# The multiple components of motor memory

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2021 · $359,235

## Abstract

When we practice a motor task, we can do it better the next time we revisit it. How is this accomplished? The
basic assumption in neuroscience has been that during practice, we learn an association between the stimulus
and the appropriate motor commands. However, it has been difficult to reconcile this view with two basic
behavioral results: (1) when learning is followed by a long period of washout (removal of the perturbation),
the motor memory appears protected from erasure (termed “savings”). How is it that learning followed by
washout does not erase the association between stimulus and motor commands? (2) When washout is
following by learning of the opposite perturbation, subjects exhibit meta-learning, i.e., performance is better
than naïve in a perturbation opposite to the one that they had initially learned. How could learning to
associate a stimulus to one direction of motor commands followed by washout help in learning in the opposite
direction? Here, we approach these problems from a new perspective: the neural architecture that supports
motor learning in the cerebellum. We propose that in the cerebellum, micro-clusters of Purkinje cells (P-cells)
are organized based on their preference for error. This preference is expressed in their complex-spike tuning
(encoding of error), which in turn provides a coordinate system in which simple spikes can be understood. The
P-cell’s error preference makes it so that when error changes, anatomically distinct P-cell micro-clusters are
recruited. As a result, when a perturbation is followed by washout, error changes direction and engages new
groups of P-cells, producing a new memory without erasing the old. The same hypothesized anatomy suggests
that meta-learning arises not because of similarity of the motor commands, but because of the similarity of
errors. Using this hypothesis we show that when simple spikes of P-cells are organized into micro-clusters, an
exquisite encoding of motion emerges. We propose to test a host of predictions regarding both the
neurophysiological correlates of error-dependent learning in the cerebellum, and its behavioral correlates of
savings and meta-learning in healthy people. Finally, we use the theory to better understand a latent form of
motor learning in people with damage to their cerebellum.
 From a clinical perspective, our work aims to understand how the brain stores motor memories, and
how it up-regulates learning from error, questions that are relevant to motor rehabilitation following neuro-
trauma and disease. Our theory provides a recipe to modulate error-sensitivity, which should produce faster
motor learning, potentially affecting the duration of rehabilitation.

## Key facts

- **NIH application ID:** 10135152
- **Project number:** 5R01NS078311-10
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** REZA SHADMEHR
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $359,235
- **Award type:** 5
- **Project period:** 2012-09-15 → 2024-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10135152

## Citation

> US National Institutes of Health, RePORTER application 10135152, The multiple components of motor memory (5R01NS078311-10). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10135152. Licensed CC0.

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