Many sophisticated essays and books have been written about the topic of consciousness. My own contributions date back some twenty-five years in an essay entitled 'Problems concerning the structure of consciousness' (Pribram 1976), and five years before that in delineating the difference between brain processes that are coordinate with awareness and those that are coordinate with habitual behavior (Pribram 1971a). I have been intrigued by what has been written since and take this occasion to reassess a few of the major (...) issues that have arisen. (shrink)
In the context of this publication on blindsight, I want to address further the brain processes critically responsible for organizing our conscious experience. As in a previous related publication , I am restricting myself to brain and conscious experience, not the fuller topic of ‘consciousness’ as this might be determined by genetic and environmental factors, nor as it is defined in Eastern traditions and in esoteric Western religion and philosophy. For my thoughts on this broader topic the reader is referred (...) to a recent publication prepared for the centennial celebration of Norbert Wiener's birth. That paper is entitled: ‘What is Mind that the Brain May Order It? (shrink)
The revolution in science inaugurated by quantum physics has made us aware of the role of observation in the construction of data. Eugene Wigner remarked that in quantum physics we no longer have observables (invariants), only observations. Tongue in cheek, I asked him whether that meant that quantum physics is really psychology, expecting a gruff reply to my sassiness. Instead, Wigner beamed understanding and replied "Yes, yes, that's exactly correct." David Bohm pointed out that were we to look at the (...) cosmos without the lenses of our telescopes we would see a hologram. I extend Bohm's insight to the lens in the optics of the eye. The receptor processes of the ear and skin work in a similar fashion. Without these lenses and lenslike operations all of our perceptions would be entangled as in a hologram. Furthermore, the retina absorbs quanta of radiation so that quantum physics uses the very perceptions that become formed by it. In turn, higher-order brain systems send signals to the sensory receptors so that what we perceive is often as much a result of earlier rather than just immediate experience. This influence from inside out becomes especially relevant to our interpretation of how we experience the contents and bounds of cosmology that come to us by way of radiation. (shrink)
This study describes the results of experiments motivated by an attempt to understand spectral processing in the cerebral cortex (DeValois and DeValois, 1988; Pribram, 1971, 1991). This level of inquiry concerns processing within a restricted cortical area rather than that by which spatially separate circuits become synchronized during certain behavioral and experiential processes. We recorded neural responses for 55 locations in the somatosensory (barrel) cortex of the rat to various combinations of spatial frequency (texture) and temporal frequency stimulation of their (...) vibrissae. The recordings obtained from single and multi-unit bursts of spikes were mapped as surface distributions of local dendritic potentials. The distributions showed a variety of patterns that are asymmetric with respect to the spatial and temporal parameters of stimulation, and were, therefore, not simply reflecting whisker flick rate. Next, a simulation of our results showed that these surface distributions of local dendritic potentials can be described by Gabor-like functions much as in the visual system. The results provide support for a model of distributed cortical processing that imposes a physiologically derived frame (the limited extent of a dendritic patch) and an anatomically derived (axonal) sampling of the distributed process. This combination provides a complex Gabor wavelet that encodes phase, which is necessary to processing such details as edges and texture in a scene. The synchronization across cortical areas that make the Gabor wavelet processes within restricted cortical areas available to one another (the binding problem) proceed at a ''higher order'' level of integration. Both levels of distributed processing accomplish computation in the conjoint spacetime and spectral domain. (shrink)
Neurophysiological evidence consonant with F&L's lambda model is reviewed and results of additional experiments are presented. The evidence shows that there are neurons in the motor cortex that respond to selective band widths of passive sinusoidal movements; the additional data show how, with movement, directionally sensitive population vectors can be shown to emerge from the data.
Having seen the development of Shepard's program at close hand, I have been inspired by the sophistication of his results. However, his program deals with only half of what is needed: Shepard's research tells what the perception/cognitive process is about, it does not tell how that process is implemented. True, Shepard has recourse to the “how” of process in evolution, but that is not the “how” of everyday implementation. For that we need to know the brain processes with which we (...) can implement Shepard's insights. [Shepard]. (shrink)