Seventy-four patients with focal brain lesions were compared to a neurologically normal control group on tasks of letter-based and category-based list generation. When patients were divided only by right frontal, left...
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Seventy-four patients with focal brain lesions were compared to a neurologically normal control group on tasks of letter-based and category-based list generation. When patients were divided only by right frontal, left frontal, or nonfrontal lesion sites, the pattern of fluency impairments confirmed prior claims. When more precise lesion sites within the frontal lobes were compared between groups classified based on their fluency performance, much more specific brain-behavior relations were uncovered. Damage to the right dorsolateral cortical or connecting striatal regions, the right posterior area, or the medial inferior frontal lobe of either hemisphere did not significantly affect letter-based fluency performance. Superior medial frontal damage, right or left, resulted in moderate impairment. Patients with left dorsolateral and/or striatal lesions were most impaired. Left parietal damage led to performance relatively equivalent to the superior medial and left dorsolateral groups. The same lesion sites produced impairments in category based fluency, but so did lesions of right dorsolateral and inferior medial regions. Task analysis and correlations with other measures revealed that different cognitive processes related to different brain regions underlie performance on verbal fluency tests.
The role of interhemispheric asymmetry in the conscious control of sensorimotor measurements of the Muller-Lyer illusion was investigated. We used this perceptual illusion as a phenomenon of consciousness to determine...
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The role of interhemispheric asymmetry in the conscious control of sensorimotor measurements of the Muller-Lyer illusion was investigated. We used this perceptual illusion as a phenomenon of consciousness to determine how error value depends on the contribution of the left and right hemisphere to the control of decision making. We compared the precision of the left- and right-hand movements on the touch screen during the measurement of segment length. It was found that the left and right hands controlled by two hemispheres in different ways made different errors during these measurements. The constant bias of right-hand movements is greater than that of the left hand. The conclusion is that the hemisphere primarily involved in movement control determines the dominant system of representation (metric vs. categorical) and the control type in decision making (automatic vs. conscious). The increase or decrease in accuracy of measurement of the illusory object depends on the increase or decrease of conscious control. [ABSTRACT FROM AUTHOR]
Replying to: H. Staunton 452, 10.1038/nature06574 (2008)Staunton highlights prior work applying deep-brain stimulation (DBS) in related thalamic and other subcortical structures in vegetative-state patients. We focuse...
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Replying to: H. Staunton 452, 10.1038/nature06574 (2008)Staunton highlights prior work applying deep-brain stimulation (DBS) in related thalamic and other subcortical structures in vegetative-state patients. We focused on patients who have plateaued at the upper end of the minimally conscious state at least one year after injury, a group distinct from patients remaining in or just above vegetative state within the low end of the minimally conscious state. Patients remaining in a chronic vegetative state have anatomic pathology consistent with widespread neuronal death and cerebral disconnection. In these patients, forebrain structures within the corticostriatopallidal-thalamocortical systems have been overwhelmingly damaged .
Event-related potentials ERPs were used to examine the organization of brain activations during single-digit multiplication. Electrophysiological, neuropsychological, and brain-imaging data suggest that left inferior ...
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Event-related potentials ERPs were used to examine the organization of brain activations during single-digit multiplication. Electrophysiological, neuropsychological, and brain-imaging data suggest that left inferior parietal areas are involved in mental calculation. We aimed at investigating the involvement of this area in simple and difficult single-digit multiplications, and at determining the time course of its activation. ERPs were recorded from 64 channels while subjects performed a sequential multiplication-verification task. Simple and difficult multiplication problems were presented either visually as arabic digits or auditorily as number words. For both modalities of input, a significant effect of difficulty was found on left and right inferior parietal electrode sites. The results suggested that simple multiplication problems may involve a short-lived activation in the left inferior parietal cortex, whereas complex problems may require longer processing which also involves the homologous right area. These findings also demonstrate the significance of ERPs as a tool for determining the temporal orchestration of brain areas involved in a cognitive task.
The article presents several studies that was published in various journals and Internet sites. They include 'Changes in brainfunctioning from infancy to early childhood: evidence from EEG power and coherence wor...
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The article presents several studies that was published in various journals and Internet sites. They include 'Changes in brainfunctioning from infancy to early childhood: evidence from EEG power and coherence working memory tasks,' 'Cortex functional connectivity as a neurophysiological correlate of hypnosis: An EGG case study,' and 'Spatial-temporal current source correlations and cortical connectivity' in 'Clinical EEG and Neuroscience.'
Researchers have identified an organizing center involved in brain patterning which is located at the prospective anterior end of the zebrafish neuraxis. They show that an early neural boundary organizer exists.
Researchers have identified an organizing center involved in brain patterning which is located at the prospective anterior end of the zebrafish neuraxis. They show that an early neural boundary organizer exists.
Driven by vivid and often colorful imaging technologies, modern neurology is progressively disclosing the "hot" areas of local activity associated with particular mental processes. The quest to identify whic...
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Driven by vivid and often colorful imaging technologies, modern neurology is progressively disclosing the "hot" areas of local activity associated with particular mental processes. The quest to identify which centers in the brain are responsible for particular functions dates back at least to classical antiquity, most notably to Aristotle's highly influential "De anima."
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