TY - JOUR
T1 - Scale-free bursting in human cortex following hypoxia at birth
AU - Roberts, J.A.
AU - Iyer, Kartik
AU - Finnigan, S.
AU - Vanhatalo, S.
AU - Breakspear, M.
PY - 2014
Y1 - 2014
N2 - The human brain is fragile in the face of oxygen deprivation. Even a briefinterruption of metabolic supply at birth challenges an otherwise healthy neonatal cortex, leading to a cascade of homeostatic responses. During recovery from hypoxia, cortical activity exhibits a period of highly irregular electrical fluctuations known as burst suppression. Here we show that these bursts have fractal properties, with power-law scaling of burst sizes across a remarkable 5 orders of magnitude and a scale-free relationship between burst sizes and durations. Although burst waveforms vary greatly, their average shape converges to a simple form that is asymmetric at long time scales. Using a simple computational model, we argue that this asymmetry reflects activity-dependent changes in the excitatory-inhibitory balance of cortical neurons. Bursts become more symmetric following the resumption of normal activity, with a corresponding reorganization of burst scaling relationships. These findings place burst suppression in the broad class of scale-free physical processes termed crackling noise and suggest that the resumption of healthy activity reflects a fundamental reorganization in the relationship between neuronal activity and its underlying metabolic constraints. © 2014 the authors.
AB - The human brain is fragile in the face of oxygen deprivation. Even a briefinterruption of metabolic supply at birth challenges an otherwise healthy neonatal cortex, leading to a cascade of homeostatic responses. During recovery from hypoxia, cortical activity exhibits a period of highly irregular electrical fluctuations known as burst suppression. Here we show that these bursts have fractal properties, with power-law scaling of burst sizes across a remarkable 5 orders of magnitude and a scale-free relationship between burst sizes and durations. Although burst waveforms vary greatly, their average shape converges to a simple form that is asymmetric at long time scales. Using a simple computational model, we argue that this asymmetry reflects activity-dependent changes in the excitatory-inhibitory balance of cortical neurons. Bursts become more symmetric following the resumption of normal activity, with a corresponding reorganization of burst scaling relationships. These findings place burst suppression in the broad class of scale-free physical processes termed crackling noise and suggest that the resumption of healthy activity reflects a fundamental reorganization in the relationship between neuronal activity and its underlying metabolic constraints. © 2014 the authors.
U2 - 10.1523/JNEUROSCI.4701-13.2014
DO - 10.1523/JNEUROSCI.4701-13.2014
M3 - Article
VL - 34
SP - 6557
EP - 6572
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 19
ER -