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ADAPTIVE NOISE SPECTRAL SHAPING AND ENTROPY coding IN predictive coding OF SPEECH

IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL PROCESSING 1979年第1期27卷 63-73页

作者： MAKHOUL, J BEROUTI, M Bolt Beranek and Newman 슠Inc. Cambridge MA USA

We report on research to code speech at 16 kbit/s with the goal of having the quality of the coded speech be equal to that of the original. Some of the original speech had been corrupted by noise and distortions typical of long-distance telephone lines. The basic structure chosen for our system was adaptive predictive coding. However, the rigorous requirements of this work led to a new outlook on the different aspects of adaptive predictive coding. We have found that the pitch predictor is not cost-effective on balance and may be eliminated. Solutions are presented to deal with the two types of quantization noise: clipping and granular noise. The clipping problem is completely eliminated by allowing the number of quantizer levels to increase indefinitely. An appropriate self-synchronizing variable-length code is proposed to minimize the average data rate; the coding scheme seems to be adequate for all speech and all conditions tested. The granular noise problem is treated by modifying the predictive coding system in a novel manner to include an adaptive noise spectral shaping filter. A design for such a filter is proposed that effectively eliminates the perception of granular noise.

关键词： Noise shaping Entropy coding predictive coding Speech enhancement Speech coding Filters Telephony Adaptive systems Quantization Automatic testing

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Electrophysiological alterations in motor-auditory predictive coding in autism spectrum disorder

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AUTISM RESEARCH 2019年第4期12卷 589-599页

作者： van Laarhoven, Thijs Stekelenburg, Jeroen J. Eussen, Mart L. J. M. Vroomen, Jean Tilburg Univ Dept Cognit Neuropsychol NL-5000 LE Tilburg Netherlands Yulius Mental Hlth Org Dept Child & Adolescent Psychiat Dordrecht Netherlands Yulius Mental Hlth Org Dept Autism Dordrecht Netherlands

The amplitude of the auditory N1 component of the event-related potential (ERP) is typically attenuated for self-initiated sounds, compared to sounds with identical acoustic and temporal features that are triggered externally. This effect has been ascribed to internal forward models predicting the sensory consequences of one's own motor actions. The predictive coding account of autistic symptomatology states that individuals with autism spectrum disorder (ASD) have difficulties anticipating upcoming sensory stimulation due to a decreased ability to infer the probabilistic structure of their environment. Without precise internal forward prediction models to rely on, perception in ASD could be less affected by prior expectations and more driven by sensory input. Following this reasoning, one would expect diminished attenuation of the auditory N1 due to self-initiation in individuals with ASD. Here, we tested this hypothesis by comparing the neural response to self- versus externally-initiated tones between a group of individuals with ASD and a group of age matched neurotypical controls. ERPs evoked by tones initiated via button-presses were compared with ERPs evoked by the same tones replayed at identical pace. Significant N1 attenuation effects were only found in the TD group. Self-initiation of the tones did not attenuate the auditory N1 in the ASD group, indicating that they may be unable to anticipate the auditory sensory consequences of their own motor actions. These results show that individuals with ASD have alterations in sensory attenuation of self-initiated sounds, and support the notion of impaired predictive coding as a core deficit underlying autistic symptomatology. Autism Res 2019, 12: 589-599. (c) 2019 The Authors. Autism Research published by International Society for Autism Research published by Wiley Periodicals, Inc.

关键词： autism spectrum disorder ERPs motor-auditory predictive coding

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Great Expectations: Is there Evidence for predictive coding in Auditory Cortex?

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NEUROSCIENCE 2018年 389卷 54-73页

作者： Heilbron, Micha Chait, Maria Ecole Normale Super Dept Biol F-75005 Paris France Univ Pierre & Marie Curie P6 F-75005 Paris France UCL Ear Inst London WC1X 8EE England Radboud Univ Nijmegen Donders Inst Brain Cognit & Behav Kapittelweg 29 NL-6525 EN Nijmegen Netherlands

predictive coding is possibly one of the most influential, comprehensive, and controversial theories of neural function. While proponents praise its explanatory potential, critics object that key tenets of the theory are untested or even untestable. The present article critically examines existing evidence for predictive coding in the auditory modality. Specifically, we identify five key assumptions of the theory and evaluate each in the light of animal, human and modeling studies of auditory pattern processing. For the first two assumptions - that neural responses are shaped by expectations and that these expectations are hierarchically organized - animal and human studies provide compelling evidence. The anticipatory, predictive nature of these expectations also enjoys empirical support, especially from studies on unexpected stimulus omission. However, for the existence of separate error and prediction neurons, a key assumption of the theory, evidence is lacking. More work exists on the proposed oscillatory signatures of predictive coding, and on the relation between attention and precision. However, results on these latter two assumptions are mixed or contradictory. Looking to the future, more collaboration between human and animal studies, aided by model-based analyses will be needed to test specific assumptions and implementations of predictive coding - and, as such, help determine whether this popular grand theory can fulfill its expectations. This article is part of a Special Issue entitled: Sensory Sequence Processing in the Brain. (C) 2017 The Author(s). Published by Elsevier Ltd on behalf of IBRO.

关键词： predictive coding auditory MMN SSA bayesian brain

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Sedation Modulates Frontotemporal predictive coding Circuits and the Double Surprise Acceleration Effect

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CEREBRAL CORTEX 2020年第10期30卷 5204-5217页

作者： Witon, Adrien Shirazibehehsti, Amirali Cooke, Jennifer Aviles, Alberto Adapa, Ram Menon, David K. Chennu, Srivas Bekinschtein, Tristan Lopez, Jose David Litvak, Vladimir Li, Ling Friston, Karl Bowman, Howard Univ Kent Sch Comp Canterbury CT2 7NF Kent England EPFL Ctr Neuroprosthet CH-1951 Sion Switzerland East Kent Hosp Univ NHS Fdn Trust Kent & Canterbury Hosp Canterbury CT1 3NG Kent England Kings Coll London Inst Psychiat Psychol & Neurosci London SE5 8AF England Univ Birmingham Sch Psychol Birmingham B15 2TT W Midlands England Univ Cambridge Div Anaesthesia Box 97Cambridge Biomed Campus Cambridge CB2 0QQ England Univ Cambridge Dept Psychol Cambridge CB2 3EB England Univ Antioquia Elect Engn Program Ciudad Univ Medellin 1226 Colombia UCL Wellcome Ctr Neuroimaging London WC1N 3AR England

Two important theories in cognitive neuroscience are predictive coding (PC) and the global workspace (GW) theory. A key research task is to understand how these two theories relate to one another, and particularly, how the brain transitions from a predictive early state to the eventual engagement of a brain-scale state (the GW). To address this question, we present a source-localization of EEG responses evoked by the local-global task-an experimental paradigm that engages a predictive hierarchy, which encompasses the GW. The results of our source reconstruction suggest three phases of processing. The first phase involves the sensory (here auditory) regions of the superior temporal lobe and predicts sensory regularities over a short timeframe (as per the local effect). The third phase is brain-scale, involving inferior frontal, as well as inferior and superior parietal regions, consistent with a global neuronal workspace (GNW;as per the global effect). Crucially, our analysis suggests that there is an intermediate (second) phase, involving modulatory interactions between inferior frontal and superior temporal regions. Furthermore, sedation with propofol reduces modulatory interactions in the second phase. This selective effect is consistent with a PC explanation of sedation, with propofol acting on descending predictions of the precision of prediction errors;thereby constraining access to the GNW.

关键词： predictive coding global workspace source inversion EEG analysis

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Multimodal evidence for predictive coding in sentence oral reading

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CEREBRAL CORTEX 2023年第13期33卷 8620-8632页

作者： Zhao, Bin Zhang, Gaoyan Wang, Longbiao Dang, Jianwu Tianjin Univ Coll Intelligence & Comp Tianjin Key Lab Cognit Comp & Applicat Tianjin 300350 Peoples R China Pengcheng Lab Shenzhen 518055 Peoples R China

Sentence oral reading requires not only a coordinated effort in the visual, articulatory, and cognitive processes but also supposes a top-down influence from linguistic knowledge onto the visual-motor behavior. Despite a gradual recognition of a predictive coding effect in this process, there is currently a lack of a comprehensive demonstration regarding the time-varying brain dynamics that underlines the oral reading strategy. To address this, our study used a multimodal approach, combining real-time recording of electroencephalography, eye movements, and speech, with a comprehensive examination of regional, inter-regional, sub-network, and whole-brain responses. Our study identified the top-down predictive effect with a phrase-grouping phenomenon in the fixation interval and eye-voice span. This effect was associated with the delta and theta band synchronization in the prefrontal, anterior temporal, and inferior frontal lobes. We also observed early activation of the cognitive control network and its recurrent interactions with the visual-motor networks structurally at the phrase rate. Finally, our study emphasizes the importance of cross-frequency coupling as a promising neural realization of hierarchical sentence structuring and calls for further investigation.

关键词： predictive coding sentence oral reading brain network dynamics microstate analysis eye-voice span

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Boredom begets creativity: A solution to the exploitation-exploration trade-off in predictive coding

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BIOSYSTEMS 2017年 162卷 168-176页

作者： Gomez-Ramirez, Jaime Costa, Tommaso Univ Toronto Hosp Sick Children Dept Neurosci & Mental Hlth Bay St 686 Toronto ON Canada Univ Turin Koelliker Hosp Dept Psychol Via Verdi 10 I-10124 Turin Italy

Here we investigate whether systems that minimize prediction error e.g. predictive coding, can also show creativity, or on the contrary, prediction error minimization unqualifies for the design of systems that respond in creative ways to non-recurrent problems. We argue that there is a key ingredient that has been overlooked by researchers that needs to be incorporated to understand intelligent behavior in biological and technical systems. This ingredient is boredom. We propose a mathematical model based on the Black-Scholes-Merton equation which provides mechanistic insights into the interplay between boredom and prediction pleasure as the key drivers of behavior. (C) 2017 Elsevier B.V. All rights reserved.

关键词： predictive coding Black-Scholes model Helmholtz machine Bayesian brain Free energy minimization Boredom

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Recent advances in the application of predictive coding and active inference models within clinical neuroscience

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PSYCHIATRY AND CLINICAL NEUROSCIENCES 2021年第1期75卷 3-13页

作者： Smith, Ryan Badcock, Paul Friston, Karl J. Laureate Inst Brain Res Tulsa OK 74136 USA Univ Melbourne Ctr Youth Mental Hlth Melbourne Vic Australia Orygen Parkville Vic Australia Univ Melbourne Melbourne Sch Psychol Sci Melbourne Vic Australia UCL Inst Neurol Wellcome Ctr Human Neuroimaging London England

Research in clinical neuroscience is founded on the idea that a better understanding of brain (dys)function will improve our ability to diagnose and treat neurological and psychiatric disorders. In recent years, neuroscience has converged on the notion that the brain is a 'prediction machine,' in that it actively predicts the sensory input that it will receive if one or another course of action is chosen. These predictions are used to select actions that will (most often, and in the long run) maintain the body within the narrow range of physiological states consistent with survival. This insight has given rise to an area of clinical computational neuroscience research that focuses on characterizing neural circuit architectures that can accomplish these predictive functions, and on how the associated processes may break down or become aberrant within clinical conditions. Here, we provide a brief review of examples of recent work on the application of predictive processing models of brain function to study clinical (psychiatric) disorders, with the aim of highlighting current directions and their potential clinical utility. We offer examples of recent conceptual models, formal mathematical models, and applications of such models in empirical research in clinical populations, with a focus on making this material accessible to clinicians without expertise in computational neuroscience. In doing so, we aim to highlight the potential insights and opportunities that understanding the brain as a prediction machine may offer to clinical research and practice.

关键词： active inference computational neuroscience computational psychiatry emotion predictive coding

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Parsing components of auditory predictive coding in schizophrenia using a roving standard mismatch negativity paradigm

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PSYCHOLOGICAL MEDICINE 2019年第7期49卷 1195-1206页

作者： McCleery, Amanda Mathalon, Daniel H. Wynn, Jonathan K. Roach, Brian J. Hellemann, Gerhard S. Marder, Stephen R. Green, Michael F. Univ Calif Los Angeles Semel Inst Neurosci & Human Behav Los Angeles CA 90024 USA Vet Affairs Greater Los Angeles Healthcare Syst Los Angeles CA 90073 USA Vet Affairs San Francisco Healthcare Syst San Francisco CA USA Univ Calif San Francisco Dept Psychiat Weill Inst Neurosci San Francisco CA USA

BackgroundMismatch negativity (MMN) is an event-related potential (ERP) component reflecting auditory predictive coding. Repeated standard tones evoke increasing positivity (repetition positivity';RP), reflecting strengthening of the standard's memory trace and the prediction it will recur. Likewise, deviant tones preceded by more standard repetitions evoke greater negativity (deviant negativity';DN), reflecting stronger prediction error signaling. These memory trace effects are also evident in MMN difference wave. Here, we assess group differences and test-retest reliability of these indices in schizophrenia patients (SZ) and healthy controls (HC).MethodsElectroencephalography was recorded twice, 2 weeks apart, from 43 SZ and 30 HC, during a roving standard paradigm. We examined ERPs to the third, eighth, and 33(rd) standards (RP), immediately subsequent deviants (DN), and the corresponding MMN. Memory trace effects were assessed by comparing amplitudes associated with the three standard repetition *** with controls, SZ showed reduced MMNs and DNs, but normal RPs. Both groups showed memory trace effects for RP, MMN, and DN, with a trend for attenuated DNs in SZ. Intraclass correlations obtained via this paradigm indicated good-to-moderate reliabilities for overall MMN, DN and RP, but moderate to poor reliabilities for components associated with short, intermediate, and long standard trains, and poor reliability of their memory trace *** deficits in SZ reflected attenuated prediction error signaling (DN), with relatively intact predictive code formation (RP) and memory trace effects. This roving standard MMN paradigm requires additional development/validation to obtain suitable levels of reliability for use in clinical trials.

关键词： deviant negativity memory trace mismatch negativity prediction error signaling predictive coding psychotic disorders repetition negativity

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Encoder Reverberations in Adaptive predictive coding

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IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING 1994年第1期2卷 18-23页

作者： Mills, James D. Rohrs, Charles E. Magill, Robert B. Tellabs Res Ctr Mishawaka IN 46545 USA

In the past, the nonlinear effects of quantization in differential speech coders either were modeled as additive white Gaussian noise or were ignored in analysis and quazntified experimentally. Describing functions are used to model the nonlinear quantizer effects of coarsely quantized difference signals found primarily in adaptive predictive coding (APC) systems. The analysis predicts marginal instabilities in APC encoders. The marginal instabilities result in ringing distortions in the reconstructed signal which, in the past, may have been attributed to pitch and spectral predictor mismatches. Adaptive order prediction is introduced, analyzed, and offered as a method for increasing the robustness of APC encoders.

关键词： Reverberation predictive coding Quantization Decoding Milling machines Speech analysis predictive models Nonlinear distortion Robustness Delta modulation

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Now you hear it: a predictive coding model for understanding rhythmic incongruity

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ANNALS OF THE NEW YORK ACADEMY OF SCIENCES 2018年第1期1423卷 19-29页

作者： Vuust, Peter Dietz, Martin J. Witek, Maria Kringelbach, Morten L. Aarhus Univ Dept Clin Med Ctr Mus Brain Aarhus Denmark Royal Acad Mus Aarhus Denmark Aarhus Univ Dept Clin Med Ctr Funct Integrat Neurosci Aarhus Denmark Univ Oxford Dept Psychiat Oxford England

Rhythmic incongruity in the form of syncopation is a prominent feature of many contemporary musical styles. Syncopations afford incongruity between rhythmic patterns and the meter, giving rise to mental models of differently accented isochronous beats. Syncopations occur either in isolation or as part of rhythmic patterns, so-called grooves. On the basis of the predictive coding framework, we discuss how brain processing of rhythm can be seen as a special case of predictive coding. We present a simple, yet powerful model for how the brain processes rhythmic incongruity: the model for predictive coding of rhythmic incongruity. Our model proposes that a given rhythm's syncopation and its metrical uncertainty (precision) is at the heart of how the brain models rhythm and meter based on priors, predictions, and prediction error. Our minimal model can explain prominent features of brain processing of syncopation: why isolated syncopations lead to stronger prediction error in the brains of musicians, as evidenced by larger event-related potentials to rhythmic incongruity, and why we all experience a stronger urge to move to grooves with a medium level of syncopation compared with low and high levels of syncopation.

关键词： rhythm music predictive coding brain

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