Theta and Learning: Dorsal and Ventral Hippocampal Theta Oscillation Respond Differently to Learning

Rhythmic oscillations within the hippocampus are thought to synchronize various subregions during learning, maximizing efficiency of the neural circuits. In rats, the most prominent oscillation is hippocampal theta. Theta is known to be modulated by an animal’s velocity, but it has also been shown to change in response to cognitive demands. To determine if theta is important for learning and memory, EEG recordings were examined for changes in theta related to the decision point of a spatial or non-spatial T-maze task. Additionally, a straight runway served as a control to verify the consistent relationship between velocity and theta during a task with no cognitive demands. Dorsal theta increases during decision points of a spatial task, while ventral theta increases during decision points of a non-spatial task. The relationship between theta and velocity was consistent during the runway task. Once the animal was familiar with the task, theta no longer changed during the decision. The data suggests that theta is responsive to learning, independent of changes in velocity