Cortex; a journal devoted to the study of the nervous system and behavior
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While previous functional neuroimaging studies have shown that semantic and episodic memory tasks activate different cortical regions, they never compared regional cerebral blood flow (rCBF) patterns associated with semantic and episodic memory within the same experimental design. In this study, we used H2(15)O PET to study subjects in the course of semantic and episodic memory tasks. rCBF was measured in 9 normal volunteers during a resting baseline condition and two cognitive tasks. In the semantic categorisation task subjects heard a list of concrete words and had to respond to words belonging to the "animals" or "food" category. ⋯ Compared to the episodic memory tasks, the semantic memory tasks activated the superior temporal/insular cortex bilaterally and the right premotor cortex. Compared to the semantic memory tasks, the episodic memory tasks activated the right frontal cortex. These results suggest that cortical networks implicated in semantic and episodic memory show both common and unique regions, with the right prefrontal cortex being the neural correlate specific of episodic remembering.
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A case is described of a young male who suffered head injuries in a motor accident and subsequently displayed a severe anterograde amnesia in the presence of a relatively intact retrograde memory. He also demonstrated marked impairment of general intellectual ability, naming, perceptual skills and executive functioning. ⋯ It is further argued that while frontal impairment occurred in this case it lacks any of the hallmarks of frontal amnesia. The case is further evidence for the fractionation of amnesic syndromes.
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This case report describes phantom limbs in four adults with congenital limb deficiency. Case 1, with congenital absence of the left arm below the elbow, received a minor injury of the stump at age 16 and subsequently developed a full-length phantom arm, hand and fingers. Cases 2 and 3, at the ages of 26 and 30, underwent minor surgery of the lower limbs and subsequently developed vivid, full-length phantoms of their legs. ⋯ Beginning at age 6, she developed a full-length phantom leg and foot that touched the floor, which persisted for more than 20 years. The descriptions by these four adults lend credibility to earlier reports of phantom limbs in congenital limb-deficient children. They also indicate that these phantoms may persist into adulthood.
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In a series of three studies with right handed subjects, left side pain is tolerated less well than right side pain with a cold pressor, and results in greater emotional disturbance, both with a cold pressor and in chronic pain patients. In the second study where comparisons are made with non-stimulated controls, acute left side pain results in higher state anxiety scores than controls; right side pain and control groups are comparable. The differences between the reactions to left and right side pain are consistent with activation of the emotional properties of the hemisphere contralateral to the painful stimulation.
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The purpose of the present experiment was to study whether a unilateral cerebral lesion modifies pain parameters with respect to a control group. Electric stimuli were applied to brain damaged patients on the forearm ipsilateral to the lesion, and to both forearms of a control group. ⋯ In the latter group, pain endurance was not significantly different from controls, although there was a tendency towards its decrease. Result are discussed in relation to the problem of the hemispheric specialization for emotional processes.