Interactions between motor learning and episodic memory

PROJECT SUMMARY/ABSTRACT As part of daily life, we regularly engage in well-learned and repetitive sequences of motor actions, such as commuting to work. Simultaneously, we are bound to encounter a stream of novel episodic information (e.g., getting a funny text during your commute), which we might hope to retain in long-term memory. Despite the prevalence of learned motor sequences in day-to-day experience, their impact on memory for concurrent episodic events is largely unknown. In the current proposal, I will explore how learned actions scaffold memory for the way that novel events unfold across time. Temporal information is a fundamental dimension of episodic memory, underlying our capacity to both anticipate future events and interpret the past. Existing work provides limited evidence for cooperative interactions between episodic memory and motor actions, finding that motor behavior during novel encoding, relative to passive observation, enhances subsequent item memory. However, this work has not considered the familiarity we have with the actions we take, nor does it address the formation of episodic memories that are rich in temporal structure. If we are to understand how memories are formed in the active and dynamic environments of everyday life, these gaps must be addressed. To this end, I propose to utilize a newly-developed task in which participants encode novel episodic sequences during the execution of learned vs. unfamiliar motor action sequences. Initial behavioral work shows that this task produces reliable enhancements in temporal order memory for novel item sequences encountered alongside learned actions. I will use fMRI to investigate the neural bases of this temporal memory effect, focusing in particular on contributions of the hippocampus and medial prefrontal cortex (mPFC). My hypotheses build on extant theories that these regions work in tandem to integrate novel episodic experiences with existing knowledge structures (e.g., learned motor patterns) in the service of memory behavior. In Aim 1, I will assess whether learned motor behaviors elicit systems-level changes in coordinated activity between hippocampus and mPFC, which in turn support the binding of novel episodic information with an existing motor sequence memory. In Aim 2, I will focus on the retrieval of novel episodes, determining whether the reactivation of learned motor representations in mPFC facilitates access to temporal order information, and how the hippocampus is involved in this process. Together, these aims will provide insight into how our everyday motor behaviors impact memory for concurrent experiences. They also have the potential to further our understanding of episodic memory dysfunction in clinical populations — both how it arises in patients with motor impairments, and how it can be remedied in those where motor function remains intact. Through this project, I will advance my understanding of the neural bases of episodic and motor memory systems, while also receiving training in fMRI task design, advanced neuroimaging analyses, and professional skills. All research will be conducted at Columbia University, which is home to a renowned community of memory researchers and state-of-the-art neuroimaging facilities.