A University of Iowa researcher has secured a five-year, $2.7 million grant from the National Institutes of Health to study associative learning. The funding will support tracking brain activity in rats using electrodes and optogenetics to see how neural networks update expectations when outcomes change.
Organisms constantly rely on past experiences to guide their expectations in fresh situations. Whether it is associating a particular sound with a predator or linking a specific smell with a favorite restaurant, associative learning shapes daily behavior. Yet brains can occasionally form false expectations when reality fails to match prior outcomes. When that happens, the environment updates the cue, and the brain adjusts its associative learning accordingly.
John Freeman, a professor in the Department of Psychological and Brain Sciences at the University of Iowa, is leading an investigation into how those associations are updated when expectations clash with reality. His team will expose rats to sounds or visual signals that they learn to associate with a non-life-threatening, negative outcome. Once researchers alter that outcome, the animals are forced to revise their learned associations.
To watch this learning process unfold inside the brain, Freeman has teamed up with Krystal Parker, an associate professor in the Department of Psychiatry. The co-principal investigators will record brain activity using tiny sensors known as electrodes. Alongside those sensors, the researchers will deploy optogenetics, a technique that involves sending precise laser pulses to switch brain cells on or off.
By combining both methods, the team intends to isolate general neural activity during associative learning and determine whether actively manipulating brain cells alters that learning. The financial backing for the five-year project comes from the National Institutes of Health and the National Institute of Neurological Disorders and Stroke.
Potential Insights for Neurological and Mental Health Disorders
Researchers hope the findings will eventually shed light on human neurological and mental health disorders, ranging from dementia to schizophrenia, by pinpointing the brain communication patterns involved in associative learning.
If we understand how optogenetics can improve communication between different areas in the brain, then that information could be used to understand how we could improve brain network communication in humans who might be suffering from neurological disorders.
John Freeman, professor in the Department of Psychological and Brain Sciences, via Uiowa
Rest Periods and Maze Training Reveal Sudden Shifts in Animal Cognition
Separate maze experiments point to how brains process such learning changes over time. In a maze setup featuring six possible locations for a food reward—each tied to a distinct scent and flavor cue—researchers trained rats until they mastered every pairing. Then, the team systematically swapped out the scent-location pairs: first three, then the remaining three, and finally all six.
While the rats could rely on basic non-associative rules—such as avoiding visiting the exact same location twice in one trial or ignoring the spot that held food in the previous turn—those strategies were not enough to solve the test. This task is associative in nature, meaning the animals had to master the new pairs to succeed.
When faced with three or six new pairs, the animals initially struggled to find the relocated rewards. Yet a single session of offline rest outside the maze changed everything. After a one-hour break, the animals navigated directly to the correct locations, demonstrating an abrupt leap in performance.
It seemed at first like none of them learned, and then they went to this one-hour rest, offline, outside this maze. When they came back, they seemed to know them all. It felt like an ‘aha’ moment had occurred.
Dragoi, via Yale
