Vertebrate brain theory

ISBN 978-3-00-064888-5

Monograph of Dr. rer. nat. Andreas Heinrich Malczan

5.8  The transformation of minimum coded signals into maximum coded

At the stage of development described so far, the limbic system was an analogous system. The rate of fire as an analog quantity encoded the signal strength, such as the strength of smell, muscle tension, etc.

This analogue limbic system realised both a rotational memory and the difference mapping for change detection.

The development of signal divergence in the olfactory cortex led to a new, minimum coded output leaving the cortex in the direction of the amygdala.

When these minimum coded signals of the scent mixtures had replaced the signals of the original pure scents, they reached the amygdala as well as the signals of the pure scents before.

However, this caused a problem: minimum coded signals were not useful for active muscle control. They first had to be converted into maximum coded signals. This could be achieved by signal inversion. We remember the amygdala system, which was able to invert signals at a very early stage.

For example, the on-off signals were inverted and superimposed on the original excitatory variant in the correct type as an inhibiting variant. Due to the time delay of the inhibitory variant on its dopaminergic detour, the resulting differential mapping was time sensitive and could detect movements in both the on and off signals.

In the amygdala there are several equivalent variants for the solution of these problems. We present here one of the possible solutions for the generation of an excitatory maximum coded signal from an excitatory minimum coded signal.

We will simplify inversion cores into two classes: positive and negative inversion cores.

Positive inversion cores provide an exciting output, negative ones an inhibiting one.

Both require an inhibiting input as well as a tonic continuous signal, which is relatively inhibited.

The tonic continuous signal reaches exciting inversion neurons in the case of positive inversion nuclei, so that the output is exciting.

For negative inversion nuclei, the inversion neurons must be inhibitory, so that the output is inhibitory.

In all cases the inversion cores need inhibiting input, which should be inverted. Therefore, the excitatory cortex output of the olfactory cortex must first be switched to an inhibitory transmitter.

We assume that the excitatory amygdala input first reaches the central amygdala where it is switched to an inhibitory transmitter GABA, while maintaining the rate of fire.

It must then be inverted once to be maximum coded. The result must be exciting, because it is the exciting component for the time-sensitive difference mapping.

Since the basal amygdala side core is a positive inversion core, it would be completely sufficient if the central amygdala sends its output to the basal amygdala side core, where it is inverted. The output is maximum coded and excited.

The excitatory continuous signal required for inversion originates from the magnocellular part of the basal amygdala, which is a mean nucleus.

The now excitatory and maximum coded output of the basal amygdala side nucleus now reaches the hippocampus and participates in the signal rotation just like the original analog signals. Now, however, they are maximum coded, and the excitation maximum encodes the mixing ratio of two types of olfactory receptors, as a fragrance mixture.

Coming from the hippocampus, it returns to the initial nucleus of the amygdala and can generate motor and other reactions in the neural tube/spinal cord in descending order.

Theorem of transformation of minimum coded signals into maximum coded signals in the amygdala system

Minimum coded olfactory signals from the cortex reach the amygdala and are switched to an inhibitory transmitter in the central amygdala to be inverted in the basal amygdala subcore, thus being maximum coded.

For inversion, the basal magnocellular amygdala delivers an excitatory tonic mean signal, the inhibition of which causes the signal inversion due to the minimum coded signal. The output is fed to the hippocampus where it takes part in the limbic signal rotation, but is available for further use as the output of the basal amygdala.

The further use consisted, among other things, of creating a time-delayed and inhibiting variant for a time-sensitive difference mapping for motion detection of olfactory perceptible objects.

Monograph of Dr. rer. nat. Andreas Heinrich Malczan