[M.D. Holloway]

Cytowic urges that the role of the limbic system in synesthesia, and indeed in the nervous system, be taken seriously. He argues that because of the Western notion of a dichotomous split between reason and emotion, hierarchical, corticocentric models of the brain have been established. He pushes for a "multiplex" concept of the brain, which is less centralized and allows for more environmental influence than our idea of "brain equals behavior." He subscribes the ideas of Ommaya, a critic of current models of brain organization and asserts that, "we are irrational creatures by design and that emotion, not reason, may play the decisive role both in how we think and act." The fact that humans have both well-developed neocortical and limbic features is used to back up his idea that "the relationship between cortex and subcortical brain is not one of dominance and hierarchy . . . but of multiplex reciprocity and interdependence." Again, he establishes the primacy of emotion with studies of people emerging from comas, whose "intellect" recovers after their more primal limbic responses return. Cytowic challenges "computational" models of the brain and instead proposes a holistic vision of the perception process (1).

Ctyowic accredits the post-1930 drop in interest to the inability of psychology and biology of the time to grapple with necessary issues. However, he states, when these sciences caught up to the phenomenon they had earlier attempted to study, the rejection of personal experience as a basis for academic work has kept synesthesia out of the scientific limelight. From 1890-1930, until now the hey day of the interest, synesthesia was primarily discussed by artists as an experiential phenomenon in which they wished to partake free of scientific explanation (1). Kandinsky is quoted as saying: Lend your ears to music, open your eyes to painting, and . . . stop thinking! Just ask yourself whether the work has enabled you to "walk about" into a hitherto unknown world. If the answer is yes, what more do you want? (1)

Despite being a scientific researcher, Cytowic agrees that "our passion for a detached and 'objective' point of view has diminished other kinds of knowing" (1). Though Cytowic is seen as an expert on synesthesia and his work is cited frequently, it is not surprising that there is challenge to his ideas from other members of the scientific community. Burt and Smith-Laittan, of Cambridge University, cling to the notion of objectivity and researcher expertise, as evidenced by a comment in their article that subjects who report themselves as identical twins are often wrong and therefore research involving them may be disregarded (in this case, it is convenient for Burt and Smith-Laittan to do so). Though they are faithful to this idea of Scientific Objectivity, Burt and Smith-Laittan have written the article in which it is most clear how scientific conclusions are informed by cultural values. To back up their statement that limbic and cortical regions work together, they cite Descartes. They continue to state that: Current perspectives appear to owe as much to the notion of hierarchy of science and so do not as much compete as models of brain function as provide explanations couched in vocabulary appropriate to the discipline.

They suggest an explanation of synesthesia based on a modular model of the brain, i.e., that different types of perception might rely on different neurological pathways (2).

Another insight into synesthesia which has yet to be significantly explored is the neo-natal sensory system. Burt and Smith-Laittan state that the genetic basis of synesthesia may cause abnormal differentiation between visual and auditory pathways (2) and other researchers discuss infants' perception. There is a sense that certain parts of the brain, like the frontal lobes (which are in the neocortex), do exhibit significant sensory integration. There is evidence that infants, perhaps immediately from birth, experience visual and auditory stimuli together (3).

In 1993, Baron-Cohen has posited the Neonatal Synaesthesia Hypothesis: . . .that early in infancy, probably up to four months of age, all babies experience sensory input in an undifferentiated way. Sound triggers both [sic] auditory, visual and tactile experiences. A truly psychedelic state (4). This transitions nicely into an idea on synesthesia which includes aspects of many theories on synesthesia. Andrews explains that: . . . in creatively encountering one's environment, one's experiences are not merely visual, nor are they an oscillation between various diverse sensory stimuli. One's perceptions are polysensory with the various sensory stimuli homogeneously combined so that when one is perceiving a situation, their encounter may include hearing, seeing, and feeling. Another time it may include seeing, tasting, and smelling . . . . explaining synesthesia as a mode of perception not necessarily so far removed from standard perception (4). The common thread between all these researchers is that they see some neurochemical basis for their understanding of synesthesia, and that they must work this understanding in with their vision of the way different parts of the brain relate to each other. All agree that synesthesia is a perceptual mode and that there is some genetic basis for its strong expression. For scientists interested in mapping out life and giving out maps for humans to navigate it, this genetic relationship gives them a chance to add something to the list for the Human Genome Project.

Yet for those more interested in looking at trends and patterns in the population, there is a sense that synesthesia may not be an experience very far removed from "normal perception." The fact that this community of scientists, often using the same data, has such divergent ideas about synesthesia shows the mythical quality of this scientific objectivity. While the phenomenon we have designated synesthesia has not changed over time, our ideas of it have, and the contemporary scientific community debates it. As Cytowic strives for a holistic vision of the parts of the brain, we must strive for a holistic idea of the scientific process so that we can identify our biases and use debate to constructively analyze problems instead of to attack each others ideas.