page_title: Neurocomputational speech processing
section_title: Action repository
hierarchical_section_title: Neurocomputational speech processing / ACT model / Structure / Action repository
caption_attribution_description: English: Phonetic Map Link Weights for ACT Model (neurocomputational model of speech processing)
context_page_description: Neurocomputational speech processing is computer-simulation of speech production and speech perception by referring to the natural neuronal processes of speech production and speech perception, as they occur in the human nervous system. This topic is based on neuroscience and computational neuroscience.
context_section_description: The phonetic map together with the motor plan state map, sensory state maps (occurring within the sensory-phonetic processing modules), and phonemic (state) map form the action repository. The phonetic map is implemented in ACT as a self-organizing neural map and different speech items are represented by different neurons within this map (punctual or local representation, see above: neural representations). The phonetic map exhibits three major characteristics: 
  More than one phonetic realization may occur within the phonetic map for one phonemic state (see phonemic link weights in Fig. 7: e.g. the syllable /de:m/ is represented by three neurons within the phonetic map)
  Phonetotopy: The phonetic map exhibits an ordering of speech items with respect to different phonetic features (see phonemic link weights in Fig. 7. Three examples: (i) the syllables /p@/, /t@/, and /k@/ occur in an upward ordering at the left side within the phonetic map; (ii) syllable-initial plosives occur in the upper left part of the phonetic map while syllable initial fricatives occur in  the lower right half; (iii) CV syllables and CVC syllables as well occur in different areas of the phonetic map.).
  The phonetic map is hypermodal or multimodal: The activation of a phonetic item at the level of the phonetic map coactivates (i) a phonemic state (see phonemic link weights in Fig. 7), (ii) a motor plan state (see motor plan link weights in Fig. 7), (iii) an auditory state (see auditory link weights in Fig. 7), and (iv) a somatosensory state (not shown in Fig. 7). All these states are learned or trained during speech acquisition by tuning the synaptic link weights between each neuron within the phonetic map, representing a particular phonetic state and all neurons within the associated motor plan and sensory state maps (see also Fig. 3).
  The phonetic map implements the action-perception-link within the ACT model (see also Fig. 5 and Fig. 6: the dual neural representation of the phonetic map in the frontal lobe and at the intersection of temporal lobe and parietal lobe).
caption: Fig. 7: Visualization of synaptic link weights for a section of the phonetic map, trained for the 200 most frequent syllables of Standard German. Each box represents a neuron within the self-organizing phonetic map. Each of the three link weight representations refers to the same section within the phonetic map and thus refers to the same 10×10 neurons
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