Hallucinations: synchronisation of thalamocortical gamma oscillations underconstrained by sensory input

What we perceive is the product of an intrinsic process and not part of external physical reality. This notion is consistent with the philosophical position of transcendental idealism but also agrees with physiological findings on the thalamocortical system. gamma-Frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in thalamocortical networks, thereby transiently forming assemblies of coherent gamma oscillations under constraints of sensory input and prefrontal attentional mechanisms. Perception and conscious experience may be based on such assemblies and sensory input to thalamic nuclei plays merely a constraining role in their formation. In schizophrenia, the ability of sensory input to modulate self-organisation of thalamocortical gamma activity may be generally reduced. If during arousal thalamocortical self-organisation is underconstrained by sensory input, then attentional mechanisms alone may determine the content of perception and hallucinations may arise.     

Anxiety and outcome predictions

Research shows that people display a downward shift in their predictions in anticipation of performance and feedback. The authors used a misattribution paradigm to explore whether anxiety serves as a signal for predictions. Participants (N = 108) anticipating results from an important test either immediately or in a few days were or were not encouraged to attribute any arousal they experienced to coffee they consumed earlier. Consistent with predictions, participants encouraged to attribute their arousal to the coffee were optimistic in their predictions even when anticipating immediate test feedback. In addition, the more participants attributed their arousal to the coffee, the more optimistic they were in their predictions. Ancillary analyses suggest that anxiety can be a cause rather than a consequence of less optimistic predictions.     

Cortical malformations and epilepsy

Brain malformations, resulting from aberrant patterns of brain development, are highly correlated with childhood seizure syndromes, as well as with cognitive disabilities and other neurological disorders. The structural malformations, often referred to as cortical dysplasia, are extremely varied, reflecting diverse underlying processes and critical timing of the developmental aberration. Recent studies have revealed a genetic basis for many forms of dysplasia. Gene mutations responsible for such common forms of dysplasia as lissencephaly and tuberous sclerosis have been identified, and investigators are beginning to understand how these gene mutations interrupt and/or misdirect the normal developmental pattern. Laboratory investigations, using animal models of cortical dysplasia, are beginning to elucidate how these structural malformations give rise to epilepsy and other functional pathologies.     

Iffy predictions and proper expectations

What individuates the speech act of prediction? The standard view is that prediction is individuated by the fact that it is the unique speech act that requires future-directed content. We argue against this view and two successor views. We then lay out several other potential strategies for individuating prediction, including the sort of view we favor. We suggest that prediction is individuated normatively and has a special connection to the epistemic standards of expectation. In the process, we advocate some constraints that we think a good theory of prediction should respect.     

Cortical coordination dynamics and cognition

New imaging techniques in cognitive neuroscience have produced a deluge of information correlating cognitive and neural phenomena. Yet our understanding of the inter-relationship between brain and mind remains hampered by the lack of a theoretical language for expressing cognitive functions in neural terms. We propose an approach to understanding operational laws in cognition based on principles of coordination dynamics that are derived from a simple and experimentally verified theoretical model. When applied to the dynamical properties of cortical areas and their coordination, these principles support a mechanism of adaptive inter-area pattern constraint that we postulate underlies cognitive operations generally.     

Cognitive Plasticity and Cortical Modules

ABSTRACT— Some organisms learn to calculate, accumulate knowledge, and communicate in ways that others do not. What factors determine which intellectual abilities a particular species or individual can easily acquire? I propose that cognitive-skill learning capacity reflects (a) the availability of specialized cortical circuits, (b) the flexibility with which cortical activity is coordinated, and (c) the customizability of cortical networks. This framework can potentially account for differences in learning capacity across species, individuals, and developmental stages. Understanding the mechanisms that constrain cognitive plasticity is fundamental to developing new technologies and educational practices that maximize intellectual advancements.     

Predicted differences and differences between predictions

WhenK tests are given toN individuals, and for each individual there are two criterion measures, then (1) the multiple regression weight to be applied to the standard score for each test to predict the criterion-difference score equals the difference of the weights for predicting each criterion separately; (2) the difference between the predicted scores equals the predicted difference (each test being assigned the appropriate multiple regression weight); (3) the square of the multiple correlation between predicted and actual criterion-difference scores equals the sum of squares of the multiple correlations of the battery with each criterion less the product of these correlations and the correlation between predicted scores all divided by twice the quantity one minus the criterion intercorrelation; and (4) the variance of errors of estimating the criterion-difference score equals the sum of the variances of errors of estimating each criterion score minus twice the criterion intercorrelation, plus twice the correlation between predicted scores multiplied by the product of the square root of one minus the variance of errors of estimating one criterion and the corresponding square root for the second criterion.The author wishes to express his appreciation for the suggestions and guidance given by Dr. Harold Gulliksen in the preparation of this article. He also wishes to acknowledge the helpful comments of Dr. Paul Horst and Dr. Ledyard Tucker on certain phases of the development.     

Self-image and predictions about future events

This study inquires the relation between a person's attitude towards himself and his way of predicting his own and the future of the world, respectively. Estimates of probabilities and utilities were made for 20 personal events and 20 general events. The attitude towards oneself was measured on bipolar Osgood type scales where the subject was asked to judge his or her self and the ideal self. A correlation was found between a person's attitude towards himself and his way of predicting the future. The more positive a person's self-image, the higher was the correlation between probability and utility estimates for a set of future events. The paper concludes with a critical discussion of the conclusions which may be drawn from data of the type presented in this study and in earlier studies.     

Election predictions: Reply

Contrary to Aubert's claim, my paper on election predictions does not seek to draw empirical conclusions from mathematical premisses alone. The empirical premiss, approximated by the continuity assumption, is that sufficiently small changes in the predicted vote will cause only small changes in the actual vote. The technical criticisms by Øfsti and Østerberg of the reaction function are answered by specifying the function's domain. Other criticisms are also answered, and the reply concludes by placing the election prediction theorem in the context of other theorizing about human expectations and outguessing phenomena.