Derivation of qualia from spatiotemporal activity patterns in neural networks

Yoshi Tamori

To scientifically explain qualia (genuine components of sensations) in terms of neural activities, it is required that we could predict a quale from a set of neural activities, which satisfy the known mechanisms. In such explanations, we should not assume any mapping from an external stimulus to the representation (or coding of a quale), thus response selectivity, since we have a quale that is independent of the mapping, and since the mapping cannot be substitute for the other one. Pattern-induced flicker colors (PIFCs) originate in phase-sensitive lateral interactions of modulated neural activity in the retina followed by additional spatial interactions in the visual cortex behind the locus of binocular fusion (Campenhausen, 1995). Therefore, color qualia of PIFCs are considered to be closely related to the spatiotemporal activity patterns in neural networks.

This study is organized by the following stages:

Stage 1: Construct experimental equipment for PIFC observations.

Fig.1

Our preliminary result shows that conventional Benham patterns have a chromatic orbit in CIE chart along with the temporal modification of stimulus pattern.

Fig.2

Stage 2: Observe (or simulate) neural activity components related to color qualia.

Stage 3: Predict the color qualia of PIFCs by neural space-time theory.

Fig.3

Stage 4: Confirm the predictions.

It is expected that we could obtain neural codings of color qualia.

There have been controversies on the origin of the PIFCs whether PIFCs are coded in the cortex or in the retinal cone cells. We presented two different spatiotemporal stimuli from each other into each eye. In spite that each stimulus does not induce any flicker color, simultaneous presentation of these patterns in time into each eye induces PIFCs. Red arrows in Figure 2 show the PIFCs that are induced by the compounded activities in the visual cortex.