Picking up a cup requires transporting the arm to (transport component) and preshaping hand appropriately grasp handle (grip component). Here, we used functional magnetic resonance imaging examine human neural substrates of transport component its relationship with grip component. Participants were shown three-dimensional objects placed either at near location, adjacent hand, or far within reach but not hand. performed three tasks each location as follows: (1) touching object knuckles right...

Superior area 6 of the macaque monkey frontal cortex is formed by two cytoarchitectonic areas: F2 and F7. In present experiment, we studied input from superior parietal lobule (SPL) to these areas injecting retrograde neural tracers into restricted parts Additional injections were made spinal cord define origin corticospinal projections SPL. The results are as follows: 1) part located around precentral dimple (F2 region) receives its main PEc PEip (PE intraparietal, rostral PEa Pandya...

Abstract The aim of this work was to study the effect eye position on activity neurons area PO (V6), a cortical region located in most posterior part superior parietal lobule. Experiments were carried out three awake macaque monkeys. Animals sat primate chair front large screen, and fixated small spot light projected different screen locations while single extracellularly recorded. Both visual non‐visual found. About 48% 32% showed position‐related total darkness, ˜61% response modulated by...

The retinotopic organization of a newly identified visual area near the midline in dorsalmost part human parieto-occipital sulcus was mapped using high-field functional magnetic resonance imaging, cortical surface-based analysis, and wide-field stimulation. This found all 34 subjects that were mapped. It represents contralateral hemifield both hemispheres subjects, with upper fields located anterior medial to areas V2/V3, lower slightly V3/V3A. contains representation center gaze distinct...

Extracellular recordings from single neurons of the prestriate area V3A were carried out in awake, behaving monkeys, to test influence direction gaze on cellular activity. The responsiveness visual stimulation about half studied (88/187) was influenced by animal's gaze: physically identical stimuli delivered retinotopic positions (on receptive field) evoked different responses, depending upon gaze. Control experiments discount possibility that observed phenomenon due changes background or...

The brain location, extent and functional organization of the cortical visual area V6A was investigated in macaque monkeys by using single cell recording techniques awake, behaving animals. Six hemispheres four animals were studied. Area occupies a horseshoe-like region cortex caudalmost part superior parietal lobule. It extends from medial surface brain, through anterior bank parieto-occipital sulcus, up to most lateral fundus same sulcus. borders on areas V6 ventrally, PEc dorsally, PGm...

Abstract The aim of this work was to study the cortical connections area V6 by injecting neuronal tracers into different retinotopic representations area. To purpose, we first functionally recognized recording from neurons parieto‐occipital cortex in awake macaque monkeys. Penetrations with syringes were performed behaving animals order inject exactly at sites. injected central or peripheral field representation hemispheres. Irrespective whether injections made centre periphery, showed...

Abstract We have compared physiological data recorded from three alert macaque monkeys with separate observations of local connectivity, to locate and characterize the functional border between two related but distinct visual areas on caudal face superior parietal gyrus. refer these as V6 V6A. They occupy almost entire extent anterior bank parieto‐occipital sulcus, V6A being more dorsal. These are strongly interconnected. Anatomically, we defined point at which labelled axon terminals first...

Abstract The brain location and topographical organization of the cortical visual area V6 was studied in five hemispheres four awake macaque monkeys. Area is located caudal aspect superior parietal lobule (SPL). It occupies a ‘C’‐shaped belt cortex whose upper branch depth parieto‐occipital sulcus (POS) lower one medial (POM), with surface as zone junction between two branches. contains topographically organized representation contralateral field up to an eccentricity at least 80 °....

Cortical-surface-based functional Magnetic Resonance Imaging mapping techniques and wide-field retinotopic stimulation were used to verify the presence of pattern motion sensitivity in human area V6. Area V6 is highly selective for coherently moving fields dots, both at individual group levels even with a visual stimulus standard size. This localizer The wide stimuli here also revealed map middle temporal cortex (area MT/V5) surrounded by several polar-angle maps that resemble mosaic small...

Brain control of prehension is thought to rely on two specific brain circuits: a dorsomedial one (involving the areas superior parietal lobule and dorsal premotor cortex) involved in transport hand toward object dorsolateral inferior ventral dealing with preshaping according features object. The present study aimed at testing whether pivotal component pathway (area V6A) also grip formation grasp objects different shapes. Two macaque monkeys were trained reach objects. For each object,...

Abstract Area V6A, a functionally defined region in the anterior bank of parietooccipital sulcus, has been subdivided into dorsal and ventral cytoarchitectonic fields (V6Ad V6Av). The aim this study was to define cortical connections field V6Ad. Retrograde bidirectional neuronal tracers were injected part sulcus seven macaque monkeys ( Macaca fascicularis ). limits injection sites compared with those fields. major V6Ad areas superior parietal lobule. densest labeling observed medial...

Reach-to-grasp actions involve several components of forelimb movements needed to direct the hand toward object be grasped, and orient preshape according axis shape. Area V6A, which represents a node dorsomedial frontoparietal circuits, has so far been implicated only in directing arm different spatial locations. The present results confirm this finding demonstrate, for first time, that during reach-to-grasp, V6A neurons are also modulated by orientation hand. In work grasped was handle...

In macaque monkeys, V6A is a visuomotor area located in the anterior bank of POs, dorsal and to retinotopically-organized extrastriate V6 (Galletti et al., 1996). Unlike V6, represents both contra- ipsilateral visual fields broadly retinotopically organized 1999b). The contralateral lower field over-represented V6A. central 20°–30° mainly represented dorsally (V6Ad) periphery ventrally (V6Av), at border with V6. Both sectors contain arm movement-related cells, active during...

Abstract Area V6A is a cortical visual area located in the posterior face of superior parietal lobule macaque monkey. It contains neurons as well not activated by any kind stimulation. The aim this study was to look for possible features able activate these latter neurons. We tested 70 non‐visual Forty‐three them showed an arm movement–related neural discharge due somatosensory stimulation and/or skeletomotor activity upper limbs animal. movement‐related started before onset movement, often...

Abstract In previous experiments we have found that several cells of area V6A in the macaque superior parietal lobule were activated by small and stereotyped movements arms (C. Galletti, P. Fattori, D. F. Kutz & Battaglini, Eur. J. Neurosci ., 1997, 9 , 410). This behaviour was not accounted for retinal information, nor somatosensory inputs from arms. We now want to investigate whether neurons are modulated purposeful aimed at reaching visual targets or located outside field view....

We recorded neural activity from the medial parieto-occipital area V6A while three monkeys performed an instructed-delay reaching task in dark. Targets to be reached were different spatial positions. Neural discharges during movements directed outward body (towards visual objects), holding phase (when hand was on target) and inward of towards home button (which near outside field view). Reach-related observed majority 207 cells, (78%) (65%) as well (62%). Most neurons (84%) modulated more...

Extracellular recordings were made in the anterior bank of parieto-occipital sulcus two waking monkeys trained to perform fixation tasks normal illumination or complete darkness. Of recorded neurons, 73% (251/343) responsive visual stimulation, but their overall organization did not conform a simple, continuous retinotopic map. Most neurons showed high degree orientation and direction sensitivity, higher than that found areas V1, V2 V3A under same experimental conditions. Whether they had...

Abstract The anterior wall of the parieto‐occipital sulcus (POs) macaque monkey, classically considered as part Brodmann's area 19, contains two functionally distinct areas: a ventral, purely visual area, V6, and dorsal V6A, containing neurons related to control arm movements. aim this study was establish whether areas V6 so far identified only on functional basis, have cytoarchitectonic counterpart. analysis 13 hemispheres from ten brains, cut along different planes section, showed that POs...

The dorsomedial area (DM), a subdivision of extrastriate cortex characterized by heavy myelination and relative emphasis on peripheral vision, remains the least understood main targets striate (V1) projections in primates. Here we placed retrograde tracer injections encompassing full extent this marmoset monkeys, performed quantitative analyses numerical strengths laminar patterns its afferent connections. We found that feedforward from V1 second visual (V2) account for over half inputs to...