Fellow's research: Somatosensory cortex, the feeling part of the brain, is involved in retaining memory of new motor skills
05 Nov 2019
Dr Neeraj Kumar, Early Career Fellow, Indian Institute of Technology Gandhinagar
Our study provides the first direct evidence that changes, which occur in the somatosensory cortex during motor learning, are necessary for consolidating or retaining new motor skills after they have been learned.
It has been known that the hippocampus—a seahorse-shaped structure of the mid brain—consolidates facts and events into long-term memory. However, how motor memories such as how to play a musical instrument are retained is still largely unknown. Understanding how motor memories are retained could help in rehabilitation and motor re-learning after injury.
We know that remapping of the somatosensory cortex (a part of the brain that processes sensory information and runs across the top of the brain from ear to ear) is known to occur with motor learning, but its involvement in memory formation is still to be established. To test whether the somatosensory cortex plays a role in the formation of long-term motor memory, we trained participants on a motor task: participants learned to move a robotic arm through a force field that perturbed normal movements. Immediately after training, continuous transcranial magnetic stimulation—a form of non-invasive brain stimulation using magnetic fields—was used to inhibit either the somatosensory or primary motor regions of the brain (the primary motor cortex runs across the top of the brain in a band just in front of the somatosensory cortex).
Motor learning was assessed the next day, and the results showed that retention of motor memory was blocked only in people whose somatosensory cortex was inhibited. Retention of memory was not affected after inhibiting the primary motor cortex. Further tests confirmed that the somatosensory cortex functions specifically in consolidating motor memories, but not in their subsequent retrieval once, consolidation has occurred.
The significance of this work is that it shows that the storage of updated somatic information, which is accumulated during training, may be central to its retention and subsequent re-use. The findings of our work point to possible benefits of an expanded focus on the somatosensory system in rehabilitation and retraining or motor re-learning post injuries.
Somatosensory cortex participates in the consolidation of human motor memory. Neeraj Kumar, Timothy F Manning, David J Ostry. PLOS Biology. October 2019