CONSCIOUSNESS

100 2. Neuroscience
can be interpreted as ‘looking’ at each other. But the inversion of all the movements depicted
on the retina sets the problem of chirality within the visual system. C3
120 A New Paradigm of Vision: 40Hz Coherence in Amacrine Cells. Microsaccade
Drift/Tremors and Visual Illusions David Saunders
(San Diego, CA)
Amacrine cells interconnect bipolar cell/ganglion cell synapses across an area in the
retina. 40Hz coherence in amacrine cells has been reported. What could be its function? I
believe it is associated with the phototransduction cascade in cone photoreceptors and the
drift/tremor phase of microsaccades, the quick transit phase being too fast and brief to sufficiently
stimulate cones. I submit that the function of some, or all, amacrine cells is to track,
correlate, contrast and compile the information gathered from a single bit of the scene bitmap
that strikes the retina as the retina moves under it when the eye executes the drift/tremors of
microsaccades and saccades. A saccade is a microsaccade with an extra long quick transit.
There are approximately 29 unique types of amacrine cells, each type dedicated to one of the
five discrete layers of the retina. The amacrine cell field of coverage varies greatly among
the types from very narrow for some to extremely wide for others, and the spatial distribution
within and among the five retinal layers produces tiling such that any quick transit of a
microsaccade or a saccade in any direction and for any distance will be tracked. This results
in the continuity of information produced by a scene bit from the previous drift/tremor to the
present drift/tremor. I contend that it is the amacrine cells that produce the signal that exits
the eye via the ganglion cells, and that the signal is composed of all the information gathered
from both the previous and present drift/tremors. This functioning offers an explanation for
many things. Our foveas, which produce our most important, detailed central vision, are composed
of only red/green cones and yet we also see blue in this area. Blue cones are found in
the parafovea, which surrounds the fovea. I contend that previous and present drift/tremors
will have traversed both the fovea and the parafovea and therefore we see both red/green and
blue in our central vision. I believe that there has to be a contrast and comparison between the
information gathered by the previous and present drift/tremors, and there will be because each
bit of the scene bit map will have traversed a constantly changing cohort of photoreceptors.
When there is no change, vision ceases because the amacrine cells no longer have cross input
to work with. This latter point, not neural adaptation, explains visual fading: when an image
is stabilized on the retina, the image disappears. It is also why we do not see the opaque blood
vessels of our retinas: wherever the retina moves, the blood vessels move. Another point is
that our vision seems to be composed of a series of frames or snapshots, and I believe this is
an artifact of the way amacrine cells function across space and time to produce an output signal.
This latter explains the ‘wagon wheel illusion’. Lastly, the passage of time in the process
explains visual masking, change blindness, change-lag effect and other visual illusions. C12
2.3 Other sensory modalities
121 What is Synesthesia? - A Current Overview Sean Day (English & Journalism, Trident Technical College, North Charleston, SC)
In 1826, Mueller posited the law of specific nerve energies, stating that perception is defined
and constrained by the pathway by which sensory information is carried. This, in turn,
became a matter of debate regarding functionalist approaches to the nature of qualia; which,
in turn, are cornerstones of some current approaches to the hard question of consciousness.
However, if we are going to explore what insights the phenomena of synesthesiae bring to
our understanding of consciousness, we must first have a good grasp as to what synesthesiae
actually are, and are not. ‘Synesthesia’ is often defined as the involuntary, invariable
overlaying of sensory perception either onto perceptions from ‘another sensory modality’,
such as color overlaid upon musical sounds, or upon a cognitive constructs, such as the letter
‘A’ or the month ‘January’ being connected with an odor or flavor. There are (at least)
four different categories of synesthesia: congenital; adventitious; drug-induced; and via altered
states of consciousness (ASC) attained through meditation or trance. This presenta-