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Table 1 Synthetic description of a guided propagation system

From: Offline encoding impaired by epigenetic regulations of monoamines in the guided propagation model of autism

Elements of guided-propagation (GP)

Definitions

GP architecture

Prewired set of processing modules defined by their relative connections within a matrix of channels and layers. The GP software deals with the modulation and growth from scratch of every module, thus simulating a global control device. Banks of elementary detectors and effectors form the predefined input/output of the full architecture

GP-cells

Elementary processing units (EPU)

Network nodes within every module. GP-cells are chained for encoding sequences of stimuli, giving rise to a dynamic tree-like structure that receives either stimuli or modulation from other modules. At least three types of GP-cells can be distinguished: the root unit, Context-Dependent units, and Event Detectors/Generators

Context-dependent (CD) unit

Main GP-cell, possibly driven by a contextual input from its upstream predecessor along a tree branch. The other activating input is a stimulus generated by the output of another module. A CD unit responds to the possible coincidence between its Contextual (C) and Stimulus (S) inputs

Event detector/generator (ED/G)

GP-cell located at the end of a module branch, among outputs which interface with other modules

Memory path

Chained GP-cells, from a module root to an ED/G

GP-cell excitability (E) and response threshold

The Excitability parameter Ei defines the total input required for cell i to fire, with a response threshold [S(t − τij) + C(t − τik)]/Ei, where τij codes for the time-delay of cell i input connection from cell j

Ratio R between the two GP-cell inputs

Combined with E, the R parameter of a GP-cell allows its operating mode to be dynamically changed

GP-cell operating modes

Different behaviors of a given cell (Fig. 4) are dynamically set by both computer program and running modules:

 1. Free

1. Uncontrolled response (to be avoided)

 2. Inhibited

2. No response

 3. Stimulus-driven

3. Can respond irrelevant of the ongoing context (to be used with caution)

 4. Context-driven

4. Can be fully activated by the only inner-flow (“Anticipation” mode)

 5. Restricted

5. Requires both input to possibly respond (“quite”/Learning mode)

Dynamic learning algorithm

A module set in the relevant (“Restricted”) operating mode allows the encoding of unexpected stimuli

 a. Differentiation

a. Sprouting of a new branch/’memory path’, provided free GP-cells.

 b. Generalization

b. Connection of a stimulus (ED/EG) with a memory path (CD unit).