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Functional MRI of auditory responses in the zebra finch forebrain reveals a hierarchical organisation based on signal strength but not selectivity.

Boumans T, Gobes SM, Poirier C, Theunissen FE, Vandersmissen L, Pintjens W, Verhoye M, Bolhuis JJ, Van der Linden A - PLoS ONE (2008)

Bottom Line: Zebra finch males were exposed to conspecific song, BOS and to synthetic variations on BOS that differed in spectro-temporal and/or modulation phase structure.In particular, we have shown that the overall signal strength to song and synthetic variations thereof was different within two sub-regions of Field L2: zone L2a was significantly more activated compared to the adjacent sub-region L2b.Based on our results we suggest that unlike nuclei in the song system, sub-regions in the primary auditory pallium do not show selectivity for the BOS, but appear to show different levels of activity with exposure to any sound according to their place in the auditory processing stream.

View Article: PubMed Central - PubMed

Affiliation: Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Background: Male songbirds learn their songs from an adult tutor when they are young. A network of brain nuclei known as the 'song system' is the likely neural substrate for sensorimotor learning and production of song, but the neural networks involved in processing the auditory feedback signals necessary for song learning and maintenance remain unknown. Determining which regions show preferential responsiveness to the bird's own song (BOS) is of great importance because neurons sensitive to self-generated vocalisations could mediate this auditory feedback process. Neurons in the song nuclei and in a secondary auditory area, the caudal medial mesopallium (CMM), show selective responses to the BOS. The aim of the present study is to investigate the emergence of BOS selectivity within the network of primary auditory sub-regions in the avian pallium.

Methods and findings: Using blood oxygen level-dependent (BOLD) fMRI, we investigated neural responsiveness to natural and manipulated self-generated vocalisations and compared the selectivity for BOS and conspecific song in different sub-regions of the thalamo-recipient area Field L. Zebra finch males were exposed to conspecific song, BOS and to synthetic variations on BOS that differed in spectro-temporal and/or modulation phase structure. We found significant differences in the strength of BOLD responses between regions L2a, L2b and CMM, but no inter-stimuli differences within regions. In particular, we have shown that the overall signal strength to song and synthetic variations thereof was different within two sub-regions of Field L2: zone L2a was significantly more activated compared to the adjacent sub-region L2b.

Conclusions: Based on our results we suggest that unlike nuclei in the song system, sub-regions in the primary auditory pallium do not show selectivity for the BOS, but appear to show different levels of activity with exposure to any sound according to their place in the auditory processing stream.

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Related in: MedlinePlus

Regional selectivity.This figure shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for all sounds separately (A) and averaged (B). All means are represented with their corresponding standard errors (SEM). Asterisks (*) indicate significant differences.
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pone-0003184-g006: Regional selectivity.This figure shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for all sounds separately (A) and averaged (B). All means are represented with their corresponding standard errors (SEM). Asterisks (*) indicate significant differences.

Mentions: An ANOVA for repeated measures with the average BOLD response amplitude as dependent variable and with Region and Stimulus as repeated factors revealed a significant effect of Region (F3 = 9.071; P = 0.002). No significant effect of Stimulus (F5 = 0.951; P = 0.470), and no significant interaction between Region and Stimulus (F15 = 1.567; P = 0.111) was observed. An ANOVA for repeated measures with the average BOLD response amplitude averaged over the different stimulus types as dependent variable and with only Region as repeated factor, showed again a significant effect Region (F3 = 9.071; P = 0.002). Post-hoc tests corrected for multiple comparisons (Bonferroni) between the four regions showed differential signal strengths between region L2a and the regions L2b (P = 0.034), L3/NCM (P = 0.028), and CMM (P = 0.025), and between region L2b and region CMM (P = 0.034). There was a non-significant trend between regions L3/NCM and CMM (P = 0.072). Figure 6 shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for the different stimuli separately (Figure 6A) and averaged (Figure 6B).


Functional MRI of auditory responses in the zebra finch forebrain reveals a hierarchical organisation based on signal strength but not selectivity.

Boumans T, Gobes SM, Poirier C, Theunissen FE, Vandersmissen L, Pintjens W, Verhoye M, Bolhuis JJ, Van der Linden A - PLoS ONE (2008)

Regional selectivity.This figure shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for all sounds separately (A) and averaged (B). All means are represented with their corresponding standard errors (SEM). Asterisks (*) indicate significant differences.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2527133&req=5

pone-0003184-g006: Regional selectivity.This figure shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for all sounds separately (A) and averaged (B). All means are represented with their corresponding standard errors (SEM). Asterisks (*) indicate significant differences.
Mentions: An ANOVA for repeated measures with the average BOLD response amplitude as dependent variable and with Region and Stimulus as repeated factors revealed a significant effect of Region (F3 = 9.071; P = 0.002). No significant effect of Stimulus (F5 = 0.951; P = 0.470), and no significant interaction between Region and Stimulus (F15 = 1.567; P = 0.111) was observed. An ANOVA for repeated measures with the average BOLD response amplitude averaged over the different stimulus types as dependent variable and with only Region as repeated factor, showed again a significant effect Region (F3 = 9.071; P = 0.002). Post-hoc tests corrected for multiple comparisons (Bonferroni) between the four regions showed differential signal strengths between region L2a and the regions L2b (P = 0.034), L3/NCM (P = 0.028), and CMM (P = 0.025), and between region L2b and region CMM (P = 0.034). There was a non-significant trend between regions L3/NCM and CMM (P = 0.072). Figure 6 shows the average BOLD signal in the four regions of interest L2a, L2b, L3/NCM and CMM, for the different stimuli separately (Figure 6A) and averaged (Figure 6B).

Bottom Line: Zebra finch males were exposed to conspecific song, BOS and to synthetic variations on BOS that differed in spectro-temporal and/or modulation phase structure.In particular, we have shown that the overall signal strength to song and synthetic variations thereof was different within two sub-regions of Field L2: zone L2a was significantly more activated compared to the adjacent sub-region L2b.Based on our results we suggest that unlike nuclei in the song system, sub-regions in the primary auditory pallium do not show selectivity for the BOS, but appear to show different levels of activity with exposure to any sound according to their place in the auditory processing stream.

View Article: PubMed Central - PubMed

Affiliation: Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Background: Male songbirds learn their songs from an adult tutor when they are young. A network of brain nuclei known as the 'song system' is the likely neural substrate for sensorimotor learning and production of song, but the neural networks involved in processing the auditory feedback signals necessary for song learning and maintenance remain unknown. Determining which regions show preferential responsiveness to the bird's own song (BOS) is of great importance because neurons sensitive to self-generated vocalisations could mediate this auditory feedback process. Neurons in the song nuclei and in a secondary auditory area, the caudal medial mesopallium (CMM), show selective responses to the BOS. The aim of the present study is to investigate the emergence of BOS selectivity within the network of primary auditory sub-regions in the avian pallium.

Methods and findings: Using blood oxygen level-dependent (BOLD) fMRI, we investigated neural responsiveness to natural and manipulated self-generated vocalisations and compared the selectivity for BOS and conspecific song in different sub-regions of the thalamo-recipient area Field L. Zebra finch males were exposed to conspecific song, BOS and to synthetic variations on BOS that differed in spectro-temporal and/or modulation phase structure. We found significant differences in the strength of BOLD responses between regions L2a, L2b and CMM, but no inter-stimuli differences within regions. In particular, we have shown that the overall signal strength to song and synthetic variations thereof was different within two sub-regions of Field L2: zone L2a was significantly more activated compared to the adjacent sub-region L2b.

Conclusions: Based on our results we suggest that unlike nuclei in the song system, sub-regions in the primary auditory pallium do not show selectivity for the BOS, but appear to show different levels of activity with exposure to any sound according to their place in the auditory processing stream.

Show MeSH
Related in: MedlinePlus