We studied the simultaneous activity of pairs neurons recorded with a single electrode in visual cortical area MT while monkeys performed direction discrimination task. Previously, we reported strength interneuronal correlation spike count on time scale behavioral epoch (2 sec) and noted its potential impact signal pooling (Zohary et al., 1994). have now examined at longer shorter scales found that pair-wise cross-correlation was predominantly short term (10–100 msec). Narrow, central peaks...

Our ability to interact with the immediate surroundings depends not only on an adequate representation of external space but also our represent location objects respect own body and especially hands. Indeed, electrophysiological studies in monkeys revealed multimodal neurons spatially corresponding tactile visual receptive fields a number brain areas, suggesting peripersonal body. In this functional magnetic resonance imaging study, we localized areas human intraparietal sulcus (IPS) lateral...

An important characteristic of visual perception is the fact that object recognition largely immune to changes in viewing conditions. This invariance obtained within a sequence ventral stream areas beginning area V1 and ending high order occipito-temporal (the lateral occipital complex, LOC). Here we studied whether this transformation could be observed contrast response these areas. Subjects were presented with line drawings common objects faces five different levels (0, 4, 6, 10, 100%)....

The electrophysiological properties of sensory neurons in the adult cortex are not immutable but can change response to alterations input caused by manipulation afferent pathways nervous system or environment. Such plasticity creates great potential for flexible processing information, actual effects neuronal on perceptual performance poorly understood. link between and was explored here recording responses directionally selective visual while rhesus monkeys practiced a familiar task...

Recently we showed that the occipital cortex of congenitally blind humans is activated during verbal-memory tasks. Activation was found in regions corresponding to retinotopic visual areas sighted humans, including calcarine sulcus (V1). No such activation humans. One year later, same subjects participated a second fMRI scan, study contribution semantic elements and episodic memory activation. The performed an episodic-memory task, requiring recognition words were originally presented first...

Purpose: Recent studies show evidence of multisensory representation in the functionally normal visual cortex, but this idea remains controversial. Occipital cortex activation is often claimed to be a reflection mental imagery processes tri

The anterior part of the human intraparietal sulcus is known to be involved in visually guided grasping. This region also active during observation object manipulation by others. Here, we explore nature action representation using functional magnetic resonance imaging (fMRI). Fourteen subjects observed video clips showing right or left hand. were presented either peripheral visual field. fMRI activation occipital cortex and caudal sections parietal was specific visual-field location clips....

Visual search for an element defined by the conjunction of its colour and orientation has previously been shown to be a serial processing task since reaction times increase linearly with number distractor elements used in display. Evidence is presented that there are parallel constituents this search. Processing time depended on ratio two types used, suggesting only one type was scanned. Which scanned also ratio, indicating decision made after stimulus presentation based figure—ground...

The spatial representation in the human ventral object-related areas (i.e., lateral occipital complex [LOC]) is currently unknown. It seems plausible, however, that it would diverge from strict retinotopic mapping (characteristic of V1) to a more invariant coordinate frame, thereby allowing for reliable object recognition face eye, head, or body movement. To study this, we compared fMRI activation LOC when displacement was limited either retina screen by manipulating eye position and...

Abstract Present theories of visual recognition emphasize the role interactive processing across populations neurons within a given network, but nature these interactions remains unresolved. In particular, data describing sufficiency feedforward algorithms for conscious vision and studies revealing functional relevance feedback connections to striate cortex seem offer contradictory accounts information processing. TMS is good method experimentally address this issue, its excellent temporal...

Humans often redirect their gaze to the same objects within a scene, even without being consciously aware of it. Here, we investigated what type visual information is accumulated across recurrent fixations on object. On each trial, subjects viewed an array comprised several and were subsequently asked report various aspects randomly chosen target object from that array. Memory performance decreased as more directed other objects, following last fixation (i.e. post-target fixations). In...