The Extrastriate Body Area and identity processing: An fMRI guided TMS study.

The extrastriate body area (EBA) is a body-selective focal region located in the lateral occipito-temporal cortex that responds strongly to images of human bodies and body parts in comparison with other classes of stimuli. Whether EBA contributes also to the body recognition of self versus others remains in debate. We investigated whether EBA contributes to self-other distinction and whether there might be a hemispheric-side specificity to that contribution using double-pulse transcranial magnetic stimulation (TMS) in right-handed participants.

Interlimb Transfer of Reach Adaptation Does Not Require an Intact Corpus Callosum: Evidence from Patients with Callosal Lesions and Agenesis.

Generalization of sensorimotor adaptation across limbs, known as interlimb transfer, is a well-demonstrated phenomenon in humans, yet the underlying neural mechanisms remain unclear. Theoretical models suggest that interlimb transfer is mediated by interhemispheric transfer of information via the corpus callosum. We thus hypothesized that lesions of the corpus callosum, especially to its midbody connecting motor, supplementary motor, and premotor areas of the two cerebral hemispheres, would impair interlimb transfer of sensorimotor adaptation.

Brain Regions Associated to a Kinesthetic Illusion Evoked by Watching a Video of One's Own Moving Hand.

It is well known that kinesthetic illusions can be induced by stimulation of several sensory systems (proprioception, touch, vision…). In this study we investigated the cerebral network underlying a kinesthetic illusion induced by visual stimulation by using functional magnetic resonance imaging (fMRI) in humans. Participants were instructed to keep their hand still while watching the video of their own moving hand (Self Hand) or that of someone else's moving hand (Other Hand).

Benefits of computer-based memory and attention training in healthy older adults.

Multifactorial cognitive training programs have a positive effect on cognition in healthy older adults. Among the age-sensitive cognitive domains, episodic memory is the most affected. In the present study, we evaluated the benefits on episodic memory of a computer-based memory and attention training.

Lateral occipitotemporal cortex and action representation.

Representation of body and body movements is essential for identifying others intentions or actions or for learning from them. Over the last 10 years, a large collection of research has demonstrated that body representations are distributed across a widely distributed brain network. In this functional magnetic resonance imaging study, we focus on lateral occipitotemporal cortex (LOTC), a recently identified brain region that could represent the body in a multisensory and dynamic manner.

Where is your shoulder? Neural correlates of localizing others' body parts.

Neuropsychological studies, based on pointing to body parts paradigms, suggest that left posterior parietal lobe is involved in the visual processing of other persons' bodies. In addition, some patients have been found with mild deficit when dealing with abstract human representations but marked impairment with realistically represented bodies, suggesting that this processing could be modulated by the abstraction level of the body to be analyzed. These issues were examined in the present fMRI experiment, designed to evaluate the effects of visually processing human bodies of different abstraction levels on brain activity.

A new vibrator to stimulate muscle proprioceptors in fMRI.

Studying cognitive brain functions by functional magnetic resonance imaging (fMRI) requires appropriate stimulation devices that do not interfere with the magnetic fields. Since the emergence of fMRI in the 90s, a number of stimulation devices have been developed for the visual and auditory modalities. Only few devices, however, have been developed for the somesthesic modality.

Relationship between the velocity of illusory hand movement and strength of MEG signals in human primary motor cortex and left angular gyrus.

We studied the relationship between the velocity of movement illusion and the activity level of primary motor area (M1) and of the left angular gyrus (AG) in humans. To induce illusory movement perception, we applied co-vibration at different frequencies on tendons of antagonistic muscle groups. Since it is well established that the velocity of illusory movement is related to the difference in vibration frequency applied to two antagonistic muscles, we compared magnetoencephalography (MEG) signals recorded in two conditions of co-vibration: in the "fast illusion" condition a frequency difference of 80 Hz was applied on the tendons of the right wrist extensor and flexor muscle groups, whereas in the "slow illusion" condition a frequency difference of 40 Hz was applied on the same muscle groups.

Cortical correlates of illusory hand movement perception in humans: a MEG study.

The present study aimed to investigate cortical activity associated with perception of illusory hand movements elicited by tendon vibration using magnetoencephalography (MEG) in humans. We compared MEG responses in two conditions of stimulation, "illusion" and "no illusion". In the "illusion" condition, covibration at different frequencies applied on the tendons of the right wrist flexor and extensor muscle groups evoked illusory movements of the hand.

Transcranial magnetic stimulation of the sensorimotor cortex alters kinaesthesia.

Tendon vibration is known to evoke perception of illusory movements, together with motor responses in the muscles antagonistic to those vibrated. In the present study, we assessed the perceptual and motor effects of transcranial magnetic stimulation of the sensorimotor cortex during illusions of hand movements evoked by vibration of wrist muscle tendons. The results showed that transcranial magnetic stimulation could accelerate or decelerate the illusory movements, depending on the site and intensity of magnetic stimulation.

The role of human left superior parietal lobule in body part localization.

Electrophysiological data in primates suggest that the superior parietal lobule integrates the position of the limbs to construct complex representations of postures. Although in humans the neural basis of these mechanisms remains largely unknown, neuropsychological studies have implicated left superior parietal regions. We devised a simple functional magnetic resonance imaging paradigm aimed at exploring this hypothesis in healthy humans.

Motor and parietal cortical areas both underlie kinaesthesia.

Tendon vibration has long been known to evoke perception of illusory movements through activation of muscle spindle primary endings. Few studies, however, have dealt with the cortical processes resulting in these kinaesthetic illusions. We conceived an fMRI experiment to investigate the cortical structures taking part in these illusory perceptions.