Representation of Geometric Borders in the Entorhinal Cortex

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Science  19 Dec 2008:
Vol. 322, Issue 5909, pp. 1865-1868
DOI: 10.1126/science.1166466
  • Fig. 1.

    Examples of border cells in the MEC and adjacent parasubiculum. (A) Sagittal Nissl-stained section showing a representative recording location in the MEC (red dot, recording location; rat number and hemisphere (R, right) are indicated; see fig. S1 for all other recording positions). (B) Color-coded rate maps for 12 border cells. Red is maximum, dark blue is zero. Pixels not covered are white. Animal numbers (five digits), cell numbers (two or three digits), and peak firing rates are indicated above each panel. Cells 287 and 677 did not pass the criterion for border cells because the fields were located at some distance from the wall; the number of such cells was fewer than 10. See fig. S2 for the complete set of rate maps, trajectories, and directional tuning curves, and representative waveforms and tetrode clusters. (C and D) Scatter plots showing correlation between border scores and grid scores (C) or head-direction scores (D) (12). Each dot in the scatter plot corresponds to one cell (red, border cells; blue, grid cells; green, head-direction cells; gray, cells not passing any criterion, including cells with high spatial or directional scores but low stability; double-colored dots, cells that satisfy criteria for two cell classes). Horizontal lines indicate thresholds for grid and head-direction cells.

  • Fig. 2.

    Border cells express proximity to boundaries in a number of environmental configurations. (A to D) Color-coded rate maps for a representative border cell in boxes with different geometric configurations (cell 205 of rat 12018). Each panel shows one trial. Symbols are as in Fig. 1B. (A) The border field follows the walls when the square enclosure is stretched to a rectangle. (B) Introducing a discrete wall (white pixels) inside the square causes a new border field to appear (middle panel). The new field has the same orientation relative to distal cues as the original field on the peripheral wall. (C) Border fields persist after removal of the box walls (middle panel). Without walls, the drop along the edges was 60 cm. (D) Preserved firing along borders across rooms and geometrical shapes. All trials in (D) were recorded in a different room than those in (A) to (C). The conditions favor hippocampal global remapping between rooms and rate remapping within rooms (12, 16, 22) (fig. S9).

  • Fig. 3.

    Border cells, grid cells, and head-direction cells respond coherently to environmental manipulations. (A) Rate and head-direction maps for two border cells (top two rows), two grid cells with some head-directional modulation (middle two rows), and two head-direction cells (bottom two rows) recorded simultaneously before and after the rotation of a polarizing cue card (left and right columns, 0°; middle column, 90°). The polar plots show firing rate as a function of head direction (black traces) and the time that the rat faced each direction (blue traces). Peak firing rate is indicated. (B) Rate maps and polar plots for two border cells (top two rows), three grid cells (middle three rows), and one head-direction cell (bottom row) in two different rooms. The cells were recorded simultaneously.

Additional Files

  • Representation of Geometric Borders in the Entorhinal Cortex
    Trygve Solstad, Charlotte N. Boccara, Emilio Kropff, May-Britt Moser, Edvard I. Moser

    Supporting Online Material

    This supplement contains:
    Materials and Methods
    SOM Text
    Figs. S1 to S12

    This file is in Adobe Acrobat PDF format.

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