The generalization of prior uncertainty during reaching.

Bayesian statistics defines how new information, given by a likelihood, should be combined with previously acquired information, given by a prior distribution. Many experiments have shown that humans make use of such priors in cognitive, perceptual, and motor tasks, but where do priors come from? As people never experience the same situation twice, they can only construct priors by generalizing from similar past experiences. Here we examine the generalization of priors over stochastic visuomotor perturbations in reaching experiments. In particular, we look into how the first two moments of the prior--the mean and variance (uncertainty)--generalize. We find that uncertainty appears to generalize differently from the mean of the prior, and an interesting asymmetry arises when the mean and the uncertainty are manipulated simultaneously.

Novel acoustic stimuli can alter locomotor speed to hippocampal theta relationship.

Hippocampal theta (6-12 Hz) plays a critical role in synchronizing the discharge of action potentials, ultimately orchestrating individual neurons into large-scale ensembles. Alterations in theta dynamics may reflect variations in sensorimotor integration, the flow of sensory input, and/or cognitive processing. Previously we have investigated septotemporal variation in the locomotor speed to theta amplitude relationship as well as how that relationship is systematically altered as a function of novel, physical space. In the present study, we ask, beyond physical space, whether persistent and passive sound delivery can alter septal theta local field potential rhythm dynamics. Results indicate pronounced alterations in the slope of the speed to theta amplitude relationship as a function of sound presentation and location. Further, this reduction in slope habituates across days. The current findings highlight that moment-to-moment alterations in theta amplitude is a rich dynamic index that is quantitatively related to both alterations in motor behavior and sensory experience. The implications of these phenomena are discussed with respect to emergent cognitive functions subserved by hippocampal circuits.