Primary Somatosensory Cortex Activation Is Not Altered in Patients With Ventroposterior Thalamic Lesions
| Autor: | Pierre Amarenco, Jean-Denis Degos, Yves Samson, Philippe Remy, Monica Zilbovicius, Pierre Cesaro |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Adult
Brain Infarction Male Movement Thalamus Somatosensory system Vibration Lesion Central nervous system disease Humans Medicine Aged Advanced and Specialized Nursing Analysis of Variance Brain Mapping Sensory stimulation therapy business.industry Somatosensory Cortex Anatomy Middle Aged Hand medicine.disease Anterior Thalamic Nuclei Cerebral blood flow Somatosensory evoked potential Case-Control Studies Female Neurology (clinical) medicine.symptom Posterior Thalamic Nuclei Cardiology and Cardiovascular Medicine business Neuroscience Perfusion Tomography Emission-Computed |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1524-4628 0039-2499 |
| DOI: | 10.1161/01.str.30.12.2651 |
| Popis: | Background and Purpose —We know remarkably little about the mechanisms underlying cortical activation. Such mechanisms might be better understood by studying the effect of well-localized lesions on the cortical activations in simple paradigms. Methods —We used H 2 15 O and positron emission tomography to measure regional cerebral blood flow (rCBF) at rest and during hand vibration in 7 patients with unilateral thalamic lesion involving the ventroposterior (VP) somatosensory thalamic relay nuclei. We compared the results with those obtained in 6 patients with thalamic lesions sparing the VP nuclei and 6 healthy controls. Results —The patients with VP lesions had a selective hypoperfusion at rest in the ipsilesional primary sensorimotor cortex (SM1). This hypoperfusion was significantly correlated with the degree of contralateral somatosensory deficit. This abnormality may reflect the deafferentation of SM1 from its somatosensory thalamic input. Despite this deafferentation, the ipsilesional SM1 was normally activated by the vibration of the hypesthetic hand. Conclusions —The fact that a lesion of the somatosensory thalamic relay nuclei alters the rCBF at rest in SM1 but not its activation by hand vibration indicates that the mechanism of cortical activation is complex, even in the case of simple sensory stimulation. In addition, a dissociation may occur between obvious neurological deficits and apparently normal activation patterns, which suggests that activation studies should be interpreted cautiously in patients with focal brain lesions. |
| Databáze: | OpenAIRE |
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