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Biomedical subjects

M Petrides

Publications and source records attributed to M Petrides.

11 recordsLinked to original sources
PubMed1991

Monitoring of selections of visual stimuli and the primate frontal cortex.

This investigation shows that lesions confined to the middle sector of the dorsolateral frontal cortex, i.e. cytoarchitectonic areas 46 and 9, cause a striking impairment in the ability of non-human primates to recall which one from a set of stimuli they chose, without in any way affecting their ability to recognize that they had previously seen those stimuli. By contrast, lesions placed within the adjacent posterior dorsolateral frontal cortex affect neither recognition of visual stimuli nor recall of prior choices. These findings delineate the mid-dorsolateral frontal cortex as a critical component of a neural system mediating the monitoring of self-generated responses.

Animals↗
PubMed1991

Functional specialization within the dorsolateral frontal cortex for serial order memory.

Monkeys with lesions restricted to two anatomically distinct regions of the dorsolateral frontal cortex were tested on a novel task that was developed to assess memory for the order of occurrence of stimuli. Monkeys with bilateral lesions of the mid-dorsolateral frontal cortex (cytoarchitectonic areas 46 and 9) were severely impaired, whereas monkeys with lesions of the posterior region of the dorsolateral frontal cortex (area 8 and rostral area 6) performed as well as the normal control animals. These results show that the primate mid-dorsolateral frontal cortex is a critical component of a neural circuit underlying the monitoring of the serial order of stimuli.

Animals↗
PubMed1990

Nonspatial conditional learning impaired in patients with unilateral frontal but not unilateral temporal lobe excisions.

The present study examined the effect of unilateral frontal- or temporal-lobe excisions on the acquisition of a conditional task requiring that the subjects respond to each one of six different coloured stimuli by selecting, from a set of six abstract designs, the correct design for each stimulus. Patients with excisions from the left or right frontal cortex were impaired in learning this task, whereas patients with left or right temporal-lobe excisions, with or without radical involvement of the hippocampal region, were not impaired. These findings demonstrate that the major role played by the frontal cortex in the acquisition of conditional responses is a general one and not restricted to situations involving different movements.

Adolescent↗
PubMed1988

Association fiber pathways to the frontal cortex from the superior temporal region in the rhesus monkey.

The projections to the frontal cortex that originate from the various areas of the superior temporal region of the rhesus monkey were investigated with the autoradiographic technique. The results demonstrated that the rostral part of the superior temporal gyrus (areas Pro, Ts1, and Ts2) projects to the proisocortical areas of the orbital and medial frontal cortex, as well as to the nearby orbital areas 13, 12, and 11, and to medial areas 9, 10, and 14. These fibers travel to the frontal lobe as part of the uncinate fascicle. The middle part of the superior temporal gyrus (areas Ts3 and paAlt) projects predominantly to the lateral frontal cortex (areas 12, upper 46, and 9) and to the dorsal aspect of the medial frontal lobe (areas 9 and 10). Only a small number of these fibers terminated within the orbitofrontal cortex. The temporofrontal fibers originating from the middle part of the superior temporal gyrus occupy the lower portion of the extreme capsule and lie just dorsal to the fibers of the uncinate fascicle. The posterior part of the superior temporal gyrus projects to the lateral frontal cortex (area 46, dorsal area 8, and the rostralmost part of dorsal area 6). Some of the fibers from the posterior superior temporal gyrus run initially through the extreme capsule and then cross the claustrum as they ascend to enter the external capsule before continuing their course to the frontal lobe. A larger group of fibers curves round the caudalmost Sylvian fissure and travels to the frontal cortex occupying a position just above and medial to the upper branch of the circular sulcus. This latter pathway constitutes a part of the classically described arcuate fasciculus.

Afferent Pathways↗
PubMed1979

Restricted posterior parietal lesions in the rhesus monkey and performance on visuospatial tasks.

Monkeys with lesions restricted to the inferior parietal lobule or the banks and depths of the superior temporal sulcus were tested on a route-following task. These areas are considered on neuroanatomical grounds to be homologous to parts of the human posterior parietal cortex, where lesions produce profound spatial disorientation. The operated monkeys were impaired on the route task, thus confirming at the behavioural level the anatomical predictions of comparability between parietal cortex in monkey and that in man. The monkeys were not impaired, however, on a visual pattern discrimination or on a visual-spatial task with cue and response separation, a task that was considered on the basis of previous investigations with extensive posterior lesions in the monkey to be sensitive to parietal lesions.

Animals↗
PubMed1979

Giant cell arteritis of the female genital tract.

In a patient who had a hysterectomy and bilateral salpingo-oophorectomy for endometrial adenocarcinoma, a giant cell arteritis was found in many of the myometrial and tubal vessels and in a few of the small arteries of the cervix and ovaries. On subsequent questioning, a history of treatment for polymyalgia rheumatica during the preceding 12 months was elicited. Of the three previously reported patients with giant cell arteritis of the uterus, two were suffering from polymyalgia rheumatica whilst one possibly had disseminated visceral giant cell arteritis.

Female↗
PubMed1979

Visual-field asymmetries in letter recognition: evidence for asymmetry in early visual registration.

Two experiments on visual-field differences in tachistoscopic letter recognition are described. In the first, a bright pre-exposure field with a black fixation point was used, and the conventionally expected dominance of the right visual field was found. However, a large number of "blank" trials were observed, in which subjects completely failed to detect the presence of the flashed target. These "blanks" were themselves significantly asymmetric between visual fields, suggesting that asymmetry in early stimulus registration may play an unsuspected role in typical measures of cerebral asymmetry in recognition accuracy. This was confirmed in a second experiment in which use of dark pre-exposure fields eliminated "blanks" and led to higher over-all accuracy, with no visual-field differences. Implications for interpretation of laterality data with normal subjects are discussed.

Adult↗
PubMed1976

Cross-modal matching and the primate frontal cortex.

Rhesus monkeys with selective lesions of the prefrontal system were tested on a tactile-visual cross-modal matching task. Monkeys with lesions in the banks and depths of the arcuate sulcus were impaired, while normal controls and monkeys with lesions in the banks and depths of the sulcus principalis and in the anterodorsal part of the head of the caudate nucleus were not.

Animals↗