Mnemonic Integration of Prefrontal-temporal Lobe Activity during Emotional Memory Formation

Marquette University, Milwaukee WI

Investigators

Abstract

The ability to lay down long-lasting memories of events is crucial for survival. Being able to predict a threat that occurs seconds or minutes after an environmental cue allows for evasive or defensive action. Despite considerable progress towards understanding how memories are formed, many questions remain, such as how the brain learns about events separated in time. This project uses cutting-edge tools in neuroscience to address a previously intractable problem about how brain systems function on a second-by-second basis to link events in memory. This contribution is significant because it is expected to identify key principles of brain function that will advance our understanding of more complex forms of learning and memory. Undergraduate students, including underrepresented groups in science (women and minorities), participate in data collection, analysis, and dissemination. This project also provides an opportunity to develop educational tools to help stimulate interest in Science, Technology, Engineering and Mathematics (STEM) fields within the broader community. These tools include an interactive demonstration of neuronal activity and brain stimulation for annual outreach efforts to high schools in the greater Milwaukee, Wisconcin area. Nearly all forms of motivated behavior require the association of events that are separated in time, but very little is known about the underlying mechanisms supporting these associations, highlighting a critical gap in the study of memory: how are sensory inputs integrated in memory when they do not overlap in time? The principal investigator recently revealed a causal link between a neural signature of working memory in the prefrontal cortex and the formation of long-term fear memory. The objective of this project is to determine how an auditory cue held in short-term working memory systems within the prefrontal cortex and hippocampus is associated with shock inputs in the amygdala to drive plasticity and adaptive fear responses. With the recent development of optogenetic tools, it is now possible to interrogate the function of discrete patterns of firing in specific neural connections. Here, the investigators leverage this tool in combination with electrophysiology in awake, behaving animals to determine when short-term mnemonic information is integrated with sensory input during memory formation. Given the importance of the prefrontal cortex and the hippocampus for the adaptive use of memory to guide behavior, a hallmark of executive function, determining how mnemonic input from these structures is integrated in downstream brain areas informs the understanding of a broad range of adaptive and maladaptive behaviors.