The brain study of gesturing and writing: association/dissociation and handedness effect

Gesturing and writing are the two important forms of communication, and therefore to know their association and dissociation on brain mechanism is valuable. However, very few studies exist in the literature. Moreover, through comparing brain activations among left-handers (LH), right-handers (RH) and converted left-handers (CLH), the common neural substrates which cannot be changed even by the culture of right handedness and left-handed heritage could be estimated as the potential brain centers of the two forms. Conversely, the distinct neural substrates in the CLH might imply the effect of culture of forced dextral use on brain reorganization. Although the brain mechanism of gesturing and writing have been substantiated respectively, the linguistic variables which might confound the results have not been controlled well. Therefore, in this sub-project, we only choose Chinese one-character verb (not compound) to guide gesturing and writing by participants, such as 切(cut)、投(pitch)、刷(brush)、抹(wipe)、按(press)、倒(pour)、剪(scissor)、 槌(hammer)、寫(write)、燙(iron)、鋸(saw)、擦(erase)、轉(screw). Then the mechanism between two forms in the three populations can be compared fairly. The works of this three-year sub-project are listed below. In the first year, functional magnetic resonance imaging (fMRI) will be used to investigate brain activation patterns on gesturing and writing. Participants have to perform the gestures and write the Chinese one character words corresponded to the aforementioned spoken transitive verbs. During the second year, we will explore the link of the N400-like MEG response (Magnetic equivalent N400, N400m) to "word-gesture incongruence" and "gesture-word incongruence", and then the issue of gesture comprehension can be addressed. The congruent and incongruent gesture targets preceded by word primes as well as the congruent and incongruent word targets preceded by gesture primes will be applied in the experimental design. Moreover, the CNV-like paradigm in ERP studies will be introduced in this MEG study to delineate how people anticipate the following unsure action of gesture and writing. The magnetic equivalent of late CNV will be the major index to address this anticipatory mechanism. In the third year, the preparation and production process of gesture and writing will be studied through exploring the patterns of movement-related cortical magnetic fields (MRFs) during self-paced gesturing and writing tasks of dominant hand in three handedness groups. The Bereitschafts Field (BF), magnetic equivalent of motor cortex potentials (MCF), and magnetic equivalent of skilled performance positivity (SPP-like MEG response) will represent the cortical mechanism on preparing, producing and monitoring respectively. In summary, this sub-project will study the neural substrate as well as the process of anticipation, preparation, execution and monitoring of gesturing and writing. A comparison will be done with the brain mechanism of gesturing and writing in CLH, LH and RH. The association and dissociation between gesturing and writing, the gesturing and writing brain center and the effect of right-handed culture (handedness conversion) on brain mechanism will be clarified.

Project ID:PF10501-2478
External Project ID:MOST105-2420-H182-001-MY2