Physiological Correlates of Sensory Consciousness: Evidence for a Generalized Awareness Negativity

We critically review the recent literature on six EEG and MEG markers of the neural correlates of consciousness (NCC) for visual, auditory and tactile stimuli in neurotypical volunteers and neurological patients. After ruling out four of these as candidate NCC, we focus on two prominent evoked signals: an early, modality-specific negativity, termed the visual or auditory awareness negativity (VAN and AAN, respectively) and a late, modality-independent positivity termed the P3b. More than twelve diverse experimental studies found that the P3b is absent despite consciously seeing, hearing, or feeling stimuli, ruling out the P3b as a true NCC. In contrast, no convincing evidence for a dissociation between the awareness negativities and consciousness has been reported thus far. Furthermore, there is evidence for an equivalent signal in the tactile domain, which we term the somatosensory awareness negativity (SAN). These three neural signals are usually maximal on the side of the scalp contralateral to the evoking stimulus, above the associated sensory cortices. We conclude that the data from these three modalities is consistent with a generalized awareness negativity (GAN) correlated with perceptual consciousness that arises 120-200 ms following stimulus onset and originates from the underlying sensory cortices. The identification of this GAN points towards new, promising avenues for future research and raises an array of concrete questions that can be empirically investigated.

THE HUMAN DEFAULT CONSCIOUSNESS, JHĀNA CONSCIOUSNESS, GAIA “CONSCIOUSNESS” AND SOME THOUGHTS ON THE COVID-19 PANDEMIC

This chapter explores the characteristics of the human default sensory consciousness as it has featured in philosophic thought, in psychoanalysis and mental health, as well as in Buddhist thought and from a modern neuroscience perspective. This default mode of consciousness is then compared and contrasted to the form of consciousness that emerges in jhāna meditation, before extending the discussion to neuroscience models of nested hierarchies within self-organising systems and their associated Markov blankets, with implications for the forms of consciousness that may or may not arise in those systems.This is followed by a brief discussion of the outermost hierarchical system, that of planet Earth in interaction with worldwide societies, and the likely information geometries linking “outer” with “inner”. In light of the current crises of climate change and the Covid-19 pandemic.

A neural correlate of sensory consciousness in a corvid bird

Subjective experiences that can be consciously accessed and reported are associated with the cerebral cortex. Whether sensory consciousness can also arise from differently organized brains that lack a layered cerebral cortex, such as the bird brain, remains unknown. We show that single-neuron responses in the pallial endbrain of crows performing a visual detection task correlate with the birds’ perception about stimulus presence or absence and argue that this is an empirical marker of avian consciousness. Neuronal activity follows a temporal two-stage process in which the first activity component mainly reflects physical stimulus intensity, whereas the later component predicts the crows’ perceptual reports. These results suggest that the neural foundations that allow sensory consciousness arose either before the emergence of mammals or independently in at least the avian lineage and do not necessarily require a cerebral cortex.

Cassirer and Kant on the Unity of Space and the Role of Imagination

The focus of this paper is Cassirer’s Neo-Kantian reading of Kant’s conception of unity of space. Cassirer’s neo-Kantian reading is largely in conformity with the mainstream of intellectualist Kant-scholars, which is unsurprising, given his own intellectualist view of space and perception and his rejection of the existence of a ‘merely sensory consciousness’ as a ‘formless mass of impression’. I argue against Cassirer’s reading by relying on a Kantian distinction first recognized by Heinrich Rickert, a neo-Kantian from the Southwest school, between Kenntnis (roughly knowledge by acquaintance) and Erkenntnis (roughly propositional knowledge). Correspondingly, I claim that concepts and categories are conditions for Erkenntnis of objects as such, namely for thinking of and apprehending the pre-existing unity as an object, rather than for the ‘constitution’ of this very unity.

Representationalism about Consciousness

According to representationalists, sensory consciousness is a matter of representing the world to be a certain way. Some (Armstrong, Tye, Dretske) have suggested that representationalism fits well with the idea that consciousness can be reduced to something physical. Others think that representationalism makes the mind–body problem harder because our usual models for reducing representation do not apply in the special case of conscious representation. This chapter formulates representationalism, discusses an argument for it, and considers standard objections. The chapter concludes by looking at reductive and nonreductive representationalism.

Travis on Frege, Kant, and the Given

Travis thinks my view that there is a myth, the Myth of the Given, to be avoided is based on a conception that would entail that our conceptual capacities cannot make contact with the non-conceptual. I explain why he is mistaken. I explain why he is wrong to connect the supposed Myth with an idea he finds in Kant, the idea that there must be a match in form between our thoughts and what we think about. I take issue with his suggestion that something fundamental to Kant is contradicted by Frege’s insistence that thoughts are not put together out of self-standing building-blocks. And I argue that he misreads Frege about how something non-sensible ‘unlocks the outer world’ for us, about the relation between the conceptual and the non-conceptual, and about the possibility of conceiving thoughts as, not objects, but contents of sensory consciousness.