Fig. 5: Primary and derivative correlates have different firing properties.
From: Angular and linear speed cells in the parahippocampal circuits
Comparison of firing properties between cells coding for primary correlates – grid cells (yellow) and HD cells (blue) – and derivative correlates – speed cells (red) and AHV cells (pink). Vertical dashed lines indicate median values. Histograms on the left depict primary and derivative averages for each firing property considered. a Distribution of the average firing rates (bin width: 0.5 Hz). Medians: grid cells 1.38, HD cells 1.06, speed cells 2.18 Hz, AHV cells 2.01 Hz. b Distribution of the peak firing rates calculated as the 5th percentile of the firing rate distribution of each cell (bin width: 1 Hz). Medians: grid cells 1.65 Hz, HD cells 1.25 Hz, speed cells 3.4 Hz, AHV cells 3.25 Hz. c Distribution of the average inter-spike interval (bin width: 0.1 s). Medians: grid cells 0.71 s, HD cells 0.9 s, speed cells 0.45 s, AHV cells 0.48 s. d Distribution of the proportion of tuning curve bin values above the average firing rate (bin width: 0.05, N = 839). Medians (+/− SEM): grid cells 0.26, HD cells 0.28, speed cells 0.7, AHV cells 0.55. Note that motion cells show a larger average and peak firing rate, as well as a lower average inter-spike interval. This difference may be related to the nature of the coding: static cells use ‘place like’, sparse coding, while motion cells have a monotonic, dense response profile.
