Fig. 3: Revealing 2-D toroidal representations in entorhinal ensembles during 1-D VR navigation.
From: Uncovering 2-D toroidal representations in grid cell ensemble activity during 1-D behavior
a Campbell et al. used Neuropixel probes to record from the MEC while head-fixed mice engaged in a VR task showing a continuously repeating linear track of 400 cm with five evenly spaced visual cues with a water reward at the end (baseline trials)14. b Correlation distance matrices (as in Fig. 1b) for two mice, with indicated clusters (‘M’, ‘M1–M3’). c Barcodes (as in Fig. 1e) from ensemble activity of M1, mouse J5 (n = 43 cells), during baseline, contrast (visual cue contrast manipulations) and dark trials. d Four examples of single-cell responses: 1-D VR linear track auto-correlation (left, ‘Acorr’) and tuning to decoded toroidal position during baseline (B), contrast (C) and dark (D) sessions, as in Fig. 2e. e Toroidal phase comparison between sessions for M1 mouse J5 (as in Fig. 2f; left, n = 43 cells) and mean phase distance for each toroidal ensemble ("Or") with more than one session vs shuffled mean ("Sh") (right, ± S.E.M., n = 25, (I1 #2 M1), 49 (I1 #2 M2), 65 (I1 #2 M1), 46 (H3), 24 (I1 #1), 28 (J1), 43 (J5 #1), 50 (J5 #2 M1), 43 (J5 #2 M3) and 25 (J5 #3) cells. f Left, 3-D toroidal parametrization of the 2-D decoded angles for the first third of baseline trials of the three ensembles of mouse I1 (n = 25, 49 and 65 cells) as indicated in (b) Note that all regions of the torus seem to be visited despite the animal running along a straight track. Right, unwrapped toroidal position for each module showing alignment of the unidirectional movement across module during dark session. g Virtual track position (y-axis) as a function of time (x-axis) colored by the 2-D toroidal position for each module as in b (indicated by color map). Bottom, gain (of optical flow) and contrast values during session. h Violin plot of decoded toroidal path lengths per trial across all animals (y-axis) categorized by gain value (x-axis, n = 1230 (gain 1), 87 (0.8), 36 (0.7), 23 (0.6) and 80 (0.5) trials, normalized by mean length at baseline trials. The black line indicates the mean value, and the dashed lines expected trial length if strictly aligned to the distance on the wheel (dark green) or to the VR track (cyan). Shading shows trial distribution and gray lines the max-min range. Source data are provided as a Source Data file.
