Place field repetition and purely local remapping in a multicompartment environment.
Bottom Line: Some studies report that place cells can disambiguate different compartments, while others report that they do not.Second, this repetition does not diminish with extended experience.Third, remapping was found to be purely local for both geometric change and contextual change.
Affiliation: Department of Cognitive, Perceptual and Brain Sciences, Division of Psychology and Language Sciences, Institute of Behavioural Neuroscience, University College London, UK.Show MeSH
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Mentions: Accordingly, we revisited the repeating-compartment experiment with place cells, using an environment with 4 compartments, instead of only 2, in which rats would forage rather than run ballistically (Fig. 1A). We expected that if the path integration informs place cells of compartment identity, the place fields should discriminate between compartments (Fig. 1D). Conversely, if the path integrator “resets” anew in every compartment, then place fields should have the same location in each compartment (Fig. 1E). In some experiments place cells have been found to discriminate different contexts by differences in their firing rate (rate coding), while maintaining their field location (Hayman et al. 2003; Leutgeb et al. 2005). Thus, place cells might be predicted to express a rate-based discrimination across compartments (Fig. 1F). As we show, place cells repeated their firing locations across these 4 compartments, even after extensive experience, and demonstrated some degree of rate-based discrimination. In addition, there was a prominent clustering of activity around the doorways of the compartments, suggesting that doorways are a particularly salient environmental feature. We then tested whether firing patterns provide a global or local code of the environment by examining whether changes to parts of the environment altered firing in connected but more distant regions. Purely local firing alterations were observed. Thus, in a free foraging situation, the location of place fields appears to be determined not by path integration but by purely local factors. We suggest that this may be due to resetting of the grid fields as the animals pass through doorways.Figure 1.
Affiliation: Department of Cognitive, Perceptual and Brain Sciences, Division of Psychology and Language Sciences, Institute of Behavioural Neuroscience, University College London, UK.