Considering structural connectivity in the triple code model of numerical cognition: differential connectivity for magnitude processing and arithmetic facts.

The current study provides a generalizable account of the anatomo-functional associations as well as the connectivity of representational codes underlying numerical processing as suggested by the triple code model (TCM) of numerical cognition. By evaluating the neural networks subserving numerical cognition in two specific and substantially different numerical tasks with regard to both grey matter localizations as well as white matter tracts we (1) considered the possibility of additional memory-related cortex areas crucial for arithmetic fact retrieval (e.g.

Damage to ventral and dorsal language pathways in acute aphasia.

Converging evidence from neuroimaging studies and computational modelling suggests an organization of language in a dual dorsal-ventral brain network: a dorsal stream connects temporoparietal with frontal premotor regions through the superior longitudinal and arcuate fasciculus and integrates sensorimotor processing, e.g. in repetition of speech.

Limb apraxia in acute ischemic stroke: a neglected clinical challenge?

Symptoms of limb apraxia and executive dysfunctions are currently not explicitly considered by the National Institutes of Health Stroke Scale and, thus, not routinely tested by clinicians in the acute care of patients with suspected stroke. Neuropsychological testing, clinical examination, MRI, and functional magnetic resonance imaging (fMRI) were performed in a right-handed patient with acute onset of left-sided sensorimotor hemiparesis due to a right hemisphere ischemic stroke. Deficits in the execution of meaningless and meaningful gestures were not detected properly on initial clinical examination but were revealed later on through neuropsychological testing.

Fiber pathways connecting cortical areas relevant for spatial orienting and exploration.

By implementing a task that closely resembled a clinical test for diagnosing spatial neglect in stroke patients, Himmelbach et al. (: Neuroimage 32:1747-1759) found significantly increased activation during active exploration in those cortical areas in healthy subjects that are known to induce spatial neglect in case of a lesion. The present study investigated whether direct intra-hemispheric cortico-cortical connections could be found between these activated clusters using a probabilistic fiber-tracking approach in 52 healthy subjects.

Neural correlates of disturbed perception of verticality.

Objective: Perception of verticality can be perturbed after cortical stroke. However, a relationship between lesion location and pathologic perception of verticality is still a matter of debate since previous studies revealed contradictory results. Thus, the aim of the current study was to test whether specific cortical lesions were associated with tilts of subjective visual vertical (SVV) and to determine the critical brain areas that cause such tilts in the case of a lesion.

Neglect severity after left and right brain damage.

While unilateral spatial neglect after left brain damage is undoubtedly less common than spatial neglect after a right hemisphere lesion, it is also assumed to be less severe. Here we directly test this latter hypothesis using a continuous measure of neglect severity: the so-called Center of Cancellation (CoC). Rorden and Karnath (2010) recently validated this index for right brain damaged neglect patients.

Spatial orienting by left hemisphere language areas: a relict from the past?

During evolution, the human brain developed remarkable functional differences between left and right hemispheres. Due to this lateralization, disorders of spatial orienting occur predominantly after right brain damage and disorders of language after left brain damage. In contrast to this general pattern, few individuals show disturbed spatial orienting (spatial neglect) after left brain damage.

Do patients with pure alexia suffer from a specific word form processing deficit? Evidence from 'wrods with trasnpsoed letetrs'.

It is widely accepted that letter-by-letter reading and a pronounced increase in reading time as a function of word length are the hallmark features of pure alexia. Why patients show these two phenomena with respect to underlying cognitive mechanisms is, however, much less clear. Two main hypotheses have been proposed, i.

Off on the wrong foot: local features in biological motion.

Biological-motion perception consists of a number of different phenomena. They include global mechanisms that support the retrieval of the coherent shape of a walker, but also mechanisms which derive information from the local motion of its parts about facing direction and animacy, independent of the particular shape of the display. A large body of the literature on biological-motion perception is based on a synthetic stimulus generated by an algorithm published by James Cutting in 1978 (Perception 7 393-405).