Involvement of the subthalamic nucleus in cognitive functions -- a concept

The involvement of the subthalamic nucleus (STN) in a broad spectrum of various non-motor functions - attention, executive functions, verbal learning and memory, verbal abstract reasoning, conflict resolution, and emotions - has been reported. The STN has an anatomically central position within the basal ganglia(BG)-thalamocortical motor, associative and limbic circuits. The STN might interfere with non-motor functions as an indirect modulator rather than a regulator. Mechanisms modulating the motor and non-motor functions might differ. The STN has been implicated in control of non-motor behaviors via the tuning of specific circuits depending on the task. The STN might modulate selected non-motor functions via contextual modulation of certain cortical areas. Based on intracerebral recordings, we proposed that the non-motor activities in the BG are organized in some way other than the well-known organization of the cortico-BG-thalamocortical circuits. These findings support the hypothesis of a cortico-STN bypass of the BG-thalamocortical circuitry under some circumstances. The exact role of the STN and the BG in non-motor functions remains an important and interesting challenge for future research.