JTW's Evolutionary Origins - Authors: Laughlin, Charles D.; Mc Manus, John; D'Aquili, Eugene
HOME
The Symbolic Process
"The Symbolic process is that function of the nervous system by which the neural network mediating the whole is entrained by the network mediating the part; that is, the mechanism by which the neurocognitive models(s) of a noumenon is evoked by partial sensory information stimulated by the noumenon. A model may be evoked by a stimulus originating either in the outer operational environment, which excites sensory receptors at the periphery of the nervous system, or in another model within the organism's cognized environment. It is customary to call the stimulus a symbol ("signifier," "vehicle") and the model or models evoked by that sysmbol its meaning ("signifier," "designatum"). The relationship between symbol and meaning is one of part to whole.It is crucial to understand that a symbol evokes a neurocognitive model whose meaning may or not be isomorphic with the event in reality that evoked the model; that is, a symbol does not evoke the noumenon itself. Put another way the sysmbol evokes knowledge about the evoking stimulus, not the process in reality that porvided the stimulus...
The symbolic process operates through all sensory modalities... Quite literally any sensory stimulus may evoke intentionality, via intentionality integrated with its meaning, and thus operate as a symbol - for instance, a heart flutter, sore throat, green light, gesture, body odor, rough surface, affect, bell, or pain."
(Laughlin, McManus, & D'Aquili, 1990, pp. 163)
Topographic Projections and The Minimal Symbol
"The symbolic process depends upon intentionality... In addition it operates on two principles: Ther first of these is topographic projection. Topographic projection refers to the point-to-point conduction of abstracted pattern about a stimulus from the periphery into central neurocognitive models. Sensory input tracts are organized in such a way that a minimal veridicality of pattern imposed by peripheral excitation is maintained at every point along the path of conduction. Veridicality is maintained along the dimensions characteristic of each sense, but for each sensory mode for which there is sufficient evidence, the topographical projection of veridical patterns seems to be a major aspect of functioning...Projection in the visual system is termed retinotopic organization...
Projection in the auditory system is termed tonotopic or cochleotopic organization...
Similarly, a map of the body is projected via the vertroposterior nucleus of the thalamus and onto the cortex in the form of a somatotopic organization... Point to point projection is also maintained in the olfactory system from the receptor surface of the olfactory bulb (Adrian 1951; Clarke 1957), but the significance of topographic projection in coding information for this sensory system is still poorly understood.
We would suggest that topographic projection in the sensory systems provides not only veridical information along discrete dimensions, but also a portion of the code for penetration into the models composing cognized reality. Along with other priciples of porcessing like perioditicity of impulse generated by the receptors, topographic projection provides a temporally shifting series of sensory patterns, orgainzed hierarchically into temporal "chunks," (Miller et al. 1960) which are recognized by pattern detector (Hubel and Wiesel 1962; Evans 1974) cells that are themselves organized inot keying patterns. Thus, a response to a stimulus consists, in part, of establishing a key to the code represented by the stimulus pattern. But because neural models are provided with veridicacal information pertaining to phenomenal patterns in development through the empirical modicfication cycle, the mechanisms would require that input, that is insuffucient to key models, be stored until a pattern allowing further entree into the models is recogniced (Primbram and McGuiness 1975). This consideration implies that there is not only a threshold for detection of stimuli at the periphery, but there is also a threshold of information about stimuli requisite for keying models. Therefore we may define a minimal symbol as any stimulus that provides sufficient patterning for entree into a model that contains more information than that provided by the stimulus. It is remarkable, for expxample, how little information need be proviede in a line drawing for a person to recognize a famous face like that of Marilyn Monroe or John F. Kennedy."
(Laughlin, McManus, & D'Aquili, 1990, pp.163-165)
- Laughlin Jr., Charles D.; Mc Manus, John; D'Aquili, Eugene G.
- Brain, Symbol, Experience: Toward A Neurophenomenology of Human Consciousness
- Columbia Unviersity Press / New Science Library - Shambala
- BF 311.L26 1990
HOME