scholarly journals Changepoint detection versus reinforcement learning: Separable neural substrates approximate different forms of Bayesian inference

2019 ◽  
Author(s):  
Wolfgang M. Pauli ◽  
Matt Jones
Keyword(s):  
Bayesian Inference ◽  
Neural Substrates ◽  
Statistical Structure ◽  
Statistical Process ◽  
Future Events ◽  
Reward Contingencies ◽  
Foraging Task ◽  
The Brain ◽  
Adaptive Foraging ◽  
Previous Learning

AbstractAdaptive behavior in even the simplest decision-making tasks requires predicting future events in an environment that is generally nonstationary. As an inductive problem, this prediction requires a commitment to the statistical process underlying environmental change. This challenge can be formalized in a Bayesian framework as a question of choosing a generative model for the task dynamics. Previous learning models assume, implicitly or explicitly, that nonstationarity follows either a continuous diffusion process or a discrete changepoint process. Each approach is slow to adapt when its assumptions are violated. A new mixture of Bayesian experts framework proposes separable brain systems approximating inference under different assumptions regarding the statistical structure of the environment. This model explains data from a laboratory foraging task, in which rats experienced a change in reward contingencies after pharmacological disruption of dorsolateral (DLS) or dorsomedial striatum (DMS). The data and model suggest DLS learns under a diffusion prior whereas DMS learns under a changepoint prior. The combination of these two systems offers a new explanation for how the brain handles inference in an uncertain environment.One Sentence SummaryAdaptive foraging behavior can be explained by separable brain systems approximating Bayesian inference under different assumptions about dynamics of the environment.

Lessons From the Neural Bases of Speech and Voice

2011 ◽  
Vol 21 (1) ◽  
pp. 5-14
Author(s):  
Christy L. Ludlow
Keyword(s):  
Brain Networks ◽  
Neural Substrates ◽  
Voice Behavior ◽  
Therapeutic Approaches ◽  
Neural Bases ◽  
Sound Foundation ◽  
The Brain ◽  
Normal Speech

The premise of this article is that increased understanding of the brain bases for normal speech and voice behavior will provide a sound foundation for developing therapeutic approaches to establish or re-establish these functions. The neural substrates involved in speech/voice behaviors, the types of muscle patterning for speech and voice, the brain networks involved and their regulation, and how they can be externally modulated for improving function will be addressed.

scholarly journals Decoding the future from past experience: learning shapes predictions in early visual cortex

2015 ◽  
Vol 113 (9) ◽  
pp. 3159-3171 ◽  
Author(s):  
Caroline D. B. Luft ◽  
Alan Meeson ◽  
Andrew E. Welchman ◽  
Zoe Kourtzi
Keyword(s):  
Visual Cortex ◽  
Large Scale ◽  
Sequence Structure ◽  
Neural Populations ◽  
Early Visual Cortex ◽  
Temporal Structures ◽  
Future Events ◽  
Sensory Predictions ◽  
Actual Stimulus ◽  
The Brain

Learning the structure of the environment is critical for interpreting the current scene and predicting upcoming events. However, the brain mechanisms that support our ability to translate knowledge about scene statistics to sensory predictions remain largely unknown. Here we provide evidence that learning of temporal regularities shapes representations in early visual cortex that relate to our ability to predict sensory events. We tested the participants' ability to predict the orientation of a test stimulus after exposure to sequences of leftward- or rightward-oriented gratings. Using fMRI decoding, we identified brain patterns related to the observers' visual predictions rather than stimulus-driven activity. Decoding of predicted orientations following structured sequences was enhanced after training, while decoding of cued orientations following exposure to random sequences did not change. These predictive representations appear to be driven by the same large-scale neural populations that encode actual stimulus orientation and to be specific to the learned sequence structure. Thus our findings provide evidence that learning temporal structures supports our ability to predict future events by reactivating selective sensory representations as early as in primary visual cortex.

scholarly journals Brain network dynamics correlate with personality traits

2019 ◽  
Author(s):  
Aya Kabbara ◽  
Veronique Paban ◽  
Arnaud Weill ◽  
Julien Modolo ◽  
Mahmoud Hassan
Keyword(s):  
Functional Connectivity ◽  
Personality Traits ◽  
Resting State ◽  
Brain Networks ◽  
Neural Substrates ◽  
Brain Network ◽  
Functional Brain ◽  
Human Connectome Project ◽  
Functional Brain Networks ◽  
The Brain

AbstractIntroductionIdentifying the neural substrates underlying the personality traits is a topic of great interest. On the other hand, it is now established that the brain is a dynamic networked system which can be studied using functional connectivity techniques. However, much of the current understanding of personality-related differences in functional connectivity has been obtained through the stationary analysis, which does not capture the complex dynamical properties of brain networks.ObjectiveIn this study, we aimed to evaluate the feasibility of using dynamic network measures to predict personality traits.MethodUsing the EEG/MEG source connectivity method combined with a sliding window approach, dynamic functional brain networks were reconstructed from two datasets: 1) Resting state EEG data acquired from 56 subjects. 2) Resting state MEG data provided from the Human Connectome Project. Then, several dynamic functional connectivity metrics were evaluated.ResultsSimilar observations were obtained by the two modalities (EEG and MEG) according to the neuroticism, which showed a negative correlation with the dynamic variability of resting state brain networks. In particular, a significant relationship between this personality trait and the dynamic variability of the temporal lobe regions was observed. Results also revealed that extraversion and openness are positively correlated with the dynamics of the brain networks.ConclusionThese findings highlight the importance of tracking the dynamics of functional brain networks to improve our understanding about the neural substrates of personality.

scholarly journals Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

2016 ◽  
Vol 113 (52) ◽  
pp. E8492-E8501 ◽  
Author(s):  
Roland G. Benoit ◽  
Daniel J. Davies ◽  
Michael C. Anderson
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Episodic Simulation ◽  
Dorsolateral Prefrontal ◽  
Future Events ◽  
The Right ◽  
Development Of Anxiety ◽  
The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

scholarly journals Neural Substrates of Social Status Inference: Roles of Medial Prefrontal Cortex and Superior Temporal Sulcus

2014 ◽  
Vol 26 (5) ◽  
pp. 1131-1140 ◽  
Author(s):  
Malia Mason ◽  
Joe C. Magee ◽  
Susan T. Fiske
Keyword(s):  
Social Order ◽  
Neural Substrates ◽  
Brain Regions ◽  
Third Party ◽  
Social Interdependence ◽  
Medial Pfc ◽  
State Inference ◽  
The Brain ◽  
Track Status

The negotiation of social order is intimately connected to the capacity to infer and track status relationships. Despite the foundational role of status in social cognition, we know little about how the brain constructs status from social interactions that display it. Although emerging cognitive neuroscience reveals that status judgments depend on the intraparietal sulcus, a brain region that supports the comparison of targets along a quantitative continuum, we present evidence that status judgments do not necessarily reduce to ranking targets along a quantitative continuum. The process of judging status also fits a social interdependence analysis. Consistent with third-party perceivers judging status by inferring whose goals are dictating the terms of the interaction and who is subordinating their desires to whom, status judgments were associated with increased recruitment of medial pFC and STS, brain regions implicated in mental state inference.

Appetite hormones and addiction

2018 ◽  
Author(s):  
David J. Nutt ◽  
Liam J. Nestor
Keyword(s):  
Eating Disorder ◽  
Food Intake ◽  
Food Consumption ◽  
Neural Substrates ◽  
Reward Sensitivity ◽  
Substance Addiction ◽  
Alcohol And Drugs ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
The Brain

Many of the same behavioural and brain disturbances observed in addiction are also seen in obesity and binge-eating disorder. This suggests that there are shared neural substrates between substance addiction and compulsive food consumption. Food intake and appetite are regulated by numerous appetite hormones that exert their effects through brain systems involved in reward sensitivity, stress, impulsivity, and compulsivity. There is now emerging evidence that appetite hormones (e.g. ghrelin, glucagon-like peptide-1, orexin) can modulate addictive behaviours (e.g. craving) and the intake of alcohol and drugs. Therefore, there is an emerging shift into a new field of testing drugs that affect appetite hormones and their receptors in the brain, and their use in regulating the brain mechanisms that lead to relapse in addiction disorders.

Interhemispheric Integration at Different Spatial Scales: The Evidence From EEG Coherence and fMRI

2006 ◽  
Vol 96 (1) ◽  
pp. 259-275 ◽  
Author(s):  
Maria G. Knyazeva ◽  
Eleonora Fornari ◽  
Reto Meuli ◽  
Philippe Maeder
Keyword(s):  
Spatial Scales ◽  
Neural Substrates ◽  
Blood Oxygen Level Dependent ◽  
Specific Information ◽  
Eeg Coherence ◽  
Blood Oxygen Level ◽  
Spatial Frequencies ◽  
Collateral Sulcus ◽  
Gestalt Grouping ◽  
The Brain

The early visual system processes different spatial frequencies (SFs) separately. To examine where in the brain the scale-specific information is integrated, we mapped the neural assemblies engaged in interhemispheric coupling with electroencephalographic (EEG) coherence and blood-oxygen-level dependent (BOLD) signal. During similar EEG and functional magnetic resonance imaging (fMRI) experiments, our subjects viewed centrally presented bilateral gratings of different SF (0.25–8.0 cpd), which either obeyed Gestalt grouping rules (iso-oriented, IG) or violated them (orthogonally oriented, OG). The IG stimuli (0.5–4.0 cpd) synchronized EEG at discrete beta frequencies (beta1, beta2) and increased BOLD (0.5 and 2.0 cpd tested) in ventral (around collateral sulcus) and dorsal (parieto-occipital fissure) regions compared with OG. At both SF, the beta1 coherence correlated with the ventral activations, whereas the beta2 coherence correlated with the dorsal ones. Thus distributed neural substrates mediated interhemispheric integration at single SF. The relative impact of the ventral versus dorsal networks was modulated by the SF of the stimulus.

Hyperdipsia in rats after electrolytic lesions of nucleus medianus

1985 ◽  
Vol 248 (2) ◽  
pp. R214-R223 ◽  
Author(s):  
T. W. Gardiner ◽  
E. M. Stricker
Keyword(s):  
Drinking Behavior ◽  
Plasma Renin ◽  
Neural Substrates ◽  
Physiological Changes ◽  
Electrolytic Lesions ◽  
Daily Water ◽  
Ad Libitum ◽  
Elevated Water ◽  
Fluid Losses ◽  
The Brain

Ablation of the ventral portion of nucleus medianus (vNM) in rats produced a temporary adipsia or hypodipsia that was accompanied by pronounced urinary fluid losses. When ad libitum drinking resumed, about half of the brain-damaged animals became hyperdipsic, exhibiting chronic two- to threefold elevations in their daily water intakes during the nocturnal hours of the day-night cycle. Rats that remained normodipsic after vNM ablation usually exhibited hyperdipsia if they were food-deprived overnight. The basis for the hyperdipsia produced by vNM ablation was not clear. The elevated water intakes appeared not to result from chronic urinary fluid losses, because hyperdipsic rats were able to concentrate their urine during the day, when they drank little. Moreover, the animals did not seem to be volume depleted; their plasma renin activities were not elevated, and they drank normally in association with meals. These and other findings suggest that vNM lesions damage neural substrates that control drinking behavior, and the hyperdipsia results from this rather than from physiological changes produced by the lesion.

Studies of Crossmodal Functions with TMS

2012 ◽  
Author(s):  
Lotfi Merabet ◽  
Alvaro Pascual-Leone
Keyword(s):  
Multisensory Processing ◽  
Sensory Deprivation ◽  
Sensory Information ◽  
Neural Substrates ◽  
Multiple Streams ◽  
Crossmodal Interactions ◽  
Sensory Changes ◽  
The Senses ◽  
The Brain

In the brain, information from all the senses interacts and is integrated in order to create a unified sensory percept. Some percepts appear unimodal, and some, cross modal. Unimodal percepts can be modified by crossmodal interactions given that our brains process multiple streams of sensory information in parallel and promote extensive interactions. TMS can provide valuable insights on the neural substrates associated with multisensory processing in humans. TMS is commonly described as a ‘relatively painless’ method of stimulating the brain noninvasively. However, TMS itself is strong multisensory and this should be considered while interpreting the results. With regard to the crossmodal sensory changes that follow sensory deprivation, these changes can be revealed using a variety of methods including the combination of TMS with neuroimaging.

Intersubjectivity evolved to fit the brain, but grammar co-evolved with the brain

2008 ◽  
Vol 31 (5) ◽  
pp. 523-524
Author(s):  
Patricia M. Greenfield ◽  
Kristen Gillespie-Lynch
Keyword(s):  
Natural Selection ◽  
Mirror Neurons ◽  
Cladistic Analysis ◽  
Neural Substrates ◽  
Neural Basis ◽  
Language Functions ◽  
Neural Substrate ◽  
The Brain

AbstractWe propose that some aspects of language – notably intersubjectivity – evolved to fit the brain, whereas other aspects – notably grammar – co-evolved with the brain. Cladistic analysis indicates that common basic structures of both action and grammar arose in phylogeny six million years ago and in ontogeny before age two, with a shared prefrontal neural substrate. In contrast, mirror neurons, found in both humans and monkeys, suggest that the neural basis for intersubjectivity evolved before language. Natural selection acts upon genes controlling the neural substrates of these phenotypic language functions.

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