scholarly journals Causal inference in the multisensory brain

2018 ◽  
Author(s):  
Yinan Cao ◽  
Christopher Summerfield ◽  
Hame Park ◽  
Bruno L. Giordano ◽  
Christoph Kayser
Keyword(s):  
Prefrontal Cortex ◽  
Causal Inference ◽  
Frontal Lobe ◽  
Multisensory Integration ◽  
Multisensory Perception ◽  
Adaptive Behaviour ◽  
Sensory Fusion ◽  
Spatio Temporal ◽  
The Brain ◽  
Combining Information

When combining information across different senses humans need to flexibly select cues of a common origin whilst avoiding distraction from irrelevant inputs. The brain could solve this challenge using a hierarchical principle, by deriving rapidly a fused sensory estimate for computational expediency and, later and if required, filtering out irrelevant signals based on the inferred sensory cause(s). Analysing time- and source-resolved human magnetoencephalographic data we unveil a systematic spatio-temporal cascade of the relevant computations, starting with early segregated unisensory representations, continuing with sensory fusion in parietal-temporal regions and culminating as causal inference in the frontal lobe. Our results reconcile previous computational accounts of multisensory perception by showing that prefrontal cortex guides flexible integrative behaviour based on candidate representations established in sensory and association cortices, thereby framing multisensory integration in the generalised context of adaptive behaviour.

scholarly journals Attention controls multisensory perception via 2 distinct mechanisms at different levels of the cortical hierarchy

PLoS Biology ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. e3001465
Author(s):  
Ambra Ferrari ◽  
Uta Noppeney
Keyword(s):  
Causal Inference ◽  
Causal Structure ◽  
Multisensory Perception ◽  
Spatial Representations ◽  
Perceptual Inference ◽  
Sensory Signals ◽  
Cortical Hierarchy ◽  
Parietal Cortices ◽  
The Brain ◽  
Different Levels

To form a percept of the multisensory world, the brain needs to integrate signals from common sources weighted by their reliabilities and segregate those from independent sources. Previously, we have shown that anterior parietal cortices combine sensory signals into representations that take into account the signals’ causal structure (i.e., common versus independent sources) and their sensory reliabilities as predicted by Bayesian causal inference. The current study asks to what extent and how attentional mechanisms can actively control how sensory signals are combined for perceptual inference. In a pre- and postcueing paradigm, we presented observers with audiovisual signals at variable spatial disparities. Observers were precued to attend to auditory or visual modalities prior to stimulus presentation and postcued to report their perceived auditory or visual location. Combining psychophysics, functional magnetic resonance imaging (fMRI), and Bayesian modelling, we demonstrate that the brain moulds multisensory inference via 2 distinct mechanisms. Prestimulus attention to vision enhances the reliability and influence of visual inputs on spatial representations in visual and posterior parietal cortices. Poststimulus report determines how parietal cortices flexibly combine sensory estimates into spatial representations consistent with Bayesian causal inference. Our results show that distinct neural mechanisms control how signals are combined for perceptual inference at different levels of the cortical hierarchy.

Editorial introduction to Greenwood/West dialogue

2000 ◽  
Vol 6 (6) ◽  
pp. 704-704
Author(s):  
JASON BRANDT
Keyword(s):  
Anorexia Nervosa ◽  
Prefrontal Cortex ◽  
Pathological Gambling ◽  
Frontal Cortex ◽  
Frontal Lobe ◽  
Editorial Introduction ◽  
Frontal Lobe Dysfunction ◽  
The Brain ◽  
Artistic Skill

Although a U.S. Presidential Proclamation designated the 1990s “The Decade of the Brain,” not all cerebral constituents shared equally in the limelight. By anyone's accounting, the prefrontal cortex was the darling of clinicians and neuroscientists throughout the '90s, with everything from schizophrenia and anorexia nervosa to pathological gambling and the emergence of artistic skill attributed to “frontal lobe dysfunction” (David, 1992; Miller et al., 1998; Rugle & Melamed, 1993). It should come as no surprise, then, that that most universal of cognitive afflictions, aging, should be linked to changes in frontal cortex.

scholarly journals Adaptive behaviour and learning in slime moulds: the role of oscillations

2021 ◽  
Vol 376 (1820) ◽  
pp. 20190757 ◽  
Author(s):  
Aurèle Boussard ◽  
Adrian Fessel ◽  
Christina Oettmeier ◽  
Léa Briard ◽  
Hans-Günther Döbereiner ◽  
...  
Keyword(s):  
Information Processing ◽  
Adaptive Behaviour ◽  
Learning Abilities ◽  
Slime Mould ◽  
Signalling Molecules ◽  
Slime Moulds ◽  
Wave Patterns ◽  
Spatio Temporal ◽  
The Brain

The slime mould Physarum polycephalum , an aneural organism, uses information from previous experiences to adjust its behaviour, but the mechanisms by which this is accomplished remain unknown. This article examines the possible role of oscillations in learning and memory in slime moulds. Slime moulds share surprising similarities with the network of synaptic connections in animal brains. First, their topology derives from a network of interconnected, vein-like tubes in which signalling molecules are transported. Second, network motility, which generates slime mould behaviour, is driven by distinct oscillations that organize into spatio-temporal wave patterns. Likewise, neural activity in the brain is organized in a variety of oscillations characterized by different frequencies. Interestingly, the oscillating networks of slime moulds are not precursors of nervous systems but, rather, an alternative architecture. Here, we argue that comparable information-processing operations can be realized on different architectures sharing similar oscillatory properties. After describing learning abilities and oscillatory activities of P. polycephalum , we explore the relation between network oscillations and learning, and evaluate the organism's global architecture with respect to information-processing potential. We hypothesize that, as in the brain, modulation of spontaneous oscillations may sustain learning in slime mould. This article is part of the theme issue ‘Basal cognition: conceptual tools and the view from the single cell’.

Set-maintenance and set-shifting problems in schizophrenic subtypes: relationship to dysfunctions of the fronto-striatal loops

2000 ◽  
Vol 12 (1) ◽  
pp. 32-38
Author(s):  
M.G. Lanser ◽  
B.A. Ellenbroek ◽  
A.R. Cools ◽  
F.G. Zitman
Keyword(s):  
Parkinson’S Disease ◽  
Prefrontal Cortex ◽  
Frontal Lobe ◽  
Neuropsychological Tests ◽  
Set Shifting ◽  
Frontal Lobe Lesions ◽  
Core Symptom ◽  
Schizophrenic Patients ◽  
Information Set ◽  
The Brain

SUMMARYResearch with patients suffering from Parkinson's disease and frontal lobe lesions has shown that disturbances in the fronto-striatal loops in the brain can cause perseveration. Perseveration is a core symptom of schizophrenia, yet the cause is not known. For schizophrenic patients disorders of many parts of the fronto-striatal loops are found, for example disturbances of the prefrontal cortex and the striatum. Perseveration in schizophrenia can be explained with set-maintenance problems, related to dysfunction of the prefrontal cortex, or with set-shifting problems that are related to disorders in the striatum. These set-maintenance and set-shifting problems can be distinguished with neuropsychological tests. Regarding the bloodflow patterns for the different subtypes of schizophrenia three problems are expected as explanations for perseveration: set-maintenance problems concerning abstract information, set-maintenance problems shifting between stimuli and enhanced set-shifting with cues.

Evolution of the Prefrontal Cortex in the Hominins

2021 ◽  
pp. 333-371
Author(s):  
Richard E. Passingham
Keyword(s):  
Body Weight ◽  
Prefrontal Cortex ◽  
Climatic Change ◽  
Frontal Lobe ◽  
Rapid Expansion ◽  
Stone Tool ◽  
Cultural Environment ◽  
Selection Pressures ◽  
The Brain ◽  
Rapid Transfer

When body weight is taken into account, there was a rapid expansion of the brain during the evolution of the hominins, with the greatest increase occurring from around 400,000 years ago. After this time there is evidence of the bulging of the frontal lobe indicating the further expansion of the prefrontal (PF) cortex. Many selection pressures could have influenced these changes, but all of them involve a change in environment. This could occur via climatic change, via changes in the ecosystem, by migration, or by changes in the cultural environment. The cultural environment includes technology such as stone tool making, cooperation in hunting, and the improvements in communication that this required. The adaptation to new environments requires the solution of new problems, and this was aided by the ability of the PF cortex to support rapid transfer from one problem to another.

scholarly journals See what you hear – How the brain forms representations across the senses

Neuroforum ◽  
2018 ◽  
Vol 24 (4) ◽  
pp. A169-A181
Author(s):  
Uta Noppeney ◽  
Samuel A. Jones ◽  
Tim Rohe ◽  
Ambra Ferrari
Keyword(s):  
Causal Inference ◽  
Sensory Processing ◽  
Sensory Integration ◽  
Causal Structure ◽  
Multisensory Perception ◽  
Common Source ◽  
Behavioural Research ◽  
Parietal Cortices ◽  
The Brain ◽  
Different Sources

Abstarct Our senses are constantly bombarded with a myriad of signals. To make sense of this cacophony, the brain needs to integrate signals emanating from a common source, but segregate signals originating from the different sources. Thus, multisensory perception relies critically on inferring the world’s causal structure (i. e. one common vs. multiple independent sources). Behavioural research has shown that the brain arbitrates between sensory integration and segregation consistent with the principles of Bayesian Causal Inference. At the neural level, recent functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) studies have shown that the brain accomplishes Bayesian Causal Inference by dynamically encoding multiple perceptual estimates across the sensory processing hierarchies. Only at the top of the hierarchy in anterior parietal cortices did the brain form perceptual estimates that take into account the observer’s uncertainty about the world’s causal structure consistent with Bayesian Causal Inference.

SPECIFIC PROPERTIES OF TUBULIN IN THE PREFRONTAL CORTEX IN CONTROL, SCHIZOPHRENIA AND VASCULAR DEMENTIA

2020 ◽  
pp. 65-71
Author(s):  
Burbaeva G.Sh. ◽  
Androsova L.V. ◽  
Vorobyeva E.A. ◽  
Savushkina O.K.
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Prefrontal Cortex ◽  
Vascular Dementia ◽  
Binding Activity ◽  
Nephelometric Method ◽  
Rate Of Polymerization ◽  
Mental Diseases ◽  
And Control ◽  
The Brain

The aim of the study was to evaluate the rate of polymerization of tubulin into microtubules and determine the level of colchicine binding (colchicine-binding activity of tubulin) in the prefrontal cortex in schizophrenia, vascular dementia (VD) and control. Colchicine-binding activity of tubulin was determined by Sherlinе in tubulin-enriched extracts of proteins from the samples. Measurement of light scattering during the polymerization of the tubulin was carried out using the nephelometric method at a wavelength of 450-550 nm. There was a significant decrease in colchicine-binding activity and the rate of tubulin polymerization in the prefrontal cortex in both diseases, and in VD to a greater extent than in schizophrenia. The obtained results suggest that not only in Alzheimer's disease, but also in other mental diseases such as schizophrenia and VD, there is a decrease in the level of tubulin in the prefrontal cortex of the brain, although to a lesser extent than in Alzheimer's disease, and consequently the amount of microtubules.

Activation of Melanocortin-4 Receptor by a Synthetic Agonist Inhibits Ethanolinduced Neuroinflammation in Rats

2020 ◽  
Vol 25 (45) ◽  
pp. 4799-4805 ◽  
Author(s):  
Osvaldo Flores-Bastías ◽  
Gonzalo I. Gómez ◽  
Juan A. Orellana ◽  
Eduardo Karahanian
Keyword(s):  
Prefrontal Cortex ◽  
Alcohol Consumption ◽  
Ethanol Intake ◽  
Neuroinflammatory Response ◽  
Agonist Peptide ◽  
Melanocortin 4 Receptor ◽  
Tnf Α ◽  
Cord Injury ◽  
High Ethanol ◽  
The Brain

Background: High ethanol intake induces a neuroinflammatory response resulting in the subsequent maintenance of chronic alcohol consumption. The melanocortin system plays a pivotal role in the modulation of alcohol consumption. Interestingly, it has been shown that the activation of melanocortin-4 receptor (MC4R) in the brain decreases the neuroinflammatory response in models of brain damage other than alcohol consumption, such as LPS-induced neuroinflammation, cerebral ischemia, glutamate excitotoxicity, and spinal cord injury. Objectives: In this work, we aimed to study whether MC4R activation by a synthetic MC4R-agonist peptide prevents ethanol-induced neuroinflammation, and if alcohol consumption produces changes in MC4R expression in the hippocampus and hypothalamus. Methods: Ethanol-preferring Sprague Dawley rats were selected offering access to 20% ethanol on alternate days for 4 weeks (intermittent access protocol). After this time, animals were i.p. administered an MC4R agonist peptide in the last 2 days of the protocol. Then, the expression of the proinflammatory cytokines interleukin 6 (IL-6), interleukin 1-beta (IL-1β), and tumor necrosis factor-alpha (TNF-α) were measured in the hippocampus, hypothalamus and prefrontal cortex. It was also evaluated if ethanol intake produces alterations in the expression of MC4R in the hippocampus and the hypothalamus. Results: Alcohol consumption increased the expression of MC4R in the hippocampus and the hypothalamus. The administration of the MC4R agonist reduced IL-6, IL-1β and TNF-α levels in hippocampus, hypothalamus and prefrontal cortex, to those observed in control rats that did not drink alcohol. Conclusion: High ethanol consumption produces an increase in the expression of MC4R in the hippocampus and hypothalamus. The administration of a synthetic MC4R-agonist peptide prevents neuroinflammation induced by alcohol consumption in the hippocampus, hypothalamus, and prefrontal cortex. These results could explain the effect of α-MSH and other synthetic MC4R agonists in decreasing alcohol intake through the reduction of the ethanol-induced inflammatory response in the brain.

Synaesthesia

2018 ◽  
Author(s):  
Bruno and
Keyword(s):  
Experimental Results ◽  
Multisensory Perception ◽  
Related Phenomenon ◽  
Perceptual Modality ◽  
Sensory Channel ◽  
Multisensory Interactions ◽  
Crossmodal Associations ◽  
The Brain

Synaesthesia is a curious anomaly of multisensory perception. When presented with stimulation in one sensory channel, in addition to the percept usually associated with that channel (inducer) a true synaesthetic experiences a second percept in another perceptual modality (concurrent). Although synaesthesia is not pathological, true synaesthetes are relatively rare and their synaesthetic associations tend to be quite idiosyncratic. For this reason, studying synaesthesia is difficult, but exciting new experimental results are beginning to clarify what makes the brain of synaesthetes special and the mechanisms that may produce the condition. Even more importantly, the related phenomenon known as ‘natural’ crossmodal associations is instead experienced by everyone, providing another useful domain for studying multisensory interactions with important implications for understanding our preferences for products in terms of spontaneously evoked associations, as well as for choosing appropriate names, labels, and packaging in marketing applications.

025 Sleep Disruption on an Orbital Shaker alters Glutamate in Prairie Vole Prefrontal Cortex

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A11-A12
Author(s):  
Carolyn Jones ◽  
Randall Olson ◽  
Alex Chau ◽  
Peyton Wickham ◽  
Ryan Leriche ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Prefrontal Cortex ◽  
Early Life ◽  
Autism Spectrum ◽  
Prairie Vole ◽  
Sleep Disruption ◽  
Glutamatergic Synapses ◽  
The Brain ◽  
Orbital Shaker

Abstract Introduction Glutamate concentrations in the cortex fluctuate with the sleep wake cycle in both rodents and humans. Altered glutamatergic signaling, as well as the early life onset of sleep disturbances have been implicated in neurodevelopmental disorders such as autism spectrum disorder. In order to study how sleep modulates glutamate activity in brain regions relevant to social behavior and development, we disrupted sleep in the socially monogamous prairie vole (Microtus ochrogaster) rodent species and quantified markers of glutamate neurotransmission within the prefrontal cortex, an area of the brain responsible for advanced cognition and complex social behaviors. Methods Male and female prairie voles were sleep disrupted using an orbital shaker to deliver automated gentle cage agitation at continuous intervals. Sleep was measured using EEG/EMG signals and paired with real time glutamate concentrations in the prefrontal cortex using an amperometric glutamate biosensor. This same method of sleep disruption was applied early in development (postnatal days 14–21) and the long term effects on brain development were quantified by examining glutamatergic synapses in adulthood. Results Consistent with previous research in rats, glutamate concentration in the prefrontal cortex increased during periods of wake in the prairie vole. Sleep disruption using the orbital shaker method resulted in brief cortical arousals and reduced time in REM sleep. When applied during development, early life sleep disruption resulted in long-term changes in both pre- and post-synaptic components of glutamatergic synapses in the prairie vole prefrontal cortex including increased density of immature spines. Conclusion In the prairie vole rodent model, sleep disruption on an orbital shaker produces a sleep, behavioral, and neurological phenotype that mirrors aspects of autism spectrum disorder including altered features of excitatory neurotransmission within the prefrontal cortex. Studies using this method of sleep disruption combined with real time biosensors for excitatory neurotransmitters will enhance our understanding of modifiable risk factors, such as sleep, that contribute to the altered development of glutamatergic synapses in the brain and their relationship to social behavior. Support (if any) NSF #1926818, VA CDA #IK2 BX002712, Portland VA Research Foundation, NIH NHLBI 5T32HL083808-10, VA Merit Review #I01BX001643

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