Journal: Cerebral Cortex (New York, NY)

Article Title: Robust Long-Range Coordination of Spontaneous Neural Activity in Waking, Sleep and Anesthesia

doi: 10.1093/cercor/bhu089

Figure Lengend Snippet: Analysis flow illustrated with data from a representative session. (a) Spatial topography of 128 electrodes in monkey S with 4 exemplary ones (14, 23, 31, and 53) marked in color; (b) raw ECoG signals acquired during a 5-min eyes-closed session with an enlarged 5-s segment for the exemplary electrodes; (c) preprocessed spectrograms of the exemplary electrodes suggest relationship not simply explained by volume conduction effect: distant pairs (14 versus 23, and 31 versus 53) show similar spectrograms whereas the adjacent pair (23 versus 31) displays distinct patterns; (d) BLPs can be derived by averaging the spectrogram within specific frequency ranges; (e) cross-electrode correlations of the spectrogram or BLPs (β-BLP for the example here) form a matrix whose row (and column) values represent correlation values of specific electrode with all others (here called profile); map representation of correlation profiles of the exemplary electrodes (white stars) suggests 2 covariation structures whose boundary lies between the electrodes 23 and 31; (f) clustering electrodes based on the similarity of their correlation profiles and then reordering the matrix accordingly reveal several diagonal blocks that correspond to different covariation structures, whose topographic distribution and correlation strength can be then represented with group-averaged correlation maps.

Article Snippet: First, we estimated δ -band (1 − 4 Hz) ECoG power within 1-s time bins (shifted every 200 ms) using the multi-taper method ( Thomson 1982 ) implemented in Chronux, a Matlab package for the analysis of neural data ( Mitra and Bokil 2008 ).

Techniques: Derivative Assay

Journal: Cerebral Cortex (New York, NY)

Article Title: Robust Long-Range Coordination of Spontaneous Neural Activity in Waking, Sleep and Anesthesia

doi: 10.1093/cercor/bhu089

Figure Lengend Snippet: Spatial patterns of broadband ECoG power covariation. (a) Spatial topography of electrode coverage in individual monkeys is presented on cortical surface rendering reconstructed from the anatomical MRI of Monkey G. Exemplary ECoG raw signals from 2 electrodes in the Monkey C underwent a dramatic transition from a high-frequency, low-amplitude voltage pattern during eyes-closed wakefulness to a low-frequency, high-amplitude one under ketamine/medetomidine anesthesia (b), which is confirmed by distinct power spectra under these 2 conditions (c). However, correlation patterns of broadband ECoG power during (d) the eyes-closed wakefulness and (e) ketamine/medetomidine anesthesia similarly resemble (f) the fMRI resting-state networks (RSNs) from isoflurane-anesthetized macaques (adapted from [Hutchison et al. 2011]). Corresponding patterns or RSNs are aligned in the same row.

Article Snippet: First, we estimated δ -band (1 − 4 Hz) ECoG power within 1-s time bins (shifted every 200 ms) using the multi-taper method ( Thomson 1982 ) implemented in Chronux, a Matlab package for the analysis of neural data ( Mitra and Bokil 2008 ).

Techniques:

Journal: Cerebral Cortex (New York, NY)

Article Title: Robust Long-Range Coordination of Spontaneous Neural Activity in Waking, Sleep and Anesthesia

doi: 10.1093/cercor/bhu089

Figure Lengend Snippet: Spatial patterns of ECoG power covariation at different frequency bands during (a) the eyes-closed wakefulness and (b) ketamine/medetomidine anesthesia. Gray dots indicate electrode locations and white lines show the brain contour.

Article Snippet: First, we estimated δ -band (1 − 4 Hz) ECoG power within 1-s time bins (shifted every 200 ms) using the multi-taper method ( Thomson 1982 ) implemented in Chronux, a Matlab package for the analysis of neural data ( Mitra and Bokil 2008 ).

Techniques:

Journal: Cerebral Cortex (New York, NY)

Article Title: Robust Long-Range Coordination of Spontaneous Neural Activity in Waking, Sleep and Anesthesia

doi: 10.1093/cercor/bhu089

Figure Lengend Snippet: Dependence of spectral difference between networks on brain state. Electrodes are assigned to 8 networks based on the ECoG broadband power covariations and displayed using different colors (blue to red from anterior to posterior). The demeaned power spectra are averaged across electrodes belonging to the same network and displayed together for (a) the eyes-closed wakefulness, (b) ketamine/medetomidine anesthesia, propofol anesthesia, and sleep conditions. (c) The upper panel shows the MBGSS lines that quantify cross-network difference in power spectra, and the lower panel presents the ratio of 2 MBGSS lines, that is, the F-lines. The dashed lines are F-values (wakefulness versus ketamine/medetomidine: F140,77 versus propofol: F140,28 and versus sleep: F140,35) corresponding to a significance level of P < 0.01. Shadows represent areas within 1 S.E.M. across experiments (n = 20, 11, 4, and 5 for the wakefulness, ketamine/medetomidine, propofol, and sleep conditions, respectively).

Article Snippet: First, we estimated δ -band (1 − 4 Hz) ECoG power within 1-s time bins (shifted every 200 ms) using the multi-taper method ( Thomson 1982 ) implemented in Chronux, a Matlab package for the analysis of neural data ( Mitra and Bokil 2008 ).

Techniques: