Neural correlates of motor learning, transfer of learning, and learning to learn

Abstract

Recent studies on the neural bases of sensorimotor adaptation demonstrate that the cerebellar and striatal thalamocortical pathways contribute to early learning. Transfer of learning involves a reduction in the contribution of early learning networks and increased reliance on the cerebellum. The neural correlates of learning to learn remain to be determined but likely involve enhanced functioning of the general aspects of early learning.

Figure 1

Panel A highlights brain regions that increase their activity with increasing target size, including the left putamen (left slice), left primary motor cortex (middle slice), and left premotor cortex (right slice). Panel B presents signal change for all areas that increased activation with increasing target size: CN (caudate nucleus), Ins (insula), M1 (primary motor cortex), MOG (middle occipital gyrus), MFG (middle frontal gyrus), IFG (inferior frontal gyrus), PUT (putamen). [Adapted from Seidler RD, Noll DC, Thiers G. Feedforward and feedback processes in motor control. NeuroImage. 2004:22(4):1775–1783. Copyright © 2004 Elsevier. Used with permission.]

Figure 2

Panel A highlights brain regions that decrease their activity with increasing target size, including the medial cerebellum (left slice), right ventral premotor cortex (middle slice), and right sensorimotor cortex (right slice). Panel B presents signal change for all areas that decreased activation with increasing target size: CB HV (cerebellum hemisphere V), SM1 (primary sensorimotor cortex), PrCG (precentral gyrus), CB HVI (cerebellum hemisphere VI), CG (cingulate gyrus), Ins (insula), Thal (thalamus). [Adapted from Seidler RD, Noll DC, Thiers G. Feedforward and feedback processes in motor control. NeuroImage. 2004:22(4):1775–1783. Copyright © 2004 Elsevier. Used with permission.]

Figure 3

Adaptation data from a typical participant. Panel A depicts single trial spatial trajectories for two trials under the 30° feedback rotation condition early in adaptation. The open circles represent target location in visual space, while the filled circles represent the target locations in joystick space. The spatial trajectory is presented in joystick coordinates as well (participants would view the cursor moving along this path in real time, rotated clockwise by 30°). Panel B depicts single trial spatial trajectories from the same participant performing under the 30° rotation late in adaptation. Learning is evidenced by the straighter trajectories compared to panel A. The arrow labeled #1 in panel A indicates where direction error (DE) is calculated, and refers to the point along the spatial trajectory at which peak velocity was achieved. DE is the angle between the dashed line from the start to the target position, and a straight line from the start to the position at peak velocity. The arrow labeled #2 indicates where initial endpoint error (IEE) is calculated, which is at the endpoint of the initial ballistic movement towards the target. IEE is the distance from this spatial location to the target. [Adapted from Anguera JA, Russell CA, Noll DC, Seidler RD. Neural correlates associated with intermanual transfer of adaptation. Brain Research 2007;1185: 136–151. Copyright © 2007 Elsevier. Used with permission.]

Figure 4

The top left slice shows brain regions that reduced their activation at transfer of learning in comparison to motor learning, including the right primary motor cortex, inferior frontal gyrus, and inferior temporal gyrus. The top right slice shows cerebellar activity that was correlated with the magnitude of transfer shown by individual participants, including activation in HIV and HV. The bottom two slices depict the location of this activation (shown in blue) in comparison to the cerebellar region showing a reduction in activation at transfer of learning (shown in red). (Reprinted from Seidler, R. D. & Noll, D. C. Neuroanatomical correlates of motor acquisition and motor transfer. J Neurophys. 2008:99:1836–1845. Copyright © 2008 The American Physiological Society. Used with permission.)

Figure 5

The left image shows a lateral view of the brain while the right depicts a midsaggital image. We and others have shown that the early phase of learning sensorimotor adaptation tasks involves the basal ganglia thalamocortical loops (not shown), the medial cerebellum (MC), the anterior cingulate cortex (ACC), the inferior frontal gyrus (IFG), and visual (VC) and parietal (PC) cortical areas. We hypothesize that learning to learn involves enhanced contributions by these regions. Late learning involves the lateral cerebellum (LC), parietal (PC) and cingulate motor areas (CMA). Transfer of learning is associated with reduced contributions of the early learning network, and overlapping activation with late learning regions. [Adapted from Martin J. Neuroanatomy: Text and Atlas (3^rd edition), 2003. McGraw-Hill Medical. New York. Copyright © 2003 McGraw Hill. Used with Permission.)