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Abstract:
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Previous research has shown that head direction (HD) cells located within the anterior dorsal thalamus (ADN) will discharge maximally when a rodent’s head is facing toward the cells’ preferred directions along the horizontal plane. These cells will respond to the position of visual landmarks and are thought to contribute to the brain network that allows accurate navigation. It has also been discovered that distal visual cues will exert more control over the HD system than proximal visual cues when the position of these cues are in conflict. The present study sought to determine whether a complex auditory cue, comprised of both a proximal and a distal tone, would exert landmark control over HD cells, and whether this brain circuitry would show a bias toward a distal auditory cue over a proximal auditory cue. Three rats were implanted with anterior thalamic recording electrodes and the firing rates of HD cells were examined while the animal moved freely within a triangular arena. During the initial testing sessions, the position of the distal and proximal auditory cues were manipulated together to determine whether auditory landmarks would control HD cell directional activity. For the last testing session the position of the auditory cues were flipped, creating a conflict between the distal and proximal cues. The data suggest that auditory cues do not exert stimulus control over HD cells, and whether they are located proximal or distal to the animal is irrelevant. |
