Rhythmic brain activity plays an important role in neural processing and behavior. Features of these oscillations, including amplitude, phase, spectrum, can be influenced by internal states (e.g., shifts arousal, attention or cognitive ability) external stimulation. Electromagnetic stimulation techniques such as transcranial magnetic stimulation, direct current alternating are used increasingly both research clinical settings. Currently, the mechanisms whereby time-dependent stimuli...

During general anesthesia, global brain activity and behavioral state are profoundly altered. Yet it remains mostly unknown how anesthetics alter sensory processing across cortical layers modulate functional cortico-cortical connectivity. To address this gap in knowledge of the micro- mesoscale effects on microcircuit, we recorded multiunit local field potential awake anesthetized ferrets ( Mustela putoris furo) during stimulation. understand a primary area representation input higher-order...

Anesthesia is widely used in medicine and research to achieve altered states of consciousness cognition. Whereas changes macroscopic cortical activity patterns by anesthesia measured at the spatial resolution electroencephalography have been studied, modulation mesoscopic microscopic network dynamics remain poorly understood. To address this gap knowledge, we recorded spontaneous (local field potential) (multiunit activity) primary visual cortex (V1) prefrontal (PFC) awake isoflurane...

This paper introduces a neuronal field model for both excitatory and inhibitory connections. A single integro-differential equation with delay is derived studied at critical point by stability analysis, which yields conditions static periodic patterns wave instabilities. It turns out that waves only occur below certain threshold of the activity propagation velocity. An additional brief study exhibits increasing phase velocities decreasing slope subject to velocities, are in accordance...

A stability analysis is presented for neural field equations in the presence of finite propagation speed along axons and a general class connectivity kernels synaptic properties. Sufficient conditions are given equilibrium solutions. It shown that delays play significant role nonstationary bifurcations equilibria, whereas stationary depend only on kernel. In case bifurcations, bounds determined frequencies resulting oscillatory perturbative scheme used to calculate types leading spatial...

We introduce distributed axonal transmission speeds and a long‐range constant feedback loop into the standard neural field model. analyze stability of spatially homogeneous equilibrium solutions for general connectivity kernels. By studying reduced models based on assumption small delays, we determine effects delays bifurcations. show in model that delayed excitatory generally facilitates stationary bifurcations Turing patterns, while suppressing bifurcation periodic traveling waves. The...

The disruption of coupling between brain areas has been suggested as the mechanism underlying loss consciousness in anesthesia. This hypothesis tested previously by measuring information transfer areas, and taking reduced a proxy for decoupling. Yet, is function amount available source-such that decreases even unchanged when less source available. Therefore, we asked whether impaired local processing leads to transfer. An important prediction this alternative changes locally (signal entropy)...

Abstract Cloud-affected radiances from geostationary satellite sensors provide the first area-wide observable signal of convection with high spatial resolution in range kilometers and temporal minutes. However, these observations are not yet assimilated operational convection-resolving weather prediction models as rapid, nonlinear evolution clouds makes assimilation related very challenging. To address challenges, we investigate visible infrared channels idealized observing system simulation...

Heterogeneity is the norm in biology. The brain no different: Neuronal cell types are myriad, reflected through their cellular morphology, type, excitability, connectivity motifs, and ion channel distributions. While this biophysical diversity enriches neural systems' dynamical repertoire, it remains challenging to reconcile with robustness persistence of function over time (resilience). To better understand relationship between excitability heterogeneity (variability within a population...

We propose an algorithm for the detection of recurrence domains complex dynamical systems from time series. Our approach exploits characteristic checkerboard texture exhibited in plots. In phase space, plots yield intersecting balls around sampling points that could be merged into cells a space partition. construct this partition by rewriting grammar applied to symbolic dynamics indices. A maximum entropy principle defines optimal size balls. The final application high-dimensional brain...

Brain stimulation can be used to engage and modulate rhythmic activity in brain networks. However, the outcomes of are shaped by behavioral states endogenous fluctuations activity. To better understand how this intrinsic oscillatory controls susceptibility stimulation, we analyzed a computational model thalamo-cortical system two distinct (rest task-engaged) identify mechanisms which alpha oscillations (8Hz–12Hz) modulated periodic stimulation. Our analysis shows that different responses...

Rhythmic activity plays a central role in neural computations and brain functions ranging from homeostasis to attention, as well neurological neuropsychiatric disorders. Despite this pervasiveness, little is known about the mechanisms whereby frequency power of oscillatory are modulated, how they reflect inputs received by neurons. Numerous studies have reported input-dependent fluctuations peak (as couplings across these features). However, it remains unresolved what mediates spectral...

Oscillatory brain activity is believed to play a central role in neural coding. Accumulating evidence shows that features of these oscillations are highly dynamic: power, frequency and phase fluctuate alongside changes behavior task demands. The mechanism supporting this variability however poorly understood. We here analyze network recurrently connected spiking neurons with time delay displaying stable synchronous dynamics. Using mean-field stability analyses, we investigate the influence...

Transcranial alternating current stimulation (tACS) represents a promising non-invasive treatment for an increasingly wide range of neurological and neuropsychiatric disorders. The ability to use periodically oscillating electric fields non-invasively engage neural dynamics opens up the possibility recruiting synaptic plasticity modulate brain function. However, despite consistent reports about tACS clinical effectiveness, strong state-dependence combined with ubiquitous heterogeneity...

The work introduces a linear neural population model that allows to derive analytically the power spectrum subjected concentration of anaesthetic propofol. analytical study systems activity gives conditions on how frequency maximum in experimental EEG changes dependent propofol concentration. In this context, we explain anaesthetic-induced increase by an oscillatory instability and under which peak shifts larger frequencies as observed experimentally EEG. Moreover predicts only occurs while...

This paper introduces a neuronal field model for both excitatory and inhibitory connections. A single integro-differential equation with delay is derived studied at critical point by stability analysis, which yields conditions static periodic patterns wave instabilities. It turns out that waves only occur below certain threshold of the activity propagation velocity. An additional brief study exhibits increasing phase velocities decreasing slope subject to velocities, are in accordance...