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Biomedical subjects

M Jones-Gotman

Publications and source records attributed to M Jones-Gotman.

8 recordsLinked to original sources
PubMed1992

Functional localization and lateralization of human olfactory cortex.

Anatomical and physiological investigations in monkeys indicate that olfaction is subserved by several cortical regions. But the areas implicated in the human olfactory system have not been definitively identified by functional criteria. Behavioural evidence has suggested that laterally specialized mechanisms for odour processing may exist, but the neuroanatomical substrate remains unknown. We used positron emission tomography to study the cortical representation of human olfactory processing by comparing cerebral blood flow changes evoked during olfactory stimulation with those of a control task. We report here significant cerebral blood flow increases at the junction of the inferior frontal and temporal lobes bilaterally, corresponding to the piriform cortex, and unilaterally, in the right orbitofrontal cortex. The results complement and extend previous data implicating these regions in olfactory processing, and indicate that a functional asymmetry exists in the human brain favouring the right orbitofrontal area in olfaction.

Cerebrovascular Circulation↗
PubMed1992

Corticoamygdalectomy in memory-impaired patients.

Sixty-seven patients who underwent resection of the amygdala and temporal neocortex for intractable temporal lobe epilepsy were analyzed. Forty-four of them failed memory tests during the intracarotid sodium amytal procedure or showed severe impairment of contralateral material specific memory. Surgical outcome ratings were seizure-free or rare seizure, 51%; worthwhile improvement, 15%; failure, 34%. The least successful outcome was noted in the group with mandatory corticoamygdalectomy and seizure origin in the dominant hemisphere. There was no postoperative exacerbation of memory deficit, whether preoperative memory was normal or impaired. When hippocampal resection is inadvisable, corticoamygdalectomy may be considered.

Adolescent↗
PubMed1992

Intracranial EEG study of brain structures affected by internal carotid injection of amobarbital.

Hippocampal function, considered critical in memory processing, is supposedly tested in the intracarotid sodium amobarbital (ISA) procedure; however, since the hippocampus is not completely irrigated by the internal carotid artery, some believe the procedure may be invalid for memory testing. We quantified delta activity in intracerebral EEGs during ISA tests. There was increased delta in ipsilateral structures as follows: amygdala (6.4 minutes), anterior hippocampus (7.2), middle hippocampus (7.4), temporal neocortex (9.1), frontal lobe (8.4), central/parietal area (11.0), and occipital lobe (9.7). Contralateral structures usually (> 64%) showed increased delta lasting 4 to 5 minutes. The ipsilateral hippocampus had delta waves in over 90% of injections. We conclude that the hippocampus is clearly affected by the ISA injection. We argue that the slow waves may not be caused by a direct effect of the drug, but rather by a functional deafferentation due to the profound inactivation of structures surrounding the hippocampus. Similarly, slow waves contralateral to injection may be caused by sudden removal of neuronal input from the regions receiving the amobarbital.

Amobarbital↗
PubMed1992

Anatomic basis of amygdaloid and hippocampal volume measurement by magnetic resonance imaging.

Both the amygdala and the hippocampus are involved in the pathogenesis of a number of neurologic conditions, including temporal lobe epilepsy, postanoxic amnesia, and Alzheimer's disease. To enhance the investigation and management of patients with these disorders, we developed a protocol to measure the volumes of the amygdala and as much of the hippocampus as possible (approximately 90 to 95%) using high-resolution MRI. We present the anatomic basis of these two protocols and our results in normal control subjects. These volumetric studies of the amygdala may clarify the role of this structure in the pathogenesis of temporal lobe epilepsy.

Adult↗
PubMed1992

Neuropsychological techniques in the identification of epileptic foci.

Neuropsychological evaluation contributes towards identification of a seizure focus through assessment of function. Tests sample widely among cognitive abilities, usually contrasting language and visuospatial competence. In patients with a temporal-lobe focus, evaluation of memory is crucial and ideally should comprise a variety of tasks tapping different aspects of learning and memory. As a means of predicting and preventing severe postoperative memory impairment, memory is further tested in many cases with the intracarotid sodium amytal (IAP) procedure; hippocampus will be spared in patients who fail IAP memory tests. Performance after temporal lobectomy on three basic memory tests was evaluated in patients who had failed pre-operative IAP memory tests compared to those who had passed. Those who had failed performed significantly worse, confirming fragility of memory function in cases who have been identified as at risk by the IAP procedure.

Amobarbital↗
PubMed1979

Incidental learning of image-mediated or pronounced words after right temporal lobectomy.

The use of visual images in word recall by patients with right temporal lobectomy was studied by testing the incidental learning of 40 (20 abstract, 20 concrete) words that had been either carefully pronounced or the referent visualized. When tested immediately after presentation of the list, the right temporal-lobe group (N = 30) did not differ from a matched normal control group, but in delayed recall 2 hours later the patient group showed impaired recall of concrete words that had been visualized. Recall of visualized abstract words was also poor but not significantly so, while pronounced words, whether abstract or concrete, were recalled normally. Further analysis revealed an impaired recall for visualized concrete words in both immediate and delayed testing in patients having a large right hippocampal removal, indicating an important role of the mesial temporal structures in image recall.

Adolescent↗