Somesthetic Disconnection Syndromes in Patients with Callosal Lesions

Ihori, Nami; Kawamura, Mitsuru; Fukuzawa, Kazuyoshi; Kamaki, Mutsuo

doi:10.1159/000008199

Cited by 13 publications

(15 citation statements)

References 13 publications

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“…Although we did not demonstrate that the kusho effect is very huge in an everyday sense, it could have a sufficient impact in terms of cost performance, particularly for those who have a low level of function for visual manipulation. It has been known that alexia patients can recognize a character that is kinetically presented as a series of passive finger movements [20, 42]. This is interpreted as an example that kinetic information through movements elicits internal representations of written languages.…”

Section: Discussionmentioning

confidence: 99%

Writing in the air: A visualization tool for written languages

et al. 2017

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The present study investigated interactions between cognitive processes and finger actions called “kusho,” meaning “air-writing” in Japanese. Kanji-culture individuals often employ kusho behavior in which they move their fingers as a substitute for a pen to write mostly done when they are trying to recall the shape of a Kanji character or the spelling of an English word. To further examine the visualization role of kusho behavior on cognitive processing, we conducted a Kanji construction task in which a stimulus (i.e., sub-parts to be constructed) was simultaneously presented. In addition, we conducted a Kanji vocabulary test to reveal the relation between the kusho benefit and vocabulary size. The experiment provided two sets of novel findings. First, executing kusho behavior improved task performance (correct responses) as long as the participants watched their finger movements while solving the task. This result supports the idea that visual feedback of kusho behavior helps cognitive processing for the task. Second, task performance was positively correlated with the vocabulary score when stimuli were presented for a relatively long time, whereas the kusho benefits and vocabulary score were not correlated regardless of stimulus-presentation time. These results imply that a longer stimulus-presentation could allow participants to utilize their lexical resources for solving the task. The current findings together support the visualization role of kusho behavior, adding experimental evidence supporting the view that there are interactions between cognition and motor behavior.

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Section: Discussionmentioning

confidence: 99%

Writing in the air: A visualization tool for written languages

et al. 2017

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“…6, *2). The somatosensory information from the left hand necessary for kinesthetic reading is thought to be transferred to the left superior parietal lobule via the anterior or dorsal part of the posterior truncus of the corpus callosum [13], although kana and kanji may not be transferred via exactly the same portion of the corpus callosum [29]. …”

Section: Discussionmentioning

confidence: 99%

Kinesthetic Alexia due to Left Parietal Lobe Lesions

Ihori

Kawamura²,

Araki³

et al. 2002

Eur Neurol

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To investigate the neuropsychological mechanisms of kinesthetic alexia, we asked 7 patients who showed kinesthetic alexia with preserved visual reading after damage to the left parietal region to perform tasks consisting of kinesthetic written reproduction (writing down the same letter as the kinesthetic stimulus), kinesthetic reading aloud, visual written reproduction (copying letters), and visual reading aloud of hiragana (Japanese phonograms). We compared the performance in these tasks and the lesion sites in each patient. The results suggested that deficits in any one of the following functions might cause kinesthetic alexia: (1) the retrieval of kinesthetic images (motor engrams) of characters from kinesthetic stimuli, (2) kinesthetic images themselves, (3) access to cross-modal association from kinesthetic images, and (4) cross-modal association itself (retrieval of auditory and visual images from kinesthetic images of characters). Each of these factors seemed to be related to different lesion sites in the left parietal lobe.

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“…The anatomical locations of these regions might depend on the type of information being processed. Indeed, evidence from partial split-brain patients suggests that callosal transfer of somatosensory information occurs between regions of posterior cortex (34)(35)(36), whereas the transfer of other higher level cognitive information might occur between more anterior regions of temporal and frontal cortex (37).…”

Section: Spatiotemporal Interhemispheric Communicationmentioning

confidence: 99%

Dynamic network structure of interhemispheric coordination

Doron

Bassett

Gazzaniga

2012

Proc. Natl. Acad. Sci. U.S.A.

137

146

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Fifty years ago Gazzaniga and coworkers published a seminal article that discussed the separate roles of the cerebral hemispheres in humans. Today, the study of interhemispheric communication is facilitated by a battery of novel data analysis techniques drawn from across disciplinary boundaries, including dynamic systems theory and network theory. These techniques enable the characterization of dynamic changes in the brain's functional connectivity, thereby providing an unprecedented means of decoding interhemispheric communication. Here, we illustrate the use of these techniques to examine interhemispheric coordination in healthy human participants performing a split visual field experiment in which they process lexical stimuli. We find that interhemispheric coordination is greater when lexical information is introduced to the right hemisphere and must subsequently be transferred to the left hemisphere for language processing than when it is directly introduced to the language-dominant (left) hemisphere. Further, we find that putative functional modules defined by coherent interhemispheric coordination come online in a transient manner, highlighting the underlying dynamic nature of brain communication. Our work illustrates that recently developed dynamic, network-based analysis techniques can provide novel and previously unapproachable insights into the role of interhemispheric coordination in cognition.T he field of split-brain research began several decades ago with the use of a drastic surgical solution for intractable epilepsy (1-3): the severing of the corpus callosum. This procedure significantly decreased the connectivity between the hemispheres, thereby irrevocably altering interhemispheric communication. Although a few interhemispheric pathways remained through subcortical structures and the anterior commissure, examination of callosal function using split visual field experiments clearly demonstrated its role in interhemispheric communication (2). The callosal projection plays a particularly crucial role in a variety of sensory-motor integrative functions of the two hemispheres (4), shows changes with age, and demonstrates the potential for dynamic changes with training (5). In fact, experiments in patients with severance of the callosum revealed that it subserves a large range of behaviors and cognitive functions that underlie the varied workings of the mind.Interhemispheric communication has been studied using two basic approaches. The first uses behavioral experiments to examine cognitive phenotypes, and the second uses neuroscientific experiments to examine brain phenotypes. Split-brain research initially focused on the former: Patients demonstrated striking behavioral phenotypes that provided clues regarding the underlying mechanics of brain communication. For example, although most perceptual processing appears to be isolated in each hemisphere following surgery, some attentional and emotional mechanisms initiated in one hemisphere can still be communicated to the other, cortically disconnected,...

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Somesthetic Disconnection Syndromes in Patients with Callosal Lesions

Cited by 13 publications

References 13 publications

Writing in the air: A visualization tool for written languages

Writing in the air: A visualization tool for written languages

Kinesthetic Alexia due to Left Parietal Lobe Lesions

Dynamic network structure of interhemispheric coordination

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