Grant: Discovery Grants Program - Individual

The development of a new skill like riding a bike is viewed as a motor task, yet the initial acquisition of that skill is linked to the unique experience of the first time you rode a bike. Dissociating the episodic memory experience of the event from the motor memory component of the experience is difficult. Despite not explicitly recalling the episodic components of that unique first bike riding experience each time you get on a bike, the implicit motor memory supports performance of the skill. Like the episodic memory for the event, the motor memory for the skill changes over time (becomes more familiar through repeated performance), and this transformed version of the motor memory is accompanied by a reorganization of neural activity. The prolonged process of systems consolidation and neural network reorganization of episodic memory has been well characterized in both humans and rodents, but the factors mediating systems consolidation and network reorganization of the motor memory network remain unclear. My research program aims to (objective 1) identify how motor memory networks reorganize over time, and (objective 2) determine how silencing key nodes of the episodic memory network (hippocampus, medial prefrontal cortex) propagates to impact activity within the motor memory network (motor cortex, striatum, cerebellum) at recent and remote timepoints. Critically, by varying the age of the memory (1 day or 1 month old), the frequency of training (2 training sessions of 20 training sessions), and the training context (familiar or novel contexts), we can dissociate the contributions of time, practice, and context in mediating motor memory systems consolidation and memory transformation observed across the brain. The necessity of key nodes of the episodic memory network in motor memory consolidation and retrieval will be determined by chemogenetically silencing the hippocampus or medial prefrontal cortex using inhibitory DREADDs in mice, then identifying changes in activation of the motor memory network in the absence of hippocampus or medial prefrontal cortical input during motor task performance. Demonstrating analogous patterns of systems consolidation and identifying how disruption of key nodes of the network alter activity will bolster, or challenge, the current understanding of memory reorganizational processes in the brain. If a consistent pattern of reorganization is observed across declarative (episodic) and non-declarative (motor) memory, this may identify memory transformation as a fundamental process of memory consolidation, and will highlight the importance of investigating other forms of non-declarative memory network reorganization in the brain.