Extrastriate cortical areas activated during visual discrimination in man.

The regional cerebral blood flow (rCBF) was measured in 254 different regions of the human extrastriate cerebral cortex during rest and during visual shape discrimination. Visual shape discrimination increased the rCBF markedly in the frontal eye fields, the upper part of the prefrontal cortex, the lateral occipital cortex and the superior parietal cortex. Moderate increases of rCBF appeared in the inferotemporal cortex, the parietotemporo-occipital region and scattered in the lateral part of the prefrontal cortex.

Supplementary motor area and other cortical areas in organization of voluntary movements in man.

1. Previous studies in man have revealed a coupling between the regional cerebral blood flow (rCBF) and the regional cerebral metabolic rate for oxygen. In normal man, increases in the regional cerebral metabolic rate for oxygen leads to proportional increases in the rCBF(34). We have measured the rCBF as an expression of the level of cortical activity simultaneously from 254 cortical regions in 28 patients with no major neurological defects, during rest and during planning and execution of a few types of learned voluntary movements with the hand. 2. We found that the rCBF increases exclusively in the supplementary motor area while subjects were programming a sequence of fast isolated movements of individual fingers, without actually executing it. 3. During execution of the same motor sequence, there were equivalent increases of the rCBF in both supplementary motor areas, but only in the contralateral primary motor area. In addition, there were more modest rCBF increases in the contralateral sensory hand area, the convexity part of the premotor area, and bilaterally in the inferior frontal region. 4. Repetitive fast flexions of the same finger or a sustained isometric muscular contraction raise the blood flow in the contralateral primary motor and sensory hand area. 5. A pure somatosensory discrimination of the shapes of objects, without any concomitant voluntary movements, also leaves the supplementary motor areas silent. 6. We conclude that the primary motor area and the part of the motor system it projects to by itself can control ongoing simple ballistic movements with the self-same body part. A sequence of different isolated finger movements requires programming in the supplementary motor areas. We suggest that the supplementary motor areas are programming areas for motor subroutines and that these areas form a queue of time-ordered motor commands before voluntary movement are executed by way of the primary motor area.

Different cortical areas in man in organization of voluntary movements in extrapersonal space.

1. This paper reports regional cerebral blood flow (rCBF) measurements in 254 cortical regions with 133Xe injected into the internal carotid artery in 19 patients, none of whom had any major neurological defect. The purpose was to demonstrate the pattern of cortical activity, as revealed by rCBF increases, during two types of unilateral voluntary movement in extrapersonal space: a) the maze test, series of fast isolated movements in various directions in a frame, executed under verbal command; and b) the drawing of a spiral in the air. 2. Both types of movements were associated with increases of rCBF in the supplementary motor area (bilaterally), the convexity part of the premotor area (bilaterally), the primary sensorimotor hand and arm area (contralaterally), and in the superior and inferior parietal region (bilaterally). 3. During the maze test there were, in addition, bilateral focal increases of the blood flow in the auditory areas, the inferior frontal regions, and the frontal eye fields. 4. It is concluded that the supplementary motor areas, which are also active during programming and execution of movement sequences in intrapersonal space (33), elaborate programs for motor subroutines necessary in skilled voluntary motion. The convexity parts of the premotor areas are activated when a new motor program is established or a previously learned motor program is modulated. The primary motor area is the exclusive executive locus for voluntary movements of the hand and arm. 5. Voluntary movements in extrapersonal space only are associated with activation of the parietal regions. These areas are assumed to provide information to the motor programming neurons about the demanded direction of motion in extrapersonal space in relation to proprioceptive reference systems. 6. The increase of rCBF in the auditory areas, the inferior frontal regions, and the frontal eye fields during the maze test were ascribed to the processing of auditory information. 7. Both tests are accompanied by a diffuse increase of the hemispheric blood flow (approximately 10%), which is assumed to be a parallel to the commonly known desynchronization of the EEG during mental work.

Regional cerebral blood flow in aphasia.

Regional cerebral blood flow (rCBF) was studied in 13 aphasic patients with left hemisphere lesions, using the intracarotid xenon 133 injection method and a 254-detector gamma camera system. The rCBF was measured during rest and during various function tests, including a simple speech test. In motor (nonfluent) aphasia, the rCBF method showed areas of cortical dysfunction that always included the lower part of the rolandic area while Broca's area was not consistently affected. In sensory (fluent) aphasia, the superior-posterior temporal cortex was involved in all cases. In global aphasia, the abnormalities included both regions consistently involved in the other types of aphasia. The 133Xe injection method for mapping abnormalities relevant for localizing the cortical speech areas was superior to the classical neuroradiological methods in that several cases failed to show any relevant lesion whatsoever. This is probably related to the functional nature of the rCBF method: subnormal flow values and lack of the normal flow increase during function tests apparently may disclose functionally inactivated but structurally intact cortex.

Regressive language in severe head injury.

In a follow-up study of 50 patients with severe head injuries three patients had echolalia. One patient with initially global aphasia had echolalia for some weeks when he started talking. Another patient with severe diffuse brain damage, dementia, and emotional regression had echolalia. The dysfunction was considered a detour performance. In the third patient echolalia and palilalia were details in a total pattern of regression lasting for months. The patient, who had extensive frontal atrophy secondary to a very severe head trauma, presented an extreme state of regression returning to a foetal-body pattern and behaving like a baby.