(a) Schematic showing the way hippocampal place cell activity represents possible trajectories in subsequent theta cycles during navigation. (b-f) Schemes for representing a target probability …
(a) Example spiking activity of 250 cells (top) and raw (black) and theta filtered (green) local field potential (bottom) for 6 consecutive theta cycles (vertical lines). (b) Place fields of 6 …
(a) Motion trajectory of the simulated rat (gray, 10 s) together with its own inferred and predicted most likely (mean) trajectory segments (colored arrows) in five locations separated by 2 s …
(a) Graphical model of the processes underlying the generation of the simulated animal’s trajectory. Arrows represent the individual steps in the generative process, orange arrows highlight sensory …
(a-h) Motion profile of the simulated animal. (a) Histogram of the running speed. Orange vertical line indicates the mean of the distribution. (b) Auto-correlation of the running speed. Orange line …
(a-e) Place cell activity in the simulated data using mean encoding. (a) Histogram of the average firing rate of the 200 simulated neurons. Numbers indicate the average firing rate across cells and …
(a) Decision-tree for identifying the encoding scheme. (b) Schematic of encoding a high-uncertainty (left) and a low-uncertainty (right) target distribution using the product scheme with 4 neurons. …
(a) The 110 tuning curves from the example session R1D2 used in this analysis as basis function (Equation 36), with . (b) Representing distributions of increasing uncertainty in the product …
(a) Location and direction-aligned motion trajectories and 0.5 confidence interval ellipses for . (b) Bias and spread of motion trajectories as a function of time in an example session. (c) Left: …
(a) Normalized firing rate of all putative excitatory neurons recorded in a single session (Achilles, up) ordered by the location of the peak activity on rightward runs from a previously published …
(a) Schematic of encoding a narrow (left) and a wide (right) distribution with spike-based DDC using four neurons. Intuitively, the standard deviation (SD) is represented by the diversity of the …
(a) Illustration of the problem of decoding bias. In the DDC scheme, the firing rate of the neurons is proportional to the overlap between the target distribution and the basis functions of the …
No evidence for DDC code when decoding spikes using the estimated basis functions instead of the empirical tuning curves. (a-b) Estimated standard deviation of the DDC-decoded distribution from …
(a) Similar to Figure 5c, d but also including data for the product scheme. Estimated standard deviation of the DDC-decoded distribution from spikes at early, mid and late theta phases using the …
(a) To discriminate sampling from mean encoding, we defined the EV-index which measures the magnitude of cycle-to-cycle variability (CCV) relative to the trajectory encoding error (TEE). (b) …
(a) Cumulative distribution of CCV (dashed) and TEE (solid) for early, mid, and late theta phase (colors) in the mean scheme using simulated data. Note the logarithmic x axis. (b) Mean CCV and TEE …
(a) Violin plots showing that the distribution of the running speeds are highly overlapping in home (goal directed navigation) and away (random foraging) trials in all recorded sessions. Symbols …
(a) Examples of sampled trajectories with positive (left) and negative (right) correlation between the direction of subsequent trajectory endpoints (squares) relative to the current position …
Similar to Figure 7d and f, using the simulated animal’s internal position and motion direction estimate to calculate the relative direction of the encoded trajectory endpoints in each theta cycle. …
Symbol | Meaning |
---|---|
index of time step in the generative model measured as the number of theta cycles | |
position at theta cycle n (two-dimensional) | |
sensory input (two-dimensional) | |
motor command (two-dimensional) | |
planned position (-dimensional) | |
planned position (two-dimensional) | |
past sensory input until theta cycle n | |
mean of the filtering posterior | |
covariance of the filtering posterior | |
theta phase | |
trajectory of the animal around theta cycle n | |
posterior mean trajectory at theta cycle n | |
posterior variance of trajectory at theta cycle n | |
trajectory sampled from | |
encoding basis function of cell i - firing rate as a function of the encoded position | |
empirical tuning curve of cell i - firing rate as a function of the real position | |
firing rate of cell i | |
spikes recorded in theta cycle n encoding trajectory xn | |
trajectory decoded from the observed spikes assuming direct encoding (Equation 18) | |
estimated trajectory mean assuming DDC encoding (Equation 19) | |
estimated trajectory variance assuming DDC encoding (Equation 19) |
Parameter | Strong + | Weak + | Independent | Weak - | Strong - |
---|---|---|---|---|---|
(slope) | -8 | -5 | 0 | 5 | 5 |
(threshold) |
p-values for panels f,g and k were calculated using a one sample t-test. p-values for panel l were estimated by bootstrapping.
Panel: f | |||||||
regular | jitter: 0 | 5 | 10 | 20 | 30 | 40 | |
8.9e-10 | 1e-06 | 4.4e-07 | 1.5e-07 | 1e-05 | 5.7e-07 | 1.8e-07 | |
panel: g | |||||||
regular | jitter: 0 | 5 | 10 | 20 | 30 | 40 | |
0.0001 | 4e-15 | 3.9e-15 | 1e-13 | 3.4e-11 | 1.5e-11 | 2.4e-06 | |
panel: k | |||||||
rat1 day1 | rat1 day2 | rat2 day1 | rat2 day2 | rat3 day1 | rat3 day2 | rat4 day1 | rat4 day2 |
5e-05 | 2.5e-18 | 2.5e-05 | 0.0001 | 2.1e-10 | 2.8e-07 | 1.4e-08 | 2.4e-06 |
panel: l | |||||||
rat1 day1 | rat1 day2 | rat2 day1 | rat2 day2 | rat3 day1 | rat3 day2 | rat4 day1 | rat4 day2 |
<0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
p-Values for panels e,f and j were calculated using a one sample t-test. p-Values for panel k were estimated by bootstrapping.
Panel: e | |||||||
regular | jitter: 0 | 5 | 10 | 20 | 30 | 40 | |
1.8e-05 | 1.4e-05 | 9e-05 | 4.8e-05 | 0.0016 | 0.0025 | 0.0006 | |
panel: f | |||||||
regular | jitter: 0 | 5 | 10 | 20 | 30 | 40 | |
0.01 | 4e-05 | 7e-05 | 0.0007 | 0.0006 | 0.014 | 0.16 | |
panel: j | |||||||
rat1 day1 | rat1 day2 | rat2 day1 | rat2 day2 | rat3 day1 | rat3 day2 | rat4 day1 | rat4 day2 |
0.0018 | 4.5e-09 | 6e-08 | 4.9e-07 | 3.7e-19 | 4e-11 | 3.3e-25 | 2.4e-07 |
panel: k | |||||||
rat1 day1 | rat1 day2 | rat2 day1 | rat2 day2 | rat3 day1 | rat3 day2 | rat4 day1 | rat4 day2 |
<0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |