We propose a model of unilateral visual extinction following right hemisphere lesions based on competition between contralesional and ipsilesional input to access a decision centre located in the left hemisphere. During bilateral presentations, the contralesional signal is on average less likely to activate the decision centre than the ipsilesional signal. This is because an intra-hemispheric l...

Many differences between the hemispheres have been observed, from the gross anatomical level to differences in dendritic structure or neurotransmitter distribution. Analytic reasoning and language functions such as grammar and vocabulary are often lateralized to the left hemisphere of the brain. The right cerebral hemisphere plays a special role in tasks involving the direction of spatial atten...

While the left hemispheric role in speech production has been extensively studied the role of the right hemisphere is less explored. Therefore, this paper addressed the question to what extend the right hemisphere is involved in prosodic production in an intonational language such as German. In particular, we explored the speech production of three patients with right hemisphere damage and comp...

We show examples of how low-level, qualitative neuroanatomical hemispheric differences can give rise to detailed psychologically realistic behaviour. We illustrate this claim with examples from the cognitive modelling of unilateral visuospatial neglect and neglect dyslexia. Our models are based on two principles: the division of information processing between the two hemispheres; and the implem...

BACKGROUND AND PURPOSE Previous research has reported impaired hand function on the "unaffected" side after stroke, but its incidence, origins, and impact on rehabilitation remain unclear. This study investigated whether impairment of ipsilateral dexterity is common early after middle cerebral artery stroke and explored the relationship to cognitive deficit. METHODS Thirty patients within 1 m...

Hemiparetic stroke is a common motor network disorder that affects a wide range of functional movements due to cortical and subcortical network lesions in stroke patients. Conventional magnetic resonance imaging (MRI) has been used to examine structural brain damage, but the integrity and connectivity of the whole brain are poorly understood. Hence, advanced neuroimaging with diffusion tensor i...

Recent lesion studies have shown that left hemisphere lesions often give rise to frank sign language aphasias in deaf signers, whereas right hemisphere lesions do not, suggesting similar patterns of hemispheric asymmetry for signed and spoken language. We present here a case of a left-handed, deaf, life-long signer who became aphasic after a right-hemisphere lesion. The subject exhibits deficit...