Limits...
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.


Bayesian model selection (BMS).(a) Exceedance probabilities and posterior expectations (in parentheses) resulting from the BMS procedure. The analysis did not reveal a clear winning family. But, with high confidence (total exceedance probability, p = 0.83), pre-SMA received either input from V1 (Fam. 3) or from A1, while Pv/V1 are not connected with the remaining areas (Fam. 4). (b) Posterior model probabilities for all subjects, assigned to the families (see also Table 2), indicating that blind subjects preferably chose Fam. 3, whereas Fam. 4 was much more likely for sighted individuals. More specifically, blind subjects showed high probability for the model m11, whereas sighted individuals primarily chose m13 or m27.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4492787&req=5

pone.0132196.g004: Bayesian model selection (BMS).(a) Exceedance probabilities and posterior expectations (in parentheses) resulting from the BMS procedure. The analysis did not reveal a clear winning family. But, with high confidence (total exceedance probability, p = 0.83), pre-SMA received either input from V1 (Fam. 3) or from A1, while Pv/V1 are not connected with the remaining areas (Fam. 4). (b) Posterior model probabilities for all subjects, assigned to the families (see also Table 2), indicating that blind subjects preferably chose Fam. 3, whereas Fam. 4 was much more likely for sighted individuals. More specifically, blind subjects showed high probability for the model m11, whereas sighted individuals primarily chose m13 or m27.

Mentions: Fig 4A showed the posterior expectations and exceeding probabilities from the random-effects BMS procedure. The analysis did not yield a clear overall winning family. However, with high confidence (total exceedance probability, p = 0.83), pre-SMA received input either from V1 (Fam. 3, exceedance probability, p = 0.52) or from A1 in case Pv/V1 are not connected with the remaining areas (Fam. 4, exceedance probability, p = 0.31). Posterior model probabilities for subjects and models (Fig 4B, Table 2) revealed that blind subjects preferred Fam. 3 whereas Fam. 4 was much more likely for sighted individuals. More detailed, blind subjects showed high probability for a model with bidirectional connections between V1 and pre-SMA as well as Pv-A1/V1 (m11), whereas a few blind subjects chose a model which, additionally, included A1-pre-SMA coupling (m03, not winning family). The sighted group chose models with bidirectional (m13) or absent (m27) connectivity between A1 and pre-SMA, without any coupling from/to Pv/V1 (Fig 4B, Table 2).


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)

Bayesian model selection (BMS).(a) Exceedance probabilities and posterior expectations (in parentheses) resulting from the BMS procedure. The analysis did not reveal a clear winning family. But, with high confidence (total exceedance probability, p = 0.83), pre-SMA received either input from V1 (Fam. 3) or from A1, while Pv/V1 are not connected with the remaining areas (Fam. 4). (b) Posterior model probabilities for all subjects, assigned to the families (see also Table 2), indicating that blind subjects preferably chose Fam. 3, whereas Fam. 4 was much more likely for sighted individuals. More specifically, blind subjects showed high probability for the model m11, whereas sighted individuals primarily chose m13 or m27.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0132196.g004: Bayesian model selection (BMS).(a) Exceedance probabilities and posterior expectations (in parentheses) resulting from the BMS procedure. The analysis did not reveal a clear winning family. But, with high confidence (total exceedance probability, p = 0.83), pre-SMA received either input from V1 (Fam. 3) or from A1, while Pv/V1 are not connected with the remaining areas (Fam. 4). (b) Posterior model probabilities for all subjects, assigned to the families (see also Table 2), indicating that blind subjects preferably chose Fam. 3, whereas Fam. 4 was much more likely for sighted individuals. More specifically, blind subjects showed high probability for the model m11, whereas sighted individuals primarily chose m13 or m27.
Mentions: Fig 4A showed the posterior expectations and exceeding probabilities from the random-effects BMS procedure. The analysis did not yield a clear overall winning family. However, with high confidence (total exceedance probability, p = 0.83), pre-SMA received input either from V1 (Fam. 3, exceedance probability, p = 0.52) or from A1 in case Pv/V1 are not connected with the remaining areas (Fam. 4, exceedance probability, p = 0.31). Posterior model probabilities for subjects and models (Fig 4B, Table 2) revealed that blind subjects preferred Fam. 3 whereas Fam. 4 was much more likely for sighted individuals. More detailed, blind subjects showed high probability for a model with bidirectional connections between V1 and pre-SMA as well as Pv-A1/V1 (m11), whereas a few blind subjects chose a model which, additionally, included A1-pre-SMA coupling (m03, not winning family). The sighted group chose models with bidirectional (m13) or absent (m27) connectivity between A1 and pre-SMA, without any coupling from/to Pv/V1 (Fig 4B, Table 2).

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.