scholarly journals Cortex-wide Changes in Extracellular Potassium Ions Parallel Brain State Transitions in Awake Behaving Mice

Cell Reports ◽  
2019 ◽  
Vol 28 (5) ◽  
pp. 1182-1194.e4 ◽  
Author(s):  
Rune Rasmussen ◽  
Eric Nicholas ◽  
Nicolas Caesar Petersen ◽  
Andrea Grostøl Dietz ◽  
Qiwu Xu ◽  
...  
Keyword(s):  
State Transitions ◽  
Brain State ◽  
Extracellular Potassium ◽  
Potassium Ions

Modulation of Jellyfish Potassium Channels by External Potassium Ions

1999 ◽  
Vol 82 (4) ◽  
pp. 1728-1739 ◽  
Author(s):  
Nikita G. Grigoriev ◽  
J. David Spafford ◽  
Andrew N. Spencer
Keyword(s):  
Potassium Channels ◽  
Motor Neurons ◽  
Fruit Fly ◽  
Site Directed Mutagenesis ◽  
High Threshold ◽  
Extracellular Potassium ◽  
Potassium Ions ◽  
Polyorchis Penicillatus ◽  
State Dependent ◽  
Inactivation Mechanism

The amplitude of an A-like potassium current ( I Kfast) in identified cultured motor neurons isolated from the jellyfish Polyorchis penicillatus was found to be strongly modulated by extracellular potassium ([K+]out). When expressed in Xenopus oocytes, two jellyfish Shaker-like genes, jShak1 and jShak2, coding for potassium channels, exhibited similar modulation by [K+]out over a range of concentrations from 0 to 100 mM. jShak2-encoded channels also showed a decreased rate of inactivation and an increased rate of recovery from inactivation at high [K+]out. Using site-directed mutagenesis we show that inactivation of jShak2 can be ascribed to an unusual combination of a weak “implicit” N-type inactivation mechanism and a strong, fast, potassium-sensitive C-type mechanism. Interaction between the two forms of inactivation is responsible for the potassium dependence of cumulative inactivation. Inactivation of jShak1 was determined primarily by a strong “ball and chain” mechanism similar to fruit fly Shaker channels. Experiments using fast perfusion of outside-out patches with jShak2 channels were used to establish that the effects of [K+]out on the peak current amplitude and inactivation were due to processes occurring at either different sites located at the external channel mouth with different retention times for potassium ions, or at the same site(s) where retention time is determined by state-dependent conformations of the channel protein. The possible physiological implications of potassium sensitivity of high-threshold potassium A-like currents is discussed.

scholarly journals Optimal trajectories of brain state transitions

NeuroImage ◽  
2017 ◽  
Vol 148 ◽  
pp. 305-317 ◽  
Author(s):  
Shi Gu ◽  
Richard F. Betzel ◽  
Marcelo G. Mattar ◽  
Matthew Cieslak ◽  
Philip R. Delio ◽  
...  
Keyword(s):  
State Transitions ◽  
Optimal Trajectories ◽  
Brain State

The Temporal Dynamics of Spontaneous Emotional Brain States and Their Implications for Mental Health

2021 ◽  
pp. 1-14
Author(s):  
Philip A. Kragel ◽  
Ahmad R. Hariri ◽  
Kevin S. LaBar
Keyword(s):  
Mental Health ◽  
Temporal Dynamics ◽  
Brain Activity ◽  
Resting State Fmri ◽  
State Transitions ◽  
Brain State ◽  
Emotional States ◽  
Affective States ◽  
Emotional Responding ◽  
Brain States

Abstract Temporal processes play an important role in elaborating and regulating emotional responding during routine mind wandering. However, it is unknown whether the human brain reliably transitions among multiple emotional states at rest and how psychopathology alters these affect dynamics. Here, we combined pattern classification and stochastic process modeling to investigate the chronometry of spontaneous brain activity indicative of six emotions (anger, contentment, fear, happiness, sadness, and surprise) and a neutral state. We modeled the dynamic emergence of these brain states during resting-state fMRI and validated the results across two population cohorts—the Duke Neurogenetics Study and the Nathan Kline Institute Rockland Sample. Our findings indicate that intrinsic emotional brain dynamics are effectively characterized as a discrete-time Markov process, with affective states organized around a neutral hub. The centrality of this network hub is disrupted in individuals with psychopathology, whose brain state transitions exhibit greater inertia and less frequent resetting from emotional to neutral states. These results yield novel insights into how the brain signals spontaneous emotions and how alterations in their temporal dynamics contribute to compromised mental health.

Extracellular potassium ions mediate specific neuronal interaction

Science ◽  
1982 ◽  
Vol 216 (4541) ◽  
pp. 80-82 ◽  
Author(s):  
Y Yarom ◽  
M. Spira
Keyword(s):  
Extracellular Potassium ◽  
Potassium Ions

scholarly journals Further observations on the inhibitory effect of extracellular potassium ions on glycine uptake by mouse ascites-tumour cells

1969 ◽  
Vol 114 (4) ◽  
pp. 807-814 ◽  
Author(s):  
A A Eddy ◽  
M. C. Hogg
Keyword(s):  
Initial Rate ◽  
Inhibitory Effect ◽  
Sodium Cyanide ◽  
Tumour Cells ◽  
Extracellular Potassium ◽  
Potassium Ions ◽  
Atp Content ◽  
Entry Rate ◽  
Mouse Ascites ◽  
Ascites Tumour Cells

1. The initial rate of uptake of glycine by the tumour cells was measured as a function of the Na+ and K+ concentrations in the solution in which the cells were suspended. When [Gly] was 1mm or 12mm, the rate in the absence of Na+ was independent of [K+] and about 3% or 10% respectively of the rate when [Na+] was 150m-equiv./l. 2. The Na+-dependent glycine entry rate, v, at a given value of [Na+] was successively lowered when [K+] was increased from 8 to 47 to 96m-equiv./l. A kinetic analysis indicated that K+ competitively inhibited the action of Na+. The results were in fair agreement with previous determinations of the kinetic parameters. 3. The presence of 2mm-sodium cyanide and 10mm-2-deoxyglucose lowered the cellular ATP content to less than 3% of the value in the respiring cells. Although v was then about 50% smaller, the relative effects of K+ and Na+ on the system were similar to those observed during respiration. 4. A theoretical analysis indicated that the variation of v with [K+] is not a reliable guide to the extent to which the K+ gradient between the cells and their environment may contribute to the net transport of glycine.

Schizophrenia as a Disorder of Cerebral State Transition

1986 ◽  
Vol 20 (2) ◽  
pp. 167-178 ◽  
Author(s):  
J. J. Wright ◽  
R. R. Kydd
Keyword(s):  
State Transition ◽  
Finite State Machines ◽  
The State ◽  
State Transitions ◽  
Brain State ◽  
State Machines ◽  
Electrocortical Activity ◽  
Wave Nature ◽  
Finite State

This paper offers a speculative consideration of the schizophrenic process in the light of recent findings concerning the wave nature of electrocortical activity. These findings indicate that changes of brain state can be described in the terminology of finite-state machines, and both the instantaneous states and the state transitions can be specified. It is suggested that the mental phenomena of schizophrenia may be reducible to events (some specific type of instability) which could be observed by appropriate analytic techniques applied to EEG. Present empirical EEG findings in schizophrenics are reviewed in this light, and the role of dopamine blockade in treatment is also considered.

scholarly journals Brain network dynamics during working memory are modulated by dopamine and diminished in schizophrenia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Urs Braun ◽  
Anais Harneit ◽  
Giulio Pergola ◽  
Tommaso Menara ◽  
Axel Schäfer ◽  
...  
Keyword(s):  
Working Memory ◽  
Receptor Gene ◽  
Network Dynamics ◽  
Brain Network ◽  
Network Control ◽  
D1 Receptor ◽  
Receptor Expression ◽  
State Transitions ◽  
Brain State ◽  
Dopamine Signaling

AbstractDynamical brain state transitions are critical for flexible working memory but the network mechanisms are incompletely understood. Here, we show that working memory performance entails brain-wide switching between activity states using a combination of functional magnetic resonance imaging in healthy controls and individuals with schizophrenia, pharmacological fMRI, genetic analyses and network control theory. The stability of states relates to dopamine D1 receptor gene expression while state transitions are influenced by D2 receptor expression and pharmacological modulation. Individuals with schizophrenia show altered network control properties, including a more diverse energy landscape and decreased stability of working memory representations. Our results demonstrate the relevance of dopamine signaling for the steering of whole-brain network dynamics during working memory and link these processes to schizophrenia pathophysiology.

scholarly journals Stretching and squeezing of neuronal log firing rate distribution by psychedelic and intrinsic brain state transitions

2021 ◽  
Author(s):  
Bradley Dearnley ◽  
Martynas Dervinis ◽  
Melissa Shaw ◽  
Michael Okun
Keyword(s):  
Neuronal Population ◽  
Neuronal Firing ◽  
State Transitions ◽  
Brain State ◽  
Rate Distribution ◽  
Firing Rates ◽  
Neuronal Populations ◽  
Psychedelic Drugs ◽  
Large Populations ◽  
Intrinsic Fluctuations

AbstractHow psychedelic drugs change the activity of cortical neuronal populations and whether such changes are specific to transition into the psychedelic brain state or shared with other brain state transitions is not well understood. Here, we used Neuropixels probes to record from large populations of neurons in prefrontal cortex of mice given the psychedelic drug TCB-2. Drug ingestion significantly stretched the distribution of log firing rates of the population of recorded neurons. This phenomenon was previously observed across transitions between sleep and wakefulness, which suggested that stretching of the log-rate distribution can be triggered by different kinds of brain state transitions and prompted us to examine it in more detail. We found that modulation of the width of the log-rate distribution of a neuronal population occurred in multiple areas of the cortex and in the hippocampus even in awake drug-free mice, driven by intrinsic fluctuations in their arousal level. Arousal, however, did not explain the stretching of the log-rate distribution by TCB-2. In both psychedelic and naturally occurring brain state transitions, the stretching or squeezing of the log-rate distribution of an entire neuronal population reflected concomitant changes in two subpopulations, with one subpopulation undergoing a downregulation and often also stretching of its neurons’ log-rate distribution, while the other subpopulation undergoes upregulation and often also a squeeze of its log-rate distribution. In both subpopulations, the stretching and squeezing were a signature of a greater relative impact of the brain state transition on the rates of the slow-firing neurons. These findings reveal a generic pattern of reorganisation of neuronal firing rates by different kinds of brain state transitions.

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