Sensory strength-duration curves were obtained using percutaneous true square-wave pulses ranging from 0.1 to 20.0 ms produced by an isolated constant current stimulator. In 119 healthy volunteers sensory thresholds were measured bilaterally by stimulating the distal phalange of the little finger. In order to examine the relationship of sensory threshold and handedness the latter was assessed b...

The effects of monocular deprivation (MD) on the ocular dominance of visual cortical neurons are a paradigmatic example of experience-dependent plasticity. Here we review recent data showing that extracellular matrix (ECM) plays an important role in the control of experience-dependent plasticity both in the developing and adult visual cortex.

In various studies, deviances of hemispheric laterality in the organization of the perisylvian region in dyslexia have been suggested. Although associated with impaired language functioning, the clinical significance of atypical cerebral lateralization remains unclear. The present study examined interhemispheric source differences of magnetic responses to the German synthetic syllable [ba:] in ...

Decades of experimental studies are available on disparity selective cells in visual cortex of macaque and cat. Recently, local disparity map for iso-orientation sites for near-vertical edge preference is reported in area 18 of cat visual cortex. No experiment is yet reported on complete disparity map in V1. Disparity map for layer IV in V1 can provide insight into how disparity selective compl...

We derive an activity-based developmental model of ocular dominance column formation in primary visual cortex that takes into account cortical growth. The resulting evolution equation for the densities of feedforward afferents from the two eyes exhibits a sequence of pattern forming instabilities as the size of the cortex increases. We use linear stability analysis to investigate the nature of ...

In animal experiments, the observed orientation preference (OP) and ocular dominance (OD) columns in the visual cortex of the brain show various pattern types. Here, we show that the different visual map formations in various species are due to the crossover behavior in anisotropic systems composed of orientational and scalar components such as easy-plane Heisenberg models. We predict the trans...

Monocular deprivation (MD) is a well-known paradigm of experience-dependent plasticity in which cortical neurons exhibit a shift of ocular dominance (OD) toward the open eye. The mechanisms underlying this form of plasticity are incompletely understood. Here we demonstrate the involvement of callosal connections in the synaptic modifications occurring during MD. Rats at the peak of the critical...

This model for understanding altered states of consciousness and dissociation is based on the hypothesis that normal consciousness depends on an illusion of mental unity generated by certain dynamic brain processes. 1i7ren these processes are altered and the illusion o/ mental unit_y is lost, the individual experiences an altered state o/ consciousness in which normal consciousness is latent or...

When the left and right eyes are simultaneously presented with different images, observers typically report exclusive awareness of only one image. This phenomenon is termed binocular rivalry, reflecting the fact that the dominant image alternates every few seconds in a cycle of perceptual competition that continues indefinitely. Despite the apparent continuity in perceptual switching, we now de...

Asymmetries in human facial expressions have long been documented and traditionally interpreted as evidence of brain laterality in emotional behavior. Recent findings in nonhuman primates suggest that this hemispheric specialization for emotional behavior may have precursors in primate evolution. In this study, we present the first data collected on our closest living relative, the chimpanzee. ...