms of lever release. Neurons in ML behaved similarly, except that significant CP disappeared during the first half of the stimulus and reappeared during the second half and prerelease periods. CP differences between A1 and ML depend on neural response type. In ML (but not A1), when activity was lower during the first half of the stimulus in nonsynchronized, decreasing neurons, the monkey was more likely to report AM. Neurons that both increased firing rate with increasing modulation depth (“increasing” neurons) and synchronized their responses to AM had similar choice-related activity dynamics in ML and A1. These results suggest that, when ascending the auditory system, there is a transformation in coding AM from primarily synchronized increasing responses in A1 to nonsynchronized and dual (increasing/decreasing) coding in ML. This sensory transformation is accompanied by changes in the timing of activity related to choice, suggesting functional differences between A1 and ML related to attention and/or behavior.

Objective To examine the validity of multi-fiber muscle velocity recovery cycles (VRCs) recorded by direct muscle stimulation with submaximal stimuli. Methods VRCs were recorded from tibialis anterior muscle in normal volunteers with 1, 2 and 5 conditioning stimuli. Recordings were made with 6 different amplitudes of conditioning stimuli. Recordings were also made with two recording electrodes, at least 15 mm apart. Results Muscle VRCs in 6 subjects were not significantly different for conditioning stimuli between 80% and 150% of test stimulus amplitude. When recorded at two sites in 9 subjects, VRCs were similar when estimated over the shorter distance, the longer distance, and from the conduction time between the two electrodes. Conclusions Multi-fiber muscle VRCs can be reliably recorded with a single recording electrode and with equal amplitude conditioning and test stimuli. Significance Clinical neurophysiologists can be assured that this new method of testing muscle membrane properties provides valid and robust measurements on normal muscles.

he effect of postural orientation on the motor corticospinal excitability (MCE) of proximal and distal upper extremity (UE) muscles was investigated. In a crossover design, recruitment curves (RCs), short interval cortical inhibition (SICI) and intracortical facilitation (ICF) of resting anterior deltoid (AD) and first dorsal interosseus (FDI) was assessed in two postures: sitting and standing. Six healthy adults with- out contraindications to transcranial magnetic stimulation (TMS) participated in the study. TMS was applied over the motor cortical representation of FDI and AD at intensities ranging from 90% to 200% of resting motor threshold (RMT) in increments of 10%. SICI and ICF were assessed for each muscle using a conditioning stimulus (80% RMT) preceding a test stimulus (120% RMT) with an interstimulus interval of 2 ms and 15 ms, respectively. For AD, but not FDI, there was a significant and consistent increase in RC slope during standing compared to sitting. For FDI, there was no difference in ICF and SICI between sitting and standing. However, for AD, while there was no difference in ICF between the two postures, there was a clear trend for SICI to decrease (p = 0.06) in standing compared to sitting. These results indicate that postural change from sitting to standing, affects the MCE of proximal but not distal muscles. While this indicates the role of proximal UE muscles in postural control, it also implies that rehabilitation protocols for enhancing proximal arm motor function may be advantaged if administered in a standing posture. ispartof: Neuroscience Letters vol:533 pages:65-70 ispartof: location:Ireland status: published

Repetitive exposure to relatively long or short sensory events has been shown to shorten or lengthen the perceived duration of a subsequent event. However, the neural basis of this phenomenon, called duration adaptation, remains unclear. In this study, we used electroencephalography (EEG) to investigate whether duration adaptation could modulate the subsequent temporal encoding represented by the contingent negative variation (CNV). Participants were asked to reproduce the duration of a test stimulus after adapting duration ( Experiment 1 ) or after anchor duration ( Experiment 2 ). We found that both adapting duration and anchor duration affected the reproduction duration of a subsequently presented test stimulus. The simultaneously recorded event-related potentials (ERPs) revealed that test stimuli evoked clearly identifiable N1, P2 and CNV components in the fronto-central scalp. Further analyses showed that the CNV amplitude was modulated by duration adaptation: adaptation to shorter duration (200 ms) increased whereas adaptation to longer duration (800 ms) decreased the CNV amplitude. These findings suggest that the neural correlates of temporal encoding represented by the CNV amplitude reflect the duration aftereffect. Additionally, the duration adaptation effect observed on the P2 component also suggests an early expectancy effect on subsequent encoding processes. Finally, no effect of anchor duration was observed on the CNV amplitude, which implies that different mechanisms underlie the duration aftereffect and the anchor effect.

Reichert and Carpenter (2004, p. 828) analyzed the content of mainstream magazine ads in the U.S. and found for 1983 that 3.7% of all ads contained motifs of couples in intimate or very intimate contact. In 2003, this portion was 7.5% and thus has doubled over the course of two decades.

Body size misperception is common amongst the general public and is a core component of eating disorders and related conditions. While perennial media exposure to the “thin ideal” has been blamed for this misperception, relatively little research has examined visual adaptation as a potential mechanism. We examined the extent to which the bodies of “self” and “other” are processed by common or separate mechanisms in young women. Using a contingent adaptation paradigm, experiment 1 gave participants prolonged exposure to images both of the self and of another female that had been distorted in opposite directions (e.g., expanded other/contracted self), and assessed the aftereffects using test images both of the self and other. The directions of the resulting perceptual biases were contingent on the test stimulus, establishing at least some separation between the mechanisms encoding these body types. Experiment 2 used a cross adaptation paradigm to further investigate the extent to which these mechanisms are independent. Participants were adapted either to expanded or to contracted images of their own body or that of another female. While adaptation effects were largest when adapting and testing with the same body type, confirming the separation of mechanisms reported in experiment 1, substantial misperceptions were also demonstrated for cross adaptation conditions, demonstrating a degree of overlap in the encoding of self and other. In addition, the evidence of misperception of one's own body following exposure to “thin” and to “fat” others demonstrates the viability of visual adaptation as a model of body image disturbance both for those who underestimate and those who overestimate their own size.

International audience; What happens to the representation of a moving stimulus when it is no longer present and its motion direction has to be maintained in working memory (WM)? Is the initial, sensorial representation maintained during the delay period or is there another representation, at a higher level of abstraction? It is also feasible that multiple representations may co-exist in WM, manifesting different facets of sensory and more abstract features. To that end, we investigated the mnemonic representation of motion direction in a series of three psychophysical experiments, using a delayed motion-discrimination task (relative clockwise\counter-clockwise judgment). First, we show that a change in the dots' contrast polarity does not hamper performance. Next, we demonstrate that performance is unaffected by relocation of the Test stimulus in either retinotopic or spatiotopic coordinate frames. Finally, we show that an arrow-shaped cue presented during the delay interval between the Sample and Test stimulus, strongly biases performance toward the direction of the arrow, although the cue itself is non-informative (it has no predictive value of the correct answer). These results indicate that the representation of motion direction in WM could be independent of the physical features of the stimulus (polarity or position) and has non-sensorial abstract qualities. It is plausible that an abstract mnemonic trace might be activated alongside a more basic, analog representation of the stimulus. We speculate that the specific sensitivity of the mnemonic representation to the arrow-shaped symbol may stem from the long term learned association between direction and the hour in the clock.

Purpose To determine the effect of reducing spatial uncertainty by attentional cueing on contrast sensitivity at a range of spatial locations and with different stimulus sizes. Methods Six observers underwent perimetric testing with the Humphrey Visual Field Analyzer (HFA) full threshold paradigm, and the output thresholds were compared to conditions where stimulus location was verbally cued to the observer. We varied the number of points cued, the eccentric and spatial location, and stimulus size (Goldmann size I, III and V). Subsequently, four observers underwent laboratory-based psychophysical testing on a custom computer program using Method of Constant Stimuli to determine the frequency-of-seeing (FOS) curves with similar variables. Results We found that attentional cueing increased contrast sensitivity when measured using the HFA. We report a difference of approximately 2 dB with size I at peripheral and mid-peripheral testing locations. For size III, cueing had a greater effect for points presented in the periphery than in the mid-periphery. There was an exponential decay of the effect of cueing with increasing number of elements cued. Cueing a size V stimulus led to no change. FOS curves generated from laboratory-based psychophysical testing confirmed an increase in contrast detection sensitivity under the same conditions. We found that the FOS curve steepened when spatial uncertainty was reduced. Conclusion We show that attentional cueing increases contrast sensitivity when using a size I or size III test stimulus on the HFA when up to 8 points are cued but not when a size V stimulus is cued. We show that this cueing also alters the slope of the FOS curve. This suggests that at least 8 points should be used to minimise potential attentional factors that may affect measurement of contrast sensitivity in the visual field.

An aftereffect is the change in the perception of a (test) stimulus after prolonged stimulation with an (adaptation) stimulus. Usually, this change is in the negative direction, that is, in a direction opposite to that of the adaptation stimulus. Aftereffects are often fast and strong. A well-known example in vision is the waterfall illusion: when looking at trees after staring at a waterfall for a minute or more, the subsequently viewed trees seem to move upwards (Addams, 1834; Swanston and Wade, 1994). Also touch is susceptible to strong aftereffects: temperature, roughness, shape, curvature, motion and size of an object all give rise to aftereffects in touch.

The pulsed-pedestal paradigm consists of the simultaneous brief presentation of a test stimulus and luminance pedestals. Processing with this paradigm is thought to be mediated by the parvocellular pathway. The steady-pedestal paradigm consists of the brief presentation of a test stimulus against a continuously presented luminance pedestals. Processing with this paradigm is thought to be mediated by the magnocellular pathway. To test the prediction that transient attention should have a differential effect on performance with these two paradigms, we added to their typical procedures peripheral precues that trigger transient attention. As expected, we have found that the attraction of transient attention to the target location improved performance with the pulsed-pedestal paradigm, but had no reliable effect on performance with the steady-pedestal paradigm. These findings support the hypothesis that transient attention favors parvocellular over magnocellular processing.

Proactive interference (PI) has traditionally been understood as an adverse consequence of stimulus repetition during memory tasks. Herein, we present data that emphasize costs as well as benefits of PI for monkeys performing an auditory delayed matching-to-sample (DMTS) task. The animals made same/different judgments for a variety of simple and complex sounds separated by a 5-s memory delay. Each session used a stimulus set that included eight sounds; thus, each sound was repeated multiple times per session for match trials and for nonmatch trials as the sample (Cue 1) or test (Cue 2) stimulus. For nonmatch trials, performance was substantially diminished when the test stimulus had been previously presented on a recent trial. However, when the sample stimulus had been recently presented, performance was significantly improved. We also observed a marginal performance benefit when stimuli for match trials had been recently presented. The costs of PI for nonmatch test stimuli were greater than the combined benefits of PI for nonmatch sample stimuli and match trials, indicating that the net influence of PI is detrimental. For all three manifestations of PI, the effects are shown to extend beyond the immediately subsequent trial. Our data suggest that PI in auditory DMTS is best understood as an enduring influence that can be both detrimental and beneficial to memory-task performance.

Rapid adaptation is an adaptation procedure in which adaptors and test stimuli are presented in rapid succession. The current study tested the validity of this method for early ERP components by investigating the specificity of the adaptation effect on the face-sensitive N170 ERP component across multiple test stimuli. Experiments 1 and 2 showed identical response patterns for house and upright face test stimuli using the same adaptor stimuli. The results were also identical to those reported in a previous study using inverted face test stimuli (Nemrodov and Itier, 2011). In Experiment 3 all possible adaptor–test combinations between upright face, house, chair and car stimuli were used and no interaction between adaptor and test category, expected in the case of test-specific adaptation, was found. These results demonstrate that the rapid adaptation paradigm does not produce category-specific adaptation effects around 170–200 ms following test stimulus onset, a necessary condition for the interpretation of adaptation results. These results suggest the rapid categorical adaptation paradigm does not work.

We show that the attentional-associative SLG model of classical conditioning, based on the 1996 research of Schmajuk, Lam, and Gray, correctly describes experimental results regarded as evidence of causal learning in rats: (a) interventions attenuate responding following common-cause training but do not interfere on subsequent responding during observation, and (b) interventions do not affect responding after direct-cause training or (c) causal-chain training. According to the model, responding to the weakly attended test stimulus is strongly inhibited by the intervention in the common-cause case. Instead, in the direct-cause and causal-chain cases, the strongly attended test stimulus becomes inhibitory, thereby overshadowing the inhibitory effect of interventions. Most importantly, the model predicted that with relatively few test trials (a) the 2008 results of Experiment 3 by Leising, Wong, Waldmann, and Blaisdell should be similar to those of Dwyer, Starns, and Honey's 2009 Experiment 1, showing that interventions equally affect responding after common-cause and direct-cause training; and (b) the 2006 results of Experiment 2a by Blaisdell, Sawa, Leising, and Waldmann should be similar to those of Dwyer, Starns, and Honey's 2009 Experiment 2, showing that interventions equally affect responding after common-cause and causal-chain training. When those data were made available to us, we confirmed those predictions. In agreement with the SLG associative model, but not with causal model theory, this evidence supports the notion that the attenuation of responding by interventions only following common-cause training is the consequence of well-known learning processes-latent inhibition, sensory preconditioning, conditioned inhibition, protection from extinction, and overshadowing.

Objectives Freezing of gait (FoG) is an invalidating symptom in patients with Parkinson’s disease (PD); it is defined as a brief, episodic absence or marked reduction of forward progression of the feet despite the intention to walk. The pathophysiology of this phenomenon remains obscure. Visual information are crucial for the initiation and control of movement, therefore an impairment of the visuomotor connections may underlie FoG. We used transcranial magnetic stimulation (TMS) to assess bilateral physiological connections (VMc) between primary visual (V1) and motor (M1) areas in PD with (PD + FoG) and without FoG (PD-FoG).We hypothesized that PD+FoG would show an abnormal response in M1. Methods Twelve PD+FoG were compared with 12 PD-FoG and 12 healthy subjects (HS) of similar age and sex. VMc was assessed bilaterally in resting participants by delivering a conditioning stimulus (CS) over the phosphene hotspot of V1 (intensity 90% phosphene threshold, PT) followed at two random interstimulus intervals (ISIs) (18 and 40 ms) by a test stimulus (TS) over left and right M1 to elicit a motor evoked potential (MEP) of ∼1 mV from the controlateral first dorsal interosseous (FDI). Results In HS, the VMc was reproducible with MEP suppression at ISI of 18 and 40 ms. Similar effects occurred in PD-FoG. PD+FoG behaved differently, since the inhibitory VMc was significantly enhanced in the right, non-dominant hemisphere. Conclusions PD+FoG had an excessive inhibitory response of the right M1 to inputs travelling from V1. Significance This may represent one core factor for the pathophysiology of FoG.

The aim of this work was to isolate and investigate subcortical and cortical lateral interactions involved in flicker perception. We quantified the perceived flicker strength (PFS) in the center of a test stimulus which was simultaneously modulated with a surround stimulus (50% Michelson contrast in both stimuli). Subjects were requested to adjust the modulation depth of a separate matching stimulus that was physically identical to the center of the test stimulus but without the surround. Using LCD goggles, synchronized to the frame rate of a CRT screen, the center and surround could be presented monoptically or dichoptically. In the monoptic condition, center-surround interactions can have both subcortical and cortical origins. In the dichoptic condition, center-surround interactions cannot occur in the retina and the LGN, therefore isolating a cortical mechanism. Results revealed both a strong monoptic (subcortical plus cortical) lateral interaction and a weaker dichoptic (cortical) lateral interaction. Subtraction of the dichoptic from the monoptic data revealed a subcortical mechanism of the lateral interaction. While the modulation of the cortical PFS component showed a low-pass temporal-frequency tuning, the modulation of the subcortical PFS component was maximal at 6 Hz. These findings are consistent with two separate temporal channels influencing the monoptic PFS, each with distinct lateral interactions strength and frequency tuning characteristics. We conclude that both subcortical and cortical lateral interactions modulate flicker perception.

Attending to a feature in one location can produce feature-specific modulation in a different location. This global feature-based attention effect has been demonstrated using two stimulus locations. Although the spread of feature-based attention is presumed to be constant across spatial locations, it has not been tested empirically. We examined the spread of feature-based attention by measuring attentional modulation of the motion aftereffect (MAE) at remote locations. Observers attended to one of two directions in a compound motion stimulus (adapter) and performed a speed-increment task. MAE was measured via a speed nulling procedure for a test stimulus at different distances from the adapter. In Experiment 1, the adapter was at fixation, while the test stimulus was located at different eccentricities. We also measured the magnitude of baseline MAE for each location in two control conditions that did not require feature-based selection necessitated by a compound stimulus. In Experiment 2, the adapter and test stimuli were all located in the periphery at the same eccentricity. Our results showed that attention induced MAE spread completely across the visual field, indicating a genuine global effect. These results add to our understanding of the deployment of feature-based attention and provide empirical constraints on theories of visual attention.

The recent studies narrowly designed to investigate the structure of working memory and its relation with intelligence emphasize the importance of the component responsible for building the relations between elements. In the present study, an expanded processing of the relations between the elements was implemented to the simplest recognition task by manipulating with a type of probe-test mismatching. The speed of recognition of meaningless figures was significantly related to intelligence only when a test stimulus differed from a probe stimulus in relative positions of the elements. In addition, regardless of the type of stimuli, the speed of processing of the constructed task was significantly related to school achievements in Algebra, Geometry, and Physics.

We examined different contrast metrics to scale visual latencies for suprathreshold stimuli modulated along tritan confusion lines. S-cone increments ('blue') and decrements ('yellow') were isolated along two different tritan confusion lines, each one having a different luminance value. Reaction times (RT) were evaluated as a function of the Weber contrast and the S-cone excitation ratio between the test stimulus and the background. RTs were described using a model that generalizes Pieron's law and incorporates the notion of threshold units and power law scaling. Our results show that RTs for S-cone increments and decrements equate better when using the S-cone excitation ratio. However, a single function did not describe all RT data. S-cone RTs are better described by separate functions. We conclude that S-cone increments and decrements do not scale in the same manner. Both Weber contrast and the S-cone excitation ratio are plausible metrics at isoluminance. The implications for the S-cone pathways are discussed.

We investigated whether center–surround interactions affect perceived speed in a manner similar to their effects on direction discrimination thresholds [e.g. Tadin, D., Lappin, J. S., Gilroy, L. A., & Blake, R. (2003). Perceptual consequences of center–surround antagonism in visual motion processing. Nature, 424, 312–315]. Observers were asked to match the speed of a test stimulus (a grating, with fixed contrast and no surround) to that of a reference stimulus of variable contrast and with a variably sized surround, moving at one of two possible velocities (1 and 12cps). At 1-cps, both lowering contrast and increasing surround-size resulted in a decrease in perceived speed, except for very low contrast stimuli, where a larger surround resulted in an increase in perceived speed. Although the effect of surround-size was comparable in the two velocity conditions, the effect of contrast was different at 12-cps. That is, in the 12cps condition, a decrease in perceived speed was observed only for the lowest contrast used. Our results suggest that, at least for the lower velocity used, center–surround interactions affect perceived speed in a manner analogous to their effect on direction discrimination.

The effect of presentation type on organization in visuospatial working memory (VSWM) was examined. Stimuli were presented sequentially or simultaneously at study, and participants made same/different judgements at test. The test array varied in four different spatial configuration conditions: one featuring no changes from study, one in which two items switched, one in which the same array repeated but in a different location, and one in which a completely novel test stimulus appeared. Results indicated the use of a global configuration for both simultaneous and sequential presentations and showed increased impairment of item-level knowledge with sequential presentations. Overall, these results support the use of a global configuration organization as a fundamental aspect of VSWM processing.

In general, perceived reverberation strength is related to physical reverberation level present at the two ears; however, this relation depends on listening condition. Pervious work using virtual auditory space techniques has demonstrated that when physical reverberation is reduced in one ear while leaving the other ear unchanged, listeners do not report a change in reverberation strength. Reducing physical reverberation equally in both ears under binaural listening or in the signal ear under monaural listening elicits a decrease in perceived reverberation strength. To better understand the relation between physical and perceived reverberation in different listening conditions, a perceptual weighting experiment was performed. Listeners reported perceived reverberation strength in a test stimulus using a magnitude estimate paradigm relative to a standard while listening over headphones. Test stimuli were generated by jittering reverberation level independently in the two channels of a binaural room impulse...

Stimulus repetition reduces neural response in cortical areas. Such adaptation is used in functional magnetic resonance imaging to infer the selectivity of neuronal populations; however, the mechanisms of adaptation remain elusive, especially in higher areas. We measured adaptation of spiking activity and local field potentials (LFPs) in macaque inferior temporal (IT) cortex for parameterized shapes by comparing tuning for test stimuli following a brief adaptation with predictions derived from different models of adaptation. Adaptation was similar during passive fixation or an attention-demanding task. We found consistent adaptation of spiking activity and LFP power in high- (gamma) but not low-frequency bands when repeating shapes. Contrary to sharpening models, repetition did not affect shape selectivity. The degree of similarity between adapter and test shapes was a stronger determinant of adaptation than was the response to the adapter. Adaptation still occurred when adapter and test stimuli did not spatially overlap, but adaptation was stronger for same, compared with different, adapters and test stimulus positions. These adaptation effects were similar for spiking and for gamma activity. In conclusion, adaptation of IT spiking activity and LFPs in IT is strongly dependent on feature similarities in the adapter and test stimuli, in agreement with input, but not firing-rate fatigue models.