Handgrip-Related Activation in the Primary Motor Cortex Relates to Underlying Neuronal Metabolism After Stroke.

Background: Abnormal task-related activation in primary motor cortices (M1) has been consistently found in functional imaging studies of subcortical stroke. Whether the abnormal activations are associated with neuronal alterations in the same or homologous area is not known.

Objective: Our goal was to establish the relationships between M1 measures of motor-task-related activation and a neuronal marker, N-acetylaspartate (NAA), in patients with severe to mild hemiparesis.

Motor and premotor cortices in subcortical stroke: proton magnetic resonance spectroscopy measures and arm motor impairment.

Background: Although functional imaging and neurophysiological approaches reveal alterations in motor and premotor areas after stroke, insights into neurobiological events underlying these alterations are limited in human studies.

Objective: We tested whether cerebral metabolites related to neuronal and glial compartments are altered in the hand representation in bilateral motor and premotor areas and correlated with distal and proximal arm motor impairment in hemiparetic persons.

Methods: In 20 participants at >6 months postonset of a subcortical ischemic stroke and 16 age- and sex-matched healthy controls, the concentrations of N-acetylaspartate and myo-inositol were quantified by proton magnetic resonance spectroscopy.

Neuronal-glial alterations in non-primary motor areas in chronic subcortical stroke.

Whether functional changes of the non-primary motor areas, e.g., dorsal premotor (PMd) and supplementary motor (SMA) areas, after stroke, reflect reorganization phenomena or recruitment of a pre-existing motor network remains to be clarified.

Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans.

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography (MEG), we examined the patterns of short-term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the hand.

Primary motor cortex in stroke: a functional MRI-guided proton MR spectroscopic study.

Background And Purpose: Our goal was to investigate whether certain metabolites, specific to neurons, glial cells, or the neuronal-glial neurotransmission system, in primary motor cortices (M1), are altered and correlated with clinical motor severity in chronic stroke.

Methods: Fourteen survivors of a single ischemic stroke located outside the M1 and 14 age-matched healthy control subjects were included. At >6 months after stroke, N-acetylaspartate, myo-inositol, and glutamate/glutamine were measured using proton magnetic resonance spectroscopic imaging (in-plane resolution=5×5 mm(2)) in radiologically normal-appearing gray matter of the hand representation area, identified by functional MRI, in each M1.