Speed modulation of hippocampal theta frequency and power predicts water maze learning

Theta oscillations in the hippocampus have many behavioural correlates, with the magnitude and vigour of ongoing movement being the most salient. Many consider correlates of locomotion with hippocampal theta to be a confound in delineating theta contributions to cognitive processes. But, theory and empirical experiments suggest theta-movement relationships are important if spatial navigation is to support higher cognitive processes. In the current study, we tested if variations in speed modulation of hippocampal theta can predict spatial learning rates in the water maze. Using multi-step regression, we find the magnitude and robustness of hippocampal theta frequency versus speed scaling can predict water maze learning rates. Using generalised linear models, we also demonstrate that speed and water maze learning are the best predictors of hippocampal theta frequency and power. Theta oscillations recorded from the supramammillary area showed much weaker, or non-existent, relationships, which supports the idea that hippocampal theta has specific roles in speed representation and spatial learning. Our findings suggest movement-speed correlations with hippocampal theta frequency may be actively used in spatial learning.