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The neural substrates of associative and item priming and recognition were investigated in a functional magnetic resonance imaging study over two separate sessions. In the priming session, participants decided which object of a pair was bigger during both study and test phases. In the recognition session, participants saw different object pairs and performed the same size-judgement task followed by an associative recognition memory task. Associative priming was accompanied by reduced activity in the right middle occipital gyrus as well as in bilateral hippocampus. Object item priming was accompanied by reduced activity in extensive priming-related areas in the bilateral occipitotemporofrontal cortex, as well as in the perirhinal cortex, but not in the hippocampus. Associative recognition was characterized by activity increases in regions linked to recollection, such as the hippocampus, posterior cingulate cortex, anterior medial frontal gyrus and posterior parahippocampal cortex. Item object priming and recognition recruited broadly overlapping regions (e.g., bilateral middle occipital and prefrontal cortices, left fusiform gyrus), even though the BOLD response was in opposite directions. These regions along with the precuneus, where both item priming and recognition were accompanied by activation, have been found to respond to object familiarity. The minimal structural overlap between object associative priming and recollection-based associative recognition suggests that they depend on largely different stimulus-related information and that the different directions of the effects indicate distinct retrieval mechanisms. In contrast, item priming and familiarity-based recognition seemed mainly based on common memory information, although the extent of common processing between priming and familiarity remains unclear. Further implications of these findings are discussed.

Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition. Here, we addressed the relevance of network facilitation and rapid response learning for priming of person recognition with a view to advance general theories of priming. In four experiments, participants performed conceptual decisions like occupation or nationality judgments for famous faces. The magnitude of rapid response learning varied across experiments, and rapid response learning co-occurred and interacted with facilitation in perceptual and conceptual networks. These findings indicate that rapid response learning and facilitation in perceptual and conceptual networks are complementary rather than competing theories of priming. Thus, future memory theories need to incorporate both rapid response learning and network facilitation as individual facets of priming.

Binocular rivalry is a bistable perception that occurs when two dissimilar stimuli are presented to each eye. Recent studies have demonstrated that the reaction time to target words under binocular rivalry was shortened when semantically related prime words were presented supraliminally (Costello, Jiang, Baartman, McGlennen, & He, 2009). We investigated whether three types of priming (repetition, semantic, and cross-script) occurred from the prime words presented under binocular rivalry, by using continuous flash suppression paradigm (Tsuchiya, Koch, Gilroy, & Blake, 2006). The prime words presented to the suppressed eye invoked repetition and cross-script priming, but not semantic priming. The results suggested that the stimuli presented to the suppressed eye underwent shape and phonological level processing, but not semantic level processing.

According to classical theories, automatic processes operate independently of attention. Recent evidence, however, shows that masked visuomotor priming, an example of an automatic process, depends on attention to visual form versus semantics. In a continuation of this approach, we probed feature-specific attention within the perceptual domain and tested in two event-related potential (ERP) studies whether masked visuomotor priming in a shape decision task specifically depends on attentional sensitization of visual pathways for shape in contrast to color. Prior to the masked priming procedure, a shape or a color decision task served to induce corresponding task sets. ERP analyses revealed visuomotor priming effects over the occipitoparietal scalp only after the shape, but not after the color induction task. Thus, top-down control coordinates automatic processing streams in congruency with higher-level goals even at a fine-grained level.

When the lateralized readiness potential (LRP) is recorded in stimulus-response compatibility (SRC) tasks, two processes may overlap in the LRP, stimulus-driven response priming and activation based on response selection rules. These overlapping processes are hard to disentangle with standard analytical tools. Here, we show that Residue Iteration Decomposition (RIDE), based on latency variability, separates the overlapping LRP components from a Simon task into stimulus-driven and response-related components. SRC affected LRP amplitudes only in the stimulus-driven component, whereas LRP onsets were affected only in the response-locked component. Importantly, the compatibility effect in reaction times was more similar to the effect in the onsets of the RIDE-derived response-locked LRP component than in the unseparated LRP. Thus, RIDE-separated LRP components are devoid of distortions inherent to standard LRPs.

Competing models of attention make different predictions of how priming from recent stimulus processing could interact with intended selection. The present experiment examined the interaction between exogenous attention and endogenous priming across trial sequences. A sound cue directed attention to left, right or both sides before a dichotic syllable pair was presented. Participants were asked to report one syllable from each trial. Results showed that responses were slower on trials where one of the presented syllables had also been presented on the previous trial. Within these trials, the repeated syllable was selected less frequently, and the responses doing so were slower. Examined according to response choice on the preceding trial, syllables that had been ignored on the preceding trial tended to be ignored on the current trial (negative priming), while syllables that had been selected on the preceding trial tended to be selected on the current trial (positive priming). Responses that followed these selection biases were faster than responses that did not. Response selection was also influenced by the attention direction cue for the current trial, but not by the cue presented on the preceding trial. The results support an attentional model where traces from the preceding processing are retained, and current selection is biased to minimize cognitive conflict between recent and current processing. Negative priming appears to be due to after-effects of preceding processing, independently of the intentions behind that processing. The study accounts for positive and negative priming of dichotic listening sequences within an established, computationally viable biased competition framework.

It has been suggested that unconscious visual processing of some stimulus features might occur without the contribution of early visual cortex (V1/V2). In the present study, the causal role of V1/V2 in unconscious processing of simple shapes in intact human brain was studied by applying transcranial magnetic stimulation (TMS) on early visual cortex or lateral occipital cortex (LO) while observers performed a metacontrast-masked response priming task with arrow figures as visual stimuli. Magnetic stimulation of V1/V2 impaired masked priming 30-90 ms after the onset of the prime. Stimulation of LO reduced the magnitude of masked priming at 90-120 ms, but this effect occurred only in the early parts of the priming experiment. A control task measuring the visibility of masked primes indicated that the orientation of masked primes could not be consciously discriminated and that TMS did not influence the conscious visibility of the primes indirectly by reducing the effectiveness of the mask in the critical time windows. We conclude that feedforward sweep of processing from V1/V2 (30-90 ms) to LO (90 ms and above) is necessary for unconscious priming of shape, whereas conscious perception requires also the contribution of recurrent (feedback) processing.

The present study used event-related potentials (ERPs) to provide precise temporal information about the modulation of masked repetition priming effects × word frequency during the course of target word recognition. Contrary to the pattern seen with behavioral response times in prior research, we predicted that high-frequency words should generate larger and earlier peaking repetition priming effects than low-frequency words in the N400 time window. This prediction was supported by the results of two experiments. Furthermore, repetition priming effects in the N250 time window were found for low-frequency words in both experiments, whereas for high-frequency words these effects were seen only at the shorter (50 ms stimulus onset asynchrony [SOA]) used in Experiment 2, and not in Experiment 1 (70 ms SOA). We explain this pattern as resulting from reset mechanisms operating on the form representations activated by prime stimuli when primes and targets are processed as separate perceptual events.

Masked prime tasks have shown that sensory information that has not been consciously perceived can nevertheless modulate behavior. The neuronal correlates of behavioral manifestations of visuomotor priming remain debated, particularly with respect to the distribution and direction (i.e. increase or decrease) of activity changes in medial frontal areas. Here, we predicted that these discrepant results could be accounted for by two automatic and unconscious processes embedded in this task: response conflict and facilitation. We used event-related functional magnetic resonance imaging (fMRI), as 24 healthy participants had to respond, as fast as possible, to a target arrow presented immediately after a subliminal masked prime arrow. There were three experimental conditions defined by the prime-target relationship: compatible, incompatible, and neutral. The classical visuomotor priming effect was reproduced, with relatively longer reaction times (RTs) in incompatible trials. Longer RTs in incompatible than in neutral trials were specifically associated with stronger blood oxygen level-dependent (BOLD) activity in a conflict-related network comprising the anterior cingulate cortex and right frontal associative areas. Motor response facilitation as shown by shorter RTs in compatible than in neutral trials was associated with reduced activation in a motor preparation network including the medial and lateral premotor cortices, as a result of the repetition suppression of the fMRI BOLD signal. The present results provide new insights into automatic and unconscious visuomotor priming processes, suggesting an involvement of either a cognitive or motor network, depending on the prime-target relationship.

r r Abstract: In making decisions, people have to balance between the competing demands of speed and accuracy, a balance generally referred to as the speed-accuracy tradeoff (SAT). In this study, we inves- tigated the role of controlled SAT in a two-choice task in which manual responses were either validly or invalidly cued. Examining electrophysiological measurements of oscillatory brain activity, theta power in the anterior cingulate cortex (ACC), alpha power in the occipital cortex, and beta power in the motor cortex were found to be related to SAT. Because oscillatory effects of SAT were found to em- anate from the SAT baseline interval preceding the two-choice task, the results indicate that SAT is modulated by a change of visuo-motor baseline activities rather than a change of response threshold. Moreover, in the two-choice task, conflict-induced theta power in the ACC was found to be more pro- nounced in speed than in accuracy trials, whereas priming-related beta power dynamics in the motor cortex were unaffected by SAT. These results indicate that conflict processing, but not response pri- ming, depends on SAT. Hum Brain Mapp 33:1834-1849, 2012. V C 2011 Wiley Periodicals, Inc.

The model of face recognition by Bruce and Young postulates a pool of structural representations for familiar faces in long-term memory, so-called face recognition units (FRUs). Event-related brain potentials show early repetition priming effects for familiar faces around 250-300 ms [N250r or early repetition effect (ERE)], which are thought to reflect the activation of these FRUs. However, small N250r effects are also seen for unfamiliar faces suggesting that priming of perceptual codes (i.e., pictorial and structural codes) also contributes to early repetition effects. Using a face-familiarity task in Experiment 1, we aimed to eliminate these perceptual contributions to face priming by backward masking the prime face with a different, unfamiliar face. As expected, a repetition priming effect appeared only for familiar faces. Experiment 2 used a semantic-decision task and compared the effects of different kinds of masks that interfered with either pictorial codes or with pictorial and structural codes. Our findings indicate that both structural codes and memory representations contribute to the N250r and that unfamiliar-face masks interfere only with structural codes. Face-masks may therefore provide a useful tool to extract the pure contributions of memory representations (i.e., FRUs) to repetition priming.

In this study, English–French bilinguals performed a lexical decision task while reaction times (RTs) and event related potentials (ERPs) were measured to L2 targets, preceded by noncognate L1 translation primes versus L1 unrelated primes (Experiment 1a) and vice versa (Experiment 1b). The prime–target stimulus onset asynchrony was 120 ms. Significant masked translation priming was observed, indicated by faster reaction times and a decreased N400 for translation pairs as opposed to unrelated pairs, both from L1 to L2 (Experiment 1a) and from L2 to L1 (Experiment 1b), with the latter effect being weaker (RTs) and less longer lasting (ERPs). A translation priming effect was also found in the N250 ERP component, and this effect was stronger and earlier in the L2 to L1 priming direction than the reverse. The results are discussed with respect to possible mechanisms at the basis of asymmetric translation priming effects in bilinguals.

We used repetition priming to investigate implicit and explicit processes of unfamiliar face categorization. During prime and test phases, participants categorized unfamiliar faces according to either age or gender. Faces presented at test were either new or primed in a task-congruent (same task during priming and test) or incongruent (different tasks) condition. During age categorization, reaction times revealed significant priming for both priming conditions, and event-related potentials yielded an increased N170 over the left hemisphere as a result of priming. During gender categorization, congruent faces elicited priming and a latency decrease in the right N170. Accordingly, information about age is extracted irrespective of processing demands, and priming facilitates the extraction of feature information reflected in the left N170 effect. By contrast, priming of gender categorization may depend on whether the task at initial presentation requires configural processing.

In this article we address the question of whether semantic ambiguity resolution involves the central inhibition of the non-selected meaning of a homograph. Most previous studies on this topic have either not clearly required semantic selection, or have induced this disambiguation by manipulating the context. These studies have not observed clear inhibitory effects on the non-selected meaning of the type studied in negative priming. We suggest that this kind of central inhibition may depend on task demands, and will be more easily observed in tasks where meaning selection is clearly required and is not made easier by cueing or context. In this study, participants had to perform a semantic judgment task in the prime display. Semantic priming from both the selected and the non-selected meaning of homographs was measured by showing facilitation for the selected meaning and inhibitory effects of the non-selected meaning. Participants with slow but accurate performance during the task were mainly responsible for this semantic negative priming effect, reflecting the role of inhibition on task-oriented control. The 'negative priming' effect is discussed in relation to current theories of attentional selection.

Prior research suggests that the affective priming effect denoting prime-congruent evaluative judgments about neutral targets preceded by affective primes increases when the primes are processed less deeply. This has been taken as evidence for greater affect misattribution. However, no study so far has combined an experimental manipulation of the depth of prime processing with the benefits of ERPs. Forty-seven participants made like/dislike responses about Korean ideographs following 800-ms affective prime words while 64-channel EEG was recorded. In a randomized within-subject design, three levels of working-memory load were applied specifically during prime processing. Affective priming was significant for all loads and even tended to decrease over loads, although efficiency of the load manipulation was confirmed by reduced amplitudes of posterior attention-sensitive prime ERPs. Moreover, ERPs revealed greater explicit affective discrimination of the prime words as load increased, with strongest valence effects on central/centroparietal N400 and on the parietal/parietooccipital late positive complex under high load. This suggests that (a) participants by default tried to inhibit the processing of the prime's affect, and (b) inhibition more often failed under cognitive load, thus causing emotional breakthrough that resulted in a binding of affect to the prime and, hence, reduced affect misattribution to the target. As a correlate of affective priming in the target ERP, medial-frontal negativity, a well-established marker of (low) stimulus value, increased with increasing negative affect of the prime. Findings support implicit prime-target affect transfer as a major source of affective priming, but also point to the role of strategic top-down processes.

A consistently reported finding in functional neuroimaging studies which compare processing of new information to processing of old information is a reduction in blood flow, and hence neural activity, associated with the old condition. This deactivation has been labeled neural priming. Some investigators have hypothesized that neural priming is the physiological mechanism underlying conceptual priming--a facilitation in the semantic processing of repeated information. Others, however, have hypothesized that neural priming reflects novelty assessment--a mechanism which minimizes the probability that redundant information will be stored in long-term memory. In this paper, the conceptual priming and novelty assessment hypotheses are compared and contrasted in order to ask, and tentatively answer, the question: Are conceptual priming and novelty assessment cognitively and neurophysiologically distinct? Based on a review of the literature, it is suggested that whereas novelty assessment and conceptual priming are distinct cognitive entities, they cannot be presently separated neurophysiologically. That is, some novelty assessment deactivations may in fact reflect priming, and some priming deactivations may in fact reflect novelty assessment.

According to Dempster, Piagetian tasks have more to do with the child’s ability to resist (inhibit) interference than they do with the ability to grasp their underlying logic. Here we used a chronometric paradigm with 9-year-olds, who succeed in Piaget’s conservation of number task, to test the role of cognitive inhibition in a priming version of this classical task. The experimental design was such that the misleading strategy ‘length-equals-number’ to inhibit on the prime (a Piaget-like item with number/length interference) became a congruent strategy to activate on the probe (a subsequent item where number and length covaried). A negative priming effect of 158 ms was observed for the prime–probe sequence. This result confirms that success on Piaget-like tasks (the prime) requires an inhibition process.

Priming effects to words are reduced when modality changes from study to test. This change was examined here using behavioral and electrophysiological measures of priming. During the study, half of the words were presented visually and half auditorally; during a subsequent lexical decision test, all words were presented visually. Lexical decisions were faster for within- than cross-modality repetitions. In contrast, modality influenced recognition only for low-frequency words. During lexical decision, event-related brain potentials were more positive to studied than unstudied words ~200‐500 ms!. A larger and shorter duration effect was observed for within- than cross-modality repetitions ~300‐ 400 ms!. This latter effect is viewed as an electrophysiological index of modality-specific processing associated with priming. Results suggest that multiple events—both modality-specific and modality-nonspecific—underlie perceptual priming phenomena. Descriptors: Memory, Cross-modality, ERP, Repetition priming, Perceptual priming, Lexical decision test

Three experiments investigated the electrophysiological consequences of repetition (e.g., scandal-scandal, buple-buple) and formal (e.g., scan-scandal, bup-buple) priming using words and nonwords. In each experiment, repetition and formal priming resulted in positive-going shifts in the event-related potential (ERP) that onset at approximately 200 ms poststimulus and were initially of similar magnitude. Subsequently, the repetition effect became larger than the formal priming effect. Although the word and nonword formal priming effects and the nonword repetition effects were greatest over midline and right hemisphere sites, the word repetition effects were greatest over the midline. It is suggested that the positive-going shift seen in the repetition and formal priming conditions was a modulation of the well-documented N400 component of the ERP. The topographic differences between the priming effects may have reflected differences in the nature of the representations to which cognitive operations are applied rather than differences in the nature of the operations themselves.

Semantic priming effects (behavioral and electrophysiological) were compared in the visual and auditory modalities across three stimulus onset asynchronies (SOAs; 0, 200, and 800 ms). When both prime and target were presented in the visual modality (the prime just to the left of a fixation point and the target to the right), there were N400 priming effects present across the three SOAs. However, the N400 in the 0-ms SOA condition extended longer in time (800 vs. 500 ms) than in the other SOAs. When both the prime and target were presented in the auditory modality (the prime to the right ear and the target to the left), the largest priming effects were found for the 800-ms SOA. Moreover, there was a relatively early priming effect present in the 0- and 800-ms SOA conditions but not in the 200-ms condition. The results are discussed in terms of modality differences in the time course of word comprehension processes.

We describe the results of a study that combines ERP recordings and sandwich priming, a variant of masked priming that provides a brief preview of the target prior to prime presentation (S. J. Lupker & C. J. Davis, 2009). This has been shown to increase the size of masked priming effects seen in behavioral responses. We found the same increase in sensitivity to ERP priming effects in an orthographic priming experiment manipulating the position of overlap of letters shared by primes and targets. Targets were 6-letter words and primes were formed of the 1st, 3rd, 4th, and 6th letters of targets in the related condition. Primes could be concatenated or hyphenated and could be centered on fixation or displaced by two letter spaces to the left or right. Priming effects with concatenated and/or displaced primes only started to emerge at 250 ms post-target onset, whereas priming effects from centrally located hyphenated primes emerged about 100 ms earlier.

An experiment was designed to examine the role and importance of data-driven processing in an implicit memory task: Word-fragment completion. We investigated the effects of priming and manipulating the context in which the target words had been read. Three main results emerged. First, replicating MacLeod's experiment (1989). we found that there was a very small priming effect for words previously studied in a text. Second, the magnitude of the priming effect increased with the perceptual difficulty of information intake during reading. Third, these variations in priming for the texts were functionally independent of subjects' recall of the text read. These results suggest that data-driven processing plays a critical role in priming. They are consistent with the transfer-appropriate processing theory recently advocated by Roediger, Weldon, and Challis (1989).

Event-related potentials (ERPs) were obtained from an identity priming task, where a green target had to be selected against a superimposed red distractor. Several priming conditions were realized in a mix of control (CO), negative priming (NP), and positive priming (PP) trials. PP and NP effects in reaction times (RTs) were significant. ERP results conceptually replicate earlier findings of left-posterior P300 reduction in PP and NP trials compared to CO. This ERP effect may reflect the detection of prime-probe similarity corresponding to the concept of a retrieval cue. A novel finding concerned amplitude increase of the frontal late positive complex (LPC) in the order NP, CO, and PP. NP therefore seemed to induce brain activity related to cognitive control and/or memory processes, with reduced LPC amplitude indicating effortful processing. Overall, retrieval-based explanations of identity NP are supported.

A major problem in outpatient treatment has been the extreme irregularity with which patients use medication prescribed for them. As a new approach to resolving this problem, a portable operant apparatus was developed based on response priming and escape reinforcement. The apparatus sounded a tone at the time that a pill was to be taken. When the user turned a knob to terminate the tone, the apparatus delivered the pill into the user's hand. The apparatus was evaluated with six normal adults using a medically inert pill. A greater proportion of the pills were taken by each subject when using the special apparatus as compared with the use of a portable alarm timer or the usual wristwatch. These results demonstrate a new approach for increasing the regularity of self-administration of medicines.