Predictive coding

Huang, Yanping; Rao, Rajesh P. N.

doi:10.1002/wcs.142

Cited by 450 publications

(407 citation statements)

References 74 publications

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“…Computational explanations of the balance between sensory evidence and prior knowledge as highlighted by our study are typically cast in terms of Bayesian models of perception and formalized within a predictive coding framework (5,31,32). In this setting, the integration of bottom-up and top-down signals is mediated by the relative amount of information each of these components provides: the stronger the sensory evidence is relative to prior knowledge, the more it will impact on the final processing output; conversely, if prior knowledge provides a relatively greater amount of information it will be weighted more strongly.…”

Section: Discussionmentioning

confidence: 99%

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

Teufel

Subramaniam

Dobler

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

235

240

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Many neuropsychiatric illnesses are associated with psychosis, i.e., hallucinations (perceptions in the absence of causative stimuli) and delusions (irrational, often bizarre beliefs). Current models of brain function view perception as a combination of two distinct sources of information: bottom-up sensory input and top-down influences from prior knowledge. This framework may explain hallucinations and delusions. Here, we characterized the balance between visual bottom-up and top-down processing in people with early psychosis (study 1) and in psychosis-prone, healthy individuals (study 2) to elucidate the mechanisms that might contribute to the emergence of psychotic experiences. Through a specialized mental-health service, we identified unmedicated individuals who experience early psychotic symptoms but fall below the threshold for a categorical diagnosis. We observed that, in early psychosis, there was a shift in information processing favoring prior knowledge over incoming sensory evidence. In the complementary study, we capitalized on subtle variations in perception and belief in the general population that exhibit graded similarity with psychotic experiences (schizotypy). We observed that the degree of psychosis proneness in healthy individuals, and, specifically, the presence of subtle perceptual alterations, is also associated with stronger reliance on prior knowledge. Although, in the current experimental studies, this shift conferred a performance benefit, under most natural viewing situations, it may provoke anomalous perceptual experiences. Overall, we show that early psychosis and psychosis proneness both entail a basic shift in visual information processing, favoring prior knowledge over incoming sensory evidence. The studies provide complementary insights to a mechanism by which psychotic symptoms may emerge.visual perception | psychosis | top-down processing | predictive coding | schizophrenia

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Section: Discussionmentioning

confidence: 99%

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

Teufel

Subramaniam

Dobler

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

235

240

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“…The predictive coding framework proposes that information residing in an internal predictive model is fed back from higher‐order cortical areas to lower‐level brain areas whose activity reflects the difference between auditory input and the predictive information, that is, the prediction error signal (Friston, 2005; Huang & Rao, 2011; Mumford, 1992; Rao & Ballard, 1999). This error signal is projected to the higher‐order cortical areas through feedforward connections to update the internal model.…”

Section: Discussionmentioning

confidence: 99%

Predictive processing increases intelligibility of acoustically distorted speech: Behavioral and neural correlates

et al. 2017

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IntroductionWe examined which brain areas are involved in the comprehension of acoustically distorted speech using an experimental paradigm where the same distorted sentence can be perceived at different levels of intelligibility. This change in intelligibility occurs via a single intervening presentation of the intact version of the sentence, and the effect lasts at least on the order of minutes. Since the acoustic structure of the distorted stimulus is kept fixed and only intelligibility is varied, this allows one to study brain activity related to speech comprehension specifically.MethodsIn a functional magnetic resonance imaging (fMRI) experiment, a stimulus set contained a block of six distorted sentences. This was followed by the intact counterparts of the sentences, after which the sentences were presented in distorted form again. A total of 18 such sets were presented to 20 human subjects.ResultsThe blood oxygenation level dependent (BOLD)‐responses elicited by the distorted sentences which came after the disambiguating, intact sentences were contrasted with the responses to the sentences presented before disambiguation. This revealed increased activity in the bilateral frontal pole, the dorsal anterior cingulate/paracingulate cortex, and the right frontal operculum. Decreased BOLD responses were observed in the posterior insula, Heschl's gyrus, and the posterior superior temporal sulcus.ConclusionsThe brain areas that showed BOLD‐enhancement for increased sentence comprehension have been associated with executive functions and with the mapping of incoming sensory information to representations stored in episodic memory. Thus, the comprehension of acoustically distorted speech may be associated with the engagement of memory‐related subsystems. Further, activity in the primary auditory cortex was modulated by prior experience, possibly in a predictive coding framework. Our results suggest that memory biases the perception of ambiguous sensory information toward interpretations that have the highest probability to be correct based on previous experience.

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“…We note that most formulations of PC rely on Bayesian principles 14,58 , an approach that we have not employed in this study. There are multiple formulations of PC that use different Bayesian-based approaches to model surprise signals and perceptual learning 11 .…”

Section: Methodsmentioning

confidence: 99%

“…However, no study has examined whether faces become familiar and recognized in a manner that conforms to the assumptions of a PC account. Here we developed a computational model of face recognition around the assumptions of PC 11,14,15 , to examine how contextual and viewpoint independent information influence face recognition and its neural underpinnings.…”

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confidence: 99%

Predictive codes of familiarity and context during the perceptual learning of facial identities

Apps

Tsakiris

2013

Nat Commun

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Face recognition is a key component of successful social behaviour. However, the computational processes that underpin perceptual learning and recognition as faces transition from unfamiliar to familiar are poorly understood. In predictive coding, learning occurs through prediction errors that update stimulus familiarity, but recognition is a function of both stimulus and contextual familiarity. Here we show that behavioural responses on a two-option face recognition task can be predicted by the level of contextual and facial familiarity in a computational model derived from predictive-coding principles. Using fMRI, we show that activity in the superior temporal sulcus varies with the contextual familiarity in the model, whereas activity in the fusiform face area covaries with the prediction error parameter that updated facial familiarity. Our results characterize the key computations underpinning the perceptual learning of faces, highlighting that the functional properties of face-processing areas conform to the principles of predictive coding.

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Predictive coding

Cited by 450 publications

References 74 publications

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

Predictive processing increases intelligibility of acoustically distorted speech: Behavioral and neural correlates

Predictive codes of familiarity and context during the perceptual learning of facial identities

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