Visual awareness and the cerebellum: possible role of decorrelation control

Dean, Paul; Porrill, John; Stone, James V.

doi:10.1016/s0079-6123(03)14404-4

Cited by 17 publications

(6 citation statements)

References 43 publications

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“…15.One of us has proposed that this first-person egocenter, or viewpoint, is only the innermost one of the three most global invariants that the brain's probabilistic inferential labors extract from the movement-contingent clusters of correlated (and uncorrelated) variances playing across its sensory systems in the course of our mobile engagement with the world (Merker, 2013b, p. 13; see also Merker, 2012, p. 54; and Philipona, O'Reagan, & Nadal, 2003, 2004; Dean, Porrill, & Stone, 2004). Thus interpreted, it supplies the necessary pivot around which the compensatory coordinate transformations between the other two super-clusters, “body” and “world,” can be managed most economically during movement.…”

Section: Notesmentioning

confidence: 99%

The integrated information theory of consciousness: A case of mistaken identity

Merker¹,

Williford²,

Rudrauf³

2021

Behav Brain Sci

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Giulio Tononi's Integrated Information Theory (IIT) proposes explaining consciousness by directly identifying it with integrated information. We examine the construct validity of IIT's measure of consciousness, phi (Φ), by analyzing its formal properties, its relation to key aspects of consciousness, and its co-variation with relevant empirical circumstances. Our analysis shows that IIT's identification of consciousness with the causal efficacy with which differentiated networks accomplish global information transfer (which is what Φ in fact measures) is mistaken. This misidentification has the consequence of requiring the attribution of consciousness to a range of natural systems and artifacts that include, but are not limited to, large-scale electrical power grids, gene-regulation networks, some electronic circuit boards, and social networks. Instead of treating this consequence of the theory as a disconfirmation, IIT embraces it. By regarding these systems as bearers of consciousness ex hypothesi, IIT is led towards the orbit of panpsychist ideation. This departure from science as we know it can be avoided by recognizing the functional misattribution at the heart of IIT's identity claim. We show, for example, what function is actually performed, at least in the human case, by the cortical combination of differentiation with integration that IIT identifies with consciousness. Finally, we examine what lessons may be drawn from IIT's failure to provide a credible account of consciousness for progress in the very active field of research concerned with exploring the phenomenon from formal and neural points of view.

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Section: Notesmentioning

confidence: 99%

The integrated information theory of consciousness: A case of mistaken identity

Merker¹,

Williford²,

Rudrauf³

2021

Behav Brain Sci

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“…Thus, the majority of connections between neurons and interneurons in the cerebellar cortex occur within individual modules. The connections between modules occur almost exclusively via parallel fibers, which contact Purkinje cells and the other inhibitory interneurons (Lainé and Axelrad, 1998; Dieudonné and Dumoulin, 2000; Dean et al, 2004). …”

Section: The Extended Cerebro-cerebellar Loopsmentioning

confidence: 99%

Seeking a unified framework for cerebellar function and dysfunction: from circuit operations to cognition

D’Angelo

Casali²

2013

Front. Neural Circuits

268

282

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Following the fundamental recognition of its involvement in sensory-motor coordination and learning, the cerebellum is now also believed to take part in the processing of cognition and emotion. This hypothesis is recurrent in numerous papers reporting anatomical and functional observations, and it requires an explanation. We argue that a similar circuit structure in all cerebellar areas may carry out various operations using a common computational scheme. On the basis of a broad review of anatomical data, it is conceivable that the different roles of the cerebellum lie in the specific connectivity of the cerebellar modules, with motor, cognitive, and emotional functions (at least partially) segregated into different cerebro-cerebellar loops. We here develop a conceptual and operational framework based on multiple interconnected levels (a meta-levels hypothesis): from cellular/molecular to network mechanisms leading to generation of computational primitives, thence to high-level cognitive/emotional processing, and finally to the sphere of mental function and dysfunction. The main concept explored is that of intimate interplay between timing and learning (reminiscent of the “timing and learning machine” capabilities long attributed to the cerebellum), which reverberates from cellular to circuit mechanisms. Subsequently, integration within large-scale brain loops could generate the disparate cognitive/emotional and mental functions in which the cerebellum has been implicated. We propose, therefore, that the cerebellum operates as a general-purpose co-processor, whose effects depend on the specific brain centers to which individual modules are connected. Abnormal functioning in these loops could eventually contribute to the pathogenesis of major brain pathologies including not just ataxia but also dyslexia, autism, schizophrenia, and depression.

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“…This procedure has multiple uses. For example, if the output itself is used as the teaching signal, the system can be used to remove interference from sensory signals, including that produced by the organism's own movements [13,14]. Alternatively, if the teaching signal relates to movement accuracy, and one of the filter inputs is an efference copy of the relevant motor commands, then successful decorrelation of motor commands from inaccuracy ensures that the commands are as accurate as possible-a major goal of cerebellar models [13,15].…”

Section: Decorrelationmentioning

confidence: 99%

Adaptive-filter Models of the Cerebellum: Computational Analysis

Dean

Porrill

2008

Cerebellum

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Many current models of the cerebellar cortical microcircuit are equivalent to an adaptive filter using the covariance learning rule. The adaptive filter is a development of the original Marr-Albus framework that deals naturally with continuous time-varying signals, thus addressing the issue of 'timing' in cerebellar function, and it can be connected in a variety of ways to other parts of the system, consistent with the microzonal organization of cerebellar cortex. However, its computational capacities are not well understood. Here we summarise the results of recent work that has focused on two of its intrinsic properties. First, an adaptive filter seeks to decorrelate its (mossy fibre) inputs from a (climbing fibre) teaching signal. This procedure can be used both for sensory processing, e.g. removal of interference from sensory signals, and for learning accurate motor commands, by decorrelating an efference copy of those commands from a sensory signal of inaccuracy. As a model of the cerebellum the adaptive filter thus forms a natural link between events at the cellular level, such as forms of synaptic plasticity and the learning rules they embody, and intelligent behaviour at the system level. Secondly, it has been shown that the covariance learning rule enables the filter to handle input and intrinsic noise optimally. Such optimality may underlie the recently described role of the cerebellum in producing accurate smooth pursuit eye movements in the face of sensory noise. Moreover, it has the consequence of driving most input weights to very small values, consistent with experimental data that many parallel-fibre synapses are normally silent. The effectiveness of silent synapses can only be altered by LTP, so learning tasks depending on a reduction of Purkinje cell firing require the synapses to be embedded in a second, inhibitory pathway from parallel fibre to Purkinje cell. This pathway and the appropriate climbing-fibre related plasticity have been described experimentally, and its presence has implications for asymmetries and hysteresis in behavioural learning rates that are also consistent with experimental observations. These computational properties of the adaptive filter suggest that it is both powerful and realistic enough to be a suitable candidate model of the cerebellar cortical microcircuit.

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Visual awareness and the cerebellum: possible role of decorrelation control

Cited by 17 publications

References 43 publications

The integrated information theory of consciousness: A case of mistaken identity

The integrated information theory of consciousness: A case of mistaken identity

Seeking a unified framework for cerebellar function and dysfunction: from circuit operations to cognition

Adaptive-filter Models of the Cerebellum: Computational Analysis

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