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Bayesian Brain

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https://www.readbyqxmd.com/read/28630937/high-precision-neural-decoding-of-complex-movement-trajectories-using-recursive-bayesian-estimation-with-dynamic-movement-primitives
#1
Guy Hotson, Ryan J Smith, Adam G Rouse, Marc H Schieber, Nitish V Thakor, Brock A Wester
Brain-machine interfaces (BMIs) are a rapidly progressing technology with the potential to restore function to victims of severe paralysis via neural control of robotic systems. Great strides have been made in directly mapping a user's cortical activity to control of the individual degrees of freedom of robotic end-effectors. While BMIs have yet to achieve the level of reliability desired for widespread clinical use, environmental sensors (e.g. RGB-D cameras for object detection) and prior knowledge of common movement trajectories hold great potential for improving system performance...
July 2016: IEEE Robotics and Automation Letters
https://www.readbyqxmd.com/read/28630885/bayesian-framework-inspired-no-reference-region-of-interest-quality-measure-for-brain-mri-images
#2
Michael Osadebey, Marius Pedersen, Douglas Arnold, Katrina Wendel-Mitoraj
We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed...
April 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28630413/bayesian-inference-of-physiologically-meaningful-parameters-from-body-sway-measurements
#3
A Tietäväinen, M U Gutmann, E Keski-Vakkuri, J Corander, E Hæggström
The control of the human body sway by the central nervous system, muscles, and conscious brain is of interest since body sway carries information about the physiological status of a person. Several models have been proposed to describe body sway in an upright standing position, however, due to the statistical intractability of the more realistic models, no formal parameter inference has previously been conducted and the expressive power of such models for real human subjects remains unknown. Using the latest advances in Bayesian statistical inference for intractable models, we fitted a nonlinear control model to posturographic measurements, and we showed that it can accurately predict the sway characteristics of both simulated and real subjects...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28628647/an-efficient-coding-theory-for-a-dynamic-trajectory-predicts-non-uniform-allocation-of-entorhinal-grid-cells-to-modules
#4
Noga Mosheiff, Haggai Agmon, Avraham Moriel, Yoram Burak
Grid cells in the entorhinal cortex encode the position of an animal in its environment with spatially periodic tuning curves with different periodicities. Recent experiments established that these cells are functionally organized in discrete modules with uniform grid spacing. Here we develop a theory for efficient coding of position, which takes into account the temporal statistics of the animal's motion. The theory predicts a sharp decrease of module population sizes with grid spacing, in agreement with the trend seen in the experimental data...
June 19, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28626019/neural-mechanisms-of-updating-under-reducible-and-irreducible-uncertainty
#5
Kenji Kobayashi, Ming Hsu
Adaptive decision-making depends on agents' ability to make use of environmental signals to reduce uncertainty. However, because there exist multiple types of uncertainty, agents should take into account not only the extent to which signals violate prior expectancy but also whether uncertainty can be reduced in the first place. Here we studied how the human brain of both sexes responds to signals under conditions of reducible and irreducible uncertainty. We show behaviorally that subjects' value updating was sensitivity to the reducibility of uncertainty, and could be quantitative characterized by a Bayesian model where agents ignore expectancy violations that do not update beliefs or values...
June 16, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28619481/computational-psychosomatics-and-computational-psychiatry-toward-a-joint-framework-for-differential-diagnosis
#6
REVIEW
Frederike H Petzschner, Lilian A E Weber, Tim Gard, Klaas E Stephan
This article outlines how a core concept from theories of homeostasis and cybernetics, the inference-control loop, may be used to guide differential diagnosis in computational psychiatry and computational psychosomatics. In particular, we discuss 1) how conceptualizing perception and action as inference-control loops yields a joint computational perspective on brain-world and brain-body interactions and 2) how the concrete formulation of this loop as a hierarchical Bayesian model points to key computational quantities that inform a taxonomy of potential disease mechanisms...
May 25, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/28615342/supramodal-representation-of-temporal-priors-calibrates-interval-timing
#7
Huihui Zhang, Xiaolin Zhou
Human timing behaviors are consistent with Bayesian inference, according to which both previous knowledge (prior) and current sensory information determine final responses. However, it is unclear whether the brain represents temporal priors exclusively for individual modalities or in a supramodal manner when temporal information comes from different modalities at different times. Here we asked participants to reproduce time intervals in either a unisensory or a multisensory context. In unisensory tasks, sample intervals drawn from a uniform distribution were presented in a single visual or auditory modality...
June 14, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28608396/information-criteria-for-firth-s-penalized-partial-likelihood-approach-in-cox-regression-models
#8
Kengo Nagashima, Yasunori Sato
In the estimation of Cox regression models, maximum partial likelihood estimates might be infinite in a monotone likelihood setting, where partial likelihood converges to a finite value and parameter estimates converge to infinite values. To address monotone likelihood, previous studies have applied Firth's bias correction method to Cox regression models. However, while the model selection criteria for Firth's penalized partial likelihood approach have not yet been studied, a heuristic AIC-type information criterion can be used in a statistical package...
June 12, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28605510/phase-i-study-of-oral-sonidegib-lde225-in-pediatric-brain-and-solid-tumors-and-a-phase-ii-study-in-children-and-adults-with-relapsed-medulloblastoma
#9
Mark W Kieran, Julia Chisholm, Michela Casanova, Alba A Brandes, Isabelle Aerts, Eric Bouffet, Simon Bailey, Sarah Leary, Tobey J MacDonald, Francoise Mechinaud, Kenneth J Cohen, Riccardo Riccardi, Warren Mason, Darren Hargrave, Stacey Kalambakas, Priya Deshpande, Feng Tai, Eunju Hurh, Birgit Geoerger
Background.: Sonidegib (LDE225) is a potent, selective Hedgehog (Hh) inhibitor of SMOOTHENED. This study explored the safety and pharmacokinetics (PK) of sonidegib in children with relapsed/recurrent tumors followed by a phase II trial in pediatric and adult patients with relapsed medulloblastoma (MB) to assess tumor response. Methods.: Pediatric patients aged ≥1-<18 years were included according to a Bayesian design starting at 372mg/m2 of continuous once daily oral sonidegib...
June 9, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/28602997/neural-mechanisms-underlying-valence-inferences-to-sound-the-role-of-the-right-angular-gyrus
#10
Fernando Bravo, Ian Cross, Sarah Hawkins, Nadia Gonzalez, Jorge Docampo, Claudio Bruno, Emmanuel Andreas Stamatakis
We frequently infer others' intentions based on non-verbal auditory cues. Although the brain underpinnings of social cognition have been extensively studied, no empirical work has yet examined the impact of musical structure manipulation on the neural processing of emotional valence during mental state inferences. We used a novel sound-based theory-of-mind paradigm in which participants categorized stimuli of different sensory dissonance level in terms of positive/negative valence. Whilst consistent with previous studies which propose facilitated encoding of consonances, our results demonstrated that distinct levels of consonance/dissonance elicited differential influences on the right angular gyrus, an area implicated in mental state attribution and attention reorienting processes...
June 8, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28595489/a-brain-model-of-disturbed-self-appraisal-in-depression
#11
Christopher G Davey, Michael Breakspear, Jesus Pujol, Ben J Harrison
OBJECTIVE: A disturbed sense of self is a core feature of depression. The medial prefrontal cortex, which has a central role in self-appraisal processes, is often implicated in the illness, although it remains unclear how functional alterations of the region contribute to the observed disturbances. The aim of this study was to clarify the role of the medial prefrontal cortex in self-appraisal processes in depression. METHOD: The authors applied a recently developed dynamic network model of self-directed cognition to functional MRI data from 71 adolescents and young adults with moderate to severe major depressive disorder, none of whom were being treated with medication, and 88 healthy control participants...
June 9, 2017: American Journal of Psychiatry
https://www.readbyqxmd.com/read/28592689/control-of-the-strength-of-visual-motor-transmission-as-the-mechanism-of-rapid-adaptation-of-priors-for-bayesian-inference-in-smooth-pursuit-eye-movements
#12
Timothy Darlington, Stefanie Tokiyama, Stephen G Lisberger
Bayesian inference provides a cogent account of how the brain combines sensory information with "priors" based on past experience to guide many behaviors, including smooth pursuit eye movements. We now demonstrate very rapid adaptation of the pursuit system's priors for target direction and speed. We go on to leverage that adaptation to outline possible neural mechanisms that could cause pursuit to show features consistent with Bayesian inference. Adaptation of the prior causes changes in the eye speed and direction at the initiation of pursuit...
June 7, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28578155/prefrontal-parietal-effective-connectivity-during-working-memory-in-older-adults
#13
Stephan Heinzel, Robert C Lorenz, Quynh-Lam Duong, Michael A Rapp, Lorenz Deserno
Theoretical models and preceding studies have described age-related alterations in neuronal activation of frontoparietal regions in a working memory (WM) load-dependent manner. However, to date, underlying neuronal mechanisms of these WM load-dependent activation changes in aging remain poorly understood. The aim of this study was to investigate these mechanisms in terms of effective connectivity by application of dynamic causal modeling with Bayesian Model Selection. Eighteen healthy younger (age: 20-32 years) and 32 older (60-75 years) participants performed an n-back task with 3 WM load levels during functional magnetic resonance imaging (fMRI)...
May 10, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28573984/a-gaussian-mixture-model-based-adaptive-classifier-for-fnirs-brain-computer-interfaces-and-its-testing-via-simulation
#14
Zheng Li, Yi-Han Jiang, Lian Duan, Chao-Zhe Zhu
OBJECTIVE: Functional near infra-red spectroscopy (fNIRS) is a promising brain imaging technology for brain-computer interfaces (BCI). Future clinical uses of fNIRS will likely require operation over long time spans, during which neural activation patterns may change. However, current decoders for fNIRS signals are not designed to handle changing activation patterns. The objective of this study is to test via simulations a new adaptive decoder for fNIRS signals, the Gaussian mixture model adaptive classifier (GMMAC)...
June 2, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28570866/differentiated-effects-of-deep-brain-stimulation-and-medication-on-somatosensory-processing-in-parkinson-s-disease
#15
Kousik Sarathy Sridharan, Andreas Højlund, Erik Lisbjerg Johnsen, Niels Aagaard Sunde, Lars Gottfried Johansen, Sándor Beniczky, Karen Østergaard
OBJECTIVES: Deep brain stimulation (DBS) and dopaminergic medication effectively alleviate the motor symptoms in Parkinson's disease (PD) patients, but their effects on the sensory symptoms of PD are still not well understood. To explore early somatosensory processing in PD, we recorded magnetoencephalography (MEG) from thirteen DBS-treated PD patients and ten healthy controls during median nerve stimulation. METHODS: PD patients were measured during DBS-treated, untreated and dopaminergic-medicated states...
July 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28569123/diffusion-weighted-imaging-or-computerized-tomography-perfusion-assessment-with-clinical-mismatch-in-the-triage-of-wake-up-and-late-presenting-strokes-undergoing-neurointervention-with-trevo-dawn-trial-methods
#16
Tudor G Jovin, Jeffrey L Saver, Marc Ribo, Vitor Pereira, Anthony Furlan, Alain Bonafe, Blaise Baxter, Rishi Gupta, Demetrius Lopes, Olav Jansen, Wade Smith, Daryl Gress, Steven Hetts, Roger J Lewis, Ryan Shields, Scott M Berry, Todd L Graves, Tim Malisch, Ansaar Rai, Kevin N Sheth, David S Liebeskind, Raul G Nogueira
Rationale Efficacy of mechanical thrombectomy for acute stroke due to large vessel occlusion initiated beyond 6 h of time last seen well has not been demonstrated in randomized trials. Aim To establish whether subjects considered to have substantial areas of salvageable brain based on age-adjusted clinical core mismatch who can undergo endovascular treatment within 6-24 h from time last seen (TLSW) well have better outcomes at three months compared to subjects treated with standard medical therapy alone...
January 1, 2017: International Journal of Stroke: Official Journal of the International Stroke Society
https://www.readbyqxmd.com/read/28566360/social-information-is-integrated-into-value-and-confidence-judgments-according-to-its-reliability
#17
Benedetto De Martino, Sebastian Bobadilla-Suarez, Takao Nouguchi, Tali Sharot, Bradley C Love
How much we like something, whether it be a bottle of wine or a new film, is affected by the opinions of others. However, the social information we receive can be contradictory and vary in its reliability. Here we test whether the brain incorporates these statistics when judging value and confidence. Participants provided value judgments about consumer goods in the presence of online reviews. We found participants updated their initial value and confidence judgments in a Bayesian fashion, taking into account both the uncertainty of their initial beliefs and the reliability of the social information...
May 31, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28566144/the-anteroposterior-and-primary-to-posterior-limbic-ratios-as-mri-derived-volumetric-markers-of-alzheimer-s-disease
#18
Adolfo Jiménez-Huete, Susana Estévez-Santé
BACKGROUND/AIMS: Alzheimer's disease (AD) shows a characteristic pattern of brain atrophy, with predominant involvement of posterior limbic structures, and relative preservation of rostral limbic and primary cortical regions. We aimed to investigate the diagnostic utility of two gray matter volume ratios based on this pattern, and to develop a fully automated method to calculate them from unprocessed MRI files. PATIENTS AND METHODS: Cross-sectional study of 118 subjects from the ADNI database, including normal controls and patients with mild cognitive impairment (MCI) and AD...
July 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28560315/proactive-control-neural-oscillatory-correlates-of-conflict-anticipation-and-response-slowing
#19
Andrew Chang, Jaime S Ide, Hsin-Hung Li, Chien-Chung Chen, Chiang-Shan R Li
Proactive control allows us to anticipate environmental changes and adjust behavioral strategy. In the laboratory, investigators have used a number of different behavioral paradigms, including the stop-signal task (SST), to examine the neural processes of proactive control. Previous functional MRI studies of the SST have demonstrated regional responses to conflict anticipation-the likelihood of a stop signal or P(stop) as estimated by a Bayesian model-and reaction time (RT) slowing and how these responses are interrelated...
May 2017: ENeuro
https://www.readbyqxmd.com/read/28553694/investigation-of-different-classifiers-and-channel-configurations-of-a-mobile-p300-based-brain-computer-interface
#20
Simone A Ludwig, Jun Kong
Innovative methods and new technologies have significantly improved the quality of our daily life. However, disabled people, for example those that cannot use their arms and legs anymore, often cannot benefit from these developments, since they cannot use their hands to interact with traditional interaction methods (such as mouse or keyboard) to communicate with a computer system. A brain-computer interface (BCI) system allows such a disabled person to control an external device via brain waves. Past research mostly dealt with static interfaces, which limit users to a stationary location...
May 29, 2017: Medical & Biological Engineering & Computing
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