No abstract

The main aim in this work was to study the interaction between auditory and kinesthetic stimuli and its influence on motion control. The study was performed on healthy subjects and patients with Parkinson's disease (PD). Thirty-five right-handed volunteers (young, PD, and age-matched healthy participants, and PD-patients) were studied with three different motor tasks (slow cyclic movements, fast cyclic movements, and slow continuous movements) and under the action of kinesthetic stimuli and sounds at different beat rates. The action of kinesthesia was evaluated by comparing real movements with virtual movements (movements imaged but not executed). The fast cyclic task was accelerated by kinesthetic but not by auditory stimuli. The slow cyclic task changed with the beat rate of sounds but not with kinesthetic stimuli. The slow continuous task showed an integrated response to both sensorial modalities. These data show that the influence of the multisensory integration on motion changes with the motor task and that some motor patterns are modulated by the simultaneous action of auditory and kinesthetic information, a cross-modal integration that was different in PD-patients.

No abstract

Projections of the centromedian-parafasicularis neurons of the intralaminar thalamus are major inputs of the striatum. Their functional role in the activity of human basal ganglia (BG) is not well known. The aim of this work was to study the functional connectivity of intralaminar thalamic nuclei with other BG by using the correlations of the BOLD signal recorded during "resting" and a motor task. Intralaminar nuclei showed a marked functional connectivity with all the tested BG, which was observed during "resting" and did not change with the motor task. As regards the intralaminar nuclei, BG connectivity was much lower for the medial dorsal nucleus (a thalamic nucleus bordering the intralaminar nuclei) and for the default mode network (although intralaminar nuclei showed a negative correlation with the default mode network). After the "regression" of intralaminar nuclei activity (partial correlation), the functional connectivity of the caudate and putamen nuclei with other BG decreased (but not with the primary sensorimotor cortex). Present data provide evidence that intralaminar nuclei are not only critical for striatal activity but also for the global performance of human BG, an action involving subcortical BG loops more than cortico-subcortical loops. The high correlation found between BG suggest that, similarly to that reported in other brain centers, the very-slow frequency fluctuations are relevant for the functional activity of these centers.

No abstract