Stability of subicular place fields across multiple light and dark transitions.
Take-home message: subicular place cells have larger and coarser place cells than CA1 cells; a plurality of subicular cells are stable across multiple light-dark-light transitions, however (not too dissimilar to CA1 cells). [Download the paper.]
Eur J Neurosci. 2010 Aug;32(4):648-58. doi: 10.1111/j.1460-9568.2010.07308.x.
Although hippocampal CA1 place cells can be strongly modulated by visual inputs, the effect of visual modulation on place cells in other areas of the hippocampal formation, such as the subiculum, has been less extensively explored. Here, we investigated the role of visual inputs on the activity of subicular place cells by manipulating ambient light levels while freely-moving rats foraged for food. Rats were implanted with tetrodes in the dorsal subiculum and units were recorded while the animal performed a pellet-chasing task during multiple light-to-dark and dark-to-light transitions. We found that subicular place fields presented a somewhat heterogeneous response to light-dark transitions, with 45% of pyramidal units showing stable locational firing across multiple light-dark-light transitions. These data suggest that visual inputs may participate in spatial information processing by the subiculum. However, as a plurality of units was stable across light-dark transitions, we suggest that the subiculum supports, probably in association with the grid cells of theentorhinal cortex, the neurocognitive processing underlying path integration.
PMID: 20718857 [PubMed – indexed for MEDLINE]