Max_B
Member
NEW... important and interesting study of rodent brain activity using an asphyxial cardiac arrest model published last month. It shows interesting neural correlates of consciousness at near electrocerebral silence.
In cases of abrupt loss of blood circulation from cardiac arrest, a silent scalp EEG is reported to occur within 30; conversely, in cases of a gradual loss of blood flow, such as hypoxic respiratory failure, the EEG has been found to become isoelectric before cardiac arrest.
This study was investigating the latter, and they found asphyxial cardiac arrest induced a period of near-electrocerebral silence that was marked by increased phase coherence in the frontal lobes (motor cortex) and increased power in the rear visual cortices, both of which look like potential markers of consciousness.
Fig 3. ECoG phase coherence during asphyxial CA. (A) During AS3, the interhemispheric frontal coherence from 13 to 39 Hz (i.e., beta and slow gamma) was significantly greater (p < 0.05) than during the period immediately before asphyxia (i.e., washout). (B–D) The coherence during AS3 in the other channel combinations was not significantly greater than washout. The coherence during AS4 was largely an artifact of the ECG signal penetrating the ECoG. Data shown as mean of n = 16 rats. Dotted lines indicate region of statistical significance. *p < 0.05 by paired two-tailed nonparametric permutation test. ECG, electrocardiogram. Color images available online at
Link to the paper...
Neural Correlates of Consciousness at Near-Electrocerebral
Silence in an Asphyxial Cardiac Arrest Model
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5399737/
Definitely worthwhile reading, particularly the discussion section, which is peppered with interesting references to other important papers.
In cases of abrupt loss of blood circulation from cardiac arrest, a silent scalp EEG is reported to occur within 30; conversely, in cases of a gradual loss of blood flow, such as hypoxic respiratory failure, the EEG has been found to become isoelectric before cardiac arrest.
This study was investigating the latter, and they found asphyxial cardiac arrest induced a period of near-electrocerebral silence that was marked by increased phase coherence in the frontal lobes (motor cortex) and increased power in the rear visual cortices, both of which look like potential markers of consciousness.
Fig 3. ECoG phase coherence during asphyxial CA. (A) During AS3, the interhemispheric frontal coherence from 13 to 39 Hz (i.e., beta and slow gamma) was significantly greater (p < 0.05) than during the period immediately before asphyxia (i.e., washout). (B–D) The coherence during AS3 in the other channel combinations was not significantly greater than washout. The coherence during AS4 was largely an artifact of the ECG signal penetrating the ECoG. Data shown as mean of n = 16 rats. Dotted lines indicate region of statistical significance. *p < 0.05 by paired two-tailed nonparametric permutation test. ECG, electrocardiogram. Color images available online at
Link to the paper...
Neural Correlates of Consciousness at Near-Electrocerebral
Silence in an Asphyxial Cardiac Arrest Model
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5399737/
Definitely worthwhile reading, particularly the discussion section, which is peppered with interesting references to other important papers.