Considerable interest has been raised by non-phase-locked episodes of synchronization in the gamma-band (30-60 Hz). One their putative roles visual modality is feature-binding. We tested stimulus specificity high-frequency oscillations humans using three types stimuli: two coherent stimuli (a Kanizsa and a real triangle) noncoherent ("no-triangle stimulus"). The task subject was to count occurrences curved illusory triangle. A time-frequency analysis single-trial EEG data recorded from eight...

The coherent representation of an object in the visual system has been suggested to be achieved by synchronization γ-band (30–70 Hz) a distributed neuronal assembly. Here we measure variations high-frequency activity on human scalp. experiment is designed allow comparison two different perceptions same picture. In first condition, apparently meaningless picture that contained hidden Dalmatian, neutral stimulus, and target stimulus (twirled blobs) are presented. After subject trained perceive...

It has been hypothesized that visual objects could be represented in the brain by a distributed cell assembly synchronized on an oscillatory mode γ-band (20–80 Hz). If this hypothesis is correct, then activity should appear any task requiring activation of object representation, and particular when representation held active short-term memory: sustained thus expected during delay delayed-matching-to-sample task. EEG was recorded while subjects performed such Induced (e.g., appearing with...

How do we keep an object in mind?Based on evidence from animal electrophysiology and human brain-imaging techniques, it is commonly held that short-term memory relies sustained activity a network distributed over sensory prefrontal cortices.How does neural firing persist such the absence of visual input?Hebb's influential but so far unproved proposal, developed more than 50 years ago, activation networks maintained by reverberating neuronal loops.We hypothesized synchronized oscillatory...

To what extent does we consciously see depend on where attend to? Psychologists have long stressed the tight relationship between visual awareness and spatial attention at behavioral level. However, amount of overlap their neural correlates remains a matter debate. We recorded magnetoencephalographic signals while human subjects attended toward or away from faint stimuli that were reported as seen only half time. Visually identical could thus be not not. Although slightly more often than...

The report 'I saw the stimulus' operationally defines visual consciousness, but where does 'I' come from? To account for subjective dimension of perceptual experience, we introduce concept neural frame. frame would be based on constantly updated maps internal state body and constitute a referential from which first person experience can created. We propose to root in representation visceral information is transmitted through multiple anatomical pathways number target sites, including...

The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line theories proposing selfhood is grounded neural internal organs, such as heart. measured magnetoencephalograhy responses evoked by heartbeats while human participants freely mind-wandered. When interrupted a visual stimulus at random...

Resting-state networks offer a unique window into the brain's functional architecture, but their characterization remains limited to instantaneous connectivity thus far. Here, we describe novel resting-state network based on delayed between brain and slow electrical rhythm (0.05 Hz) generated in stomach. The gastric cuts across classical with partial overlap autonomic regulation areas. This is composed of regions convergent properties involved mapping bodily space through touch, action or...

We studied the existence, localization and attentional modulation of gamma-band oscillatory activity (30–130 Hz) in human intracranial region. Two areas known to play a key role visual object processing: lateral occipital (LO) cortex fusiform gyrus. These consistently displayed large gamma oscillations during stimulus encoding, while other extrastriate remained systematically silent, across 14 patients 291 recording sites scattered throughout cortex. The extent responsive regions was small,...

In a visual delayed matching-to-sample task, compared to control condition, we had previously identified different components of the human EEG that could reflect rehearsal an object representation in short-term memory (Tallon-Baudry et al., 1998). These were induced oscillatory activities gamma (24–60 Hz) and beta (15–20 bands, peaking during delay at occipital frontal electrodes, two negativities evoked potentials. Sustained (lasting until end delay) are more likely continuous rehearsing...

The human brain is expert in analyzing rapidly and precisely facial features, especially emotional expressions representing a powerful communication vector. involvement of insula disgust recognition has been reported behavioral functional imaging studies. However, we do not know whether specific insular fields are involved processing nor what the time course is. Using depth electrodes implanted during presurgical evaluation patients with drug-refractory temporal lobe epilepsy, recorded...

Visual perception fluctuates across repeated presentations of the same near-threshold stimulus. These perceptual fluctuations have often been attributed to baseline shifts—i.e., ongoing modulations neuronal activity in visual areas—driven by top-down attention. Using magnetoencephalography, we directly tested whether attentional could fully account for impact prestimulus on a subsequent seen–unseen decision. We found that gamma-band lateral occipital areas (LO) predicted awareness, but did...

Abstract Neural oscillatory synchrony could implement grouping processes, act as an attentional filter, or foster the storage of information in short-term memory. Do these findings indicate that is unspecific epiphenomenon occurring any demanding task, a fundamental mechanism involved whenever neural cooperation requested? If latter hypothesis true, then should be specific, with distinct visual processes eliciting different types oscillations. We recorded magnetoencephalogram (MEG) signals...

Oscillatory synchrony has been proposed to dynamically coordinate distributed neural ensembles, but whether this mechanism is effectively used in processing remains controversial. We trained two monkeys perform a delayed matching-to-sample task using new visual shapes at each trial. Measures of population-activity patterns (cortical field potentials) were obtained from chronically implanted array electrodes placed over area V4 and posterior infero-temporal cortex. In correct trials,...

Recent research has shown that heartbeat-evoked potentials (HEPs), brain activity in response to heartbeats, are a useful neural measure for investigating the functional role of brain–body interactions cognitive processes including self-consciousness. In 2 experiments, using intracranial electroencephalography (EEG), we investigated (1) sources HEPs, (2) underlying mechanisms HEP generation, and (3) HEPs bodily Experiment-1, found shortly after heartbeat onset, phase distributions across...

A fundamental feature of the temporal organization neural activity is phase-amplitude coupling between brain rhythms at different frequencies, where amplitude a higher frequency varies according to phase lower frequency. Here, we show that this rule extends brain-organ interactions. We measured both infra-slow (~0.05Hz) rhythm intrinsically generated by stomach - gastric basal using electrogastrography, and spontaneous dynamics with magnetoencephalography during resting-state eyes open....