#5 How consciousness keeps its house in order- RAS Switching and Sleep Staging

One of the most convincing demonstrations of the veracity of GOLEM theory's 2X2 (ie 2 channels X 2 levels) model of mind is the close fit with the known functions and architecture of the Reticular Activation System (RAS) [1], which is the part of the brainstem which controls states of consciousness and transitions between those states. The RAS is a distributed network of interlaced neurons which wrap around the brainstem, and modulate its arousal levels. Briefly, the RAS consists of the Ascending RAS (ARAS) and the Descending RAS (DRAS). 

If the ARAS is damaged, the subject/patient goes into a permanent coma, and never wakes up. Therefore the normal function of the ARAS is to create wakefulness, by bringing the brain's arousal up to a level which can then be maintained by ambient sensory inputs. If the DRAS is damaged, the subject/patient is unable to fall asleep, and will die in a few days if medical intervention is not found. Therefore the normal function of the DRAS is to create sleepiness, by causing the motor paralysis which then signals the VLPO ( a part of the hypothalamus) to start the ultradian (~90 minute) cycling between shallow and deep sleep phases. 

Lets take a closer look at the detailed operation of the two RAS branches. The two channel GOLEM model associates inputs with the states of conscious/unconscious, and transitions between them. We would expect, therefore, that the ARAS controls the level of the consciousness transition threshold. Its normal action is to lower the threshold, increasing the range of inputs which are synchronised, and therefore enter awareness as perceptual features which can further combine into concepts that can be consciously attended to [2]. 

The two channel GOLEM model associates outputs with the states of agency (voluntary 'master' role vs involuntary 'slave' role), and transitions between them. We would thus expect that the DRAS controls the level of the volition transition threshold. Its normal action is to increase the threshold, reducing the range of mental processes under the subject's voluntary command, and increasing the range of involuntary processes, eg those which cause motor system paralysis (sleep onset atonia).

It seems as if the two branches of the RAS are tied together, so that when one increases its threshold, so does the other. The effects of moving the thresholds in unison are opposite in their effect on the organism. The channels may move together, but when one leads, the other follows. When the input channel increases its consciousness, acting as the master, the output channel acts as the slave, by decreasing its command (although it increases its volition). When the input channel is the slave (allowing unconsciousness), the activity in the motor channel is that of the master, creating unsynchronised involuntaryness, and allowing restorative processes such as those performed by autonomous reflexes (eg bodily repair, 'dream work' [3]) without creating events which penetrate the conscious threshold. 

The hypothalamus is the supervisor, allocating agency to the branch of the RAS whose turn it is to be the master. That branch in turn inhibits the other side's agency, causing them to adopt a passive 'slave' role. Like the spinal motor circuit responsible for walking in land animals, wriggling in snakes and swimming in fish [4], the alternation between waking and sleeping corresponds to one of Powers' PCT levels.  See Figure 5b below.

Figure 5a - Ascending and Descending branches of Reticular Activation System (RAS) 

This is as good a point in the discussion to discuss the differences between the right and left cerebral hemispheres (RCH & LCH). It seems that, with few if any exceptions, all complex living and non-living vehicles consist of a closed cycle generator (eg an 'engine', like your car), matched to an open trajectory path follower (eg the chassis, steering, suspension, brakes of your car). In animals and humans, the RCH is the closed cycle motion generator, using embodied computations to produce repetitive cycles of shapeshifting (ie postural state transitions). The LCH uses spatially situated computations to perform intersubjective interpretations of the RCH's temporally embodied computations [5]. The analogous vehicle driver state is when you are both controlling the rate of the engine's rotation while also navigating the vehicle across the earth. It is the embodied computations performed by the RCH which provide semantic grounding for the situated computations in the LCH. The organism must first understand the object-like properties of its own limbs, before is it able to successfully identify background features as locatable landmarks and foreground features as tangible objects. In human babies, this process occurs early in infancy, and is termed 'motor babbling'.

Figure 5b. The diagram above demonstrates the lateralised differences in experiential interpretations - embodied computations of postural states in RCH vs situated computations of positional states in LCH. These differences form the basis of Semantic Grounding mechanisms in all animals. 

1. 'Reticula' is the latin word for a woven rope mesh, or net, and also the name for the type of gladiator that is armed with an edge-weighted throwing net and a lightweight trident. Our metropolitan water supply is reticulated, in that it is distributed by a network of pipes. Each customer has water supplied from more than one water main, or trunk, so that if one pipe bursts, that section can be isolated, and water rerouted around the problem. This is also a Roman invention, but like Roman concrete, it was stolen from the Egyptians.

2. TREISMAN, A., & GELADE, G. (1980). A feature-integration theory of attention.Cognitive Psychology,12, 97-136.

3. like sleep deprivation, dream deprivation has serious negative health consequences. Therefore it is not flippant, or unscientific to talk of 'dream work'. It is important, as Freud claims, its just we don't know why. Freud was right about so much stuff, maybe his dream interpretations have real scientific basis. But sometimes a cigar is just... more work for oncologists.

4. and cool, natural, sexy dancing motions in everyone else in the club, it seems, except me. As one attractive female DJ told me, someone has to fix my darn computer when it crashes <sigh>.

5. Whew! Thats some mouthful, but unavoidable if this condensed digest of my wider body of research is to be completed on time.