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Ongoing brain activity preceding visual stimulation has been suggested to shape conscious perception. According to the pulsed inhibition framework, bouts of functional inhibition arise in each alpha cycle (every ~100 ms), allowing information to be processed in a pulsatile manner. Consequently, it has been hypothesized that perceptual outcome can be influenced by the specific phase of alpha oscillations prior to the stimulus onset, although empirical findings are controversial. In this study, we aimed to shed light on the role of prestimulus alpha oscillations in visual perception. To this end, we recorded electroencephalographic activity, while participants performed three near‐threshold visual detection tasks with different attentional involvement: a no‐cue task, a noninformative cue task (50% validity), and an informative cue task (100% validity). Cluster‐based permutation statistics were complemented with Bayesian analyses to test the effect of prestimulus oscillatory amplitude and phase on visual awareness. We additionally examined whether these effects differed in trials with low and high oscillatory amplitude, as expected from the pulsed inhibition theory. Our results show a clear effect of prestimulus alpha amplitude on conscious perception, but only when alpha fluctuated spontaneously. In contrast, we did not find any evidence that prestimulus alpha phase influenced perceptual outcome, not even when differentiating between low‐ and high‐amplitude trials. Furthermore, Bayesian analysis provided moderate evidence in favor of the absence of phase effects. Taken together, our results challenge the central theoretical predictions of the pulsed inhibition framework, at least for the particular experimental conditions used here. According to the pulsed‐inhibition theory, perception waxes and wanes every alpha cycle (~100 ms). Thus, a near‐threshold stimulus may only be detected if it arrives at the optimal alpha phase. However, in line with a growing number of studies, we found evidence that pre‐stimulus alpha phase has no effect on subsequent perception. In contrast, our results show that the spontaneous decrease of pre‐stimulus alpha amplitude does improve perceptual outcome. [ABSTRACT FROM AUTHOR]

Gestures and vocal elements interact from the early stages of language development, but the role of this interaction in the language learning process is not yet completely understood. The aim of this study is to explore gestural accompaniment's influence on the acoustic properties of vocalizations in the transition to first words. Eleven Spanish children aged 0;9 to 1;3 were observed longitudinally in a semi-structured play situation with an adult. Vocalizations were analyzed using several acoustic parameters based on those described by Oller et al. (2010). Results indicate that declarative vocalizations have fewer protosyllables than imperative ones, but only when they are produced with a gesture. Protosyllables duration and f(0) are more similar to those of mature speech when produced with pointing and declarative function than when produced with reaching gestures and imperative purposes. The proportion of canonical syllables produced increases with age, but only when combined with a gesture.

The tip-of-the-tongue state (TOT) in face naming is a transient state of difficulty in access to a person's name along with the conviction that the name is known. The aim of the present study was to characterize the spatio-temporal course of brain activation in the successful naming and TOT states, by means of magnetoencephalography, during a face-naming task. Following famous face presentations, subjects indicated whether they knew the name, did not know the name, or experienced a TOT state. Next they produced the name aloud, if they could, although they did not indicate whether they retrieved any other information about the person. The TOT state was characterized by lower activation than for successful retrieval, in the 310-520ms poststimulus interval, localized to left temporal and frontal areas, bilateral parahippocampal gyrus, and right fusiform gyrus, which may underlie the genesis of TOT. Greater activation was also found in the 740-820 ms interval, localized to bilateral occipital, left temporal, and right frontal and parietal areas, corresponding with the unfruitful search for the name after the TOT state was produced. These results showed the differential brain dynamics underlying searching for the name of a known individual according to whether the search was successful or subjectively rated as just short of success. (Contains 2 tables and 4 figures.)

Alpha-band oscillations (8–14 Hz) are essential for attention and perception processes by facilitating the selection of relevant information. Directing visuospatial endogenous (voluntary) attention to a given location consistently results in a power suppression of alpha activity over occipito-parietal areas contralateral to the attended visual field. In contrast, the neural oscillatory dynamics underlying the involuntary capture of attention, or exogenous attention, are currently under debate. By exploiting the inherent capacity of emotionally salient visual stimuli to capture attention, we aimed to investigate whether exogenous attention is characterized by either a reduction or an increase in alpha-band activity. Electroencephalographic activity was recorded while participants completed a Posner visuospatial cueing task, in which a lateralized image with either positive, negative, or neutral emotional content competed with a target stimulus presented in the opposite hemifield. Compared with trials with no distractors, alpha power was reduced over occipital regions contralateral to distracting images. This reduction of alpha activity turned out to be functionally relevant, as it correlated with impaired behavioral performance on the ongoing task and was enhanced for distractors with negative valence. Taken together, our results demonstrate that visuospatial exogenous attention is characterized by a suppression of alpha-band activity contralateral to distractor location, similar to the oscillatory underpinnings of endogenous attention. Further, these results highlight the key role of exogenous attention as an adaptive mechanism for the efficient detection of biologically salient stimuli. [ABSTRACT FROM AUTHOR]

One's own face is recognized more efficiently than any other face, although the neural mechanisms underlying this phenomenon remain poorly understood. Considering the extensive visual experience that we have with our own face, some authors have proposed that self‐face recognition involves a more analytical perceptual strategy (i.e., based on face features) than other familiar faces, which are commonly processed holistically (i.e., as a whole). However, this hypothesis has not yet been tested with brain activity data. In the present study, we employed an inversion paradigm combined with event‐related potential (ERP) recordings to investigate whether the self‐face is processed more analytically. Sixteen healthy participants were asked to identify their own face and a familiar face regardless of its orientation, which could either be upright or inverted. ERP analysis revealed an enhanced amplitude and a delayed latency for the N170 component when faces were presented in an inverted orientation. Critically, both the self and a familiar face were equally vulnerable to the inversion effect, suggesting that the self‐face is not processed more analytically than a familiar face. In addition, we replicated the recent finding that the attention‐related P200 component is a specific neural index of self‐face recognition. Overall, our results suggest that the advantage for self‐face processing might be better explained by the engagement of self‐related attentional mechanisms than by the use of a more analytical visuoperceptual strategy. Our findings have important implications for understanding how the self‐face is processed by the brain and suggest that the key element of such processing could be linked to social relevance rather than accumulated visual experience. Results presented in this work contribute toward the validation and expansion of the current Neural Model of the Self proposed by Sui and Gu (2017). [ABSTRACT FROM AUTHOR]

The activation of G-protein coupled receptors by agonist compounds results in diverse biological responses in cells, such as the endocytosis process consisting in the translocation of receptors from the plasma membrane to the cytoplasm within internalizing vesicles or endosomes. In order to functionally evaluate endocytosis events resulted from pharmacological responses, we have developed an image analysis method –the Q-Endosomes algorithm– that specifically discriminates the fluorescent signal originated at endosomes from that one observed at the plasma membrane in images obtained from living cells by fluorescence microscopy. Mu opioid (MOP) receptor tagged at the carboxy-terminus with yellow fluorescent protein (YFP) and permanently expressed in HEK293 cells was used as experimental model to validate this methodology. Time-course experiments performed with several agonists resulted in different sigmoid curves depending on the drug used to initiate MOP receptor endocytosis. Thus, endocytosis resulting from the simultaneous activation of co-expressed MOP and serotonin 5-HT2C receptors by morphine plus serotonin was significantly different, in kinetics as well as in maximal response parameters, from the one caused by DAMGO, sufentanyl or methadone. Therefore, this analytical tool permits the pharmacological characterization of receptor endocytosis in living cells with functional and temporal resolution. [ABSTRACT FROM AUTHOR]

Despite the importance of change detection (CD) for visual perception and for performance in our environment, observers often miss changes that should be easily noticed. In the present study, we employed time-frequency analysis to investigate the neural activity associated with CD and change blindness (CB). Observers were presented with two successive visual displays and had to look for a change in orientation in any one of four sinusoid gratings between both displays. Theta power increased widely over the scalp after the second display when a change was consciously detected. Relative to no-change and CD, CB was associated with a pronounced theta power enhancement at parietal-occipital and occipital sites and broadly distributed alpha power suppression during the processing of the prechange display. Finally, power suppressions in the beta band following the second display show that, even when a change is not consciously detected, it might be represented to a certain degree. These results show the potential of time-frequency analysis to deepen our knowledge of the temporal curse of the neural events underlying CD. The results further reveal that the process resulting in CB begins even before the occurrence of the change itself. [ABSTRACT FROM AUTHOR]

Background: One common criterion for classifying electrophysiological brain responses is based on the distinction between transient (i.e. event-related potentials, ERPs) and steady-state responses (SSRs). The generation of SSRs is usually attributed to the entrainment of a neural rhythm driven by the stimulus train. However, a more parsimonious account suggests that SSRs might result from the linear addition of the transient responses elicited by each stimulus. This study aimed to investigate this possibility. Methodology/Principal Findings: We recorded brain potentials elicited by a checkerboard stimulus reversing at different rates. We modeled SSRs by sequentially shifting and linearly adding rate-specific ERPs. Our results show a strong resemblance between recorded and synthetic SSRs, supporting the superposition hypothesis. Furthermore, we did not find evidence of entrainment of a neural oscillation at the stimulation frequency. Conclusions/Significance: This study provides evidence that visual SSRs can be explained as a superposition of transient ERPs. These findings have critical implications in our current understanding of brain oscillations. Contrary to the idea that neural networks can be tuned to a wide range of frequencies, our findings rather suggest that the oscillatory response of a given neural network is constrained within its natural frequency range. [ABSTRACT FROM AUTHOR]

The neural processes underlying tactile decisions in the human brain remain elusive. We addressed this question in a functional magnetic resonance imaging study using a somatosensory discrimination task, requiring participants to compare the frequency of two successive tactile stimuli. Tactile stimuli per se engaged somatosensory, parietal, and frontal cortical regions. Using a statistical model that accounted for the relative difference in frequencies (i.e., Weber fraction) and discrimination accuracy (i.e., correct or incorrect), we show that trial-by-trial relative frequency difference is represented linearly by activity changes in the left dorsolateral prefrontal cortex (DLPFC), the dorsal anterior cingulate cortex, and bilateral anterior insular cortices. However, a circumscribed region within the left DLPFC showed a different response pattern expressed as activity changes that were monotonically related to relative stimulation difference only for correct but not for incorrect trials. Our findings suggest that activity in the left DLPFC encodes stimulus representations that underlie veridical tactile decisions in humans. [ABSTRACT FROM AUTHOR]

Self-related information, such as one's own face, is prioritized by our cognitive system. Whilst recent theoretical developments suggest that this is achieved by an interplay between bottom-up and top-down attentional mechanisms, their underlying neural dynamics are still poorly understood. Furthermore, it is still matter of discussion as to whether these attentional mechanisms are truly self-specific or instead driven by face familiarity. To address these questions, we used EEG to record the brain activity of twenty-five healthy participants whilst identifying their own face, a friend's face and a stranger's face. Time-frequency analysis revealed a greater sustained power decrease in the alpha and beta frequency bands for the self-face, which emerged at late latencies and was maintained even when the face was no longer present. Critically, source analysis showed that this activity was generated in key brain regions for self-face recognition, such as the fusiform gyrus. As in the Myth of Narcissus, our results indicate that one's own face might have the potential to hijack attention. We suggest that this effect is specific to the self and driven by a top-down attentional control mechanism, which might facilitate further processing of personally relevant events. • Self-face processing induces a sustained alpha-beta power suppression. • Alpha power reduction is generated around face-sensitive regions. • Modulation of the alpha band indicates increased attention to one's own face. • Fostered attention is specific to the self and cannot be explained by familiarity. [ABSTRACT FROM AUTHOR]

The interplay between exogenous attention to emotional distractors and the baseline affective state has not been well established yet. The present study aimed to explore this issue through behavioral measures and event-related potentials (ERPs). Participants (N = 30) completed a digit categorization task depicted over negative, positive or neutral distractor background pictures, while they experienced negative, positive and neutral affective states elicited by movie scenes. Behavioral results showed higher error rates and longer reaction times for negative distractors than for neutral and positive ones, irrespective of the current emotional state. Neural indices showed that the participants' affective state modulated N1 amplitudes, irrespective of distractor type, while the emotional charge of distractors modulated N2, irrespective of the emotional state. Importantly, an interaction of state and distractor type was observed in LPP. These results demonstrate that exogenous attention to emotional distractors is independent from modulating effects of the emotional baseline state at early, automatic stages of processing. However, attention to emotional distractors and affective state interact at later latencies.

Arabic writing differs greatly from western scripts. To evaluate the influence of written Arabic on the pattern of language-related brain activation, a group of native Arab speakers and a control group of native Spanish speakers were scanned with magnetoencephalography during a reading task. In both groups, brain activity was strongly left lateralized during the time window between 200 and 500 ms after stimulus onset. During late latencies (beyond 500 ms), however, the right and the left hemispheres reached a similar activation level in the Arabic but not in the Spanish group. This suggests a time-dependent role of both hemispheres during Arabic language reading.

Alcoholism is one of the most important problems today. Chronic alcohol intake produces many cognitive deficits in humans, especially in memory. To evaluate the memory deficits in alcoholism it is very common to use animal models. In the present work, rats receiving chronic alcohol intake and not submitted to withdrawal were evaluated in a spontaneous delayed nonmatching-to-sample test (EDNMS). Ninety-six male Wistar rats, 90 and 180 days old, were used in the experiment. Alcohol-treated rats (ALCY and ALCA) had free access to an aqueous ethanol solution as the only available liquid source from 21 days of age to the end of experiment for both groups (90 and 180 days). Animals were then evaluated in a nonspatial memory test based on the paradigm EDNMS using delays of 1, 15, and 60 min. The results show that chronic alcohol intake impairs the rats' performance, both at 90 and 180 days old, in this test of object recognition when the delay interval is of 1 h. Chronic alcohol intake with no withdrawal periods produces memory deficits and these effects of alcohol begin in the early period of intake. Moreover, we may state that the paradigm of EDNMS with a delay interval of 60 min is useful to evaluate several cognitive deficits such as hippocampal-derived memory impairment.