Neural basis of sensory and motor learning

Sensory perception is vital for accurate hand movement, and learning is known to occur in both sensory
and motor systems to keep movement accurate in a changing environment. Unfortunately, how the
brain’s sensory and motor systems interact to achieve this is poorly understood. This knowledge gap limits
advances in areas that depend on understanding the mechanisms underlying sensorimotor function. Existing
roadblocks include: (i) Independent evolution of motor control and sensory perception research, where the
importance of bridging these fields has only recently been recognized. (ii) Research that does bridge sensory
and motor function typically deals with one sensory modality in isolation, rather than the natural multisensory
state of the system. This makes it difficult to translate laboratory research to natural contexts. Hand position,
for example, is perceived through both vision and proprioception (position sense, from the joints and muscles).
(iii) Neuroimaging has identified human cortical regions active during simple multisensory stimuli but has rarely
studied higher level multisensory processes such as visuo-proprioceptive realignment, one form of sensory
learning related to spatial perception. To successfully shape multisensory-motor interactions in human
behavior, the neural basis of complex multisensory processes must be understood. This project addresses all
three roadblocks. The overall objective is to identify, in the context of visuo-proprioceptive processing, the
roles of sensory vs. motor brain systems in sensory vs. motor learning. The central hypothesis is that
sensory and motor brain areas interact reciprocally in hand control, with each having a role in both sensory and
motor learning. Aim 1 will identify the role of sensory vs. motor brain areas in sensory vs. motor learning
using transcranial magnetic stimulation (TMS), which transiently and focally reduces neural activity. In
different groups of healthy participants, stimulation will be applied to brain regions traditionally considered
unisensory, multisensory, or motor. Participants will then experience either: (Aim 1A) visuo-proprioceptive
sensory learning; or (Aim 1B) motor learning. If learning is affected by TMS, a causal role for the stimulated
brain region can be inferred. Using neuroimaging, Aim 2 will identify functional connections among
unisensory, multisensory, and motor areas that change in association with visuo-proprioceptive
realignment. This project is innovative in two ways: (i) It represents a shift from current research paradigms by
studying brain regions traditionally considered unisensory, multisensory, and motor in a single set of
experiments comprising multisensory vs. motor learning. (ii) The use of brain stimulation to infer the role of
activity within brain areas, and neuroimaging to identify relevant connections between brain areas. The
significance of the proposed research is that it will address the roadblocks to progress in the field by bridging
sensory and motor research in a multisensory context and testing complex sensory and motor learning
processes involved in natural human behavior.

Grant Number: 5R01NS112367-05
NIH Institute/Center: NIH
Principal Investigator: HANNAH BLOCK