Supplementary Materials

Persistence of neuronal representations through time and damage in the hippocampus

Walter G. Gonzalez, Hanwen Zhang, Anna Harutyunyan, Carlos Lois

Materials/Methods, Supplementary Text, Tables, Figures, and/or References

Download Supplement
  • Materials and Methods
  • Supplementary Text
  • Figs. S1 to S21
  • Tables S1 to S4
  • Captions for Movies S1 to S9
  • References

Images, Video, and Other Media

Movie S1
(Top row) Unprocessed 15 second recording of the left hemisphere in one animal and right hemisphere in another while running in the linear track. (Bottom row) Temporally down-sampled (4-fold) and spatially smoothed 15 second video of CA1 activity while two different mice run in the linear track. Left hemisphere is shown on the left panel and right hemisphere on the right.
Movie S2
Simultaneous bilateral recording of a mouse while running in the linear track. Image is background subtracted. Left hemisphere shown on the left and right hemisphere on the right. Neuronal activity extracted from this animal is shown on figure 1e.
Movie S3
(Left) Correlation image of CA1 activity across two months not motion corrected, each frame represents a 30-minute session (home cage exploration and linear track), 45 sessions in total. (right) The same data but motion corrected. The sudden shift between session 14 and 15 is due to the 10-day period of no task.
Movie S4
Motion corrected correlation image of CA1 activity in one mouse recorded for 8 months (76 sessions, data from home cage recordings and linear track). Sessions between 33 and 42 not included due to abnormal activity due to damage prevent accurate registration using individual sessions. The data presented in the manuscript is motion corrected and analyzed in a different manner (see methods).
Movie S5
Direction specific burst activity in CA1 in three mice after damage. Note the continuously fluorescent cells, these cells will eventually become inactive. All three mice have a leftward direction burst in the video, but the direction could change between days (see figure S11 and S13).
Movie S6
The same data used in movie 5 but at a closer view showing how some neurons persist in the field of view while other stop being active after the CA1 lesion.
Movie S7
(Top left) Changes in the topology of a network graph of CA1 activity in a mouse in its home cage across days. Note the small cluster of nodes leaving and joining the larger cluster. (Top right) Changes in the topology of a network graph of CA1 activity while the mouse becomes familiar with the linear track. (Bottom) The same data but nodes are colored by cell groups determined on the last day once the mouse is familiar with the environment. The video proceeds in reverse order, trained periods are shown in the first frames and learning are the last. Note that modules retain a large portion of neurons across days but eventually fall apart during learning. Also, the diffusion of colors indicates that some neurons can change their role in the network.
Movie S8
The number of edges between clusters can be used to extract the sequence of events in the behavior (see figure S21). In this video, we show that a sequential behavior has a clear sequential activity in the graph. Cell groups are shown in color once at least 5 neurons in the group are active, only on cell group per frame shown.
Movie S9
In some cases, we observe that sequences in a graph can bifurcate, activating different groups. In graph shown in this video we have at the right side of the maze four cell groups: cell group 3 shown in light blue (time cells), cell group 10 in dark blue, 11 in black, and 7 in green (place cells). Using the graph connectivity, we observe that the pathway 3-10-7 and 3-11-7 have very similar transition probabilities. Here we show 20 frame segments of behavior centered at when either cell group 10 (left video) or cell group 11 (right) are active. We observe that each of these sequences correspond to turning counterclockwise or clockwise.