Flashing carotids in aortic valve disease.
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Aged↗
Biomedical subjects
Alexandre Croquelois
Publications and source records attributed to Alexandre Croquelois.
Cortical origin of functional recovery in the somatosensory cortex of the adult mouse after thalamic lesion.
To study the degree and time course of the functional recovery in the somatosensory cortex (SI) after an excitotoxic lesion in the adult mouse thalamus, metabolic activity was determined in SI at various times points post-lesion. Immediately after the lesion, metabolic activity in the thalamically deafferented part of SI was at its lowest value but increased progressively at subsequent time points. This was seen in all cortical layers; however, layers I and Vb recovered more rapidly than layers II, III, IV, Va and VI. Removal of the mystacial whiskers corresponding to the deafferented area, 5 weeks after cortical recovery, produced a subsequent 32% drop in metabolic activity, demonstrating peripheral sensory activation of this part of the cortex. Tracing experiments revealed that the deafferented cortex did not receive a novel thalamic input but that cortico-cortical and contralateral barrel cortex projections to this area were reinforced. We conclude that the cortical functional recovery after a thalamic lesion is, at least partially, due to modified cortico-cortical and callosal projections to the deafferented cortical area.
Animals↗
Cognitive deficits in hyperacute stroke.
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Acute Disease↗
Aphasia in hyperacute stroke: language follows brain penumbra dynamics.
During the first few hours after onset, stroke symptoms may evolve rapidly. We studied the correlation between brain perfusion and aphasia changes during the hyperacute phase of stroke using a new technique of perfusion computed tomography (P-CT). Using an aphasia score developed for each language modality, language was evaluated within 6 hours after onset, then sequentially during the first week. Maps of the penumbra and infarct obtained from P-CT images and definite infarct size evaluated using T2 and diffusion-weighted MRI (DWI) on day 3 were rated by a neuroradiologist, blinded to the clinical deficit. Within 6 hours, deficits in all language modalities were present in 13 out of 24 consecutive patients, corresponding to large anterior-posterior perfusion deficits of the left middle cerebral artery (MCA) territory. The aphasia score correlated with a corresponding perfusion deficit in specific areas of the MCA territory, and showed significantly less improvement when the penumbra evolved toward infarction than when at least part of the penumbra was rescued. Our findings suggest a particularly good correlation between the evolution of aphasic symptoms and penumbra dynamics. Further studies on the relevance of penumbra dynamics in function-specific brain areas to decision taking in hyperacute stroke management are required.
Adult↗