Biology subjects

Chrastil, E. R.

Publications and source records attributed to Chrastil, E. R..

3 recordsLinked to original sources

bioRxiv2023

Neuroanatomical changes observed over the course of a human pregnancy

Pregnancy is a period of profound hormonal and physiological change experienced by millions of women annually, yet the neural changes unfolding in the maternal brain throughout gestation have not been studied in humans. Leveraging precision imaging, we mapped neuroanatomical changes in an individual from preconception through two years postpartum. Pronounced decreases in gray matter volume and cortical thickness were evident across the brain, which stand in contrast to increases in white matter microstructural integrity, ventricle volume, and cerebrospinal fluid, with few regions untouched by the transition to motherhood. This dataset serves as the first comprehensive map of the human brain across gestation, providing an open-access resource for the brain imaging community to stimulate further exploration and discovery.

neuroscience↗

bioRxiv2023

Navigational systems in the human brain dynamically code for past, present, and future trajectories

Navigational trajectory planning requires the interaction of systems that include spatial orientation and memory. Here, we used a complex navigation task paired with fMRI pattern classification to examine head and travel direction tuning throughout the human brain. Rather than a single, static network, we report multiple simultaneous subnetworks that 1) have strong connections with both allocentric (world-centered) and egocentric (viewer-centered) movement trajectories, 2) change during the course of exploration, 3) code for past and future movements as well as the present direction, and 4) are strongest for individuals who convert their trajectories into egocentric movements once they have learned the environment. These findings shift our understanding of the neural processes underlying navigation from static structure-function relationships to a dynamic understanding of the multiple brain networks that support active navigation. The insights into the nature of individual navigation abilities uncovered here challenge the dominant framework of largely allocentric coding for successful navigation in complex environments, and replace this with a new framework that relies on multiple co-existing dynamic computations.

neuroscience↗

bioRxiv2022

Evidence for a travel direction signal in humans that is independent of head direction

We often assume that travel direction is redundant with head direction, but from first principles these two factors provide differing spatial information. Although head direction has been found to be a fundamental component of human navigation, it is unclear how self-motion signals for travel direction contribute to forming a travel trajectory. Employing a novel motion adaptation paradigm from visual neuroscience designed to preclude a contribution of head direction, we found high-level aftereffects of perceived travel direction, indicating that travel direction is a fundamental component of human navigation. Interestingly, we discovered a higher frequency of reporting perceived travel toward the adapted direction compared to a no-adapt control - an aftereffect that runs contrary to low-level motion aftereffects. This travel aftereffect was maintained after controlling for possible response biases and approaching effects, and it scaled with adaptation duration. These findings demonstrate the first evidence of how a pure travel direction signal might be represented in humans, independent of head direction.

neuroscience↗