How History Gets Things Wrong by Alex Rosenberg

Author:Alex Rosenberg
Language: eng
Format: epub
Tags: theory of mind; mind reading; folk psychology; human evolution; fMRI; neuroscience; cognitive social psychology; the brain; hippocampus; entorhinal cortex; memory; neo-cortex; Kandel; O’Keefe; Edvard and May-Britt Moser; History; biography; narrative; story telling; understanding; Watson (the IBM computer); Kissinger; Talleyrand; Congress of Vienna; Jared Diamond; Gerald Mackie; Alexander Solzhenitsyn
Publisher: The MIT Press

Figure 8.3

(A) Different-sized dots identify the grid cells sensitive to larger and larger spaces in the rat’s environment. (B) The waves represent “theta wave” oscillations from the grid cells that combine at the place cells to locate the rat. From Kubie and Fox, 2015, fig. 2.

The neurons in the rat’s brain fire almost all the time. In the hippocampus, the rate of firing is between 4 and 8 cycles per second per cell; these firings are called “theta waves.” Kubie and Fox found that when the cells fire together, they produce phase oscillations in these theta waves (the blue waves in figure 8.3). Oscillations in theta waves produced by the grid and other cells in the medial entorhinal cortex combine to generate oscillations in the place cells (Kubie and Fox, 2015). O’Keefe discovered that grid cells electrochemically signal the place cells in two ways: by firing at higher rates and by the timing of individual bursts of firing against a background oscillation of circuitry firing (O’Keefe, 2014).

Figure 8.4 (plate 6) will help make this clear. In it are five place cells, N1–N5, each with a distinct “place field”—the location in the box or track where each fires. The larger circuitry in which they figure fires at a theta frequency. But each of N1–N5 fires at a slightly higher frequency and at a slightly later phase of the theta firing frequency when its particular place field in the box is crossed. The farther along in the place cell’s place field, the greater the phase shift of its firing relative to the theta oscillations. The phase shift registers the rat’s location.

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