Striatal versus hippocampal representations during win-stay maze performance.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Behavioral Neuroscience

Background:

• The striatum and hippocampus are traditionally viewed as separate memory systems guiding different behaviors.
• Some studies suggest overlapping neuronal encoding of spatial information in both structures.

Purpose of the Study:

• To investigate the neural coding of spatial information and behavioral strategies in the dorsal hippocampus and striatum.
• To determine if spatial working memory demands alter neural representations in these regions.

Main Methods:

• Simultaneous electrophysiological recordings from the dorsal hippocampus and multiple striatal subregions in rats trained on a win-stay radial maze task.
• Analysis of neuronal firing patterns during maze navigation, choices, and reward delivery across different training stages.

Main Results:

• Hippocampal neurons predominantly exhibited place-cell firing, active at specific spatial locations.
• Striatal neurons fired at discrete points within trials, independent of spatial position, even in medial subregions.
• No evidence of place-cell-type firing or trajectory encoding was found in the striatum, regardless of training stage or hippocampal theta rhythm entrainment.

Conclusions:

• The dorsal hippocampus utilizes a spatial representation for information processing, not significantly altered by spatial working memory.
• The striatum does not rely on a spatial foundation for its neural coding, even when cooperating with the hippocampus on spatial strategies.
• Strategy shifts towards striatum-dependent behavior may be resolved by mechanisms beyond changes in hippocampal or striatal single-cell representations.