Human anterior cingulate function has been explained primarily within a cognitive framework. We used functional MRI experiments with simultaneous electrocardiography to examine regional brain activity associated with autonomic cardiovascular control during performance of cognitive and motor tasks. Using indices of heart rate variability, and high- and low-frequency power in the cardiac rhythm, we observed activity in the dorsal anterior cingulate cortex (ACC) related to sympathetic modulation of heart rate that was dissociable from cognitive and motor-related activity. The findings predict that during effortful cognitive and motor behaviour the dorsal ACC supports the generation of associated autonomic states of cardiovascular arousal. We subsequently tested this prediction by studying three patients with focal damage involving the ACC while they performed effortful cognitive and motor tests. Each showed abnormalities in autonomic cardiovascular responses with blunted autonomic arousal to mental stress when compared with 147 normal subjects tested in identical fashion. Thus, converging neuroimaging and clinical findings suggest that ACC function mediates context-driven modulation of bodily arousal states.

In this paper we studied three brain-damaged patients: the first two, DR and FG, had limb apraxia whilst the third was a control patient (WH2) with an executive function disorder but without limb apraxia. DR and FG were impaired in carrying out everyday actions, whilst they maintained the ability to sequence photographs representing those same activities. The failure in the action production task was not caused by visual agnosia for objects, as the patients could recognise them from sight. Nor was it produced by a loss of knowledge about their functions (De Renzi & Lucchelli, 1988), as DR and FG could identify objects from descriptions of their use. WH2's pattern of performance doubly dissociated from that of the apraxic patients, namely spared action production on the multiple object test, but faulty sequencing of photographs. WH2's difficulties in sequencing photographs were not due to a failure to understand the task, as she could sequence stimuli other than actions (e.g., shapes and numbers). Nor were the differences due to a loss of knowledge about the actions, since she could perform and identify them from photographs. These results show that the kind of apraxia observed in DR and FG is not produced by a degraded action sequence representation (Lehmkuhl & Poeck, 1981; Poeck & Lehmkuhl, 1980). We interpreted our results within a contention scheduling model (Cooper & Shallice, 2000; Norman & Shallice, 1986).

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Objective: To investigate the presence of syntactic impairments in native language in Parkinson's disease. Methods: Twelve bilingual patients, with Friulian as their first language (L1) and Italian as their second (L2), with Parkinson's disease and 12 normal controls matched for age, sex, and years of schooling, were studied on three syntactic tasks. Results: Patients with Parkinson's disease showed a greater impairment of L1 than L2. Conclusions: These findings provide evidence of greater basal ganglia involvement in the acquisition and further processing of grammar in L1 v L2 possibly due to a major involvement of procedural memory in representing L1 grammar.