While the striatum is well known to control and modulate movements and tasks involving motor memory, striatal integration is also a key component in executive functions and decision making, and in processing motivational and emotional information relating to reward and anxiety (Voytek and Knight 2010; Balleine et al. 2007; Helfinstein et al. 2012).
We investigated whether aging also impairs motor memory consolidation by assessing the susceptibility to memory interference and off-line gains in motor skill learning after practice in children, young, and older adults.
In fact, Experiment V suggested that the (re)afferent feedback could be highly important since ankle plantar flexion produced by peripheral nerve stimulation of the agonist nerve (rENS), which generates strong sensory input, also interfered with motor memory consolidation.
At a neural level, recent functional imaging data have also demonstrated that these overnight motor memory improvements are associated with a systems-level, plastic reorganization within the brain, including a lateralized expansion and increased activation in the right primary motor cortex; contralateral to the hand (left) learning the motor skill memory [14].
Moreover, the recent past has been shown to also affect the selection of the current motor memory [ 8].
Since multiple brain regions are undoubtedly involved in such varied deficits, we specifically examined striatum, which is clearly impacted by HIV and is also involved as a coordinating center in multiple motor, memory, and motivational/emotional tasks and behaviors.
In this context, M1 has been demonstrated as one key brain structure engaged not only in the fast acquisition but also in consolidation and re-consolidation processes of a motor memory trace (Censor et al., 2010, Muellbacher et al., 2002).
Oscillating GC plasma concentrations along the circadian rhythm appear to be important for the elimination of spines present before motor learning, and also for the maintenance of new spines along with the retention of motor memory [ 115].
However, we also found that subthreshold TMS, which is also known to activate M1 and corticospinal outputs [17], [27], [28], failed to interfere with motor memory.
Shadmehr, R. & Holcomb, H.H. Neural correlates of motor memory consolidation.
