The minimal cyclical pathway

The task set performs a random search on its basic elements in order to find the target stimulus element. Because the task set is spontaneously active, it may scan the stimulus element when this is activated by the sensory pathway. The activation goes back to the layer 5 of the PFC and then by chance immediately activates the response elements. This is the minimal cyclical pathway ever possible. It lasts two elementary times. 

The median cyclical pathway depends on the mode and the number of 

In the non-minimal pathway, the search of the task set for the stimulus element is succeeded by the activation of the corresponding sensorimotor set and its search for the response element. This search may use slow mode or fast mode, one searching set (the SMS) or two searching sets (the SMS plus the task set). The first case is called double search, the last triple search. The difference between the two search and the three search pathways is the fact that in the first pathway, the tSMS activates the response element without the help of the task set and in the second path- 

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An alternative to these prolongation of the linear portions is the prolongation of the minimal cyclical pathway. Trials with mincycEN = 2 are not possible any more. The searching set has difficulties to activate the stimulus element because of the asynchrony between searching set and linear activities or because of the decreased activity exerted by the searching set on the basic elements. 

But the subjects with triple search have a longer minimal cyclical pathway because the third searching set has to coincide with the second searching set even in the minimal pathway. Therefore the minimal cyclical pathway of these subjects is mincycEN = 4 (or 6). That means that the equations of all the subjects with triple search have to be corrected by reducing the linear pathway by 2ET and increasing the cyclical pathway by 2ET (the minimal cyclical pathway needs these additional 2ET). With this correction, the correspondence between the break of ERP(a22rSEB) and HnEN(a22rSEA) is much better. 

If the SMS is learned very well, it is activated instantly and the minimal cyclical pathway (mincycEN) lasts only 2ET. 

Fig. 126. Standard pathway with two local shortcuts in the sensory areas and minimal cyclical pathway summing up to 6ETs...

This is the confirmation that subjects with double search have a minimal cyclical pathway mincycEN = 2,... 

In the case of a minimal cyclical pathway of 2ET, both elementary times are used by the sensorimotor set. The task set finds (scans) the stimulus element at the moment of its facilitation by the stimulus. How can the first peak (Fp) be as early as 2ET after the linear path When the target stimulus arrives in layer 2,3, the task set is just activating the target stimulus element. As a consequence, the target SMS can become active and the central portion of the pathway can be transversed in 2 ET... 

This is another important point at the x-axis of the reaction time distribution. Its meaning can only be understood on a theoretical basis. The hypothetical neural representation suggests that there are two parts of the pathway within the cortex a linear part and a cyclical part. According to this theory, the point (Fp-2ET) divides these two parts in the minimal stimulus-response pathway. It has to be shown that this division by (Fp-2ET) is valid in all pathways. 

The same is true for vl 11H30A, where (Fp-con)/ET = 2.7. That means, Fp is produced by a process which only needs about 3 ET (presumably a linear local shortcut pathway). I therefore take 4ET right of con for the minimal pathway, remaining 2 cycET left of the median. This makes a linear pathway of 2 linET and a cyclical pathway of 2 + 2 = 4 cycET,... 

The pathways of the individual subjects show certain variations there are a number of variations of the linear portion and a number of variations of the cyclical portion of the pathway. The variability of the linear pathway is the theme of the following chapter. Of special interest are the minimal pathway and the median pathway. 

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