Head direction cell firing properties and behavioural performance in 3-D space.
Previous studies have identified a population of neurons in the rat brain that discharge as a function of the animal's directional heading in the horizontal plane, independent of their location and on-going behaviour. Most studies on head direction (HD) cells have explored how they respond in two-dimensional environments within the horizontal plane. Many animals, however, live and locomote in a three-dimensional world. This paper reviews how HD cells respond when the animal locomotes on a vertical surface or inverted on a ceiling. We found that HD cells fire in a normal, direction-dependent manner when the rat is in the vertical plane, but not when the animal is inverted. Recent behavioural studies reported that rats are capable of accurately performing a navigational task when inverted, but only when the task was simple and started from not more than one or two entry points. Probe trials found that they did not have a flexible, map-like representation of space when inverted. The loss of the directional signal when the animal is in an inverted orientation may account for the absence of the map-like representation. Taken together, these findings indicate that a normal otolith signal contributes an important role to HD cell discharge.
Taube
Jeffrey S
JS
Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, USA. jeffrey.taube@dartmouth.edu
D000818:Animals; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D051379:Mice; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D051381:Rats; D013028:Space Perception / Q000502:physiology*