Predictability of arousal in mouse slow wave sleep by accelerometer data
Fig 1
Schematic presentation of experimental procedure, data acquisition and morphological patterns in physiological dynamics associated with sleep stages and arousals.
(a) Histological analysis. After all behavioral procedures and data collection, all implanted C57-BL/6J mice were perfused and brain slices were obtained in order to confirm if electrodes were targeted in M1 and S1 cortical regions and in hippocampus CA1 sub-field as an inclusion criterion. (b) Surgical Matrix Electrode Implant. Under a isofurane anesthesia a rectangle was opened in cranial bones for allowing a 16-tungsten electrode matrix to be implanted in the skull with dental cement: eight electrodes were placed in the S1/M1cortex (layers 3-5) and another eight in the CA1 sub-field of hippocampus. (c) Electrophysiology record. One week after surgery, animals were submitted to a session of 12 hours continuous recording in a round open field maze. Simultaneous LFP and Accelerometer recordings were performed in the headstage using the Plexon system. The animals were allowed to perform their natural behaviors—including the sleep-wake cycle—during the recordings. (d) LFP and Accelerometer fluctuations. All channels of hippocampus, cortex and accelerometer were displayed in real time analysis in order to get track the quality of the signal recordings. (e) State map generation. Two-dimensional behavioral state maps were generated by plotting the according to specific spectral-band ratios (see Method section) to display the stage regions: SWS(red), REM (green) and wake (black). The blue is the transition stage (left). Also accelerometer data in the state map was used to isolate wake cluster (right). Raw LFP and EMG activity were also analyzed during periods of WK, SWS, and REM sleep predicted by the two-dimensional state map. (f) A typical AR fluctuation (intermediate) associated with the hypnogram (top) generated by identification of Waking (blue), SWS (red) and REM (green) sleep cluster separation and two zooms (bottom) of the raw accelerometer signal during SWS and awake states, which were selected here for visualization.