Brain : a journal of neurology
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Brain atrophy as determined by quantitative MRI can be used to characterize disease progression in multiple sclerosis. Many studies have addressed white matter (WM) alterations leading to atrophy, while changes of the cerebral cortex have been studied to a lesser extent. In vivo, the cerebral cortex has been difficult to study due to its complex structure and regional variability. ⋯ Patients with longstanding disease or severe disability, however, presented additionally with focal thinning of the motor cortex area [2.35 mm (SD 0.19) versus 2.74 mm (SD 0.15)]. We conclude that in vivo measurement of cortical thickness is feasible in patients suffering from multiple sclerosis. The data provide new insight into the cortical pathology in multiple sclerosis patients, revealing focal cortical thinning beside an overall reduction of the cortical thickness with disease progression.
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Sensory abnormalities have been reported in Parkinson's disease and may contribute to the motor deficits. Peripheral sensory stimulation inhibits the motor cortex, and the effects depend on the interstimulus interval (ISI) between the sensory stimulus and transcranial magnetic stimulation (TMS) to the motor cortex. Short latency afferent inhibition (SAI) occurs at an ISI of approximately 20 ms, and long latency afferent inhibition (LAI) at an ISI of approximately 200 ms. ⋯ This pathway is unaffected by Parkinson's disease but is altered by dopaminergic medication in Parkinson's disease patients and may contribute to the side effects of dopaminergic drugs. LAI probably involves other pathways such as the basal ganglia or cortical association areas. This defective sensorimotor integration may be a non-dopaminergic manifestation of Parkinson's disease.
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The somatic marker hypothesis posits that deficits in emotional signalling (somatic states) lead to poor judgment in decision-making, especially in the personal and social realms. Similar to this hypothesis is the concept of emotional intelligence, which has been defined as an array of emotional and social abilities, competencies and skills that enable individuals to cope with daily demands and be more effective in their personal and social life. Patients with lesions to the ventromedial (VM) prefrontal cortex have defective somatic markers and tend to exercise poor judgment in decision-making, which is especially manifested in the disadvantageous choices they typically make in their personal lives and in the ways in which they relate with others. ⋯ Only patients with lesions in the somatic marker circuitry revealed significantly low emotional intelligence and poor judgment in decision-making as well as disturbances in social functioning, in spite of normal levels of cognitive intelligence (IQ) and the absence of psychopathology based on DSM-IV criteria. The findings provide preliminary evidence suggesting that emotional and social intelligence is different from cognitive intelligence. We suggest, moreover, that the neural systems supporting somatic state activation and personal judgment in decision-making may overlap with critical components of a neural circuitry subserving emotional and social intelligence, independent of the neural system supporting cognitive intelligence.