Internally Organized Activity During Offline Brain States

2019 ◽  
pp. 199-218
Author(s):  
György Buzsáki
Keyword(s):  
Trial And Error ◽  
The Past ◽  
Sharp Wave ◽  
Assembly Sequences ◽  
Brain States ◽  
Episodic Memories ◽  
Neuronal Assembly ◽  
Vicarious Trial And Error ◽  
The Brain ◽  
Future Plans

A prime example of internally organized patterns is observed during sleep. The best studied of these is the sharp wave ripple in the hippocampus. Neuronal sequences during ripple events reach back to the past to replay snippets of waking experience at times when the brain is disengaged from the outside world. This process may consolidate episodic memories and stitch together discontiguous experiences, thereby giving rise to creative thoughts. In addition, neuronal assembly sequences during ripples also act as internalized, vicarious, trial-and-error mechanisms that can assist with subconscious optimization of future plans. Because the same neuronal substrate can perform both retrospective and prospective operations, it is not clear whether the traditional separation of postdiction (i.e., memory) from prediction (i.e., planning) is justified.

scholarly journals Unsupervised seizure localisation with attention-based graph neural networks

2020 ◽  
Author(s):  
Daniele Grattarola ◽  
Lorenzo Livi ◽  
Cesare Alippi ◽  
Richard Wennberg ◽  
Taufik Valiante
Keyword(s):  
Neural Networks ◽  
Brain Activity ◽  
Functional Networks ◽  
Seizure Onset ◽  
The Past ◽  
Seizure Onset Zone ◽  
Brain States ◽  
Graph Neural Networks ◽  
Intracranial Electroencephalography ◽  
The Brain

Abstract Graph neural networks (GNNs) and the attention mechanism are two of the most significant advances in artificial intelligence methods over the past few years. The former are neural networks able to process graph-structured data, while the latter learns to selectively focus on those parts of the input that are more relevant for the task at hand. In this paper, we propose a methodology for seizure localisation which combines the two approaches. Our method is composed of several blocks. First, we represent brain states in a compact way by computing functional networks from intracranial electroencephalography recordings, using metrics to quantify the coupling between the activity of different brain areas. Then, we train a GNN to correctly distinguish between functional networks associated with interictal and ictal phases. The GNN is equipped with an attention-based layer which automatically learns to identify those regions of the brain (associated with individual electrodes) that are most important for a correct classification. The localisation of these regions is fully unsupervised, meaning that it does not use any prior information regarding the seizure onset zone. We report results both for human patients and for simulators of brain activity. We show that the regions of interest identified by the GNN strongly correlate with the localisation of the seizure onset zone reported by electroencephalographers. We also show that our GNN exhibits uncertainty on those patients for which the clinical localisation was also unsuccessful, highlighting the robustness of the proposed approach.

scholarly journals Predictability changes what we remember in familiar temporal contexts

2018 ◽  
Author(s):  
Hyojeong Kim ◽  
Margaret L. Schlichting ◽  
Alison R. Preston ◽  
Jarrod A. Lewis-Peacock
Keyword(s):  
Human Brain ◽  
Pattern Classification ◽  
Prediction Error ◽  
Fmri Data ◽  
The Past ◽  
The Future ◽  
Abstract Level ◽  
Episodic Memories ◽  
The Brain

AbstractThe human brain constantly anticipates the future based on memories of the past. Encountering a familiar situation reactivates memory of previous encounters which can trigger a prediction of what comes next to facilitate responsiveness. However, a prediction error can lead to pruning of the offending memory, a process that weakens its representation in the brain and leads to forgetting. Our goal in this study was to evaluate whether memories are spared from pruning in situations that allow for more abstract yet reliable predictions. We hypothesized that when the category, but not the identity, of a new stimulus can be anticipated, this will reduce pruning of existing memories and also reduce encoding of the specifics of new memories. Participants viewed a sequence of objects, some of which reappeared multiple times (“cues”), followed always by novel items. Half of the cues were followed by new items from different (unpredictable) categories, while others were followed by new items from a single (predictable) category. Pattern classification of fMRI data was used to identify category-specific predictions after each cue. Pruning was observed only in unpredictable contexts, while encoding of new items suffered more in predictable contexts. These findings demonstrate that how episodic memories are updated is influenced by the reliability of abstract-level predictions in familiar contexts.

scholarly journals Interplay between Hippocampal Sharp-Wave-Ripple Events and Vicarious Trial and Error Behaviors in Decision Making

Neuron ◽  
2016 ◽  
Vol 92 (5) ◽  
pp. 975-982 ◽  
Author(s):  
Andrew E. Papale ◽  
Mark C. Zielinski ◽  
Loren M. Frank ◽  
Shantanu P. Jadhav ◽  
A. David Redish
Keyword(s):  
Decision Making ◽  
Trial And Error ◽  
Sharp Wave ◽  
Vicarious Trial And Error

NON-INVASIVE BCI METHOD: EEG - ELECTROENCEPHALOGRAPHY

2019 ◽  
pp. 139-145
Author(s):  
Selma Büyükgöze
Keyword(s):  
Brain Computer Interface ◽  
Computer Interface ◽  
Electrode Placement ◽  
Eeg Signals ◽  
Non Invasive ◽  
Brain Signals ◽  
Brain States ◽  
The Brain

Brain Computer Interface consists of hardware and software that convert brain signals into action. It changes the nerves, muscles, and movements they produce with electro-physiological signs. The BCI cannot read the brain and decipher the thought in general. The BCI can only identify and classify specific patterns of activity in ongoing brain signals associated with specific tasks or events. EEG is the most commonly used non-invasive BCI method as it can be obtained easily compared to other methods. In this study; It will be given how EEG signals are obtained from the scalp, with which waves these frequencies are named and in which brain states these waves occur. 10-20 electrode placement plan for EEG to be placed on the scalp will be shown.

Neuro-Clinical Signatures of Language Impairments: A Theoretical Framework for Function-to-structure Mapping in Clinics

2020 ◽  
Vol 20 (9) ◽  
pp. 800-811 ◽  
Author(s):  
Ferath Kherif ◽  
Sandrine Muller
Keyword(s):  
Brain Mapping ◽  
Theoretical Framework ◽  
Brain Regions ◽  
Language Impairments ◽  
Structure Mapping ◽  
Language Functions ◽  
The Past ◽  
Language Recovery ◽  
The Brain ◽  
Bow Tie

In the past decades, neuroscientists and clinicians have collected a considerable amount of data and drastically increased our knowledge about the mapping of language in the brain. The emerging picture from the accumulated knowledge is that there are complex and combinatorial relationships between language functions and anatomical brain regions. Understanding the underlying principles of this complex mapping is of paramount importance for the identification of the brain signature of language and Neuro-Clinical signatures that explain language impairments and predict language recovery after stroke. We review recent attempts to addresses this question of language-brain mapping. We introduce the different concepts of mapping (from diffeomorphic one-to-one mapping to many-to-many mapping). We build those different forms of mapping to derive a theoretical framework where the current principles of brain architectures including redundancy, degeneracy, pluri-potentiality and bow-tie network are described.

Brains as Engines of Association

2019 ◽  
Author(s):  
Dale Purves
Keyword(s):  
Neural Systems ◽  
Neural Function ◽  
Trial And Error ◽  
Nervous Systems ◽  
The Past ◽  
Sensing Systems ◽  
Lifetime Experience ◽  
Survival And Reproduction ◽  
Pros And Cons ◽  
And Behavior

Brains as Engines of Association seeks an operating principle of the human brain and is divided into four parts. The first part (“What Nervous Systems Do for Animals”) is intended to set the stage for understanding the emergence of neural systems as promoting what all organisms must accomplish: survival and reproduction. The second part (“Neural Systems as Engines of Association”) lays out the general argument that biological sensing systems face a daunting problem: they cannot measure the parameters of the world in the way physical instruments can. As a result, nervous systems must make and update associations (synaptic connections) on the basis of empirical success or failure over both evolutionary and individual time. The third part (“Evidence that Neural Systems Operate Empirically”) reviews evidence accumulated over the past 20 years that supports this interpretation in vision and audition, the sensory systems that have been most studied from this or any other perspective. Finally, the fourth part (“Alternative Concepts of Neural Function”) considers the pros and cons of other interpretations of how brains operate. The overarching theme is that the nervous systems of humans and every other animal operate on the basis associations between stimuli and behavior made by trial and error over species and lifetime experience.

Chemo- and Optogenetic Strategies for the Elucidation of Pain Pathways

2019 ◽  
pp. 816-832 ◽  
Author(s):  
Sascha R. A. Alles ◽  
Anne-Marie Malfait ◽  
Richard J. Miller
Keyword(s):  
Chronic Pain ◽  
Pain Response ◽  
Conscious Perception ◽  
Novel Therapies ◽  
The Past ◽  
Nociceptive Pathways ◽  
Pain Pathways ◽  
Technical Advances ◽  
The Brain

Pain is not a simple phenomenon and, beyond its conscious perception, involves circuitry that allows the brain to provide an affective context for nociception, which can influence mood and memory. In the past decade, neurobiological techniques have been developed that allow investigators to elucidate the importance of particular groups of neurons in different aspects of the pain response, something that may have important translational implications for the development of novel therapies. Chemo- and optogenetics represent two of the most important technical advances of recent times for gaining understanding of physiological circuitry underlying complex behaviors. The use of these techniques for teasing out the role of neurons and glia in nociceptive pathways is a rapidly growing area of research. The major findings of studies focused on understanding circuitry involved in different aspects of nociception and pain are highlighted in this article. In addition, attention is drawn to the possibility of modification of chemo- and optogenetic techniques for use as potential therapies for treatment of chronic pain disorders in human patients.

scholarly journals DNA Methylation Profiles of Tph1A and BDNF in Gut and Brain of L. Rhamnosus-Treated Zebrafish

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 142
Author(s):  
Mariella Cuomo ◽  
Luca Borrelli ◽  
Rosa Della Monica ◽  
Lorena Coretti ◽  
Giulia De Riso ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
The Past ◽  
Targeted Analysis ◽  
Lack Of Information ◽  
High Resolution Power ◽  
Resolution Level ◽  
Health And Disease ◽  
High Doses ◽  
The Brain

The bidirectional microbiota–gut–brain axis has raised increasing interest over the past years in the context of health and disease, but there is a lack of information on molecular mechanisms underlying this connection. We hypothesized that change in microbiota composition may affect brain epigenetics leading to long-lasting effects on specific brain gene regulation. To test this hypothesis, we used Zebrafish (Danio Rerio) as a model system. As previously shown, treatment with high doses of probiotics can modulate behavior in Zebrafish, causing significant changes in the expression of some brain-relevant genes, such as BDNF and Tph1A. Using an ultra-deep targeted analysis, we investigated the methylation state of the BDNF and Tph1A promoter region in the brain and gut of probiotic-treated and untreated Zebrafishes. Thanks to the high resolution power of our analysis, we evaluated cell-to-cell methylation differences. At this resolution level, we found slight DNA methylation changes in probiotic-treated samples, likely related to a subgroup of brain and gut cells, and that specific DNA methylation signatures significantly correlated with specific behavioral scores.

scholarly journals (Ascorb)ing Pb Neurotoxicity in the Developing Brain

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1311
Author(s):  
Faraz Ahmad ◽  
Ping Liu
Keyword(s):  
Ascorbic Acid ◽  
Animal Studies ◽  
Redox Homeostasis ◽  
Special Role ◽  
Developmental Exposure ◽  
Brain Functions ◽  
Brain States ◽  
Pb Exposure ◽  
The Brain ◽  
Potent Therapeutic Agent

Lead (Pb) neurotoxicity is a major concern, particularly in children. Developmental exposure to Pb can alter neurodevelopmental trajectory and has permanent neuropathological consequences, including an increased vulnerability to further stressors. Ascorbic acid is among most researched antioxidant nutrients and has a special role in maintaining redox homeostasis in physiological and physio-pathological brain states. Furthermore, because of its capacity to chelate metal ions, ascorbic acid may particularly serve as a potent therapeutic agent in Pb poisoning. The present review first discusses the major consequences of Pb exposure in children and then proceeds to present evidence from human and animal studies for ascorbic acid as an efficient ameliorative supplemental nutrient in Pb poisoning, with a particular focus on developmental Pb neurotoxicity. In doing so, it is hoped that there is a revitalization for further research on understanding the brain functions of this essential, safe, and readily available vitamin in physiological states, as well to justify and establish it as an effective neuroprotective and modulatory factor in the pathologies of the nervous system, including developmental neuropathologies.

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