CONSCIOUSNESS

98 2. Neuroscience
place at many brain loci simultaneously. However, it is best understood in a midbrain structure
that is involved in orientation and localization behavior: the superior colliculus (SC). SC
neurons can integrate information from various combinations of visual, auditory, and somatosensory
inputs; a process that dramatically alters their responses and the behaviors that depend
on them. Cross-modal stimuli that appear to be derived from the same event have preferential
access to SC neurons, and can produce striking enhancements in their activity. In contrast,
cross-modal stimuli that are likely to be associated with different events either yield no multisensory
integration or degrade physiological responses and behavioral performance. Contrary
to some theories of sensory development, these multisensory integrative abilities are not present
in the newborn’s brain, and their fundamental characteristics are not pre-specified. Rather,
the acquisition of multisensory integration capability, and the crafting of its operational principles
is a postnatal process that depends heavily on at least two factors: the development of
a cooperative interaction between descending projections from association cortex, and the
acquisition of experience with the statistics of cross-modal events. These factors are used by
the brain to develop the neural circuitry underlying multisensory integration, and to adapt its
operational principles to the environment in which it will be used. The anatomical, physiological
and behavioral properties of this circuit, its developmental antecedents, its plasticity, and
the likely neural site at which early experience is coded will be discussed. This research was
supported by NIH grants EY016716 and NS36916. PL5
117 Searching for Evidence of Phenomenal Consciousness in NCC Research Justin
Sytsma (HPS, University of Pittsburgh, Pittsburgh, PA)
The search for neural correlates of consciousness (NCC) is at the forefront of current scientific
interest in consciousness. It is frequently asserted that the NCC project is the starting
point for a science of consciousness. This is especially true for those researchers who aim to
give a neurobiological theory of phenomenal consciousness – members of what I have termed
the new science of consciousness. Many prominent new scientists hold that the first step in
developing such a theory is to find neural activity that specifically correlates with the contents
of a subject’s phenomenal consciousness. If these researchers are correct in their assessment
of the importance of the NCC project, then the new science will rise or fall with the search for
neural correlates of the contents of phenomenal consciousness. In this paper, I assess the empirical
prospects of this research project. I challenge the claim that phenomenal consciousness
exists, concluding that new scientists are erroneously trying to correlate neural activity with
the contents of phenomenal consciousness. To see this, we need to begin by articulating the
phenomena that new scientists are interested in (the contents of phenomenal consciousness)
and the data that are collected during NCC experiments (records of the behavioral reports of
subjects and measures of their neural activity). I argue that the data that are collected in these
experiments are insufficient evidence to establish the reality of the hypothesized phenomena
of interest. This is shown by considering two alternative interpretations of the standard NCC
experiment – viz. an eliminativist interpretation and a disjunctivist interpretation. C17
118 Framework of Consciousness from the Semblance Hypothesis of
Memory Kunjumon Vadakkan (Neurology, University of
Manitoba, Winnipeg, Manitoba, Canada)
A causal relationship between neuronal activity and consciousness is not yet discovered.
Here, we present the framework for consciousness derived from the semblance hypothesis of
memory(www.semblancehypothesis.org). A unit of memory, in the presence of an external or
internal cue stimulus, results from the ability to induce specific postsynaptic events at the synapses
of the neurons from the learned item without the requirement of action potentials reaching
their presynaptic sides. For this, co-activation of the fibers from the item to be learned and
the cue during learning need to induce specific changes that will later allow the cue stimulus
alone evoke activation of a set of postsynapses that belong to the learned item. Oxygenationstate
dependent functional LINKs are hypothesized to form between the postsynapses of the
synapses belonging to the item to be learned and the cue during learning. During retrieval, by
re-activating these functional LINKs the activity from the cue stimulus spreads to the post-