Mapping Motor Circuit Mechanisms During Voluntary Movement

Several users of our O’Hara behavioral testing systems are presenting their research at SfN.

Matsuzaki and colleagues at the University of Tokyo are investigating the role of primary and secondary motor cortices in information processing during self-initiated versus externally triggered movements. To do this they are using the TaskForcer for mice in combination with in vivo widefield two-photon imaging. Below is a summary of what they plan to present at SFN.

Voluntary motor movements can either be self-initiated, or externally triggered. Neuronal ensembles in the primary (M1) and secondary (M2) both play a role in information processing during voluntary movement, but the relative contribution of each remains unclear. Furthermore, how each region processes information when the same movement is self-initiated (SI) versus externally triggered (ET) remains unknown. Terada and colleagues in the Matsuzaki lab examined whether the pattern of activation differed in M2 compared to M1 during SI and ET movements. They hypothesized that the presence of external stimuli would be sufficient to alter neural activity patterns in M2 when the same movement was self-initiated versus externally triggered. To test this, they trained head-fixed mice to perform a self-initiated lever-pull task (SI) and an external cue-triggered lever-pull task (ET) using the TaskForcer. During task performance, they conducted calcium imaging of GcAMP infected layer 2/3 neurons concurrently in M2 and M1 using super-wide-field two-photon microscopy (Terada et al., 2018) in mice implanted with large cranial windows.
They found that the proportion of neurons that responded to movement-related activity specific to either learning type was greater in M2 compared to M1. Furthermore, calcium activity in M2 was differed significantly between the self-initiated and externally triggered trials, indicating that external stimuli are sufficient to drive differential neuronal responses in M2. These results also suggested that M2 can distinguish between learning trials even when the same body part is initiated.