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Network Modeling for Functional Magnetic Resonance Imaging (fMRI) Signals during Ultra-Fast Speech Comprehension in Late-Blind Listeners.

Dietrich S, Hertrich I, Ackermann H - PLoS ONE (2015)

Bottom Line: Regarding the output V1 was significantly connected to pre-SMA in blind individuals, and the strength of V1-SMA connectivity correlated with the performance of ultra-fast speech comprehension.By contrast, in sighted controls, not understanding ultra-fast speech, pre-SMA did neither receive input from A1 nor V1.Taken together, right V1 might facilitate the "parsing" of the ultra-fast speech stream in blind subjects by receiving subcortical auditory input via the Pv (= secondary visual pathway) and transmitting this information toward contralateral pre-SMA.

View Article: PubMed Central - PubMed

Affiliation: Department of General Neurology, Hertie Institute for Clinical Brain Research, Center for Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, D-72076 Tübingen, Germany.

ABSTRACT
In many functional magnetic resonance imaging (fMRI) studies blind humans were found to show cross-modal reorganization engaging the visual system in non-visual tasks. For example, blind people can manage to understand (synthetic) spoken language at very high speaking rates up to ca. 20 syllables/s (syl/s). FMRI data showed that hemodynamic activation within right-hemispheric primary visual cortex (V1), bilateral pulvinar (Pv), and left-hemispheric supplementary motor area (pre-SMA) covaried with their capability of ultra-fast speech (16 syllables/s) comprehension. It has been suggested that right V1 plays an important role with respect to the perception of ultra-fast speech features, particularly the detection of syllable onsets. Furthermore, left pre-SMA seems to be an interface between these syllabic representations and the frontal speech processing and working memory network. So far, little is known about the networks linking V1 to Pv, auditory cortex (A1), and (mesio-) frontal areas. Dynamic causal modeling (DCM) was applied to investigate (i) the input structure from A1 and Pv toward right V1 and (ii) output from right V1 and A1 to left pre-SMA. As concerns the input Pv was significantly connected to V1, in addition to A1, in blind participants, but not in sighted controls. Regarding the output V1 was significantly connected to pre-SMA in blind individuals, and the strength of V1-SMA connectivity correlated with the performance of ultra-fast speech comprehension. By contrast, in sighted controls, not understanding ultra-fast speech, pre-SMA did neither receive input from A1 nor V1. Taken together, right V1 might facilitate the "parsing" of the ultra-fast speech stream in blind subjects by receiving subcortical auditory input via the Pv (= secondary visual pathway) and transmitting this information toward contralateral pre-SMA.

No MeSH data available.


Related in: MedlinePlus

The hypothesized network.An anatomically and functionally based model describing the in- and output stream of the right primary visual area (V1): Besides the primary auditory pathway (red arrows), auditory information coming from the cochlear thread at the level of the tectum, inferior and superior colliculus (IC, SC) (an audiovisual interface), and the secondary visual pathway, pulvinar (Pv), into V1 (blue arrows). Further, sensory areas, A1 and V1, modulate via the thalamus (Tha) the supplementary motor area (pre-SMA) in order to optimize temporal processing and predictive coding (cerebello-thalamic-pre-SMA loop). Investigating this network, four areas (green) were used for the DCM analyses. BG = basal ganglia, Cb = cerebellum, LGN = lateral geniculate nucleus, MGN = medial geniculate nucleus.
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pone.0132196.g001: The hypothesized network.An anatomically and functionally based model describing the in- and output stream of the right primary visual area (V1): Besides the primary auditory pathway (red arrows), auditory information coming from the cochlear thread at the level of the tectum, inferior and superior colliculus (IC, SC) (an audiovisual interface), and the secondary visual pathway, pulvinar (Pv), into V1 (blue arrows). Further, sensory areas, A1 and V1, modulate via the thalamus (Tha) the supplementary motor area (pre-SMA) in order to optimize temporal processing and predictive coding (cerebello-thalamic-pre-SMA loop). Investigating this network, four areas (green) were used for the DCM analyses. BG = basal ganglia, Cb = cerebellum, LGN = lateral geniculate nucleus, MGN = medial geniculate nucleus.

Mentions: As an extension of our preceding fMRI group study [10], the present investigation addresses network modeling (dynamic causal modeling) regarding brain regions the activation of which had shown covariance with behavioral performance in ultra-fast speech comprehension. Considering the hypothesized mechanism [12], connectivity analysis will focus on a single network comprising the right-hemispheric primary auditory cortex (A1), ipsilateral Pv, the right-hemispheric V1, and left-hemispheric pre-SMA. Based on anatomical and functional considerations, Pv, A1, and V1 interaction may be considered as a perceptual input structure while A1, V1, and pre-SMA coupling refers to output from sensory regions toward frontal cortex:


Network Modeling for Functional Magnetic Resonance Imaging (fMRI) Signals during Ultra-Fast Speech Comprehension in Late-Blind Listeners.

Dietrich S, Hertrich I, Ackermann H - PLoS ONE (2015)

The hypothesized network.An anatomically and functionally based model describing the in- and output stream of the right primary visual area (V1): Besides the primary auditory pathway (red arrows), auditory information coming from the cochlear thread at the level of the tectum, inferior and superior colliculus (IC, SC) (an audiovisual interface), and the secondary visual pathway, pulvinar (Pv), into V1 (blue arrows). Further, sensory areas, A1 and V1, modulate via the thalamus (Tha) the supplementary motor area (pre-SMA) in order to optimize temporal processing and predictive coding (cerebello-thalamic-pre-SMA loop). Investigating this network, four areas (green) were used for the DCM analyses. BG = basal ganglia, Cb = cerebellum, LGN = lateral geniculate nucleus, MGN = medial geniculate nucleus.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492787&req=5

pone.0132196.g001: The hypothesized network.An anatomically and functionally based model describing the in- and output stream of the right primary visual area (V1): Besides the primary auditory pathway (red arrows), auditory information coming from the cochlear thread at the level of the tectum, inferior and superior colliculus (IC, SC) (an audiovisual interface), and the secondary visual pathway, pulvinar (Pv), into V1 (blue arrows). Further, sensory areas, A1 and V1, modulate via the thalamus (Tha) the supplementary motor area (pre-SMA) in order to optimize temporal processing and predictive coding (cerebello-thalamic-pre-SMA loop). Investigating this network, four areas (green) were used for the DCM analyses. BG = basal ganglia, Cb = cerebellum, LGN = lateral geniculate nucleus, MGN = medial geniculate nucleus.
Mentions: As an extension of our preceding fMRI group study [10], the present investigation addresses network modeling (dynamic causal modeling) regarding brain regions the activation of which had shown covariance with behavioral performance in ultra-fast speech comprehension. Considering the hypothesized mechanism [12], connectivity analysis will focus on a single network comprising the right-hemispheric primary auditory cortex (A1), ipsilateral Pv, the right-hemispheric V1, and left-hemispheric pre-SMA. Based on anatomical and functional considerations, Pv, A1, and V1 interaction may be considered as a perceptual input structure while A1, V1, and pre-SMA coupling refers to output from sensory regions toward frontal cortex:

Bottom Line: Regarding the output V1 was significantly connected to pre-SMA in blind individuals, and the strength of V1-SMA connectivity correlated with the performance of ultra-fast speech comprehension.By contrast, in sighted controls, not understanding ultra-fast speech, pre-SMA did neither receive input from A1 nor V1.Taken together, right V1 might facilitate the "parsing" of the ultra-fast speech stream in blind subjects by receiving subcortical auditory input via the Pv (= secondary visual pathway) and transmitting this information toward contralateral pre-SMA.

View Article: PubMed Central - PubMed

Affiliation: Department of General Neurology, Hertie Institute for Clinical Brain Research, Center for Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, D-72076 Tübingen, Germany.

ABSTRACT
In many functional magnetic resonance imaging (fMRI) studies blind humans were found to show cross-modal reorganization engaging the visual system in non-visual tasks. For example, blind people can manage to understand (synthetic) spoken language at very high speaking rates up to ca. 20 syllables/s (syl/s). FMRI data showed that hemodynamic activation within right-hemispheric primary visual cortex (V1), bilateral pulvinar (Pv), and left-hemispheric supplementary motor area (pre-SMA) covaried with their capability of ultra-fast speech (16 syllables/s) comprehension. It has been suggested that right V1 plays an important role with respect to the perception of ultra-fast speech features, particularly the detection of syllable onsets. Furthermore, left pre-SMA seems to be an interface between these syllabic representations and the frontal speech processing and working memory network. So far, little is known about the networks linking V1 to Pv, auditory cortex (A1), and (mesio-) frontal areas. Dynamic causal modeling (DCM) was applied to investigate (i) the input structure from A1 and Pv toward right V1 and (ii) output from right V1 and A1 to left pre-SMA. As concerns the input Pv was significantly connected to V1, in addition to A1, in blind participants, but not in sighted controls. Regarding the output V1 was significantly connected to pre-SMA in blind individuals, and the strength of V1-SMA connectivity correlated with the performance of ultra-fast speech comprehension. By contrast, in sighted controls, not understanding ultra-fast speech, pre-SMA did neither receive input from A1 nor V1. Taken together, right V1 might facilitate the "parsing" of the ultra-fast speech stream in blind subjects by receiving subcortical auditory input via the Pv (= secondary visual pathway) and transmitting this information toward contralateral pre-SMA.

No MeSH data available.


Related in: MedlinePlus