scholarly journals Bidirectional and context-dependent changes in theta and gamma oscillatory brain activity in noradrenergic cell-specific Hypocretin/Orexin receptor 1-KO mice

2017 ◽  
Author(s):  
Sha Li ◽  
Paul Franken ◽  
Anne Vassalli
Keyword(s):  
High Frequency ◽  
Slow Wave Sleep ◽  
Brain Activity ◽  
Orienting Response ◽  
Network Activity ◽  
Θ Rhythm ◽  
Narrow Bandwidth ◽  
Oscillatory Brain Activity ◽  
Na Release ◽  
Fine Tune

AbstractNoradrenaline (NA) and hypocretins/orexins (HCRT), and their receptors, dynamically modulate the circuits that configure behavioral states, and their associated oscillatory activities. Salient stimuli activate spiking of locus coeruleus noradrenergic (NALC) cells, inducing NA release and brain-wide noradrenergic signalling, thus resetting network activity, and mediating an orienting response. Hypothalamic HCRT neurons provide one of the densest input to NALC cells. To functionally address the HCRT-to-NA connection, we selectively disrupted the Hcrtr1 gene in NA neurons, and analyzed resulting (Hcrtr1Dbh-CKO) mice’, and their control littermates’ electrocortical response in several contexts of enhanced arousal. Under enforced wakefulness (EW), or after cage change (CC), Hcrtr1Dbh-CKO mice exhibited a weakened ability to lower infra-θ frequencies (1-7 Hz), and mount a robust, narrow-bandwidth, high-frequency θ rhythm (~8.5 Hz). A fast-γ (55-80 Hz) response, whose dynamics closely parallelled θ, also diminished, while β/slow-γ activity (15-45 Hz) increased. Furthermore, EW-associated locomotion was lower. Surprisingly, nestbuilding-associated wakefulness, inversely, featured enhanced θ and fast-γ activities. Thus HCRT-to-NA signalling may fine-tune arousal, up in alarming conditions, and down during self-motivated, goal-driven behaviors. Lastly, slow-wave-sleep following EW and CC, but not nestbuilding, was severely deficient in slow-δ waves (0.75-2.25 Hz), suggesting that HCRT-to-NA signalling regulates the slow-δ rebound characterizing sleep after stress-associated arousal.

scholarly journals Hypocretin (orexin) is critical in sustaining theta/gamma-rich waking behaviors that drive sleep need

2017 ◽  
Vol 114 (27) ◽  
pp. E5464-E5473 ◽  
Author(s):  
Anne Vassalli ◽  
Paul Franken
Keyword(s):  
Slow Wave Sleep ◽  
Paradoxical Sleep ◽  
Brain Activity ◽  
Network Activity ◽  
Power Dynamics ◽  
Poor Sleep ◽  
Sleep Homeostasis ◽  
Episode Duration ◽  
Global Brain ◽  
Motivated Behaviors

Hcrt gene inactivation in mice leads to behavioral state instability, abnormal transitions to paradoxical sleep, and cataplexy, hallmarks of narcolepsy. Sleep homeostasis is, however, considered unimpaired in patients and narcoleptic mice. We find that whereas Hcrtko/ko mice respond to 6-h sleep deprivation (SD) with a slow-wave sleep (SWS) EEG δ (1.0 to 4.0 Hz) power rebound like WT littermates, spontaneous waking fails to induce a δ power reflecting prior waking duration. This correlates with impaired θ (6.0 to 9.5 Hz) and fast-γ (55 to 80 Hz) activity in prior waking. We algorithmically identify a theta-dominated wakefulness (TDW) substate underlying motivated behaviors and typically preceding cataplexy in Hcrtko/ko mice. Hcrtko/ko mice fully implement TDW when waking is enforced, but spontaneous TDW episode duration is greatly reduced. A reformulation of the classic sleep homeostasis model, where homeostatic pressure rises exclusively in TDW rather than all waking, predicts δ power dynamics both in Hcrtko/ko and WT mouse baseline and recovery SWS. The low homeostatic impact of Hcrtko/ko mouse spontaneous waking correlates with decreased cortical expression of neuronal activity-related genes (notably Bdnf, Egr1/Zif268, and Per2). Thus, spontaneous TDW stability relies on Hcrt to sustain θ/fast-γ network activity and associated plasticity, whereas other arousal circuits sustain TDW during SD. We propose that TDW identifies a discrete global brain activity mode that is regulated by context-dependent neuromodulators and acts as a major driver of sleep homeostasis. Hcrt loss in Hcrtko/ko mice causes impaired TDW maintenance in baseline wake and blunted δ power in SWS, reproducing, respectively, narcolepsy excessive daytime sleepiness and poor sleep quality.

scholarly journals The separation of auditory experience and the temporal structure of MEG recorded brain activity

2017 ◽  
Author(s):  
Chris Allen
Keyword(s):  
High Frequency ◽  
Temporal Dynamics ◽  
Brain Activity ◽  
Temporal Structure ◽  
Oscillatory Activity ◽  
Auditory Stimuli ◽  
Brain Oscillations ◽  
Successful Separation ◽  
Auditory Experience ◽  
Oscillatory Brain Activity

AbstractDo brain oscillations limit the temporal dynamics of experience? This pre-registered study used the separation of auditory stimuli to track perceptual experience and related this to oscillatory activity using magnetoencephalography. The rates at which auditory stimuli could be individuated matched the rates of oscillatory brain activity. Stimuli also entrained brain activity at the frequencies at which they were presented and a progression of high frequency gamma band events appeared to predict successful separation. These findings support a generalised function for brain oscillations, across frequency bands, in the alignment of activity to delineate representations.

scholarly journals Experience and sleep-dependent synaptic plasticity: from structure to activity

2020 ◽  
Vol 375 (1799) ◽  
pp. 20190234 ◽  
Author(s):  
Linlin Sun ◽  
Hang Zhou ◽  
Joseph Cichon ◽  
Guang Yang
Keyword(s):  
Synaptic Plasticity ◽  
Learning And Memory ◽  
Synapse Formation ◽  
Slow Wave Sleep ◽  
Neurological Diseases ◽  
Brain Activity ◽  
Network Activity ◽  
Sleep State ◽  
State Dependent ◽  
Function Of Sleep

Synaptic plasticity is important for learning and memory. With increasing evidence linking sleep states to changes in synaptic strength, an emerging view is that sleep promotes learning and memory by facilitating experience-induced synaptic plasticity. In this review, we summarize the recent progress on the function of sleep in regulating cortical synaptic plasticity. Specifically, we outline the electroencephalogram signatures of sleep states (e.g. slow-wave sleep, rapid eye movement sleep, spindles), sleep state-dependent changes in gene and synaptic protein expression, synaptic morphology, and neuronal and network activity. We highlight studies showing that post-experience sleep potentiates experience-induced synaptic changes and discuss the potential mechanisms that may link sleep-related brain activity to synaptic structural remodelling. We conclude that both synapse formation or strengthening and elimination or weakening occur across sleep. This sleep-dependent synaptic plasticity plays an important role in neuronal circuit refinement during development and after learning, while sleep disorders may contribute to or exacerbate the development of common neurological diseases. This article is part of the Theo Murphy meeting issue ‘Memory reactivation: replaying events past, present and future’.

scholarly journals Detection of event-related modulations of oscillatory brain activity with multivariate statistical analysis of MEG data

2009 ◽  
Vol 30 (6) ◽  
pp. 1922-1934 ◽  
Author(s):  
Juan L.P. Soto ◽  
Dimitrios Pantazis ◽  
Karim Jerbi ◽  
Jean-Phillipe Lachaux ◽  
Line Garnero ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Brain Activity ◽  
Multivariate Statistical ◽  
Oscillatory Brain Activity

scholarly journals Correlation between Traits of Emotion-Based Impulsivity and Intrinsic Default-Mode Network Activity

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jizheng Zhao ◽  
Dardo Tomasi ◽  
Corinde E. Wiers ◽  
Ehsan Shokri-Kojori ◽  
Şükrü B. Demiral ◽  
...  
Keyword(s):  
Brain Activity ◽  
Low Frequency ◽  
Cingulate Cortex ◽  
Posterior Cingulate Cortex ◽  
Anterior Cingulate ◽  
Network Activity ◽  
High Risk Behaviors ◽  
Posterior Cingulate ◽  
Healthy Humans ◽  
Dorsolateral Prefrontal

Negative urgency (NU) and positive urgency (PU) are implicated in several high-risk behaviors, such as eating disorders, substance use disorders, and nonsuicidal self-injury behavior. The current study aimed to explore the possible link between trait of urgency and brain activity at rest. We assessed the amplitude of low-frequency fluctuations (ALFF) of the resting-state functional magnetic resonance imaging (fMRI) signal in 85 healthy volunteers. Trait urgency measures were related to ALFF in the lateral orbitofrontal cortex, dorsolateral prefrontal cortex, ventral and dorsal medial frontal cortex, anterior cingulate, and posterior cingulate cortex/precuneus. In addition, trait urgency measures showed significant correlations with the functional connectivity of the posterior cingulate cortex/precuneus seed with the thalamus and midbrain region. These findings suggest an association between intrinsic brain activity and impulsive behaviors in healthy humans.

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