scholarly journals Interhemispheric gamma synchrony between parvalbumin interneurons supports behavioral adaptation

2019 ◽  
Author(s):  
Kathleen K.A. Cho ◽  
Thomas J. Davidson ◽  
Jesse D. Marshall ◽  
Mark J. Schnitzer ◽  
Vikaas S. Sohal
Keyword(s):  
Behavioral Outcomes ◽  
Neural Systems ◽  
Voltage Imaging ◽  
Neuronal Communication ◽  
New Associations ◽  
Gamma Frequency ◽  
Parvalbumin Interneurons ◽  
Cell Type Specific ◽  
Brain States ◽  
Gamma Synchrony

AbstractOrganisms 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within prefrontal parvalbumin interneurons, when mice received feedback that previously-learned associations were no longer valid. Disrupting this synchronization by delivering out-of-phase optogenetic stimulation caused mice to perseverate on outdated associations, an effect not reproduced by stimulating in-phase or out-of-phase at other frequencies.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.

scholarly journals Molecular and cellular adaptations in hippocampal parvalbumin neurons mediate behavioral responses to chronic social stress

2021 ◽  
Author(s):  
Dionnet L Bhatti ◽  
Lucian Medrihan ◽  
Michelle X Chen ◽  
Junghee Jin ◽  
Kathryn McCabe ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Affinity Purification ◽  
Behavioral Outcomes ◽  
Behavioral Responses ◽  
Specific Gene ◽  
Mrna Levels ◽  
Cell Type ◽  
Stress Resilience ◽  
Cell Type Specific ◽  
Stress Susceptibility

BACKGROUND: Behavioral responses to stress are, in part, mediated by the hippocampus and Parvalbumin (PV)-expressing neurons. However, whether chronic stress induces molecular and cellular adaptations in hippocampal PV neurons contribute to stress-induced behavioral outcomes remains elusive. METHOD: Using chronic social defeat stress (CSDS), we investigated the role of neuronal activity and gene expression in hippocampal PV neurons in mediating stress-resilience and -susceptibility. We first used in vivo high-density silicon probe recordings and chemogenetics to test whether the activity of PV neurons in ventral dentate gyrus (PVvDG) is associated with particular behavioral outcomes. To find critical molecular pathways associated with stress-resilience and -susceptibility, we used PV-neuron-selective translating ribosome affinity purification and RNAseq. We used immunoblotting, RNAscope, and region- or cell type-specific gene deletion to determine whether Ahnak, a molecule regulating depression-like behavior, was necessary for behavioral divergence after CSDS. RESULTS: We find CSDS modulates neuronal activity in vDG. Notably, stress-susceptibility is associated with an increase of PVvDG firing, which we find is necessary and sufficient for susceptibility. Additionally, genes involved in mitochondrial function, protein synthesis and synaptogenesis are differentially expressed in hippocampal PV neurons of stress-resilient and -susceptible mice. Interestingly, protein and mRNA levels of Ahnak, an endogenous regulator of L-type calcium channels are associated with susceptibility after CSDS. vDG- and PV cell type-specific deletions reveal that Ahnak is required for stress-susceptibility to CSDS. CONCLUSIONS: These findings indicate that CSDS-induced molecular and cellular adaptations in hippocampal PV neurons mediate behavioral consequences, proposing a mechanism underlying individual differences in stress vulnerability.

Roles of default-mode network and supplementary motor area in human vigilance performance: evidence from real-time fMRI

2013 ◽  
Vol 109 (5) ◽  
pp. 1250-1258 ◽  
Author(s):  
Oliver Hinds ◽  
Todd W. Thompson ◽  
Satrajit Ghosh ◽  
Julie J. Yoo ◽  
Susan Whitfield-Gabrieli ◽  
...  
Keyword(s):  
Real Time ◽  
Default Mode Network ◽  
Human Performance ◽  
Supplementary Motor Area ◽  
Brain Regions ◽  
Motor Area ◽  
Neural Systems ◽  
Brain State ◽  
Default Mode ◽  
Brain States

We used real-time functional magnetic resonance imaging (fMRI) to determine which regions of the human brain have a role in vigilance as measured by reaction time (RT) to variably timed stimuli. We first identified brain regions where activation before stimulus presentation predicted RT. Slower RT was preceded by greater activation in the default-mode network, including lateral parietal, precuneus, and medial prefrontal cortices; faster RT was preceded by greater activation in the supplementary motor area (SMA). We examined the roles of these brain regions in vigilance by triggering trials based on brain states defined by blood oxygenation level-dependent activation measured using real-time fMRI. When activation of relevant neural systems indicated either a good brain state (increased activation of SMA) or a bad brain state (increased activation of lateral parietal cortex and precuneus) for performance, a target was presented and RT was measured. RTs on trials triggered by a good brain state were significantly faster than RTs on trials triggered by a bad brain state. Thus human performance was controlled by monitoring brain states that indicated high or low vigilance. These findings identify neural systems that have a role in vigilance and provide direct evidence that the default-mode network has a role in human performance. The ability to control and enhance human behavior based on brain state may have broad implications.

scholarly journals Estimating anisotropy directly via neural timeseries

2021 ◽  
Author(s):  
Erik D. Fagerholm ◽  
W.M.C. Foulkes ◽  
Yasir Gallero-Salas ◽  
Fritjof Helmchen ◽  
Rosalyn J. Moran ◽  
...  
Keyword(s):  
Synthetic Data ◽  
Neural Systems ◽  
Imaging Data ◽  
Individual Organism ◽  
Model Inversion ◽  
Brain States ◽  
Anisotropic Systems ◽  
Cortical Regions ◽  
Insight Into

An isotropic dynamical system is one that looks the same in every direction, i.e., if we imagine standing somewhere within an isotropic system, we would not be able to differentiate between different lines of sight. Conversely, anisotropy is a measure of the extent to which a system deviates from perfect isotropy, with larger values indicating greater discrepancies between the structure of the system along its axes. Here, we derive the form of a generalised scalable (mechanically similar) discretized field theoretic Lagrangian that allows for levels of anisotropy to be directly estimated via timeseries of arbitrary dimensionality. We generate synthetic data for both isotropic and anisotropic systems and, by using Bayesian model inversion and reduction, show that we can discriminate between the two datasets - thereby demonstrating proof of principle. We then apply this methodology to murine calcium imaging data collected in rest and task states, showing that anisotropy can be estimated directly from different brain states and cortical regions in an empirical in vivo biological setting. We hope that this theoretical foundation, together with the methodology and publicly available MATLAB code, will provide an accessible way for researchers to obtain new insight into the structural organization of neural systems in terms of how scalable neural regions grow - both ontogenetically during the development of an individual organism, as well as phylogenetically across species.

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

2021 ◽  
Author(s):  
Jingcheng Shi ◽  
Aarron J Phensy ◽  
Vikaas Singh Sohal
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Sensory Stimulation ◽  
Auditory Stimulation ◽  
Invasive Treatment ◽  
Non Invasive ◽  
Gamma Frequency ◽  
Gamma Synchrony ◽  
Circuit Function ◽  
40 Hz

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.

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

2019 ◽  
Vol 11 (1) ◽  
pp. 13-40
Author(s):  
Judith Pennington ◽  
Debbie Sabot ◽  
Dawson Church
Keyword(s):  
Stress Reduction ◽  
Mental States ◽  
High Amplitude ◽  
Emotional States ◽  
Brain Wave ◽  
Eyes Closed ◽  
States Of Consciousness ◽  
Brain States ◽  
Gamma Synchrony ◽  
Emotional Freedom Techniques

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.

scholarly journals Cross-hemispheric gamma synchrony between prefrontal parvalbumin interneurons supports behavioral adaptation during rule shift learning

2020 ◽  
Vol 23 (7) ◽  
pp. 892-902 ◽  
Author(s):  
Kathleen K. A. Cho ◽  
Thomas J. Davidson ◽  
Guy Bouvier ◽  
Jesse D. Marshall ◽  
Mark J. Schnitzer ◽  
...  
Keyword(s):  
Behavioral Adaptation ◽  
Parvalbumin Interneurons ◽  
Gamma Synchrony

scholarly journals Voltage imaging to understand connections and functions of neuronal circuits

2016 ◽  
Vol 116 (1) ◽  
pp. 135-152 ◽  
Author(s):  
Srdjan D. Antic ◽  
Ruth M. Empson ◽  
Thomas Knöpfel
Keyword(s):  
Cellular Mechanisms ◽  
Voltage Imaging ◽  
Brain Functions ◽  
Brain Circuits ◽  
Learned Behaviors ◽  
Cell Type Specific ◽  
Circuit And System ◽  
Novel Approaches ◽  
Made In

Understanding of the cellular mechanisms underlying brain functions such as cognition and emotions requires monitoring of membrane voltage at the cellular, circuit, and system levels. Seminal voltage-sensitive dye and calcium-sensitive dye imaging studies have demonstrated parallel detection of electrical activity across populations of interconnected neurons in a variety of preparations. A game-changing advance made in recent years has been the conceptualization and development of optogenetic tools, including genetically encoded indicators of voltage (GEVIs) or calcium (GECIs) and genetically encoded light-gated ion channels (actuators, e.g., channelrhodopsin2). Compared with low-molecular-weight calcium and voltage indicators (dyes), the optogenetic imaging approaches are 1) cell type specific, 2) less invasive, 3) able to relate activity and anatomy, and 4) facilitate long-term recordings of individual cells' activities over weeks, thereby allowing direct monitoring of the emergence of learned behaviors and underlying circuit mechanisms. We highlight the potential of novel approaches based on GEVIs and compare those to calcium imaging approaches. We also discuss how novel approaches based on GEVIs (and GECIs) coupled with genetically encoded actuators will promote progress in our knowledge of brain circuits and systems.

scholarly journals Subthreshold Voltage Analysis Demonstrates Neuronal Cell-Surface Sialic Acids Modulate Excitability and Network Integration

2020 ◽  
Author(s):  
Rishikesh U. Kulkarni ◽  
Catherine L. Wang ◽  
Carolyn R. Bertozzi
Keyword(s):  
Functional Connectivity ◽  
Hippocampal Neurons ◽  
Neuronal Cell ◽  
Thick Layer ◽  
Pharmacological Interventions ◽  
Voltage Imaging ◽  
Neuronal Communication ◽  
Culture Model ◽  
Neurological Processes ◽  
Subthreshold Voltage

SummaryAll neurons are covered in a thick layer of carbohydrates called glycans. Glycans are modified during neurological processes and are thought to play a role in neuronal communication. We develop a voltage imaging platform for analyzing functional connectivity changes using simultaneous voltage recordings in small populations of neurons. We validate this platform using a culture model of development as well as with several pharmacological interventions. Using this platform, we show that ablation of SNA-binding glycans results in loss of functional connectivity in mouse hippocampal neurons, while ablation of MAL II binding glycans minimally perturbs functional connectivity. Altogether, our data reveal that subpopulations of glycans play different roles in maintenance of electrophysiology and provide a platform for modeling changes in functional connectivity with simultaneous voltage recordings.

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