Hippocampal Pyramidal Cells

The electric cells then coordinate their nurture to produce a memory. Evidence for this comes from the fact that a point cell has the same arc field every fourth dimension it is introduced into the same surroundings; and the paper bag of a particular cell in one environment does not predict its firing in another environment. New maps be made in each cell in each new environment it is exposed to, and they do not interfere with previous maps.

It has been set that a form of long-term potentiation (LTP), the NMDA- sensory receptor dependent LTP, occurs in the Schaffer substantiative pathway connecting CA1 cells with CA3 cells (2122). Disrupting this type of LTP disrupts the formation of spacial memory. Kentros et al investigated this theme using ([+ or -])-3--(2-carboxypiperazin-4-yl)propyl-1-phorphoric acid (CPP) as a receptor antagonist to test three things: if blockade of the NMDA sites degrades the position firing patterns of the place cells; if it inhibits the formation of new spatial memories; and if it affects the perceptual constancy of freshly formed place fields, either short-term or long-term.

provide of this get showed that blocking of the NMDA sites had no effect on previously formed maps, or creating maps of new environments for the short-term, but it abolished the long-term stability of maps of new environments made after blockage (2123). This must bastardly that the place cells still receive spatial nurture from approximately other source when the NMDA-receptors are

Wiebe, S. P., & Staubli, SU. V. (1999). Dynamic filtering of recognition memory codes in the hippocampus. The Journal of Neuroscience, 19(23):10562-10574.

The study by Wiebe and Staubli (1999) favors the argument that the place cells of the hippocampus do not take part in general memory government agency since the majority of odor and match/nonmatch cells were related to spatial correlates (10571). Also, spatial encoding was twice as prevalent in these cells as match/nonmatch, again supporting the view that spatial fixture is the most important function of these cells. The delay activity ascertained also appeared to be connected to spatial representations.

Although these cells may be able to respond to other sensory input, they still are mainly responsible for processing spatial cues. There appears to be an inverse distribution of cue- discriminating activity in the ample with CA1>CA3>DG compared to the kinship found in the test, which showed GDG>CA3>CA1. In the match/mismatch comparison, is was absolve that DG>CA3>CA1, which the authors claim is the first demonstration of the transformation of cue-specific stimuli from the parahippocampal cortices into cue-general stimuli in the CA1 cells in the match/nonmatch arena. Odor specific activity was restricted to divergent subfields in the hippocampus.

The experiments of Kentros et al (1998) suggested that place cells can form spatial maps even when NMDA receptor activation is blocked, but Brun et al (2002) looked to inspect if these cells could receive input from a source other than the intrahippocampal associatory network in the CA3 area. They questioned how distinct hippocampal circuits take part in this information transfer organisation, and what role each plays in the system (2243). Place fields still exist after selective dentate gyrus lesions, and they are not affected by moderately reducing area CA3 neuronal function, suggesting positional information may come to the place cells from the entorhinal cortex.

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