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The role of left and right hemispheres in the comprehension of idiomatic language: an electrical neuroimaging study.

Proverbio AM, Crotti N, Zani A, Adorni R - BMC Neurosci (2009)

Bottom Line: Time-course and neural bases of literal vs. idiomatic language processing were compared.The intra-cortical generators of this effect included the left and right FG, the left cingulate gyrus, the right limbic area, the right MTG (BA21) and the left middle frontal gyrus (BA46).ERPs also showed a larger right centro-parietal N400 to associated than non-associated targets (not differing as a function of sentence type), and a greater right frontal P600 to idiomatic than literal associated targets.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychology, University of Milano-Bicocca, 20126, Milan, Italy. mado.proverbio@unimib.it

ABSTRACT

Background: The specific role of the two cerebral hemispheres in processing idiomatic language is highly debated. While some studies show the involvement of the left inferior frontal gyrus (LIFG), other data support the crucial role of right-hemispheric regions, and particularly of the middle/superior temporal area. Time-course and neural bases of literal vs. idiomatic language processing were compared. Fifteen volunteers silently read 360 idiomatic and literal Italian sentences and decided whether they were semantically related or unrelated to a following target word, while their EEGs were recorded from 128 electrodes. Word length, abstractness and frequency of use, sentence comprehensibility, familiarity and cloze probability were matched across classes.

Results: Participants responded more quickly to literal than to idiomatic sentences, probably indicating a difference in task difficulty. Occipito/temporal N2 component had a greater amplitude in response to idioms between 250-300 ms. Related swLORETA source reconstruction revealed a difference in the activation of the left fusiform gyrus (FG, BA19) and medial frontal gyri for the contrast idiomatic-minus-literal. Centroparietal N400 was much larger to idiomatic than to literal phrases (360-550 ms). The intra-cortical generators of this effect included the left and right FG, the left cingulate gyrus, the right limbic area, the right MTG (BA21) and the left middle frontal gyrus (BA46). Finally, an anterior late positivity (600-800 ms) was larger to idiomatic than literal phrases. ERPs also showed a larger right centro-parietal N400 to associated than non-associated targets (not differing as a function of sentence type), and a greater right frontal P600 to idiomatic than literal associated targets.

Conclusion: The data indicate bilateral involvement of both hemispheres in idiom comprehension, including the right MTG after 350 ms and the right medial frontal gyrus in the time windows 270-300 and 500-780 ms. In addition, the activation of left and right limbic regions (400-450 ms) suggests that they have a role in the emotional connotation of colourful idiomatic language. The data support the view that there is direct access to the idiomatic meaning of figurative language, not dependent on the suppression of its literal meaning, for which the LIFG was previously thought to be responsible.

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Final words. (Top) Grand-averaged ERPs recorded from left and right inferior frontal sites in response to idiomatic and literal phrases. This indicates the strong right-hemispheric lateralization of the anterior P3 component to idiomatic phrases. (Bottom) Two axial sections (deepness indicated below the head) of swLORETA inverse solution performed on the difference wave obtained by subtracting ERPs to literal from ERPs to idiomatic sentences in the time window 620-640 ms, corresponding to the peak of anterior late positivity. Grid spacing = 10 mm; estimated SNR = 3. The solution offered three strong sources of statistically significant activation explaining the surface difference-potential, one located in the left fusiform gyrus (BA 19), one in the left superior temporal gyrus (BA38), and one in the right medial frontal gyrus (BA9).
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Figure 4: Final words. (Top) Grand-averaged ERPs recorded from left and right inferior frontal sites in response to idiomatic and literal phrases. This indicates the strong right-hemispheric lateralization of the anterior P3 component to idiomatic phrases. (Bottom) Two axial sections (deepness indicated below the head) of swLORETA inverse solution performed on the difference wave obtained by subtracting ERPs to literal from ERPs to idiomatic sentences in the time window 620-640 ms, corresponding to the peak of anterior late positivity. Grid spacing = 10 mm; estimated SNR = 3. The solution offered three strong sources of statistically significant activation explaining the surface difference-potential, one located in the left fusiform gyrus (BA 19), one in the left superior temporal gyrus (BA38), and one in the right medial frontal gyrus (BA9).

Mentions: This component showed a hemispheric asymmetry (F1,10 = 11.93; p < 0.006), with much larger amplitudes over the right (3.52 μV) than the left (2.86 μV) hemisphere, as clearly appreciable in Figure 4 (top). The amplitude of this component was strongly affected by "sentence type", both per se (F1,10 = 9.92; p < 0.01) and in interaction with "electrode" (F1,10 = 5.74; p < 0.04) and "hemisphere" (F1,10 = 6.94; p < 0.025). Post-hoc comparisons indicated more positive responses to idiomatic than literal phrases only over the right hemisphere at inferior frontal sites, and bilaterally at mesial frontal sites.


The role of left and right hemispheres in the comprehension of idiomatic language: an electrical neuroimaging study.

Proverbio AM, Crotti N, Zani A, Adorni R - BMC Neurosci (2009)

Final words. (Top) Grand-averaged ERPs recorded from left and right inferior frontal sites in response to idiomatic and literal phrases. This indicates the strong right-hemispheric lateralization of the anterior P3 component to idiomatic phrases. (Bottom) Two axial sections (deepness indicated below the head) of swLORETA inverse solution performed on the difference wave obtained by subtracting ERPs to literal from ERPs to idiomatic sentences in the time window 620-640 ms, corresponding to the peak of anterior late positivity. Grid spacing = 10 mm; estimated SNR = 3. The solution offered three strong sources of statistically significant activation explaining the surface difference-potential, one located in the left fusiform gyrus (BA 19), one in the left superior temporal gyrus (BA38), and one in the right medial frontal gyrus (BA9).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2749859&req=5

Figure 4: Final words. (Top) Grand-averaged ERPs recorded from left and right inferior frontal sites in response to idiomatic and literal phrases. This indicates the strong right-hemispheric lateralization of the anterior P3 component to idiomatic phrases. (Bottom) Two axial sections (deepness indicated below the head) of swLORETA inverse solution performed on the difference wave obtained by subtracting ERPs to literal from ERPs to idiomatic sentences in the time window 620-640 ms, corresponding to the peak of anterior late positivity. Grid spacing = 10 mm; estimated SNR = 3. The solution offered three strong sources of statistically significant activation explaining the surface difference-potential, one located in the left fusiform gyrus (BA 19), one in the left superior temporal gyrus (BA38), and one in the right medial frontal gyrus (BA9).
Mentions: This component showed a hemispheric asymmetry (F1,10 = 11.93; p < 0.006), with much larger amplitudes over the right (3.52 μV) than the left (2.86 μV) hemisphere, as clearly appreciable in Figure 4 (top). The amplitude of this component was strongly affected by "sentence type", both per se (F1,10 = 9.92; p < 0.01) and in interaction with "electrode" (F1,10 = 5.74; p < 0.04) and "hemisphere" (F1,10 = 6.94; p < 0.025). Post-hoc comparisons indicated more positive responses to idiomatic than literal phrases only over the right hemisphere at inferior frontal sites, and bilaterally at mesial frontal sites.

Bottom Line: Time-course and neural bases of literal vs. idiomatic language processing were compared.The intra-cortical generators of this effect included the left and right FG, the left cingulate gyrus, the right limbic area, the right MTG (BA21) and the left middle frontal gyrus (BA46).ERPs also showed a larger right centro-parietal N400 to associated than non-associated targets (not differing as a function of sentence type), and a greater right frontal P600 to idiomatic than literal associated targets.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychology, University of Milano-Bicocca, 20126, Milan, Italy. mado.proverbio@unimib.it

ABSTRACT

Background: The specific role of the two cerebral hemispheres in processing idiomatic language is highly debated. While some studies show the involvement of the left inferior frontal gyrus (LIFG), other data support the crucial role of right-hemispheric regions, and particularly of the middle/superior temporal area. Time-course and neural bases of literal vs. idiomatic language processing were compared. Fifteen volunteers silently read 360 idiomatic and literal Italian sentences and decided whether they were semantically related or unrelated to a following target word, while their EEGs were recorded from 128 electrodes. Word length, abstractness and frequency of use, sentence comprehensibility, familiarity and cloze probability were matched across classes.

Results: Participants responded more quickly to literal than to idiomatic sentences, probably indicating a difference in task difficulty. Occipito/temporal N2 component had a greater amplitude in response to idioms between 250-300 ms. Related swLORETA source reconstruction revealed a difference in the activation of the left fusiform gyrus (FG, BA19) and medial frontal gyri for the contrast idiomatic-minus-literal. Centroparietal N400 was much larger to idiomatic than to literal phrases (360-550 ms). The intra-cortical generators of this effect included the left and right FG, the left cingulate gyrus, the right limbic area, the right MTG (BA21) and the left middle frontal gyrus (BA46). Finally, an anterior late positivity (600-800 ms) was larger to idiomatic than literal phrases. ERPs also showed a larger right centro-parietal N400 to associated than non-associated targets (not differing as a function of sentence type), and a greater right frontal P600 to idiomatic than literal associated targets.

Conclusion: The data indicate bilateral involvement of both hemispheres in idiom comprehension, including the right MTG after 350 ms and the right medial frontal gyrus in the time windows 270-300 and 500-780 ms. In addition, the activation of left and right limbic regions (400-450 ms) suggests that they have a role in the emotional connotation of colourful idiomatic language. The data support the view that there is direct access to the idiomatic meaning of figurative language, not dependent on the suppression of its literal meaning, for which the LIFG was previously thought to be responsible.

Show MeSH
Related in: MedlinePlus