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Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution.

Hertz U, Amedi A - Cereb. Cortex (2014)

Bottom Line: Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory.Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus.These 2 factors allow for both stability and a fast, dynamic tuning of the system when required.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem 91220, Israel Interdisciplinary Center for Neural Computation, The Edmond & Lily Safra Center for Brain Sciences (ELSC), Hebrew University of Jerusalem, Jerusalem 91905, Israel.

No MeSH data available.


Related in: MedlinePlus

Dynamic shift in sensory responses outside sensory areas. (A) Statistical parametric map of the interaction effect (Modality × Learning) revealed by a two-way ANOVA analysis, Pre-Visual + Post-Auditory versus Post-Visual + Pre-Auditory (P < 0.05, corr.), is presented on a flattened cortical reconstruction of one of the subjects. The analysis was carried out within areas that were responsive to either vision or auditory, before or after learning SSA. Positive responses represent areas which were more responsive to visual stimuli than auditory stimuli before learning, but more responsive to auditory stimuli than visual stimuli after learning. In the pre-learning condition, only visual input is informative, while after learning SSA auditory soundscapes input can be deciphered to reveal shape information. Cortical areas that shifted their sensory preferences from one informative sensory input to the other after learning include the left IFS, the left aSMG, the left and right IPS, and the left MFG. (B) Beta values were sampled from the clusters depicted in the statistical parametric map, and presented for the clusters in which both Pre-Visual and Post-Auditory were statistically significant (*P < 0.05, **P < 0.005, ***P < 0.0005, corr.). The location of these clusters is marked with black asterisks on the flat cortical reconstructions. Left IFS clusters and left IPS also showed significant responses to both auditory and visual stimuli in the “Plus” experiment, in which information from both modalities had to be used to perform the task. (C) Auditory and visual responses outside sensory areas (compared with baseline, P < 0.01, uncorrected). Left IFS (z = 23, top row) and left aSMG (z = 31, bottom row) were found to change their sensory preference across experiments (marked by a rectangle). Before learning SSA both were significantly responsive to visual stimuli, but not significantly to auditory stimuli. After learning they became significantly responsive to auditory stimuli, but not to visual stimuli. In the Plus detection experiment, the left IFS was significantly responsive to both auditory and visual stimuli, whereas the left aSMG preferred visual stimuli. Both areas could access both visual and auditory inputs, but changed their sensory preference according to the information, novelty, and task relevance of the sensory input.
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BHU010F4: Dynamic shift in sensory responses outside sensory areas. (A) Statistical parametric map of the interaction effect (Modality × Learning) revealed by a two-way ANOVA analysis, Pre-Visual + Post-Auditory versus Post-Visual + Pre-Auditory (P < 0.05, corr.), is presented on a flattened cortical reconstruction of one of the subjects. The analysis was carried out within areas that were responsive to either vision or auditory, before or after learning SSA. Positive responses represent areas which were more responsive to visual stimuli than auditory stimuli before learning, but more responsive to auditory stimuli than visual stimuli after learning. In the pre-learning condition, only visual input is informative, while after learning SSA auditory soundscapes input can be deciphered to reveal shape information. Cortical areas that shifted their sensory preferences from one informative sensory input to the other after learning include the left IFS, the left aSMG, the left and right IPS, and the left MFG. (B) Beta values were sampled from the clusters depicted in the statistical parametric map, and presented for the clusters in which both Pre-Visual and Post-Auditory were statistically significant (*P < 0.05, **P < 0.005, ***P < 0.0005, corr.). The location of these clusters is marked with black asterisks on the flat cortical reconstructions. Left IFS clusters and left IPS also showed significant responses to both auditory and visual stimuli in the “Plus” experiment, in which information from both modalities had to be used to perform the task. (C) Auditory and visual responses outside sensory areas (compared with baseline, P < 0.01, uncorrected). Left IFS (z = 23, top row) and left aSMG (z = 31, bottom row) were found to change their sensory preference across experiments (marked by a rectangle). Before learning SSA both were significantly responsive to visual stimuli, but not significantly to auditory stimuli. After learning they became significantly responsive to auditory stimuli, but not to visual stimuli. In the Plus detection experiment, the left IFS was significantly responsive to both auditory and visual stimuli, whereas the left aSMG preferred visual stimuli. Both areas could access both visual and auditory inputs, but changed their sensory preference according to the information, novelty, and task relevance of the sensory input.

Mentions: Importantly, the ANOVA interaction effect (Modality × Learning) revealed a dynamic shift in sensory preference in associative areas (Table 1, interaction effect). These areas responded to both sensory inputs, but changed their sensory response profile, that is, which sensory input elicited the strongest response (which sensory input was preferred). A post hoc contrast was carried out to detect the direction of the sensory shift (Fig. 4A). This comparison was carried out within areas which were responsive either to auditory or visual inputs, before or after learning (i.e., these areas had to exhibit a positive response to at least one of the sensory conditions, in one of the experiments), and was corrected for cluster size. Only one direction of sensory preference shift was found: from visual preference to auditory preference; namely, visual responses were higher than auditory responses before SSA learning, and auditory responses were stronger than visual responses after SSA learning. This change in the profile of sensory responses does not mean that these areas responded to only one sensory input, but that the relation between the strength of the auditory and visual responses changed. This direction of sensory preference shift is in line with the fact that learning involved the auditory input, by transforming it from noninformative to informative stimuli, whereas the visual stimuli remained unchanged. These shifts were detected in associative areas and were mostly lateralized to the left hemisphere, in areas previously reported to exhibit multisensory responses (Jones and Powell 1970; Calvert 2001; Fairhall and Macaluso 2009; Beauchamp et al. 2010; Noppeney et al. 2010). Clusters were located in the left prefrontal cortex, the left IFS, the IFG and the Middle Frontal Gyrus (MFG), the bilateral anterior Supermarginal Gyrus (aSMG), and the left IPS. A close examination of the beta values within these areas revealed a shift in sensory preference. With the exception of the left IPS, all the regions demonstrated a significant (P < 0.05, FDR corrected) response to visual stimuli but not to auditory stimuli before learning, and to auditory stimuli but not to visual after learning. The left IPS exhibited a significant response to both visual and auditory stimuli before and after learning, but with changes in the magnitude of the effect (lower mean response to pre-auditory and post-visual stimuli; Fig. 4B).Figure 4.


Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution.

Hertz U, Amedi A - Cereb. Cortex (2014)

Dynamic shift in sensory responses outside sensory areas. (A) Statistical parametric map of the interaction effect (Modality × Learning) revealed by a two-way ANOVA analysis, Pre-Visual + Post-Auditory versus Post-Visual + Pre-Auditory (P < 0.05, corr.), is presented on a flattened cortical reconstruction of one of the subjects. The analysis was carried out within areas that were responsive to either vision or auditory, before or after learning SSA. Positive responses represent areas which were more responsive to visual stimuli than auditory stimuli before learning, but more responsive to auditory stimuli than visual stimuli after learning. In the pre-learning condition, only visual input is informative, while after learning SSA auditory soundscapes input can be deciphered to reveal shape information. Cortical areas that shifted their sensory preferences from one informative sensory input to the other after learning include the left IFS, the left aSMG, the left and right IPS, and the left MFG. (B) Beta values were sampled from the clusters depicted in the statistical parametric map, and presented for the clusters in which both Pre-Visual and Post-Auditory were statistically significant (*P < 0.05, **P < 0.005, ***P < 0.0005, corr.). The location of these clusters is marked with black asterisks on the flat cortical reconstructions. Left IFS clusters and left IPS also showed significant responses to both auditory and visual stimuli in the “Plus” experiment, in which information from both modalities had to be used to perform the task. (C) Auditory and visual responses outside sensory areas (compared with baseline, P < 0.01, uncorrected). Left IFS (z = 23, top row) and left aSMG (z = 31, bottom row) were found to change their sensory preference across experiments (marked by a rectangle). Before learning SSA both were significantly responsive to visual stimuli, but not significantly to auditory stimuli. After learning they became significantly responsive to auditory stimuli, but not to visual stimuli. In the Plus detection experiment, the left IFS was significantly responsive to both auditory and visual stimuli, whereas the left aSMG preferred visual stimuli. Both areas could access both visual and auditory inputs, but changed their sensory preference according to the information, novelty, and task relevance of the sensory input.
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BHU010F4: Dynamic shift in sensory responses outside sensory areas. (A) Statistical parametric map of the interaction effect (Modality × Learning) revealed by a two-way ANOVA analysis, Pre-Visual + Post-Auditory versus Post-Visual + Pre-Auditory (P < 0.05, corr.), is presented on a flattened cortical reconstruction of one of the subjects. The analysis was carried out within areas that were responsive to either vision or auditory, before or after learning SSA. Positive responses represent areas which were more responsive to visual stimuli than auditory stimuli before learning, but more responsive to auditory stimuli than visual stimuli after learning. In the pre-learning condition, only visual input is informative, while after learning SSA auditory soundscapes input can be deciphered to reveal shape information. Cortical areas that shifted their sensory preferences from one informative sensory input to the other after learning include the left IFS, the left aSMG, the left and right IPS, and the left MFG. (B) Beta values were sampled from the clusters depicted in the statistical parametric map, and presented for the clusters in which both Pre-Visual and Post-Auditory were statistically significant (*P < 0.05, **P < 0.005, ***P < 0.0005, corr.). The location of these clusters is marked with black asterisks on the flat cortical reconstructions. Left IFS clusters and left IPS also showed significant responses to both auditory and visual stimuli in the “Plus” experiment, in which information from both modalities had to be used to perform the task. (C) Auditory and visual responses outside sensory areas (compared with baseline, P < 0.01, uncorrected). Left IFS (z = 23, top row) and left aSMG (z = 31, bottom row) were found to change their sensory preference across experiments (marked by a rectangle). Before learning SSA both were significantly responsive to visual stimuli, but not significantly to auditory stimuli. After learning they became significantly responsive to auditory stimuli, but not to visual stimuli. In the Plus detection experiment, the left IFS was significantly responsive to both auditory and visual stimuli, whereas the left aSMG preferred visual stimuli. Both areas could access both visual and auditory inputs, but changed their sensory preference according to the information, novelty, and task relevance of the sensory input.
Mentions: Importantly, the ANOVA interaction effect (Modality × Learning) revealed a dynamic shift in sensory preference in associative areas (Table 1, interaction effect). These areas responded to both sensory inputs, but changed their sensory response profile, that is, which sensory input elicited the strongest response (which sensory input was preferred). A post hoc contrast was carried out to detect the direction of the sensory shift (Fig. 4A). This comparison was carried out within areas which were responsive either to auditory or visual inputs, before or after learning (i.e., these areas had to exhibit a positive response to at least one of the sensory conditions, in one of the experiments), and was corrected for cluster size. Only one direction of sensory preference shift was found: from visual preference to auditory preference; namely, visual responses were higher than auditory responses before SSA learning, and auditory responses were stronger than visual responses after SSA learning. This change in the profile of sensory responses does not mean that these areas responded to only one sensory input, but that the relation between the strength of the auditory and visual responses changed. This direction of sensory preference shift is in line with the fact that learning involved the auditory input, by transforming it from noninformative to informative stimuli, whereas the visual stimuli remained unchanged. These shifts were detected in associative areas and were mostly lateralized to the left hemisphere, in areas previously reported to exhibit multisensory responses (Jones and Powell 1970; Calvert 2001; Fairhall and Macaluso 2009; Beauchamp et al. 2010; Noppeney et al. 2010). Clusters were located in the left prefrontal cortex, the left IFS, the IFG and the Middle Frontal Gyrus (MFG), the bilateral anterior Supermarginal Gyrus (aSMG), and the left IPS. A close examination of the beta values within these areas revealed a shift in sensory preference. With the exception of the left IPS, all the regions demonstrated a significant (P < 0.05, FDR corrected) response to visual stimuli but not to auditory stimuli before learning, and to auditory stimuli but not to visual after learning. The left IPS exhibited a significant response to both visual and auditory stimuli before and after learning, but with changes in the magnitude of the effect (lower mean response to pre-auditory and post-visual stimuli; Fig. 4B).Figure 4.

Bottom Line: Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory.Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus.These 2 factors allow for both stability and a fast, dynamic tuning of the system when required.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem 91220, Israel Interdisciplinary Center for Neural Computation, The Edmond & Lily Safra Center for Brain Sciences (ELSC), Hebrew University of Jerusalem, Jerusalem 91905, Israel.

No MeSH data available.


Related in: MedlinePlus