Fig. 4: Wireless neural recording of freely moving mouse.

a Schematic illustration of approximate locations of neural probes, primary visual cortex (blue) and hippocampus (green). Brain image was from Allen Mouse Brain Atlas. b Schematic illustration showing the behavior of mouse in T-maze, including the active movements and head-rotation motions. c Representative sequential snapshots of a freely moving mouse in T-maze for ten times of trials. Scale bars, 5 cm. d Representative single-unit traces and spike raster of the hippocampus CA1 and the primary visual cortex L6 regions during the T-maze test. Scale bars, 300 µV (vertical) and 100 ms (horizontal). Local field potential and superimposed theta waves (e), the corresponding theta angle (f), and single-unit trace (g) recorded from CA1 region during the active movement of mouse. Local field potential and superimposed theta waves (h), the corresponding theta angle (i), and single-unit trace (j) recorded from CA1 region during the standstill state of mouse. k PCA-clustered single-unit spikes recorded in CA1 region. Scale bars, 100 µV (vertical) and 1 ms (horizontal). Shaded regions represent 95% confidence intervals. l Circular distribution of theta angles for the firing events of each neuron recorded in CA1. m Distribution of single-unit spikes to theta phase angle. Black lines represent a theta cycle. n PCA-clustered single-unit spikes recorded in L6 region. Scale bars, 100 µV (vertical) and 1 ms (horizontal). Shaded regions represent 95% confidence intervals. Representative local field potential and corresponding spike raster of PCA-clustered neurons during left-turn task of mouse (o) and right-turn task of mouse (p). Red lines are linear fit of LFP signals. q Average spike ratio of PCA-clustered neurons between left-turn and right-turn tasks for five times of trials. Error bars represent the standard deviation (n = 5 independent left- and right-turn experiments of the mouse).