Parieto-frontal network in humans studied by cortico-cortical evoked potential.

Parieto-frontal network is essential for sensorimotor integration in various complex behaviors, and its disruption is associated with pathophysiology of apraxia and visuo-spatial disorders. Despite advances in knowledge regarding specialized cortical areas for various sensorimotor transformations, little is known about the underlying cortico-cortical connectivity in humans. We investigated inter-areal connections of the lateral parieto-frontal network in vivo by means of cortico-cortical evoked potentials (CCEPs).

Differences in corpus callosum volume and diffusivity between temporal and frontal lobe epilepsy.

We analyzed volume and diffusivity measures of the corpus callosum (CC) in patients with temporal (TLE) and frontal (FLE) lobe epilepsy in comparison with healthy subjects. On high-resolution T1-weighted scans of 18 controls and 44 patients the volumes (cm(3)) of Witelson regions (WRs) and the entire CC were measured. The apparent diffusion coefficients (ADCs, 10(-5)mm(2)s(-1)) for the entire CC and three areas of interest were measured from co-registered ADC maps.

Diffusion tensor imaging in patients with focal epilepsy due to cortical dysplasia in the temporo-occipital region: electro-clinico-pathological correlations.

Purpose: Diffusion tensor imaging (DTI) provides information about magnitude (diffusivity) and directionality (anisotropy, FA) of water diffusion. We explored the characteristics of pathology-proven cortical dysplasia (CD) in the posterior quadrant in a case series of three patients using DTI measures, to assess associated alterations in subcortical connectivity and correlate with in situ epileptogenicity, seizure propagation and functional outcome.

Methods: The FA maps were visually inspected by a Neuroradiologist blinded to clinical data and conventional MRI (PR) and tractography was performed to assess connectivity of the dysplastic cortex and correlate with seizure propagation on invasive EEG.

Cortical stimulation for language mapping in focal epilepsy: correlations with tractography of the arcuate fasciculus.

Purpose: Diffusion tensor imaging (DTI) provides information about magnitude (diffusivity) and directionality (fractional anisotropy, FA) of water diffusion and allows visualization of major white matter tracts. The arcuate fasciculus (AF) connects anterior (Broca's) and posterior (Wernicke's) language areas. We hypothesized that essential language areas identified by direct cortical stimulation would colocalize with areas revealing subcortical connectivity via the AF.

Evidence for a basal temporal visual language center: cortical stimulation producing pure alexia.

Background: Dejerine and Benson and Geschwind postulated disconnection of the dominant angular gyrus from both visual association cortices as the basis for pure alexia, emphasizing disruption of white matter tracts in the dominant temporooccipital region. Recently functional imaging studies provide evidence for direct participation of basal temporal and occipital cortices in the cognitive process of reading. The exact location and function of these areas remain a matter of debate.