scholarly journals Dopamine modulates prediction error forwarding in the nonlemniscal inferior colliculus

2019 ◽  
Author(s):  
Catalina Valdés-Baizabal ◽  
Guillermo V. Carbajal ◽  
David Pérez-González ◽  
Manuel S. Malmierca

AbstractThe predictive processing framework describes perception as a hierarchical predictive model of sensation. Higher-level neural structures constrain the processing at lower-level structures by suppressing synaptic activity induced by predictable sensory input. But when predictions fail, deviant input is forwarded bottom-up as ‘prediction error’ to update the perceptual model. The earliest prediction error signals identified in the auditory pathway emerge from the nonlemniscal inferior colliculus (IC). The drive that these feedback signals exert on the perceptual model depends on their ‘expected precision’, which determines the postsynaptic gain applied in prediction error forwarding. Expected precision is theoretically encoded by the neuromodulatory (e.g., dopaminergic) systems. To test this empirically, we recorded extracellular responses from the rat nonlemniscal IC to oddball and cascade sequences before, during and after the microiontophoretic application of dopamine or eticlopride (a D2-like receptor antagonist). Hence, we studied dopaminergic modulation on the subcortical processing of unpredictable and predictable auditory changes. Results demonstrate that dopamine reduces the net neuronal responsiveness exclusively to unexpected input, without significantly altering the processing of expected auditory events at population level. We propose that, in natural conditions, dopaminergic projections from the thalamic subparafascicular nucleus to the nonlemniscal IC could serve as a precision-weighting mechanism mediated by D2-like receptors. Thereby, the levels of dopamine release in the nonlemniscal IC could modulate the early bottom-up flow of prediction error signals in the auditory system by encoding their expected precision.

2021 ◽  
Vol 15 ◽  
Author(s):  
Alejandro Tabas ◽  
Katharina von Kriegstein

Predictive processing, a leading theoretical framework for sensory processing, suggests that the brain constantly generates predictions on the sensory world and that perception emerges from the comparison between these predictions and the actual sensory input. This requires two distinct neural elements: generative units, which encode the model of the sensory world; and prediction error units, which compare these predictions against the sensory input. Although predictive processing is generally portrayed as a theory of cerebral cortex function, animal and human studies over the last decade have robustly shown the ubiquitous presence of prediction error responses in several nuclei of the auditory, somatosensory, and visual subcortical pathways. In the auditory modality, prediction error is typically elicited using so-called oddball paradigms, where sequences of repeated pure tones with the same pitch are at unpredictable intervals substituted by a tone of deviant frequency. Repeated sounds become predictable promptly and elicit decreasing prediction error; deviant tones break these predictions and elicit large prediction errors. The simplicity of the rules inducing predictability make oddball paradigms agnostic about the origin of the predictions. Here, we introduce two possible models of the organizational topology of the predictive processing auditory network: (1) the global view, that assumes that predictions on the sensory input are generated at high-order levels of the cerebral cortex and transmitted in a cascade of generative models to the subcortical sensory pathways; and (2) the local view, that assumes that independent local models, computed using local information, are used to perform predictions at each processing stage. In the global view information encoding is optimized globally but biases sensory representations along the entire brain according to the subjective views of the observer. The local view results in a diminished coding efficiency, but guarantees in return a robust encoding of the features of sensory input at each processing stage. Although most experimental results to-date are ambiguous in this respect, recent evidence favors the global model.


2018 ◽  
Author(s):  
Beren Millidge ◽  
Richard Shillcock

We propose a novel predictive processing account of bottom-up visual saliency in which salience is simply the low-level prediction error between the sense-data and the predictions produced by the generative models in the brain. We test this with modelling in which we use cross-predicting deep autoencoders to create salience maps in an entirely unsupervised way. The resulting maps closely mimic experimentally derived human saliency maps and also spontaneously learn a centre bias, a robust viewing behaviour seen in human participants.


Author(s):  
Lauren Swiney

Over the last thirty years the comparator hypothesis has emerged as a prominent account of inner speech pathology. This chapter discusses a number of cognitive accounts broadly derived from this approach, highlighting the existence of two importantly distinct notions of inner speech in the literature; one as a prediction in the absence of sensory input, the other as an act with sensory consequences that are themselves predicted. Under earlier frameworks in which inner speech is described in the context of classic models of motor control, I argue that these two notions may be compatible, providing two routes to inner speech pathology. Under more recent accounts grounded in the architecture of Bayesian predictive processing, I argue that “active inference” approaches to action generation pose serious challenges to the plausibility of the latter notion of inner speech, while providing the former notion with rich explanatory possibilities for inner speech pathology.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Gloria G. Parras ◽  
Javier Nieto-Diego ◽  
Guillermo V. Carbajal ◽  
Catalina Valdés-Baizabal ◽  
Carles Escera ◽  
...  

Author(s):  
Michiel Van Elk ◽  
Harold Bekkering

We characterize theories of conceptual representation as embodied, disembodied, or hybrid according to their stance on a number of different dimensions: the nature of concepts, the relation between language and concepts, the function of concepts, the acquisition of concepts, the representation of concepts, and the role of context. We propose to extend an embodied view of concepts, by taking into account the importance of multimodal associations and predictive processing. We argue that concepts are dynamically acquired and updated, based on recurrent processing of prediction error signals in a hierarchically structured network. Concepts are thus used as prior models to generate multimodal expectations, thereby reducing surprise and enabling greater precision in the perception of exemplars. This view places embodied theories of concepts in a novel predictive processing framework, by highlighting the importance of concepts for prediction, learning and shaping categories on the basis of prediction errors.


Author(s):  
A. Greenhouse-Tucknott ◽  
J. B. Butterworth ◽  
J. G. Wrightson ◽  
N. J. Smeeton ◽  
H. D. Critchley ◽  
...  

AbstractFatigue is a common experience in both health and disease. Yet, pathological (i.e., prolonged or chronic) and transient (i.e., exertional) fatigue symptoms are traditionally considered distinct, compounding a separation between interested research fields within the study of fatigue. Within the clinical neurosciences, nascent frameworks position pathological fatigue as a product of inference derived through hierarchical predictive processing. The metacognitive theory of dyshomeostasis (Stephan et al., 2016) states that pathological fatigue emerges from the metacognitive mechanism in which the detection of persistent mismatches between prior interoceptive predictions and ascending sensory evidence (i.e., prediction error) signals low evidence for internal generative models, which undermine an agent’s feeling of mastery over the body and is thus experienced phenomenologically as fatigue. Although acute, transient subjective symptoms of exertional fatigue have also been associated with increasing interoceptive prediction error, the dynamic computations that underlie its development have not been clearly defined. Here, drawing on the metacognitive theory of dyshomeostasis, we extend this account to offer an explicit description of the development of fatigue during extended periods of (physical) exertion. Accordingly, it is proposed that a loss of certainty or confidence in control predictions in response to persistent detection of prediction error features as a common foundation for the conscious experience of both pathological and nonpathological fatigue.


2019 ◽  
Author(s):  
Beren Millidge

Initial and preliminary implementations of predictive processing and active inference models are presented. These include the baseline hierarchical predictive coding models of (Friston 2003, 2005), and dynamical predictive coding models using generalised coordinates (Friston 2008, 2010, Buckley 2017). Additionally, we re-implement and experiment with the active inference thermostat presented in (Buckley 2017) and also implement an active inference agent with a hierarchical predictive coding perceptual model on the more challenging cart-pole task from OpanAI gym. We discuss the initial performance, capabilities, and limitations of these models in their preliminary stages and consider how they might be further scaled up to tackle more challenging tasks.


2019 ◽  
pp. 191-205 ◽  
Author(s):  
Jakob Hohwy

Andy Clark’s exciting work on predictive processing provides the umbrella under which his hugely influential previous work on embodied and extended cognition seeks a unified home. This chapter argues that in fact predictive processing harbours internalist, inferentialist and epistemic tenets that cannot leave embodied and extended cognition unchanged. Predictive processing cannot do the work Clark requires of it without relying on rich, preconstructive internal representations of the world, nor without engaging in paradigmatically rational integration of prior knowledge and new sensory input. Hence, next to Clark’s image of fluid “uncertainty surfing” is an equally valid image of more emaciated and plodding world-modelling. Rather than underpinning orthodox embodied and extended approches, predictive processing therefore presents an opportunity for a potentially fruitful new synthesis of cognitivist and embodied approaches to cognition.


1989 ◽  
Vol 61 (2) ◽  
pp. 257-268 ◽  
Author(s):  
R. Batra ◽  
S. Kuwada ◽  
T. R. Stanford

1. The difference in the time of arrival of a sound at the two ears can be used to locate its source along the azimuth. Traditionally, it has been thought that only the on-going interaural temporal disparities (ITDs) produced by sounds of lower frequency (approximately less than 2 kHz) could be used for this purpose. However, ongoing ITDs of low frequency are also produced by envelopes of amplitude-modulated (AM) tones. These ITDs can be detected and used to lateralize complex high-frequency sounds (1, 8, 12, 15, 22, 24, 26). Auditory neurons synchronize to the modulation envelope, but do so at progressively lower modulation frequencies at higher levels of the auditory pathway. Some neurons of the cochlear nucleus synchronize best to frequencies as high as 700 Hz, but those of the inferior colliculus (IC) exhibit their best synchrony below 200 Hz. Even though synchrony to higher modulation frequencies is reduced at higher levels of the auditory pathway, is information about ITDs retained? 2. We answered this question by extracellularly recording the responses of neurons in the IC of the unanesthetized rabbit. We used an unanesthetized preparation because anesthesia alters the responses of neurons in the IC to both monaurally presented tones and ITDs. The unanesthetized rabbit is ideal for auditory research. Recordings can be maintained for long periods, and the acoustic stimulus to each ear can be independently controlled. 3. We studied the responses of 89 units to sinusoidally AM tones presented to the contralateral ear. For each unit, we recorded the response at several modulation frequencies. The degree of phase locking to the envelope at each frequency was measured using the synchronization coefficient. Two measures were used to assess the range of modulation frequencies over which phase locking occurred. The "best AM frequency" was the frequency at which we observed the greatest phase locking. The "highest AM frequency" was the highest frequency at which significant phase locking (0.001 level) was observed. We could not assess synchrony to ipsilateral AM tones directly, because most units did not respond to ipsilateral stimulation. 4. We studied the sensitivity of 63 units to ITDs produced by the envelopes of AM tones. Sensitivity to ITDs was tested by presenting AM tones to the two ears that had the same carrier frequency, but modulation frequencies that differed by 1 Hz. Units that were sensitive to ITDs responded to this stimulus by varying their response rate cyclically at the difference frequency, i.e., 1 Hz.(ABSTRACT TRUNCATED AT 400 WORDS)


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