Mirror-image discrimination and reversal in the disconnected hemispheres

Corballis, Michael C.; Birse, Kylie; Paggi, A; Manzoni, T; Pierpaoli, Chiara; Fabri, Mara

doi:10.1016/j.neuropsychologia.2010.02.011

Cited by 23 publications

(18 citation statements)

References 40 publications

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“…Their dyslexic participants demonstrated an increased LVF advantage, consistent with an impairment in the transfer of RVF input to the specialised right hemisphere. Interestingly, such a pattern has also been reported in split brain patients, who showed a larger LVF advantage for this orientation matching task (Corballis et al, 2010). Together with the present findings, this therefore suggests that dyslexia involves a general impairment in the transfer of visual information across the corpus callosum, regardless of the required direction or the stimulus domain.…”

Section: Poorer Lvf Accuracy In Dyslexiasupporting

confidence: 89%

Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

Bradshaw¹,

Bishop²,

Woodhead³

2019

Preprint

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A deficit in interhemispheric transfer has been proposed as a neuropsychological theory of dyslexia. The role of interactions between the hemispheres during word recognition is demonstrated in two behavioural effects robustly reported using the visual half field paradigm. The well-established recognition advantage for right visual field (RVF) words over left visual field (LVF) words reflects the additional processing costs associated with callosal transfer of LVF word representations to the language specialised left hemisphere. Additionally, a further gain in recognition for bilateral presentation of a word is attributed to cooperative interactions between the hemispheres. These recognition advantages can therefore be seen as behavioural indices of the efficiency of callosal transfer. This study aimed to replicate the finding of an absence of the bilateral advantage in developmental dyslexia, previously reported by Henderson, Barca and Ellis (2007). 47 dyslexic and 43 control adult participants were tested, and no significant difference found in the size of their bilateral advantages. Our data did however replicate the previous finding of an increased RVF advantage in right handed dyslexic participants caused by poorer accuracy for LVF words. This evidence provides partial support for the interhemispheric deficit theory of dyslexia, suggesting an impairment in the transfer of visual word information from the right to the left hemisphere during reading.

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Section: Poorer Lvf Accuracy In Dyslexiasupporting

confidence: 89%

Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

Bradshaw¹,

Bishop²,

Woodhead³

2019

Preprint

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“…Somehow paradoxically, a similar difficulty in processing mirror images in the right visual field/left hemisphere was reported by Funnel and colleagues [ 62 ] and by Corballis and colleagues [ 51 ] in three split-brain participants. The JV patient was administered a number of tests with visual objects to discriminate, either nameable or not, rich or poor in details: in all tests the patient exhibited a clear impairment of left hemisphere at judging mirror objects.…”

Section: Discussionsupporting

confidence: 69%

“…Fifty-two percent of healthy children aged 3–8 would spontaneously mirror write their name, while 82% and 61% of 5- and 6-year-old children, respectively, would show mirror writing at least accidentally [ 48 ]. Patients with unilateral brain injury show mirror writing and reversing of letters or numbers during writing [ 49 , 50 ], as well as slip-brain [ 51 ]. Samuel Torrey Orton [ 23 ] used the term strephosymbolia to describe the phenomenon of inversion of letters either isolated or within words, shown by dyslexic children.…”

Section: Introductionmentioning

confidence: 99%

Revisiting Strephosymbolie: The Connection between Interhemispheric Transfer and Developmental Dyslexia

et al. 2018

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The hypothesis that an atypical hemispheric specialization is associated to developmental dyslexia (DD) is receiving renewed interest, lending some support to Orton’s theory. In this article, we investigated whether interhemispheric transfer processes (IHT) are likely to be involved in developmental dyslexia. In this study, we tested 13 children with developmental dyslexia and 13 matched controls (aged 8 to 13 years) in four different tasks. In a tactile transfer task, the dyslexic children’s performance was less accurate. In a standard Poffenberger paradigm, dyslexic children performed slower than the controls in all conditions and did not show any difference between crossed and uncrossed conditions. Furthermore, they showed an increased asymmetry of performance according to the responding hand, while controls gave more coherent responses. In a visual task of object orientation discrimination, dyslexic children had slower Response Times (RTs) than controls, especially for mirror-reversed objects in the right visual field. Finally, a higher number of dyslexic children showed mirror-drawing or mirror-writing with respect to controls. Our results as a whole show that children with DD are impaired in interhemispheric transfer, although the differences in performance among dyslexic individuals suggest the impairment of different psychophysiological mechanisms. As such, a common origin in terms of connectivity problems is proposed.

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“…The right-hemispheric superiority for spatial processing in split-brain patients has already been shown [12,13], but it has not been investigated for symmetry detection. In a study involving two split-brain patients, including the patient tested here, Corballis et al [40] found a right-hemispheric superiority when patients were asked to distinguish between canonical and mirror-reversed letters (F and R), concluding that this task depends on matching to an exemplar (the canonical oriented letter), for which the right-hemisphere is dominant (as opposed to the left-hemispheric superiority in letter naming). In contrast to that study, in the present study we presented geometrical shapes, for which no comparison with a "model" is required, and thus we aimed at investigating the pure hemispheric imbalance in symmetry detection.…”

Section: Introductionmentioning

confidence: 71%

Asymmetry for Symmetry: Right-Hemispheric Superiority in Bi-Dimensional Symmetry Perception

Prete

Fabri

Foschi³

et al. 2017

Symmetry

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Abstract:A right-hemispheric superiority has been shown for spatial symmetry perception with mono-dimensional stimuli (e.g., bisected lines). Nevertheless, the cerebral imbalance for bi-dimensional stimuli is still controversial, and the aim of the present study is to investigate this issue. Healthy participants and a split-brain patient (D.D.C.) were tested in a divided visual field paradigm, in which a square shape was presented either in the left or right visual field and they were asked to judge whether a dot was placed exactly in the center of the square or off-center, by using the left/right hand in two separate sessions. The performance of healthy participants was better when the stimuli presented in the left visual field (LVF) were on-center rather than off-center. The performance of D.D.C. was higher than chance only when on-center stimuli were presented in the LVF in the left hand session. Only in this condition did his accuracy not differ with respect to that of the control group, whereas in all of the other conditions, it was lower than the controls' accuracy. We conclude that the right-hemispheric advantage already shown for mono-dimensional stimuli can be extended also to bi-dimensional configurations, confirming the right-hemispheric superiority for spatial symmetry perception.

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Mirror-image discrimination and reversal in the disconnected hemispheres

Cited by 23 publications

References 40 publications

Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

Testing the interhemispheric deficit theory of dyslexia using the visual half-field technique

Revisiting Strephosymbolie: The Connection between Interhemispheric Transfer and Developmental Dyslexia

Asymmetry for Symmetry: Right-Hemispheric Superiority in Bi-Dimensional Symmetry Perception

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