scholarly journals Propofol anesthesia alters cortical traveling waves

2022 ◽  
Author(s):  
Sayak Bhattacharya ◽  
Jacob A Donoghue ◽  
Meredith Mahnke ◽  
Scott L Brincat ◽  
Emery N. Brown ◽  
...  
Keyword(s):  
Traveling Waves ◽  
Loss Of Consciousness ◽  
Awake State ◽  
Oscillatory Dynamics ◽  
Delta Waves ◽  
Cortical Oscillations ◽  
Oscillatory Power

Oscillatory dynamics in cortex seem to organize into traveling waves that serve a variety of functions. Recent studies show that propofol, a widely used anesthetic, dramatically alters cortical oscillations by increasing slow-delta oscillatory power and coherence. It is not known how this affects traveling waves. We compared traveling waves across the cortex of non-human primates (NHPs) before, during, and after propofol-induced loss-of-consciousness (LOC). After LOC, traveling waves in the slow-delta (~ 1Hz) range increased, grew more organized, and travelled in different directions relative to the awake state. Higher frequency (8-30 Hz) traveling waves, by contrast, decreased, lost structure, and switched to directions where the slow-delta waves were less frequent. The results suggest that LOC may be due, in part, to changes in slow-delta traveling waves that, in turn, alter and disrupt traveling waves in the higher frequencies associated with cognition.

scholarly journals 0124 A Prefrontal-Amygdala Network Model of the Cellular and Circuit-Level Mechanisms of Emotional Memory Consolidation During the Awake State and REM Sleep

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A49-A49
Author(s):  
Y Rho ◽  
S Vijayan
Keyword(s):  
Network Model ◽  
Rem Sleep ◽  
Memory Consolidation ◽  
Large Scale ◽  
Cell Types ◽  
Awake State ◽  
Oscillatory Dynamics ◽  
Emotional Memories ◽  
Large Scale Network ◽  
Single Spike

Abstract Introduction Rapid eye movement (REM) sleep has been implicated in the consolidation of emotional memories. Our recent work found a candidate system for REM-related memory consolidation. We showed that during REM sleep, the frontal cortices are dominated by theta (4–8 Hz) oscillations and bursts of beta (15–35 Hz) activity. Studies suggest that rhythmic interactions between the frontal cortices and limbic structures, in particular the amygdala, play a critical role in the consolidation of emotional memories. However, the mechanisms responsible for memory consolidation during these rhythmic interactions during REM sleep remain unknown. Methods We used biophysically based neural models to build a large-scale network model of the prefrontal cortex (PFC) and amygdala (AMY) and incorporated synaptic plasticity mechanisms, such as spike-timing dependent plasticity (STDP), into the connections between these two regions. Norepinephrine (NE) and serotonin (SE) levels were manipulated to mimic the different physiological conditions during the awake state and REM sleep. Results We were able to reproduce the oscillatory dynamics observed in experimental studies and identify cell-type specific synaptic changes caused by STDP. During the awake state, PFC connections to all cell types of the AMY become strengthened when PFC neurons provide theta frequency inputs, with the connections strengthening to a greater extent when inputs are in burst mode rather than single spike mode. When the PFC provides beta inputs, we see the exact opposite relationship: synaptic strengths become weaker when inputs are in burst mode rather than single spike mode. During REM sleep conditions, the connections to all principal cell types of the AMY become strengthened, with synaptic connections to some subtypes of pyramidal cells becoming stronger than others. Surprisingly, however, the synaptic connections to the interneurons become weaker in response to theta frequency inputs. Conclusion Using our large-scale network model, we show how the levels of the neurotransmitters NE and SE during the awake state and REM sleep affect oscillatory dynamics and in turn influence the strengthening or weakening of connections related to emotional memories. Support United States Army Research Office, Award number ARO W91lNF-17-1-0300

scholarly journals Abnormal beta power is a hallmark of explicit movement control in functional movement disorders

Neurology ◽  
2017 ◽  
Vol 90 (3) ◽  
pp. e247-e253 ◽  
Author(s):  
Tiago Teodoro ◽  
Anne Marthe Meppelink ◽  
Simon Little ◽  
Robert Grant ◽  
Glenn Nielsen ◽  
...  
Keyword(s):  
Movement Disorders ◽  
Movement Control ◽  
Motor Preparation ◽  
Functional Movement ◽  
Cue Validity ◽  
Cortical Oscillations ◽  
Beta Power ◽  
Oscillatory Power ◽  
Functional Movement Disorders ◽  
Beta Frequency

ObjectiveTo determine whether sensorimotor beta-frequency oscillatory power is raised during motor preparation in patients with functional movement disorders (FMD) and could therefore be a marker of abnormal “body-focused” attention.MethodsWe analyzed motor performance and beta-frequency cortical oscillations during a precued choice reaction time (RT) task with varying cue validity (50% or 95% congruence between preparation and go cues). We compared 21 patients with FMD with 13 healthy controls (HCs).ResultsIn HCs, highly predictive cues were associated with faster RT and beta desynchronization in the contralateral hemisphere (contralateral slope −0.045 [95% confidence interval (CI) −0.057 to −0.033] vs ipsilateral −0.033 [95% CI −0.046 to −0.021], p < 0.001) and with a tendency for reaching lower contralateral end-of-preparation beta power (contralateral −0.482 [95% CI −0.827 to −0.137] vs ipsilateral −0.328 [95% CI −0.673 to 0.016], p = 0.069). In contrast, patients with FMD had no improvement in RTs with highly predictive cues and showed an impairment of beta desynchronization and lateralization before movement.ConclusionsPersistent beta synchronization during motor preparation could reflect abnormal explicit control of movement in FMD. Excessive attention to movement itself rather than the goal might maintain beta synchronization and impair performance.

scholarly journals Behavioral and Neural Dynamics of Interpersonal Synchrony Between Performing Musicians: A Wireless EEG Hyperscanning Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Anna Zamm ◽  
Caroline Palmer ◽  
Anna-Katharina R. Bauer ◽  
Martin G. Bleichner ◽  
Alexander P. Demos ◽  
...  
Keyword(s):  
Music Performance ◽  
Solo Performance ◽  
Temporal Coordination ◽  
Oscillatory Dynamics ◽  
Spontaneous Rate ◽  
Cortical Oscillations ◽  
Interpersonal Synchrony ◽  
The Difference ◽  
Brain And Behavior ◽  
Wireless Eeg

Interpersonal synchrony refers to the temporal coordination of actions between individuals and is a common feature of social behaviors, from team sport to ensemble music performance. Interpersonal synchrony of many rhythmic (periodic) behaviors displays dynamics of coupled biological oscillators. The current study addresses oscillatory dynamics on the levels of brain and behavior between music duet partners performing at spontaneous (uncued) rates. Wireless EEG was measured from N = 20 pairs of pianists as they performed a melody first in Solo performance (at their spontaneous rate of performance), and then in Duet performances at each partner’s spontaneous rate. Influences of partners’ spontaneous rates on interpersonal synchrony were assessed by correlating differences in partners’ spontaneous rates of Solo performance with Duet tone onset asynchronies. Coupling between partners’ neural oscillations was assessed by correlating amplitude envelope fluctuations of cortical oscillations at the Duet performance frequency between observed partners and between surrogate (re-paired) partners, who performed the same melody but at different times. Duet synchronization was influenced by partners’ spontaneous rates in Solo performance. The size and direction of the difference in partners’ spontaneous rates were mirrored in the size and direction of the Duet asynchronies. Moreover, observed Duet partners showed greater inter-brain correlations of oscillatory amplitude fluctuations than did surrogate partners, suggesting that performing in synchrony with a musical partner is reflected in coupled cortical dynamics at the performance frequency. The current study provides evidence that dynamics of oscillator coupling are reflected in both behavioral and neural measures of temporal coordination during musical joint action.

Fit Vs Faint: Assessing Work Causation in “Idiopathic Fall” Cases

2014 ◽  
Vol 19 (5) ◽  
pp. 3-12
Author(s):  
Lorne Direnfeld ◽  
David B. Torrey ◽  
Jim Black ◽  
LuAnn Haley ◽  
Christopher R. Brigham
Keyword(s):  
Blood Flow ◽  
Electrical Activity ◽  
Loss Of Consciousness ◽  
Brain Electrical Activity ◽  
Medical Terminology ◽  
Scientific Analysis ◽  
Medical Causation ◽  
The Individual ◽  
The Brain ◽  
Current Science

Abstract When an individual falls due to a nonwork-related episode of dizziness, hits their head and sustains injury, do workers’ compensation laws consider such injuries to be compensable? Bearing in mind that each state makes its own laws, the answer depends on what caused the loss of consciousness, and the second asks specifically what happened in the fall that caused the injury? The first question speaks to medical causation, which applies scientific analysis to determine the cause of the problem. The second question addresses legal causation: Under what factual circumstances are injuries of this type potentially covered under the law? Much nuance attends this analysis. The authors discuss idiopathic falls, which in this context means “unique to the individual” as opposed to “of unknown cause,” which is the familiar medical terminology. The article presents three detailed case studies that describe falls that had their genesis in episodes of loss of consciousness, followed by analyses by lawyer or judge authors who address the issue of compensability, including three scenarios from Arizona, California, and Pennsylvania. A medical (scientific) analysis must be thorough and must determine the facts regarding the fall and what occurred: Was the fall due to a fit (eg, a seizure with loss of consciousness attributable to anormal brain electrical activity) or a faint (eg, loss of consciousness attributable to a decrease in blood flow to the brain? The evaluator should be able to fully explain the basis for the conclusions, including references to current science.

Sophistry and Circumstance at the End of Life

2008 ◽  
Vol 5 (1) ◽  
pp. 81-88
Author(s):  
Philip Berry
Keyword(s):  
Liver Failure ◽  
Medical Personnel ◽  
Medical Decision ◽  
Loss Of Consciousness ◽  
Supportive Treatment ◽  
Medical Decisions ◽  
Life Threatening Illness ◽  
Two Factors ◽  
Life Threatening ◽  
Counselling Process

When life-threatening illness robs a patient of the ability to express their desires, medical personnel must work through the issues of management and prognosis with relatives. Management decisions are guided by medical judgement and the relatives’ account of the patient’s wishes, but difficulties occur when distance grows between these two factors. In these circumstances the counselling process may turn into a doctor-led justification of the medical decision. This article presents two strands of dialogue, in which a doctor, counselling for and against continuation of supportive treatment in two patients with liver failure, demonstrates selectivity and inconsistency in constructing an argument. The specific issues of loss of consciousness (with obscuration of personal identity), statistical ‘futility’ and removal of autonomy are explored and used to bolster diametrically opposed medical decisions. By examining the doctor’s ability to interpret these issues according to circumstance, the author demonstrates how it is possible to shade medical facts depending on the desired outcome.

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