Asymmetry of parietal interhemispheric connections in humans.
1 : Fondazione S Lucia IRCCS
Visuospatial abilities are preferentially mediated by the right
hemisphere. Although this asymmetry of function is thought to be due
to an unbalanced interaction between cerebral hemispheres, the
underlying neurophysiological substrate is still largely unknown.
Here, using a method of trifocal transcranial magnetic stimulation, we
show that the right, but not left, human posterior parietal cortex
exerts a strong inhibitory activity over the contralateral homologous
area by a short-latency connection. We also clarify, using
diffusion-tensor magnetic resonance imaging, that such an interaction
is mediated by direct transcallosal projections located in the
posterior corpus callosum. We argue that this anatomo-functional
network may represent a possible neurophysiological basis for the
ongoing functional asymmetry between parietal cortices, and that its
damage could contribute to the clinical manifestations of neglect.
hemisphere. Although this asymmetry of function is thought to be due
to an unbalanced interaction between cerebral hemispheres, the
underlying neurophysiological substrate is still largely unknown.
Here, using a method of trifocal transcranial magnetic stimulation, we
show that the right, but not left, human posterior parietal cortex
exerts a strong inhibitory activity over the contralateral homologous
area by a short-latency connection. We also clarify, using
diffusion-tensor magnetic resonance imaging, that such an interaction
is mediated by direct transcallosal projections located in the
posterior corpus callosum. We argue that this anatomo-functional
network may represent a possible neurophysiological basis for the
ongoing functional asymmetry between parietal cortices, and that its
damage could contribute to the clinical manifestations of neglect.
| Subject : | : | Symposium |
| Topics | : | SY: The asymmetry of attention in visual processing |
| PDF version | : |  PDF version |
