Anterior Intraparietal Area: a Hub in the Observed Manipulative Action Network.

Current knowledge regarding the processing of observed manipulative actions (OMAs) (e.g., grasping, dragging, or dropping) is limited to grasping and underlying neural circuitry remains controversial. Here, we addressed these issues by combining chronic neuronal recordings along the anteroposterior extent of monkeys\u2019 anterior intraparietal (AIP) area with tracer injections into the recorded sites. We found robust neural selectivity for 7 distinct OMAs, particularly in the posterior part of AIP (pAIP), where it was associated with motor coding of grip type and own-hand visual feedback. This cluster of functional properties appears to be specifically grounded in stronger direct connections of pAIP with the temporal regions of the ventral visual stream and the prefrontal cortex, as connections with skeletomotor related areas and regions of the dorsal visual stream exhibited opposite or no rostrocaudal gradients. Temporal and prefrontal areas may provide visual and contextual information relevant for manipulative action processing. These results revise existing models of the action observation network, suggesting that pAIP constitutes a parietal hub for routing information about OMA identity to the other nodes of the network

Neural activity in the medial parietal area V6A while grasping with or without visual feedback

Recent works have reported that grasping movements are controlled not only by the dorsolateral visual stream, as generally thought, but also by the dorsomedial visual stream, and in particular by the medial posterior parietal area V6A. To date, the grasping activity of V6A neurons has been studied only in darkness. Here we studied the effect of visual feedback on grasp-related discharges of V6A neurons while the monkey was preparing and executing the grasping of a handle. We found that V6A grasping activity could be excited or inhibited by visual information. The neural population was divided into Visual, Motor, and Visuomotor cells. The majority of Visual and Visuomotor neurons did not respond to passive observation of the handle, suggesting that vision of action, rather than object vision, is the most effective factor. The present findings highlight the role of the dorsomedial visual stream in integrating visual and motor signals to monitor and correct grasping

PLAsticiTY of Perceptual space Under Sensorimotor interactions

Space is the foundational characteristic of visual perception and we generally perceive it as continuous and uniform. Behavioural measurements and the properties of our sensory systems however, demonstrate that this is an illusory situation and our percept is constructed by the brain. One example is our lack of awareness of the blind spot that exists in each eye. Space is non-uniformly represented in the visual brain and this representation is dynamically influenced by motor behaviour, in particular by eye movements. The PLATYPUS consortium will investigate the dynamic nature of spatial sensation and perception, focussing on the continuous mutual interaction of motor behaviour and perception. Our research objectives integrate human behavioural and cutting edge non-human primate electrophysiological research techniques and focus on translation of basic into applied research. Focussing on the adaptive nature of vision and action, strategies to perturb and probe perceptual space and geometry will allow measurement of spatial and geometrical perception in humans and the representation of such in non-human primates. This research will extend to applications for people wearing progressive lenses which distort action and space perception, patients with a blind area in their visual field and for virtual reality technology development. PLATYPUS researchers will grow existing and establish new collaborative teams, sharing research techniques, knowledge and mentoring between established and with upcoming researchers in academia and industry. Individuals will benefit from intense scientific and career development training while institutions will benefit from the exchange of state-of-the-art techniques. The ultimate outcome will be increased understanding of the continuously updating neural construction of space and the production of assistive technologies for people needing corrective lenses, with ocular or visual discontinuity and for the growing virtual reality industry

Sensory properties of the caudal aspect of the macaque's superior parietal lobule

In the superior parietal lobule (SPL), the anterior part (area PE) is known to process somatosensory information, while the caudalmost part (areas V6Av and V6) processes visual information. Here we studied the visual and somatosensory properties of the areas PEc and V6Ad located in between the somatosensory and visual domains of SPL. About 1500 neurons were extracellularly recorded in 19 hemispheres of 12 monkeys (Macaca fascicularis). Visual and somatosensory properties of single neurons were generally studied separately, while in a subpopulation of neurons, both the sensory properties were tested. Visual neurons were more represented in V6Ad and somatosensory neurons in PEc. The visual neurons of these two areas showed similar properties and represented a large part of the contralateral visual field, mostly the lower part. In contrast, somatosensory neurons showed remarkable differences. The arms were overrepresented in both the areas, but V6Ad represented only the upper limbs, whereas PEc both the upper and lower limbs. Interestingly, we found that in both the areas, bimodal visualâsomatosensory cells represented the proximal part of the arms. We suggest that PEc is involved in locomotion and in the control of hand/foot interaction with the objects of the environment, while V6Ad is in the control of the object prehension specifically performed with the upper limbs. Neuroimaging and lesion studies from literature support a strict homology with humans

Claustral afferents of superior parietal areas PEc and PE in the macaque.

The exposed surface of the primate superior parietal cortex includes two cytoarchitectonically defined areas, the PEc and PE. In the present study we describe the distribution of neurons projecting from the claustrum to these areas. Retrograde neuronal tracers were injected by direct visualization of regions of interest, and the location of injection sites was reconstructed relative to cytoarchitectural borders. For comparison, the patterns of claustral label that resulted from injections involving neighboring cytoarchitectonic areas were analyzed. We found that the claustral territories sending projections to areas PE and PEc partially overlapped zones previously shown to form projections to the posterior parietal, somatosensory, visual, and motor cortex. The projection zones to the PE and PEc overlapped extensively, and consisted of multiple patches separated by label-free zones. Most of the labeled neurons were located in the posterior\u2013ventral part of the claustrum. Area PE received additional inputs from a posterior\u2013dorsal part of the claustrum, which has been previously reported to project to the somatosensory cortex, while the PEc receives additional input from an anterior\u2013ventral region of the claustrum, which has been reported to project to the visual association cortex. These observations reflect the known functional properties of the PE and PEc, with the former containing neurons that are predominantly involved in somatosensory processing, and the latter including both somatosensory and visual neurons. The present results suggest that the claustrum projections may help coordinate the activity of an extensive neural circuit involved in sensory and motor processing for movement execution

Cortical Afferents and Myeloarchitecture Distinguish the Medial Intraparietal Area (MIP) from Neighboring Subdivisions of the Macaque Cortex

The parietal reach region (PRR) in the medial bank of the macaque intraparietal sulcus has been a subject of considerable interest in research aimed at the development of brain-controlled prosthetic arms, but its anatomical organization remains poorly characterized. We examined the anatomical organization of the putative PRR territory based on myeloarchitecture and retrograde tracer injections. We found that the medial bank includes three areas: an extension of the dorsal subdivision of V6A (V6Ad), the medial intraparietal area (MIP), and a subdivision of area PE PEip). Analysis of corticocortical connections revealed that both V6Ad and MIP receive inputs from visual area V6, from the ventral subdivision of V6A (V6Av), from medial (PGm, 31), superior (PEc), and inferior (PFG/PF) parietal association areas, and from intraparietal areas AIP and VIP. They also receive long-range projections from the superior temporal sulcus (MST, TPO), cingulate area 23, and the dorsocaudal (area F2) and ventral (areas F4/F5) premotor areas. In comparison with V6Ad, MIP receives denser input from somatosensory areas, the primary motor cortex, and the medial motor fields, as well as from visual cortex in the ventral precuneate cortex and frontal regions associated with oculomotor guidance. Unlike MIP, V6Ad receives stronger visual input, from the caudal inferior parietal cortex (PG/Opt) and V6Av, whereas PEip shows marked emphasis on anterior parietal, primary motor and ventral premotor connections. These anatomical results suggest that MIP and V6A have complementary roles in sensorimotor behavior, with MIP more directly involved in movement planning and execution in comparison with V6A

Anterior Intraparietal Area: A Hub in the Observed Manipulative Action Network

Current knowledge regarding the processing of observed manipulative actions (OMAs) (e.g., grasping, dragging, or dropping) is limited to grasping and underlying neural circuitry remains controversial. Here, we addressed these issues by combining chronic neuronal recordings along the anteroposterior extent of monkeys' anterior intraparietal (AIP) area with tracer injections into the recorded sites. We found robust neural selectivity for 7 distinct OMAs, particularly in the posterior part of AIP (pAIP), where it was associated with motor coding of grip type and own-hand visual feedback. This cluster of functional properties appears to be specifically grounded in stronger direct connections of pAIP with the temporal regions of the ventral visual stream and the prefrontal cortex, as connections with skeletomotor related areas and regions of the dorsal visual stream exhibited opposite or no rostrocaudal gradients. Temporal and prefrontal areas may provide visual and contextual information relevant for manipulative action processing. These results revise existing models of the action observation network, suggesting that pAIP constitutes a parietal hub for routing information about OMA identity to the other nodes of the network.status: publishe