On the functions, mechanisms, and malfunctions of intracortical contextual modulation

Abstract

A broad neuron-centric conception of contextual modulation is reviewed and re-assessed in the light of recent neurobiological studies of amplification, suppression, and synchronization. Behavioural and computational studies of perceptual and higher cognitive functions that depend on these processes are outlined, and evidence that those functions and their neuronal mechanisms are impaired in schizophrenia is summarized. Finally, we compare and assess the long-term biological functions of contextual modulation at the level of computational theory as formalized by the theories of coherent infomax and free energy reduction. We conclude that those theories, together with the many empirical findings reviewed, show how contextual modulation at the neuronal level enables the cortex to flexibly adapt the use of its knowledge to current circumstances by amplifying and grouping relevant activities and by suppressing irrelevant activities.

Partial and Entropic Information Decompositions of a Neuronal Modulatory Interaction

“…Our argument here is that in addition to "enhancing computational capabilities via synergy" information processing also includes distinguishing between currently relevant and currently irrelevant inputs. That is far from trivial, and though we have not considered the various criteria by which relevance can be assessed, we have done so elsewhere; see e.g., [19,39]. Here we have shown that it is possible to use any such assessment to amplify relevant and disamplify irrelevant signals without corrupting their semantic content.…”

Cognitive functions of intracellular mechanisms for contextual amplification

“…There has also long been evidence that contextual modulation includes processes that group elements into coherent wholes (Phillips & Silverstein, 2013;Phillips & Singer, 1997). Recent evidence provides further support for the hypothesis that contextual amplification of relevant signals plays a major role in these perceptual processes, and it has been argued that direct interactions between pyramidal cells via their apical dendrites is a simple way to implement this amplification (Häusser & Mel, 2003;Phillips et al, 2015). For a recent neurocomputational model of dynamic grouping and other basic functions that explicitly uses the mechanism of AA see Brosch and Neumann (2014).…”

“…Phillips & Silverstein, 2003;Self, Kooijmansa, Supèr, Lamme, & Roelfsema, 2012). As this apical amplification could have far-reaching implications for our understanding of brain and cognition (Jadi, Behabadi, Poleg-Polsky, Schiller, & Mel, 2014;Major, Larkum, & Schiller, 2013;Phillips et al, 2015), its essentials are outlined in Figs. 1 and 2.…”

“…Gilbert and Sigman (2007) review neurophysiological studies of top-down modulation in relation to sensory and higher processes. The functions, mechanisms, and malfunctions of contextual modulation in general have been reviewed recently (Phillips, Clark, & Silverstein, 2015), so this paper is focussed specifically on intracellular mechanisms that amplify response to driving inputs and on the cognitive functions that they are thought to have.…”

Optimality of Social Choice Systems: Complexity, Wisdom, and Wellbeing Centrality

“…Our evolving cultural practices thus generate minds that go where no human minds have gone before. [79] Learning and problem solving, seen from this light, encompasses the full range of human experience [80]. Thus, the better a person or society is at problem solving, the more likely that person or society is to thrive, in the broad sense.…”