Somatotopical tuning of postcentral gyrus during focal attention in man. A regional cerebral blood flow study

Publisher Website
Google Scholar
Abstract
In normal man, increases in regional cerebral metabolic rate of O2 leads to proportional increases in 2 regional cerebral blood flow (rCBF). After intracarotid injection of 133Xe in 8 patients with no major neurological deficits, rCBF was measured in 254 cortical regions. When the subjects focused their attention toward the index finger without being stimulated, rCBF increased by 25% in the contralateral somatosensory finger area. More moderate increases appeared in the superior prefrontal area and in the midfrontal region. A very weak increase was noted in the middle part of the posterior parietal region. When the attention was directed toward the upper lip instead of the finger, rCBF increased in the contralateral sensory lip area plus the other regions mentioned above. There is apparently a preparatory tuning of the relevant somatotopical postcentral area when attention is focused on a spot on the skin surface. The rCBF increase may reflect the metabolic activity following postsynaptic potentials. Tuning of the sensory area is most likely controlled by the superior and midfrontal areas.