The Robotics Institute

Carnegie Mellon Robotics Institute

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Abstract

The firing fields of the ?rid cells?found in the rat dorsocaudal medial entorhinal cortex (dMEC) present a surprising pattern of context-independent regularity. We use computational means to analyze and validate the geometric and algebraic invariant properties of the firing fields, leading to a context invariant spatial map. Our method computes the specific symmetry group implicitly associated with the spatial map, and quantifies the regularity of the firing fields to achieve a symmetry-based clustering of two different types of ?rid cells.?This quantified regularity makes spatial mapping more computationally efficient and suggests a way to use the dMEC firing patterns to estimate the probabilty of the rat being located at different points in the room. Finally, general properties of context-independent population codes are suggested. Namely, context-independent population codes gain robustness by introducing uncertainty and ambiguity.

Notes

Associated Center(s) / Consortia: Vision and Autonomous Systems Center and Medical Robotics Technology Center

Associated Lab(s) / Group(s): Biomedical Image Analysis

Number of pages: 16

Text Reference

Erick Chastain and Yanxi Liu, "Firing Fields of Dorsocaudal Medial Entorhinal Cortex as a Context-Independent Spatial Map," tech. report CMU-RI-TR-06-02, Robotics Institute, Carnegie Mellon University, January, 2006

BibTeX Reference

@techreport{Liu_2006_5290,
   author = "Erick Chastain and Yanxi Liu",
   title = "Firing Fields of Dorsocaudal Medial Entorhinal Cortex as a Context-Independent Spatial Map",
   booktitle = "",
   institution = "Robotics Institute",
   month = "January",
   year = "2006",
   number= "CMU-RI-TR-06-02",
   address= "Pittsburgh, PA",
}

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