scholarly journals From Mechanisms to Functions: The Role of Synchronization in the Intrahippocampal Circuits

2021 ◽  
Author(s):  
Ivan Mysin ◽  
Liubov Shubina
Keyword(s):  
Information Processing ◽  
Information Transfer ◽  
Hippocampal Formation ◽  
Field Potential ◽  
Brain Regions ◽  
In Vivo Studies ◽  
Attention And Memory ◽  
Neuronal Spike ◽  
Gamma Frequency ◽  
The Brain

The brain rhythms are essential for information processing in neuronal networks. Oscillations recorded in different brain regions can be synchronized and have a constant phase difference, i.e. be coherent. Coherence between local field potential (LFP) signals from different regions in the brain may be correlated with the performance of cognitive tasks, from which it is concluded that these regions of the brain are involved in the task performance together. In this review, we discuss why coherence occurs and how it is coupled to the information transfer between different regions of the hippocampal formation. Coherence in theta and gamma frequency ranges is described since these rhythms are most pronounced during the hippocampus-dependent attention and memory. We review in vivo studies of interactions between different regions of the hippocampal formation in theta and gamma frequency bands. The kay provisions of the review: 1) coherence emerges from synchronous postsynaptic currents in principal neurons, occurring as a result of synchronization of neuronal spike activity; 2) synchronization of neuronal spike patterns in two regions of the hippocampal formation can be realised through induction or resonance; 3) coherence at a specific time point reflects the transfer of information between regions of the hippocampal formation, in particular, gamma coherence reflects the coupling of active neuronal ensembles. Overall, coherence is not an epiphenomenon, but an important physiological process that has certain generation mechanisms and performs important functions in information processing and transmission across the brain regions.

Capacity of a Single Spiking Neuron Channel

2009 ◽  
Vol 21 (6) ◽  
pp. 1714-1748 ◽  
Author(s):  
Shiro Ikeda ◽  
Jonathan H. Manton
Keyword(s):  
Information Processing ◽  
Channel Capacity ◽  
Information Transfer ◽  
Communication Channel ◽  
Discrete Distribution ◽  
Random Variable ◽  
Temporal Coding ◽  
Reasonable Assumption ◽  
Rate Coding ◽  
The Brain

Information transfer through a single neuron is a fundamental component of information processing in the brain, and computing the information channel capacity is important to understand this information processing. The problem is difficult since the capacity depends on coding, characteristics of the communication channel, and optimization over input distributions, among other issues. In this letter, we consider two models. The temporal coding model of a neuron as a communication channel assumes the output is τ where τ is a gamma-distributed random variable corresponding to the interspike interval, that is, the time it takes for the neuron to fire once. The rate coding model is similar; the output is the actual rate of firing over a fixed period of time. Theoretical studies prove that the distribution of inputs, which achieves channel capacity, is a discrete distribution with finite mass points for temporal and rate coding under a reasonable assumption. This allows us to compute numerically the capacity of a neuron. Numerical results are in a plausible range based on biological evidence to date.

scholarly journals Transitions in brain-network level information processing dynamics are driven by alterations in neural gain

2019 ◽  
Author(s):  
Mike Li ◽  
Yinuo Han ◽  
Matthew J. Aburn ◽  
Michael Breakspear ◽  
Russell A. Poldrack ◽  
...  
Keyword(s):  
Information Processing ◽  
Information Transfer ◽  
Large Scale ◽  
Functional Integration ◽  
Brain Network ◽  
Information Storage ◽  
Transfer Entropy ◽  
Arousal System ◽  
Neural Gain ◽  
The Brain

AbstractA key component of the flexibility and complexity of the brain is its ability to dynamically adapt its functional network structure between integrated and segregated brain states depending on the demands of different cognitive tasks. Integrated states are prevalent when performing tasks of high complexity, such as maintaining items in working memory, consistent with models of a global workspace architecture. Recent work has suggested that the balance between integration and segregation is under the control of ascending neuromodulatory systems, such as the noradrenergic system. In a previous large-scale nonlinear oscillator model of neuronal network dynamics, we showed that manipulating neural gain led to a ‘critical’ transition in phase synchrony that was associated with a shift from segregated to integrated topology, thus confirming our original prediction. In this study, we advance these results by demonstrating that the gain-mediated phase transition is characterized by a shift in the underlying dynamics of neural information processing. Specifically, the dynamics of the subcritical (segregated) regime are dominated by information storage, whereas the supercritical (integrated) regime is associated with increased information transfer (measured via transfer entropy). Operating near to the critical regime with respect to modulating neural gain would thus appear to provide computational advantages, offering flexibility in the information processing that can be performed with only subtle changes in gain control. Our results thus link studies of whole-brain network topology and the ascending arousal system with information processing dynamics, and suggest that the constraints imposed by the ascending arousal system constrain low-dimensional modes of information processing within the brain.Author summaryHigher brain function relies on a dynamic balance between functional integration and segregation. Previous work has shown that this balance is mediated in part by alterations in neural gain, which are thought to relate to projections from ascending neuromodulatory nuclei, such as the locus coeruleus. Here, we extend this work by demonstrating that the modulation of neural gain alters the information processing dynamics of the neural components of a biophysical neural model. Specifically, we find that low levels of neural gain are characterized by high Active Information Storage, whereas higher levels of neural gain are associated with an increase in inter-regional Transfer Entropy. Our results suggest that the modulation of neural gain via the ascending arousal system may fundamentally alter the information processing mode of the brain, which in turn has important implications for understanding the biophysical basis of cognition.

scholarly journals Neuroscience Research on Human Visual Path Integration: Empirical Overview and Strategic Considerations

2021 ◽  
Author(s):  
Jimmy Y. Zhong
Keyword(s):  
Path Integration ◽  
Hippocampal Formation ◽  
Brain Activity ◽  
Brain Regions ◽  
Neural Basis ◽  
Age Related ◽  
Neuroscience Research ◽  
Integration Strategies ◽  
The Impact ◽  
The Brain

Over the past two decades, many neuroimaging studies have attempted uncover the brain regions and networks involved in path integration and identify the underlying neurocognitive mechanisms. Although these studies made inroads into the neural basis of path integration, they have yet to offer a full disclosure of the functional specialization of the brain regions supporting path integration. In this paper, I reviewed notable neuroscientific studies on visual path integration in humans, identified the commonalities and discrepancies in their findings, and incorporated fresh insights from recent path integration studies. Specifically, this paper presented neuroscientific studies performed with virtual renditions of the triangle/path completion task and addressed whether or not the hippocampus is necessary for human path integration. Based on studies that showed evidence supporting and negating the involvement of the hippocampal formation in path integration, this paper introduces the proposal that the use of different path integration strategies may determine the extent to which the hippocampus and entorhinal cortex are engaged during path integration. To this end, recent studies that investigated the impact of different path integration strategies on behavioral performance and functional brain activity were discussed. Methodological concerns were raised with feasible recommendations for improving the experimental design of future strategy-related path integration studies, which can cover cognitive neuroscience research on age-related differences in the role of the hippocampal formation in path integration and Bayesian modelling of the interaction between landmark and self-motion cues. The practical value of investigating different path integration strategies was also discussed briefly from a biomedical perspective.

scholarly journals Dentate Gyrus and CA3 GABAergic Interneurons Bidirectionally Modulate Signatures of Internal and External Drive to CA1

2021 ◽  
Author(s):  
Emily A. Aery Jones ◽  
Antara Rao ◽  
Misha Zilberter ◽  
Biljana Djukic ◽  
Anna K. Gillespie ◽  
...  
Keyword(s):  
Information Processing ◽  
Dentate Gyrus ◽  
Entorhinal Cortex ◽  
Local Field ◽  
Opposite Effect ◽  
Field Potential ◽  
Gabaergic Neurons ◽  
Gabaergic Interneurons ◽  
Flow Of Information ◽  
The Brain

SUMMARYSpecific classes of GABAergic neurons are thought to play specific roles in regulating information processing in the brain. In the hippocampus, two major classes – parvalbumin-expressing (PV+) and somatostatin-expressing (SST+) neurons – differentially regulate endogenous firing patterns and target different subcellular compartments of principal cells, but how these classes regulate the flow of information throughout the hippocampus is poorly understood. We hypothesized that PV+ and SST+ interneurons in the dentate gyrus (DG) and CA3 might differentially modulate CA3 patterns of output, thereby altering the influence of CA3 on CA1. We found that while suppressing either interneuron type increased DG and CA3 output, the effects on CA1 were very different. Suppressing PV+ interneurons increased local field potential signatures of coupling from CA3 to CA1 and decreased signatures of coupling from entorhinal cortex to CA1; suppressing SST+ interneurons had the opposite effect. Thus, DG and CA3 PV+ and SST+ interneurons bidirectionally modulate the flow of information through the hippocampal circuit.

scholarly journals The deep and slow breathing characterizing rest favors brain respiratory-drive

2020 ◽  
Author(s):  
Baptiste Girin ◽  
Maxime Juventin ◽  
Samuel Garcia ◽  
Laura Lefèvre ◽  
Corine Amat ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Field Potential ◽  
Brain Regions ◽  
Airflow Rate ◽  
Respiratory Drive ◽  
Nasal Airflow ◽  
Waking And Sleep ◽  
Potential Activity ◽  
Slow Breathing ◽  
The Brain

A respiration-locked activity in the olfactory brain, mainly originating in the mechano-sensitivity of olfactory sensory neurons to air pressure, propagates from the olfactory bulb to the rest of the brain. Interestingly, changes in nasal airflow rate result in reorganization of olfactory bulb response. Therefore, if the respiratory drive of the brain originates in nasal airflow movements, then it should vary with respiration dynamics that occur spontaneously during natural conditions. We took advantage of the spontaneous variations of respiration dynamics during the different waking and sleep states to explore respiratory drive in various brain regions. We analyzed their local field potential activity relative to respiratory signal. We showed that respiration regime was state-specific, and that quiet waking was the only vigilance state during which all the recorded structures can be respiration-driven whatever the respiration frequency. We used a CO2-enriched air to change the respiratory regime associated to each state and, using a respiratory cycle-by-cycle analysis, we evidenced that the large and strong brain entrainment during quiet waking was the consequence of its associated respiration regime consisting in an optimal trade-off between deepness and duration of inspiration. These results show for the first time that changes in respiration regime alter the cortical dynamics and that the respiratory regime associated with rest is optimal for respiration to drive the brain.

20 years after “The ontogeny of human memory: A cognitive neuroscience perspective,” where are we?

2015 ◽  
Vol 39 (4) ◽  
pp. 293-303 ◽  
Author(s):  
Adeline Jabès ◽  
Charles A Nelson
Keyword(s):  
Cognitive Neuroscience ◽  
Explicit Memory ◽  
Structural Changes ◽  
Current Knowledge ◽  
Hippocampal Formation ◽  
Human Memory ◽  
Brain Regions ◽  
Memory Functions ◽  
Current Article ◽  
The Brain

In 1995, Nelson published a paper describing a model of memory development during the first years of life. The current article seeks to provide an update on the original work published 20 years ago. Specifically, we review our current knowledge on the relation between the emergence of explicit memory functions throughout development and the maturation of associated brain regions. It is now well established that the brain regions subserving explicit memory functions (i.e. the hippocampal formation) are far from mature at birth, and exhibit important and gradual structural changes during childhood and beyond. Accordingly, explicit memory functions develop progressively. While some functions are present shortly after birth (formerly proposed as pre-explicit memory), others exhibit protracted developmental profiles during the first years of life. We examine the link between the emergence of different memory functions and the maturation of specific hippocampal circuits.

Neural Mechanisms of Evaluation and Memory of Product

2014 ◽  
Author(s):  
Kazutaka Ueda
Keyword(s):  
Cognitive Processes ◽  
Declarative Memory ◽  
Brain Activity ◽  
Neural Model ◽  
Product Evaluation ◽  
Brain Regions ◽  
Preference Rating ◽  
Gamma Frequency ◽  
The Brain ◽  
Healthy Participants

A consumer’s emotional response to a product is influenced by cognitive processes, such as memories associated with use of the product and expectations of its performance. Here, we propose a cognitive neural model of Expectology, called PEAM (Prediction - Experience - Appraisal - Memory), as a novel tool that considers consumers’ emotional responses in order to aid in product design. The PEAM model divides cognitive processes associated with product use into 4 phases: prediction, experience, appraisal, and memory. We examined the spatiotemporal changes in brain activity associated with product evaluation and memory during the prediction phase, by obtaining electroencephalograms (EEGs). EEGs of 10 healthy participants with normal or corrected-to-normal vision were recorded while they viewed images of products as well as when they provided a preference rating for each product. Our results revealed significantly increased neural activity in the gamma frequency in the temporal areas, the brain regions where declarative memory is stored, and in the prefrontal area for products that were rated as preferable. Our data suggest that memory is used for product evaluation in the prediction phase. These findings also suggest that activity in these specific brain areas are reliable predictors for product evaluation.

scholarly journals Towards an information theoretical description of communication in brain networks

2021 ◽  
pp. 1-23
Author(s):  
Enrico Amico ◽  
Kausar Abbas ◽  
Duy Anh Duong-Tran ◽  
Uttara Tipnis ◽  
Meenusree Rajapandian ◽  
...  
Keyword(s):  
Information Transfer ◽  
Large Scale ◽  
Brain Networks ◽  
Brain Regions ◽  
Brain Network ◽  
Theoretical Description ◽  
Structural Topology ◽  
Communication Dynamics ◽  
The Brain ◽  
The Way

Modeling communication dynamics in the brain is a key challenge in network neuroscience. We present here a framework that combines two measurements for any system where different communication processes are taking place on top of a fixed structural topology: Path Processing Score (PPS) estimates how much the brain signal has changed or has been transformed between any two brain regions (source and target); Path Broadcasting Strength (PBS) estimates the propagation of the signal through edges adjacent to the path being assessed. We use PPS and PBS to explore communication dynamics in large-scale brain networks. We show that brain communication dynamics can be divided into three main “communication regimes” of information transfer: absent communication (no communication happening); relay communication (information is being transferred almost intact); transducted communication (the information is being transformed). We use PBS to categorize brain regions based on the way they broadcast information. Subcortical regions are mainly direct broadcasters to multiple receivers; Temporal and frontal nodes mainly operate as broadcast relay brain stations; Visual and somato-motor cortices act as multi-channel transducted broadcasters. This work paves the way towards the field of brain network information theory by providing a principled methodology to explore communication dynamics in large-scale brain networks.

scholarly journals Networked information interactions of epileptic EEG based on symbolic transfer entropy

2019 ◽  
Author(s):  
Wenpo Yao ◽  
Jun Wang
Keyword(s):  
Healthy Subjects ◽  
Information Transfer ◽  
Probability Distributions ◽  
Brain Area ◽  
Brain Regions ◽  
Transfer Entropy ◽  
Symbolic Transfer Entropy ◽  
Electrical Activities ◽  
The Brain

AbstractIdentifying networked information exchanges among brain regions is important for understanding the brain structure. We employ symbolic transfer entropy to facilitate the construction of networked information interactions for EEGs of 22 epileptics and 22 healthy subjects. The epileptic patients during seizure-free interval have lower information transfer in each individual and whole brain regions than the healthy subjects. Among all of the brain regions, the information flows out of and into the brain area of O1 of the epileptic EEGs are significantly lower than those of the healthy (p<0.0005), and the information flow from F7 to F8 (p<0.00001) is particularly promising to discriminate the two groups of EEGs. Moreover, Shannon entropy of probability distributions of information exchanges suggests that the healthy EEGs have higher complexity and irregularity than the epileptic brain electrical activities. By characterizing the brain networked information interactions, our findings highlight the long-term reduced information exchanges, degree of brain interactivities and informational complexity of the epileptic EEG.

scholarly journals The mGluR2/3 agonist LY379268 reverses NMDA receptor antagonist effects on cortical gamma oscillations and phase coherence, but not working memory impairments, in mice

2019 ◽  
Vol 33 (12) ◽  
pp. 1588-1599 ◽  
Author(s):  
Elysia Sokolenko ◽  
Matthew R Hudson ◽  
Jess Nithianantharajah ◽  
Nigel C Jones
Keyword(s):  
Working Memory ◽  
Nmda Receptor ◽  
Metabotropic Glutamate Receptor ◽  
Dorsal Hippocampus ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Nmda Receptor Antagonist ◽  
Mk 801 ◽  
Gamma Frequency

Background: Abnormalities in neural oscillations that occur in the gamma frequency range (30–80 Hz) may underlie cognitive deficits in schizophrenia. Both cognitive impairments and gamma oscillatory disturbances can be induced in healthy people and rodents by administration of N-methyl-D-aspartate receptor (NMDAr) antagonists. Aims: We studied relationships between cognitive impairment and gamma abnormalities following NMDAr antagonism, and attempted to reverse deficits with the metabotropic glutamate receptor type 2/3 (mGluR2/3) agonist LY379268. Methods: C57/Bl6 mice were trained to perform the Trial-Unique Nonmatching to Location (TUNL) touchscreen test for working memory. They were then implanted with local field potential (LFP) recording electrodes in prefrontal cortex and dorsal hippocampus. Mice were administered either LY379268 (3 mg/kg) or vehicle followed by the NMDAr antagonist MK-801 (0.3 or 1 mg/kg) or vehicle prior to testing on the TUNL task, or recording LFPs during the presentation of an auditory stimulus. Results: MK-801 impaired working memory and increased perseveration, but these behaviours were not improved by LY379268 treatment. MK-81 increased the power of ongoing gamma and high gamma (130–180 Hz) oscillations in both brain regions and regional coherence between regions, and these signatures were augmented by LY379268. However, auditory-evoked gamma oscillation deficits caused by MK-801 were not affected by LY379268 pretreatment. Conclusions: NMDA receptor antagonism impairs working memory in mice, but this is not reversed by stimulation of mGluR2/3. Since elevations in ongoing gamma power and regional coherence caused by MK-801 were improved by LY379268, it appears unlikely that these specific oscillatory abnormalities underlie the working memory impairment caused by NMDAr antagonism.

Sign in / Sign up

Export Citation Format

Share Document