Rhythmic auditory stimulation rescues cognitive flexibility in mutant mice with impaired gamma synchrony

Neural synchronization at gamma (~40 Hz) frequencies is believed to contribute to brain function and be deficient in disorders including Alzheimer's disease and schizophrenia. Gamma-frequency sensory stimulation has been proposed as a non-invasive treatment for deficient gamma synchrony and associated cognitive deficits, and has been shown to be effective in mouse models of Alzheimer's disease. However, both the mechanism and applicability of this approach remain unclear. Here we tested this approach using mutant (Dlx5/6+/-) mice which have deficits in gamma synchrony and the ability to learn to shift between rules which use different types of cues to indicate reward locations. 40 Hz auditory stimulation rescues rule shifting in Dlx5/6+/- mice. However, this improvement does not outlast the period of stimulation, and is not associated with normalized gamma synchrony, measured using genetically encoded voltage indicators. These results show how gamma-frequency sensory stimulation may improve behavior without fully restoring normal circuit function.

Decreased Gamma Auditory Steady-State Response Is Associated With Impaired Real-World Functioning in Unmedicated Patients at Clinical High Risk for Psychosis

Aim Deficits in synchronous, gamma-frequency neural oscillations may contribute to schizophrenia patients’ real-world functional impairment and can be measured electroencephalographically using the auditory steady-state response (ASSR). Gamma ASSR deficits have been reported in schizophrenia patients and individuals at clinical high risk (CHR) for developing psychosis. We hypothesized that, in CHR patients, gamma ASSR would correlate with real-world functioning, consistent with a role for gamma synchrony deficits in functional impairment. Methods A total of 35 CHR patients rated on Global Functioning: Social and Role scales had EEG recorded while listening to 1-ms, 93-dB clicks presented at 40 Hz in 500-ms trains, in response to which 40-Hz evoked power and intertrial phase-locking factor (PLF) were measured. Results In CHR patients, lower 40-Hz PLF correlated with lower social functioning. Conclusions Gamma synchrony deficits may be a biomarker of real-world impairment at early stages of the schizophrenia disease trajectory.

From Coral to Coal

From coral to coal. A course from life to decay; from fluid plasticity to sedimentary rigidity; from tropical reef polyps expansion to combustible oxidative free radicals reaction; from expression to suppression; from flourish to perish. All these contrasting dynamics, this vivid antithesis of an integer ecosystem to a compressed peat bog, this endless colorful miracle of delight to a blackish stratum shell of scorn, get to be defined by a single letter; an “r”. The reflection that stands in between and makes all the difference; the reflection that stands in between and as a pivotal criterion reverberates opposed conditions and qualities; the reflection that stands in between and as a sword decides and divides. Which way it will be: light or darkness, real or unreal, allostasis or allostatic load, neuroinflammation or neuroprotection, progressive neurodegeneration or cell control and communication, gamma synchrony or hyperexcitability, well-being or mind-body infirmity, is determined by a serious consideration and careful thought. The conceptual operation of inverting a system or event with respect to a plane. A level of existence and cogitation, or development in accordance with a vectoring, a direction, orientation and attention. And for all the above, the mind-eye mirror connection which perceives and interprets, and creates a neuronal abstract substrate of bound distinct circuits that form as a whole memory, undoubtedly holds the key.

Interhemispheric gamma synchrony between parvalbumin interneurons supports behavioral adaptation

Organisms must learn novel strategies to adapt to changing environments. Synchrony, which enhances neuronal communication, might create dynamic brain states, facilitating such adaptation. Although synchronization is common in neural systems, its functional significance remains controversial. We studied the role of gamma-frequency (~40 Hz) synchronization, promoted by parvalbumin interneurons, in mice learning multiple new cue-reward associations. Voltage imaging revealed cell type-specific increases of interhemispheric gamma synchrony within prefrontal parvalbumin interneurons, when mice received feedback that previously-learned associations were no longer valid. Disrupting this synchronization by delivering out-of-phase optogenetic stimulation caused mice to perseverate on outdated associations, an effect not reproduced by stimulating in-phase or out-of-phase at other frequencies. Gamma synchrony was specifically required when new associations utilized familiar cues that were previously irrelevant to behavioral outcomes, not when associations involved novel cues, or for reversing previously learned associations. Thus, gamma synchrony is indispensable for reappraising the behavioral salience of external cues.

EcoMeditation and Emotional Freedom Techniques (EFT) Produce Elevated Brain-wave Patterns and States of Consciousness

Background Stress-reduction techniques can be used in combination with each other. Two such methods are Emotional Freedom Techniques (EFT) and EcoMeditation. EFT is an evidence-based self-help method. Reviews and meta-analyses examining more than 100 studies demonstrate the efficacy of EFT for anxiety, depression, and posttraumatic stress disorder (PTSD). EcoMeditation is a secular meditation technique that combines neurofeedback, mindfulness, and heart coherence. Studies demonstrate that EFT and EcoMeditation can improve cortisol levels, heart rate, and other health markers. Objectives EFT is most commonly used to relieve stress and treat traumatic childhood memories, while EcoMeditation is used to produce calm emotional states. This study sought to elucidate whether the release of traumatic stress facilitated by EFT would enhance entry into meditative states, and secondly whether EcoMeditation prior to EFT might establish a baseline of wellbeing that assists in the resolution of trauma. Methods The Mind Mirror 6 (MM) electroencephalogram (EEG) was used to assess brain states in eight participants attending a weekend workshop. The MM measures changes in three advanced neurophysiological states of consciousness characterized by relative amplitude relationships between brain-wave frequencies: 1) the Awakened Mind pattern of lucid awareness, creativity, insight, intuition, and spiritual connection; 2) the Evolved Mind of nondual unity consciousness; and 3) the Gamma Synchrony pattern of whole-brain synchrony, mental integration, nonlocal awareness, and insight. Assessments included eyes-closed (EC) and eyes-open (EO) states, in order to determine whether changes in consciousness were sustained in waking life. Baselines were collected at the start and end of each day, and after EcoMeditation, which was performed for 20 minutes on day two. Results A statistically significant EO posttest change was found in the Awakened Mind pattern (p = 0.003). Cohen’s d = 0.79 indicated a large treatment effect. Increased brainwave coherence—a measure of efficient brain function—was found in all participants in at least one frequency category, while six increased EO Gamma Synchrony. Coherence analytics showed increased brain-wave coherence primarily in alpha but also in theta and delta and occasionally in low and midrange gamma. During EcoMeditation, all participants generated high-amplitude 45–65 Hz gamma frequencies and Gamma Synchrony values, some at the top of the statistical range, with high synchrony at posttest. Conclusions EcoMeditation produced extraordinarily high levels of Gamma Synchrony. In two days, many participants acquired elevated brain states normally found only after years of meditation practice. EcoMeditation facilitated participants’ ability to induce and sustain the alpha brain waves characteristic of high-level emotional, mental, and spiritual integration. A combination of the two methods produced statistical gains in the EO Awakened Mind, indicating that participants were able to carry elevated mental states into waking consciousness.