Limits...
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.


Consistent sensory preference in sensory areas. (A) Statistical parametric map of the modality effect revealed by a two-way ANOVA, vision versus auditory preference (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. Auditory and visual responses are distinct and localized in accordance with their respective sensory areas, as defined by retinotopic (red) and tonotopic blue) borders. This was enabled even though the auditory and visual stimuli were delivered at the same time, in a semioverlapped manner (see Methods). White lines delineate group average of borders between tonotopic and retinotopic gradients. (B) Auditory responses in the auditory cortex (blue box, left) and visual responses in the visual cortex (red box, right) in all 3 experimental conditions (Pre, Post, and Plus, in left to right panels), compared with baseline. Auditory responses in auditory cortex were always positive (P < 0.01, uncorrected), as were the visual responses in the visual cortex (P < 0.01, uncorrected), also demonstrated by beta values in Figure 2B. Here, as well tonotopic borders are in blue and retinotopic borders are depicted in red.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4494022&req=5

BHU010F2: Consistent sensory preference in sensory areas. (A) Statistical parametric map of the modality effect revealed by a two-way ANOVA, vision versus auditory preference (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. Auditory and visual responses are distinct and localized in accordance with their respective sensory areas, as defined by retinotopic (red) and tonotopic blue) borders. This was enabled even though the auditory and visual stimuli were delivered at the same time, in a semioverlapped manner (see Methods). White lines delineate group average of borders between tonotopic and retinotopic gradients. (B) Auditory responses in the auditory cortex (blue box, left) and visual responses in the visual cortex (red box, right) in all 3 experimental conditions (Pre, Post, and Plus, in left to right panels), compared with baseline. Auditory responses in auditory cortex were always positive (P < 0.01, uncorrected), as were the visual responses in the visual cortex (P < 0.01, uncorrected), also demonstrated by beta values in Figure 2B. Here, as well tonotopic borders are in blue and retinotopic borders are depicted in red.

Mentions: Our experiments were aimed at determining the dynamic nature of sensory responses; for example, how they change according to the experimental context in which they are delivered. We decided to use independent datasets, not confounded by our experimental design or the group of subjects who participated in the main experiment, and to provide an approximation of the boundaries of sensory cortices to which our main results could be compared. We delineated sensory cortices according to their response to pure tones and retinotopic stimuli (Sereno et al. 1995; Engel et al. 1997; Striem-Amit et al. 2011). Data from 2 independent experiments were used here to establish these boundaries. None of the 3 groups of subjects (retinotopy, tonotopy, and main experiment) overlapped. The boundaries of the auditory cortex were estimated using the tonotopy data from Striem-Amit et al. 2011. In their experiments, 10 subjects were scanned while listening to an ascending 30-s chirp, ranging from 250 Hz to 4 kHz, repeated 15 times (a descending chirp was also used in the original experiment to verify the results of the rising chirp). First, tonotopic responsive areas were detected as areas with a significant response to auditory stimuli. The tonotopic organization within these areas, for example, multiple gradual maps of preferred tones (from high to low and vice versa), was detected. These were found in core auditory areas and in associative auditory area, extending toward the temporal areas. Average maps from these 10 subjects were used here to determine cortical areas responsive to pure tones (P < 0.05, corr.) and to delineate boundaries between multiple tonotopic maps (delineated on a flattened cortical reconstruction in Fig. 2). It should be noted that the tonotopic responsive areas include associative auditory areas (such as the Superior Temporal Gyrus) and are not confounds of the auditory core areas.Figure 2.


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

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

Consistent sensory preference in sensory areas. (A) Statistical parametric map of the modality effect revealed by a two-way ANOVA, vision versus auditory preference (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. Auditory and visual responses are distinct and localized in accordance with their respective sensory areas, as defined by retinotopic (red) and tonotopic blue) borders. This was enabled even though the auditory and visual stimuli were delivered at the same time, in a semioverlapped manner (see Methods). White lines delineate group average of borders between tonotopic and retinotopic gradients. (B) Auditory responses in the auditory cortex (blue box, left) and visual responses in the visual cortex (red box, right) in all 3 experimental conditions (Pre, Post, and Plus, in left to right panels), compared with baseline. Auditory responses in auditory cortex were always positive (P < 0.01, uncorrected), as were the visual responses in the visual cortex (P < 0.01, uncorrected), also demonstrated by beta values in Figure 2B. Here, as well tonotopic borders are in blue and retinotopic borders are depicted in red.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494022&req=5

BHU010F2: Consistent sensory preference in sensory areas. (A) Statistical parametric map of the modality effect revealed by a two-way ANOVA, vision versus auditory preference (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. Auditory and visual responses are distinct and localized in accordance with their respective sensory areas, as defined by retinotopic (red) and tonotopic blue) borders. This was enabled even though the auditory and visual stimuli were delivered at the same time, in a semioverlapped manner (see Methods). White lines delineate group average of borders between tonotopic and retinotopic gradients. (B) Auditory responses in the auditory cortex (blue box, left) and visual responses in the visual cortex (red box, right) in all 3 experimental conditions (Pre, Post, and Plus, in left to right panels), compared with baseline. Auditory responses in auditory cortex were always positive (P < 0.01, uncorrected), as were the visual responses in the visual cortex (P < 0.01, uncorrected), also demonstrated by beta values in Figure 2B. Here, as well tonotopic borders are in blue and retinotopic borders are depicted in red.
Mentions: Our experiments were aimed at determining the dynamic nature of sensory responses; for example, how they change according to the experimental context in which they are delivered. We decided to use independent datasets, not confounded by our experimental design or the group of subjects who participated in the main experiment, and to provide an approximation of the boundaries of sensory cortices to which our main results could be compared. We delineated sensory cortices according to their response to pure tones and retinotopic stimuli (Sereno et al. 1995; Engel et al. 1997; Striem-Amit et al. 2011). Data from 2 independent experiments were used here to establish these boundaries. None of the 3 groups of subjects (retinotopy, tonotopy, and main experiment) overlapped. The boundaries of the auditory cortex were estimated using the tonotopy data from Striem-Amit et al. 2011. In their experiments, 10 subjects were scanned while listening to an ascending 30-s chirp, ranging from 250 Hz to 4 kHz, repeated 15 times (a descending chirp was also used in the original experiment to verify the results of the rising chirp). First, tonotopic responsive areas were detected as areas with a significant response to auditory stimuli. The tonotopic organization within these areas, for example, multiple gradual maps of preferred tones (from high to low and vice versa), was detected. These were found in core auditory areas and in associative auditory area, extending toward the temporal areas. Average maps from these 10 subjects were used here to determine cortical areas responsive to pure tones (P < 0.05, corr.) and to delineate boundaries between multiple tonotopic maps (delineated on a flattened cortical reconstruction in Fig. 2). It should be noted that the tonotopic responsive areas include associative auditory areas (such as the Superior Temporal Gyrus) and are not confounds of the auditory core areas.Figure 2.

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.