Activity in Occipito-Temporal Cortex Is Involved in Tool-Use Planning and Contributes to Tool-Related Semantic Neural Representations.

Tool use and language are highly refined human abilities which may show neural commonalities due to their potential reciprocal interaction during evolution. Recent work provided evidence for shared neural resources between tool use and syntax. However, whether activity within the tool-use network also contributes to semantic neural representations of tool nouns remains untested.

Learning-related contraction of gray matter in rodent sensorimotor cortex is associated with adaptive myelination.

From observations in rodents, it has been suggested that the cellular basis of learning-dependent changes, detected using structural MRI, may be increased dendritic spine density, alterations in astrocyte volume, and adaptations within intracortical myelin. Myelin plasticity is crucial for neurological function, and active myelination is required for learning and memory. However, the dynamics of myelin plasticity and how it relates to morphometric-based measurements of structural plasticity remains unknown.

Tool use and language share syntactic processes and neural patterns in the basal ganglia.

Does tool use share syntactic processes with language? Acting with a tool is thought to add a hierarchical level into the motor plan. In the linguistic domain, syntax is the cognitive function handling interdependent elements. Using functional magnetic resonance imaging, we detected common neurofunctional substrates in the basal ganglia subserving both tool use and syntax in language.

Associative learning in peripersonal space: fear responses are acquired in hand-centered coordinates.

Space coding affects perception of stimuli associated to negative valence: threatening stimuli presented within the peripersonal space (PPS) speed up behavioral responses compared with nonthreatening events. However, it remains unclear whether the association between stimuli and their negative valence is acquired in a body part-centered reference system, a main feature of the PPS coding. Here we test the hypothesis that associative learning takes place in hand-centered coordinates and can therefore remap according to hand displacement.

Peripersonal and reaching space differ: Evidence from their spatial extent and multisensory facilitation pattern.

Peripersonal space (PPS) is a multisensory representation of the space near body parts facilitating interactions with the close environment. Studies on non-human and human primates agree in showing that PPS is a body part-centered representation that guides actions. Because of these characteristics, growing confusion surrounds peripersonal and arm-reaching space (ARS), that is the space one's arm can reach.

Me, you, and our object: Peripersonal space recruitment during executed and observed actions depends on object ownership.

Peripersonal space (PPS) is a spatial representation that codes objects close to one's own and to someone else's body in a multisensory-motor frame of reference to support appropriate motor behavior. Recent theories framed PPS beyond its original sensorimotor aspects and proposed to relate it to social aspects of the self. Here, we manipulated the ownership status of an object ("whose object this is") to test the sensitivity of PPS to such a pervasive aspect of society.

Aim and Plausibility of Action Chains Remap Peripersonal Space.

Successful interaction with objects in the peripersonal space requires that the information relative to current and upcoming positions of our body is continuously monitored and updated with respect to the location of target objects. Voluntary actions, for example, are known to induce an anticipatory remapping of the peri-hand space (PHS, i.e.

Language as a Tool: Motor Proficiency Using a Tool Predicts Individual Linguistic Abilities.

Different disciplines converge to trace language evolution from motor skills. The human ability to use tools has been advocated as a fundamental step toward the emergence of linguistic processes in the brain. Neuropsychological and neuroimaging research has established that linguistic functions and tool-use are mediated by partially overlapping brain networks.

Action Planning Modulates Peripersonal Space.

Peripersonal space is a multisensory representation relying on the processing of tactile and visual stimuli presented on and close to different body parts. The most studied peripersonal space representation is perihand space (PHS), a highly plastic representation modulated following tool use and by the rapid approach of visual objects. Given these properties, PHS may serve different sensorimotor functions, including guidance of voluntary actions such as object grasping.

Expansion and Renormalization of Human Brain Structure During Skill Acquisition.

Research on human brain changes during skill acquisition has revealed brain volume expansion in task-relevant areas. However, the large number of skills that humans acquire during ontogeny militates against plasticity as a perpetual process of volume growth. Building on animal models and available theories, we promote the expansion-renormalization model for plastic changes in humans.

Proprioception Is Necessary for Body Schema Plasticity: Evidence from a Deafferented Patient.

The ability of using a large variety of tools is important in our daily life. Behind human tool-use abilities lays the brain capacity to incorporate tools into the body representation for action (Body Schema, BS), thought to rely mainly on proprioceptive information. Here, we tested whether tool incorporation is possible in absence of proprioception by studying a patient with right upper-limb deafferentation.

The rules of tool incorporation: Tool morpho-functional & sensori-motor constraints.

Previous studies showed that using tools modifies the agent's body and space representation. However, it is still not clear which rules govern those remapping processes. Here, we studied the differential role played by the morpho-functional characteristics of a tool and the sensori-motor constraints that a tool imposes on the hand.

Multisensory representation of the space near the hand: from perception to action and interindividual interactions.

When interacting with objects and other people, the brain needs to locate our limbs and the relevant visual information surrounding them. Studies on monkeys showed that information from different sensory modalities converge at the single cell level within a set of interconnected multisensory frontoparietal areas. It is largely accepted that this network allows for multisensory processing of the space surrounding the body (peripersonal space), whose function has been linked to the sensory guidance of appetitive and defensive movements, and localization of the limbs in space.

A shared representation of the space near oneself and others in the human premotor cortex.

Interactions between people require shared high-level cognitive representations of action goals, intentions, and mental states, but do people also share their representation of space? The human ventral premotor (PMv) and parietal cortices contain neuronal populations coding for the execution and observation of actions, analogous to the mirror neurons identified in monkeys. This neuronal system is tuned to the location of the acting person relative to the observer and the target of the action. Therefore, it can be theorized that the observer's brain constructs a low-level, body-centered representation of the space around others similar to one's own peripersonal space representation.

Disintegration of multisensory signals from the real hand reduces default limb self-attribution: an fMRI study.

The perception of our limbs in space is built upon the integration of visual, tactile, and proprioceptive signals. Accumulating evidence suggests that these signals are combined in areas of premotor, parietal, and cerebellar cortices. However, it remains to be determined whether neuronal populations in these areas integrate hand signals according to basic temporal and spatial congruence principles of multisensory integration.

That's near my hand! Parietal and premotor coding of hand-centered space contributes to localization and self-attribution of the hand.

The ability to identify and localize our own limbs is crucial for survival. Indeed, the majority of our interactions with objects occur within the space surrounding the hands. In non-human primates, neurons in the posterior parietal and premotor cortices dynamically represent the space near the upper limbs in hand-centered coordinates.

Keeping the world at hand: rapid visuomotor processing for hand-object interactions.

The existence of hand-centred visual processing has long been established in the macaque premotor cortex. These hand-centred mechanisms have been thought to play some general role in the sensory guidance of movements towards objects, or, more recently, in the sensory guidance of object avoidance movements. We suggest that these hand-centred mechanisms play a specific and prominent role in the rapid selection and control of manual actions following sudden changes in the properties of the objects relevant for hand-object interactions.

Neglect: a multisensory deficit?

Neglect is a neurological syndrome characterised by a lack of conscious perception of events localised in the contralesional side of space. Here, we consider the possible multisensory nature of this disorder, critically reviewing the literature devoted to multisensory manifestations and processing in neglect. Although its most striking manifestations have been observed in the visual domain, a number of studies demonstrate that neglect can affect virtually any sensory modality, in particular touch and audition.

Grab an object with a tool and change your body: tool-use-dependent changes of body representation for action.

Along the evolutionary history, humans have reached a high level of sophistication in the way they interact with the environment. One important step in this process has been the introduction of tools, enabling humans to go beyond the boundaries of their physical possibilities. Here, we focus on some "low level" aspects of sensorimotor processing that highlight how tool-use plays a causal role in shaping body representations, an essential plastic feature for efficient motor control during development and skilful tool-use in the adult life.

When action is not enough: tool-use reveals tactile-dependent access to Body Schema.

Proper motor control of our own body implies a reliable representation of body parts. This information is supposed to be stored in the Body Schema (BS), a body representation that appears separate from a more perceptual body representation, the Body Image (BI). The dissociation between BS for action and BI for perception, originally based on neuropsychological evidence, has recently become the focus of behavioural studies in physiological conditions.

Studying Multisensory Processing and Its Role in the Representation of Space through Pathological and Physiological Crossmodal Extinction.

The study of crossmodal extinction has brought a considerable contribution to our understanding of how the integration of stimuli perceived in multiple sensory modalities is used by the nervous system to build coherent representations of the space that directly surrounds us. Indeed, by revealing interferences between stimuli in a disturbed system, extinction provides an invaluable opportunity to investigate the interactions that normally exist between those stimuli in an intact system. Here, we first review studies on pathological crossmodal extinction, from the original demonstration of its existence, to its role in the exploration of the multisensory neural representation of space and the current theoretical accounts proposed to explain the mechanisms involved in extinction and multisensory competition.

FMRI adaptation reveals a cortical mechanism for the coding of space near the hand.

Behavioral studies in humans and electrophysiological recordings in nonhuman primates have suggested the existence of a specific representation of the space immediately surrounding the body. In macaques, neurons that have visual receptive fields limited to a region of space close around a body part have been found in premotor and parietal areas. These cells are hypothesized to encode the location of external objects in coordinate systems that are centered on individual body parts.