Symptoms in Parkinson's disease are accompanied by bursting oscillation in the basal ganglia. Although it is clinically important to elucidate the mechanism underlying the oscillatory dynamics, complex interactions among the nuclei in the basal ganglia make it difficult to understand. We review recent hypotheses on the origin of the bursting oscillation, and explain an important role of the subthalamic nucleus and the regions connected to it. We also discuss a computational model on the NMDA-activated burst in the subthalamic nucleus.
It is generally believed that depression impedes functional recovery after neuronal damage such as spinal-cord injury. Here we review our investigation of the neuronal mechanism underlying such psychological effects on functional recovery. We show that activity of the ventral striatum, which plays a critical role in processing of motivation, increased and its functional connectivity with motor cortex (M1) was progressively strengthened during the recovery. In addition, functional connectivity of the M1 with other structures belonging to the mesolimbic system was also strengthened. These results give clues to the neuronal substrate for motivational regulation of motor learning required for functional recovery.