Abstract
Two patients with corpus callosum resection, one complete and the other sparing the genu and the rostrum, were tested for discrimination of three basic taste stimuli (sour, bitter, salty) applied to the right or left sides of the tongue. Responses were made by pointing with either hand to written words or images of visual objects corresponding to the stimuli, a language-based discrimination. In both patients, response accuracy was significantly above chance for both hemitongues but there was a significant advantage for the left side. Reaction time was shorter for left stimuli than for right stimuli but the difference was not significant. Eight normal controls matched for age with the patients performed equally well with right and left hemitongue stimuli and so did a third callosotomy patient with sparing of the posterior callosum, including the splenium. Tactile and visual tests showed that the left hemisphere was responsible for language-based responses in the first two patients. The results confirm and extend previous findings in another callosotomy patient, indicating that: (i) taste information from either side of the tongue can reach the left hemisphere in the absence of the corpus callosum; (ii) the ipsilateral input from the tongue to the left hemisphere is more potent functionally than the contralateral input and (iii) in the normal brain, the corpus callosum, specifically its posterior part including the splenium, appears to equalize the effects of the ipsilateral and contralateral gustatory inputs on the left hemisphere. Taken together with evidence about lateralized taste deficits following unilateral cortical lesions, the results also suggest that the gustatory pathways from tongue to cortex are bilaterally-distributed with an ipsilateral predominance that may be subject to individual variations.
| Original language | English |
|---|---|
| Pages (from-to) | 195-200 |
| Number of pages | 6 |
| Journal | European Journal of Neuroscience |
| Volume | 13 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2001 |
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Keywords
- Corpus callosum section
- Gustatory recognition
- Hemispheric asymmetry
- Man
- Tongue representation
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Taste laterality in the split brain. / Aglioti, S. M.; Tassinari, G.; Fabri, M.; Del Pesce, M.; Quattrini, A.; Manzoni, T.; Berlucchi, G.
In: European Journal of Neuroscience, Vol. 13, No. 1, 2001, p. 195-200.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Taste laterality in the split brain
AU - Aglioti, S. M.
AU - Tassinari, G.
AU - Fabri, M.
AU - Del Pesce, M.
AU - Quattrini, A.
AU - Manzoni, T.
AU - Berlucchi, G.
PY - 2001
Y1 - 2001
N2 - Two patients with corpus callosum resection, one complete and the other sparing the genu and the rostrum, were tested for discrimination of three basic taste stimuli (sour, bitter, salty) applied to the right or left sides of the tongue. Responses were made by pointing with either hand to written words or images of visual objects corresponding to the stimuli, a language-based discrimination. In both patients, response accuracy was significantly above chance for both hemitongues but there was a significant advantage for the left side. Reaction time was shorter for left stimuli than for right stimuli but the difference was not significant. Eight normal controls matched for age with the patients performed equally well with right and left hemitongue stimuli and so did a third callosotomy patient with sparing of the posterior callosum, including the splenium. Tactile and visual tests showed that the left hemisphere was responsible for language-based responses in the first two patients. The results confirm and extend previous findings in another callosotomy patient, indicating that: (i) taste information from either side of the tongue can reach the left hemisphere in the absence of the corpus callosum; (ii) the ipsilateral input from the tongue to the left hemisphere is more potent functionally than the contralateral input and (iii) in the normal brain, the corpus callosum, specifically its posterior part including the splenium, appears to equalize the effects of the ipsilateral and contralateral gustatory inputs on the left hemisphere. Taken together with evidence about lateralized taste deficits following unilateral cortical lesions, the results also suggest that the gustatory pathways from tongue to cortex are bilaterally-distributed with an ipsilateral predominance that may be subject to individual variations.
AB - Two patients with corpus callosum resection, one complete and the other sparing the genu and the rostrum, were tested for discrimination of three basic taste stimuli (sour, bitter, salty) applied to the right or left sides of the tongue. Responses were made by pointing with either hand to written words or images of visual objects corresponding to the stimuli, a language-based discrimination. In both patients, response accuracy was significantly above chance for both hemitongues but there was a significant advantage for the left side. Reaction time was shorter for left stimuli than for right stimuli but the difference was not significant. Eight normal controls matched for age with the patients performed equally well with right and left hemitongue stimuli and so did a third callosotomy patient with sparing of the posterior callosum, including the splenium. Tactile and visual tests showed that the left hemisphere was responsible for language-based responses in the first two patients. The results confirm and extend previous findings in another callosotomy patient, indicating that: (i) taste information from either side of the tongue can reach the left hemisphere in the absence of the corpus callosum; (ii) the ipsilateral input from the tongue to the left hemisphere is more potent functionally than the contralateral input and (iii) in the normal brain, the corpus callosum, specifically its posterior part including the splenium, appears to equalize the effects of the ipsilateral and contralateral gustatory inputs on the left hemisphere. Taken together with evidence about lateralized taste deficits following unilateral cortical lesions, the results also suggest that the gustatory pathways from tongue to cortex are bilaterally-distributed with an ipsilateral predominance that may be subject to individual variations.
KW - Corpus callosum section
KW - Gustatory recognition
KW - Hemispheric asymmetry
KW - Man
KW - Tongue representation
UR - http://www.scopus.com/inward/record.url?scp=0035176841&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035176841&partnerID=8YFLogxK
U2 - 10.1046/j.0953-816X.2000.01378.x
DO - 10.1046/j.0953-816X.2000.01378.x
M3 - Article
C2 - 11135018
AN - SCOPUS:0035176841
VL - 13
SP - 195
EP - 200
JO - European Journal of Neuroscience
JF - European Journal of Neuroscience
SN - 0953-816X
IS - 1
ER -