scholarly journals Phase transitions in single neurons and neural populations: Critical slowing, anesthesia, and sleep cycles

2009 ◽  
pp. 1-26 ◽  
Author(s):  
D.A. Steyn-Ross ◽  
M.L. Steyn-Ross ◽  
M.T. Wilson ◽  
J.W. Sleigh
Keyword(s):  
Phase Transitions ◽  
Single Neurons ◽  
Neural Populations ◽  
Sleep Cycles

scholarly journals Phase transitions in the neuropercolation model of neural populations with mixed local and non-local interactions

2005 ◽  
Vol 92 (6) ◽  
pp. 367-379 ◽  
Author(s):  
Robert Kozma ◽  
Marko Puljic ◽  
Paul Balister ◽  
Bela Bollobás ◽  
Walter J. Freeman
Keyword(s):  
Phase Transitions ◽  
Local Interactions ◽  
Neural Populations ◽  
Non Local

scholarly journals A Statistical Model of Shared Variability in the Songbird Auditory System

2017 ◽  
Author(s):  
Lars Buesing ◽  
Ana Calabrese ◽  
John P. Cunningham ◽  
Sarah M. N. Woolley ◽  
Liam Paninski
Keyword(s):  
Simple Model ◽  
Simple Structure ◽  
Vocal Communication ◽  
Factor Model ◽  
Primary Auditory Cortex ◽  
Single Neurons ◽  
Correlated Activity ◽  
Neural Populations ◽  
Cortical Regions ◽  
Simultaneous Activity

AbstractVocal communication evokes robust responses in primary auditory cortex (A1) of songbirds, and single neurons from superficial and deep regions of A1 have been shown to respond selectively to songs over complex, synthetic sounds. However, little is known about how this song selectivity arises and manifests itself on the level of networks of neurons in songbird A1. Here, we examined the network-level coding of song and synthetic sounds in A1 by simultaneously recording the responses of multiple neurons in unanesthetized zebra finches. We developed a latent factor model of the joint simultaneous activity of these neural populations, and found that the shared variability in the activity has a surprisingly simple structure; it is dominated by an unobserved latent source with one degree-of-freedom. This simple model captures the structure of the correlated activity in these populations in both spontaneous and stimulus-driven conditions, and given both song and synthetic stimuli. The inferred latent variability is strongly suppressed under stimulation, consistent with similar observations in a range of mammalian cortical regions.

scholarly journals MODELING GOAL-ORIENTED DECISION MAKING THROUGH COGNITIVE PHASE TRANSITIONS

2009 ◽  
Vol 05 (01) ◽  
pp. 143-157 ◽  
Author(s):  
ROBERT KOZMA ◽  
MARKO PULJIC ◽  
LEONID PERLOVSKY
Keyword(s):  
Decision Making ◽  
Phase Transitions ◽  
Cognitive Processing ◽  
Probabilistic Models ◽  
Temporal Dynamics ◽  
Mathematical Tool ◽  
Neural Populations ◽  
Spatio Temporal ◽  
Experimental Findings ◽  
High Level

Cognitive experiments indicate the presence of discontinuities in brain dynamics during high-level cognitive processing. Non-linear dynamic theory of brains pioneered by Freeman explains the experimental findings through the theory of metastability and edge-of-criticality in cognitive systems, which are key properties associated with robust operation and fast and reliable decision making. Recently, neuropercolation has been proposed to model such critical behavior. Neuropercolation is a family of probabilistic models based on the mathematical theory of bootstrap percolations on lattices and random graphs and motivated by structural and dynamical properties of neural populations in the cortex. Neuropercolation exhibits phase transitions and it provides a novel mathematical tool for studying spatio-temporal dynamics of multi-stable systems. The present work reviews the theory of cognitive phase transitions based on neuropercolation models and outlines the implications to decision making in brains and in artificial designs.

DOUBLE-LAYERED MODELS CAN EXPLAIN MACRO AND MICRO STRUCTURE OF HUMAN SLEEP

2013 ◽  
Vol 23 (02) ◽  
pp. 1350008 ◽  
Author(s):  
ILARIA STURA ◽  
LORENZO PRIANO ◽  
ALESSANDRO MAURO ◽  
CATERINA GUIOT ◽  
EZIO VENTURINO
Keyword(s):  
Sleep Stage ◽  
Nrem Sleep ◽  
Micro Structure ◽  
Predator Prey ◽  
Human Sleep ◽  
Prey System ◽  
Neural Populations ◽  
Normal Human ◽  
Layered Models ◽  
Sleep Cycles

The model simulates the activity of three neural populations using a Lotka–Volterra predator–prey system and, based on neuro-anatomical and neuro-physiological recent findings, assumes that a functional thalamo-cortical gate should be crossed by 'queuing' thalamic signals and that a sleep promoting substance acts as a modulator. The resultant activity accounts for the sleep stage transitions. In accordance with sleep cycles timing, the model proves to be able to reproduce the clustering and randomness of those peculiar transient synchronized EEG patterns (TSEP) described in normal human sleep and supposed to be related to the dynamic building up of NREM sleep until its stabilization against perturbations.

scholarly journals Single Neurons Can Induce Phase Transitions of Cortical Recurrent Networks with Multiple Internal States

2005 ◽  
Vol 16 (5) ◽  
pp. 639-654 ◽  
Author(s):  
Shigeyoshi Fujisawa ◽  
Norio Matsuki ◽  
Yuji Ikegaya
Keyword(s):  
Phase Transitions ◽  
Recurrent Networks ◽  
Single Neurons ◽  
Internal States ◽  
Induce Phase

scholarly journals High precision coding in visual cortex

2019 ◽  
Author(s):  
Carsen Stringer ◽  
Michalis Michaelos ◽  
Marius Pachitariu
Keyword(s):  
Visual Cortex ◽  
Sensory Cortex ◽  
Visual Features ◽  
Single Neurons ◽  
Neural Noise ◽  
Learning Tasks ◽  
Visual Areas ◽  
Neural Populations ◽  
Behavioral States ◽  
Sequential Nature

Single neurons in visual cortex provide unreliable measurements of visual features due to their high trial-to-trial variability. It is not known if this “noise” extends its effects over large neural populations to impair the global encoding of stimuli. We recorded simultaneously from ∼20,000 neurons in mouse primary visual cortex (V1) and found that the neural populations had discrimination thresholds of ∼0.34° in an orientation decoding task. These thresholds were nearly 100 times smaller than those reported behaviorally in mice. The discrepancy between neural and behavioral discrimination could not be explained by the types of stimuli we used, by behavioral states or by the sequential nature of perceptual learning tasks. Furthermore, higher-order visual areas lateral to V1 could be decoded equally well. These results imply that the limits of sensory perception in mice are not set by neural noise in sensory cortex, but by the limitations of downstream decoders.

Electron Microscopy of Graphite Intercalation Compounds

1982 ◽  
Vol 40 ◽  
pp. 544-545
Author(s):  
G. Timp ◽  
L. Salamanca-Riba ◽  
L.W. Hobbs ◽  
G. Dresselhaus ◽  
M.S. Dresselhaus
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Domain Wall ◽  
Intercalation Compounds ◽  
Lattice Plane ◽  
Wall Model ◽  
Graphite Intercalation Compounds ◽  
Fundamental Symmetry ◽  
Graphite Intercalation

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

Configurational studies of phase transitions

1984 ◽  
Vol 127 (1-3) ◽  
pp. 180-186
Author(s):  
A BRUCE
Keyword(s):  
Phase Transitions
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