The Research Plan describes two experiments that will examine how spatial information is processed in the mammalian brain ? particularly in regards to navigation in three-dimensional (3-D) space. Previous studies have identified a population of neurons, referred to as head direction cells, that discharge as a function of the animal?s directional heading in the horizontal plane. HD cells have primarily been recorded in two-dimensional space. Different theories have postulated how they respond in 3-D space.
Aim 1 will test these theories by recording HD cells as an animal locomotes different routes on the surface of a 3-D cube. In particular, we will determine whether cell firing is comutative as the animal travels different routes from the floor up the vertical walls to the top surface. Each theory makes different predictions as how the cells will fire when the animal reaches the top surface. A second spatial cell type are grid cells in the entorhinal cortex. These cells fire when the animal is at multiple locations; the locations form a regular, repeating hexagonal pattern that forms a grid.
Aim 2 will assess how grid cells fire across two horizontal planes that occupy the same location in the environment, but are offset in the vertical plane. We will determine if the grid patterns between the two surfaces are in alignment or offset from one another. Knowing how grid cells respond under these conditions has important implications for understanding how the grid cell signal is generated. In sum, these studies will provide insight into how 3-D spatial information is organized and processed in the brain and will enhance our understanding of the functional role of HD and grid cells during navigation. The results have implications for human health and behavior. It is common for patients with vestibular disorders and patients with Alzheimer?s disease, a disease often associated with marked pathology in limbic system structures, to experience spatial disorientation to the extent that constant supervision is required. Learning how spatial information is processed in the rat brain will give us clues about the complex nature of spatial processes in humans.

Public Health Relevance

The results from these experiments will provide key information in understanding the basic neural mechanisms underlying spatial orientation in three dimensional space. Ultimately, we would like to develop a better neurophysiological understanding of how spatial orientation information is organized in the brain to enable an organism to navigate accurately. This information could then be used to develop effective treatments for spatial disorders such as vertigo, motion sickness, and navigational disorders. Further, it is common for patients with vestibular disorders, strokes in certain brain areas, and patients with Alzheimer's disease, a disease often associated with marked pathology in limbic system structures, to experience spatial disorientation to the extent that constant supervision is required. Learning how 3-D spatial information is processed in the rat brain will provide important clues about the complex nature of spatial processes in humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21NS106218-01A1
Application #
9668729
Study Section
Neurobiology of Learning and Memory Study Section (LAM)
Program Officer
Babcock, Debra J
Project Start
2018-09-01
Project End
2020-08-31
Budget Start
2018-09-01
Budget End
2019-08-31
Support Year
1
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code