Chronobiology - Part Six

Evoked potentials and internal time consciousness

Evoked potentials refer to specific kinds of electrical activity in the brain that arise in response to the presentation of certain stimuli. Evoked potentials can be distinguished from background electrical activity by means of various techniques of analysis involving computers and mathematics.

Different waveforms of evoked potential have been associated with different contexts of stimulation. For example, an evoked potential waveform known as P300 occurs whenever an individual is surprised by one of the events in a sequence of stimuli. Another evoked potential is known as a contingent negative variation or, in less technical terms, the expectancy wave.

As the latter expression suggests, an evoked potential occurs when an individual is led to believe a certain kind of stimulus will occur at a given point in time or at a given point in a series of events. As the time approaches for the stimulus to appear, the contingent negative variation waveform increases in amplitude. The size of the amplitude increase will be a function of various factors in the personality, past history and current circumstances of the individual in whom the expectancy wave potential is being evoked.

An individual's perception of internal time consciousness can be affected by the structural character of the contingent negative variation waveform which is present. Generally speaking, the larger the amplitude of this wave - that is, the greater the individual's expectations concerning the time of occurrence of a given event, then, the more rapidly will run the individual's perception of events in internal time consciousness relative to some external measurement of the temporal duration of such an event. As a result, during the course of some event, the individual will feel external time measurement of the event is running very slowly relative to the individual's perception of the rate at which internal time consciousness measurement of the event is taking place.

The experimental work of Robert Hicks, a psychologist, seems to indicate the appearance of the expectancy wave can be traced to the activity of cells in the frontal lobes of the cerebral cortex. Apparently, these cells either: (a) are responsible for the synthesis and release (when activated by the action potential) of the neurotransmitter dopamine; or, (b) are sensitive to the presence of dopamine (i.e., they have receptor sites on their membranes which are dopamine-specific and which modulate the cells activity when dopamine occupies these sites). Hicks and others have found that the perception of events in internal time consciousness can be affected by giving the individual drugs which either increase the synthesis and release of dopamine or which prevent dopamine from occupying the relevant receptor sites on the membranes of dopamine sensitive cells.

Thus, for example, amphetamines, which lead to increased synthesis and release of dopamine, have the effect of speeding up the perception of events in internal time consciousness relative to some external mode of temporal measurement concerning those events. On the other hand, haldol, which is a neuroleptic (i.e., a class of drugs used in the treatment of certain psychotic conditions), blocks the action of dopamine through competitive inhibition. As a result, the individual's perception of events, as measured by internal time consciousness, slows down relative to some external mode of temporal measurement with respect to those events.

Jeremy Campbell ties the expectancy wave phenomenon to the biological clock in the frontal lobes of the cerebral cortex. In other words, he believes the cells responsible for generating the sense of the 'passing moment of the present are the cells giving expression to the individual's perception of internal time consciousness. Therefore, according to Campbell, such cells are responsible for the individual's experience of the present as having a certain kind of structural character of duration.

Even if one accepts the proposal that increases or decreases in the levels of dopamine in the receptor sites of the membranes of certain cells in the frontal lobes are associated with the modulation of the individual's perception of internal time consciousness, this does not explain what is responsible for the process which leads to the increase of dopamine production, or to the increase of substances that will block the action or synthesis of dopamine. In other words, the presence or absence of dopamine is only a step in the causal sequence resulting in the modulation of an individual's perception of internal time consciousness.

Dopamine does not initiate this causal sequence. It merely is one of the effects of such an initiation process.

Consequently, in order to say one understands what sets an expectancy wave in motion or why a given expectancy wave has the amplitude it does, one is going to have to fill in quite a few missing facts. Moreover, these facts that are missing are not a matter of insignificant details. They go to the very heart of what is really going on in the case of the emergence of a contingent negative variation waveform of a given structural character.

Equally important, as far as problems with the dopamine hypothesis are concerned, is the following consideration. That theory provides no account of how the individual becomes conscious of the presence of such an evoked potential waveform of given character.

All that has been shown, at best, is there is an association between the presence of such a wave and the character of the individual's perception of internal time consciousness. The existence of the wave and the individual's awareness of the wave may be two separate things.

If one treats consciousness as a separate dimension (rather than an emergent by-product of a certain level of complexity of neuronal activity), then, the phenomenology of the experiential field or the phenomenological manifold can be dialectically linked to the waveforms of evoked potentials by means of phase relationships - both in terms of being shaped by such wave forms, as well as in terms of giving rise to such wave forms. Because both neural activity and the phenomenological manifold share a common bond by virtue of their respective links with the temporal dimension, they have an opportunity to exchange phase quanta during states in which phase relationships are established between these dimensions.

Moreover, phase relationships are established through focal, intentional activity whose structural character is a joint function of physical/material processes (i.e., neural activity) as well as phenomenological awareness and reflexive awareness. Consequently, focal awareness is like a complex vortex or twistorl which forms at the intersection of a dialectic involving, among other things, dimensions such as awareness, intelligence, materiality, energy and time.

As such, neural activity can act as an attractor which draws focal activity into its sphere of influence, just as focal activity can serve as an attractor when it draws certain aspects of neural functioning into its sphere of influence. However, in each case, the process of 'drawing into a sphere of influence' occurs on the level of phase relationships and will subsequently be manifested in an appropriate structural form of the dimensional medium to which a given set of phase quanta has been transmitted.

Phase relationships do not occur at a physical, material locus. They occur in the temporal dimension as a function of the ordered, sequential, rhythmic, oscillatory character of the way in which a given structure, taken as a spectrum of ratios of constraints and degrees of freedom, temporally relates to different aspects of itself.

Said in a slightly different way, phase relationships are a matter of the way in which the different ratios of constraints and degrees of freedom of a given spectrum are temporally ordered with respect to one another. The aspect of being 'temporally ordered with respect to one another does not just refer to what comes before and after. It also encompasses the dialectic of these ratios.

As a result, the character of the phase relationships established through this dialectic are capable of shaping the manner in which the ratios will be activated. Indeed, even in the case of a single ratio, the dialectic between the constraints and degrees of freedom of that ratio will generate phase relationships capable of causing the ratio to undergo transitions, thereby altering the manner in which the structure, to which the ratio gives expression, is manifested.

Underlying all of this dialectical and phase relationship activity is the order-field by means of which a variety of dimensional currents are given expression. These dimensional currents are different ways in which the order-field manifests itself in an structural fashion. In other words, each dimension constitutes one of the ways in which an order-field has of giving expression to itself.

Every dimension has a structural character which is, in a sense, prime. In other words, the structural character of the dimension cannot be reduced or factored further to some set of sub-dimensions. Consequently, a dimension cannot be shown to be a function of either another dimension, or some combination of such dimensions. Each dimension brings something unique to dimensional dialectics, and the order-field generates, shapes, organizes and regulates the unique structural currents of different dialectic of dimensions.