Figure 3.
Calcium Response of Layer 2/3 and Layer 5 PT Neurons in Motor Cortex Scales Linearly with Amplitude of Spontaneous Turns
(A) Top: calcium activity of one layer 2/3 neuron that was preferentially active during contraversive turns (black line) and one layer 2/3 neuron that was preferentially active during ipsiversive turns (gray line). Bottom: the mouse’s rotational acceleration. Times of positive acceleration mark contraversive turns (blue line and shading) and negative values mark ipsiversive turns (red line and shading).
(B) Average change in fluorescence aligned on contraversive (blue) and ipsiversive (red) turns throughout training (days 1 to 8) for the two neurons shown in (A). Shading indicates SEM over turns (number of contraversive turns: n = 1,654; ipsiversive turns: n = 1,668).
(C) To record the activity of layer 2/3 excitatory neurons, we injected AAV2/1-EF1α-GCaMP6f into vGAT-Cre x ROSA-LSL-tdTomato mice (n = 8).
(D) We split all spontaneous turns recorded throughout training (days 1 to 8) into bins of high (black line) and low (gray line) acceleration. Shading indicates SEM over turns (number of turns for high acceleration bin: n = 6,174; low acceleration bin: n = 14,018).
(E) Larger turns were associated with higher neuronal activity. Average population activity of layer 2/3 neurons for the turns shown in (D) (n = 1,154 neurons). Colors as in (D). Shading indicates SEM over neurons.
(F) Average population activity of layer 2/3 neurons as a function of acceleration of the spontaneous turn. Error bars indicate SEM over neurons (n = 1,154). Dashed black line is a linear fit to the data. Shading marks bins used for the turning and activity traces in (A) and (B). ∗∗∗p < 10−3, R2 = 0.08, n = 1,154 neurons; linear trend analysis (see STAR Methods). n.s., not significant, lowest bin is not different from zero; Student’s t test.
(G) To record the activity of layer 5 PT neurons, we injected conditional AAV2/1-DIO-EF1α-GCaMP6f into Sim1(KJ18)-Cre mice (n = 11 mice).
(H) As in (D), but for the layer 5 PT experiments (number of turns for high acceleration bin: n = 5,764; low acceleration bin: n = 21,865).
(I) As in (E), but for layer 5 PT neurons (n = 560 neurons).
(J) As in (F), but for layer 5 PT neurons. ∗∗∗p < 10−3, R2 = 0.04, n = 560 neurons; linear trend analysis (see STAR Methods).