Neuron reveals the basis for the formation of motor memory

When you first start learning how to ride a bike or play an instrument, your body movements are at best uncoordinated

What is the cellular basis of this kinematic learning process? In a study published this week, the study, led by Dr Simon Chan of the University of Ottawa School of Medicine, provides new and valuable insights into

His lab focuses on unlocking how memories are encoded and stored in the brain, particularly motor learning, the complex process

Dr.

"If we understand how the acquisition of motor skills is regulated in the brain, then maybe one day we can help people with stroke or Parkinson's disease regain those skills

The study was about mice, not humans

So how are these experiments conducted?

By restricting the head movements of mice during the imaging phase, which allowed the scientists to probe the brain at single-cell resolution, the research team trained the animals to perform a specific motor task: picking up and grabbing a food ball

Initially, the head-constrained mice showed tentativeness and clumsiness

The team wanted to observe the activation of neurons associated with these tentacle gripping movements and see how synaptic pathways in the brain are formed when they occur

Dr.

Using two-photon imaging techniques, a microscopy technique that can observe living tissue at the micron scale, his team was able to observe the reorganization of dendritic spines in the excitatory neurons of the primary motor cortex during long periods of time when mice with fixed heads performed ball-grabbing maneuvers

Zooming in to the cellular level, the researchers found that motor learning selectively induces the expression

What these new findings reveal, Dr.

Essentially, NPAS4 regulates genetic changes in inhibitory neurons that control the activity of those neurons, just as the volume slider controls the speakers of a laptop

In other words, repeating these movements over time changes the way the animal's primary motor cortex works internally—a part of the brain that only mammals possess and controls complex movements
.

The team found that the expression of NPAS4 transcription factors in inhibitory neurons is key
to how the brain screens for options and forms the strongest motor memory for specific actions.
During repetitive exercises, NPAS4 transcription factors need to be continuously reexpressed in order for these memories to stay and refine
in the brain.

essay

Functionally Distinct NPAS4-Expressing Somatostatin Interneuron Ensembles Critical for Motor Skill Learning