A time-stamp mechanism may provide temporal information necessary for egocentric to allocentric spatial transformations.
Learning the spatial organization of the environment is essential for most animals' survival. This requires the animal to derive allocentric spatial information from egocentric sensory and motor experience. The neural mechanisms underlying this transformation are mostly unknown. We addressed this problem in electric fish, which can precisely navigate in complete darkness and whose brain circuitry is relatively simple. We conducted the first neural recordings in the preglomerular complex, the thalamic region exclusively connecting the optic tectum with the spatial learning circuits in the dorsolateral pallium. While tectal topographic information was mostly eliminated in preglomerular neurons, the time-intervals between object encounters were precisely encoded. We show that this reliable temporal information, combined with a speed signal, can permit accurate estimation of the distance between encounters, a necessary component of path-integration that enables computing allocentric spatial relations. Our results suggest that similar mechanisms are involved in sequential spatial learning in all vertebrates.
['Wallach|Avner|A|http://orcid.org/0000-0003-2345-2942', 'Harvey-Girard|Erik|E|', 'Jun|James Jaeyoon|JJ|', 'Longtin|André|A|http://orcid.org/0000-0003-0678-9893', 'Maler|Len|L|http://orcid.org/0000-0001-7666-2754']
D000200:Action Potentials D000818:Animals D020747:Calcium Channels, T-Type D000078663:Egocentrism D004555:Electric Fish D008954:Models, Biological D009038:Motion D009474:Neurons D013028:Space Perception D013788:Thalamus D013997:Time Factors D014795:Visual Pathways
electrosensation neuroscience path integration renewal process spike frequency adaptation thalamus time-coding