TY - JOUR
T1 - Mapping mental calculation systems with electrocorticography
AU - Ueda, Keisuke
AU - Brown, Erik C.
AU - Kojima, Katsuaki
AU - Juhász, Csaba
AU - Asano, Eishi
N1 - Funding Information:
This work was supported by NIH grants NS47550 and NS64033 (to E. Asano). We are grateful to Harry T. Chugani, MD, Sandeep Sood, MD, and Carol Pawlak, REEG/EPT at Children’s Hospital of Michigan, Wayne State University for the collaboration and assistance in performing the studies described above.
Publisher Copyright:
© 2014 International Federation of Clinical Neurophysiology.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Objective: We investigated intracranially-recorded gamma activity during calculation tasks to better understand the cortical dynamics of calculation. Methods: We studied 11 patients with focal epilepsy (age range: 9-28. years) who underwent measurement of calculation- and naming-related gamma-augmentation during extraoperative electrocorticography (ECoG). The patients were instructed to overtly verbalize a one-word answer in response to auditorily-delivered calculation and naming questions. The assigned calculation tasks were addition and subtraction involving integers between 1 and 17. Results: Out of the 1001 analyzed cortical electrode sites, 63 showed gamma-augmentation at 50-120. Hz elicited by both tasks, 88 specifically during naming, and 7 specifically during calculation. Common gamma-augmentation mainly took place in the Rolandic regions. Calculation-specific gamma-augmentation, involving the period between the question-offset and response-onset, was noted in the middle-temporal, inferior-parietal, inferior post-central, middle-frontal, and premotor regions of the left hemisphere. Calculation-specific gamma-augmentation in the middle-temporal, inferior-parietal, and inferior post-central regions peaked around the question offset, while that in the frontal lobe peaked after the question offset and before the response onset. This study failed to detect a significant difference in calculation-specific gamma amplitude between easy trials and difficult ones requiring multi-digit operations. Conclusions: Auditorily-delivered stimuli can elicit calculation-specific gamma-augmentation in multiple regions of the left hemisphere including the parietal region. However, the additive diagnostic value of measurement of gamma-augmentation related to a simple calculation task appears modest. Significance: Further studies are warranted to determine the functional significance of calculation-specific gamma-augmentation in each site, and to establish the optimal protocol for mapping mental calculation.
AB - Objective: We investigated intracranially-recorded gamma activity during calculation tasks to better understand the cortical dynamics of calculation. Methods: We studied 11 patients with focal epilepsy (age range: 9-28. years) who underwent measurement of calculation- and naming-related gamma-augmentation during extraoperative electrocorticography (ECoG). The patients were instructed to overtly verbalize a one-word answer in response to auditorily-delivered calculation and naming questions. The assigned calculation tasks were addition and subtraction involving integers between 1 and 17. Results: Out of the 1001 analyzed cortical electrode sites, 63 showed gamma-augmentation at 50-120. Hz elicited by both tasks, 88 specifically during naming, and 7 specifically during calculation. Common gamma-augmentation mainly took place in the Rolandic regions. Calculation-specific gamma-augmentation, involving the period between the question-offset and response-onset, was noted in the middle-temporal, inferior-parietal, inferior post-central, middle-frontal, and premotor regions of the left hemisphere. Calculation-specific gamma-augmentation in the middle-temporal, inferior-parietal, and inferior post-central regions peaked around the question offset, while that in the frontal lobe peaked after the question offset and before the response onset. This study failed to detect a significant difference in calculation-specific gamma amplitude between easy trials and difficult ones requiring multi-digit operations. Conclusions: Auditorily-delivered stimuli can elicit calculation-specific gamma-augmentation in multiple regions of the left hemisphere including the parietal region. However, the additive diagnostic value of measurement of gamma-augmentation related to a simple calculation task appears modest. Significance: Further studies are warranted to determine the functional significance of calculation-specific gamma-augmentation in each site, and to establish the optimal protocol for mapping mental calculation.
KW - Angular gyrus
KW - Auditory
KW - Cognition
KW - Event-related synchronization
KW - Functional brain mapping
KW - Intracranial ECoG recording
KW - Language
KW - Number
KW - Numeral
KW - Pediatric epilepsy surgery
KW - Physiological high-frequency oscillations (HFOs)
KW - Ripples
KW - Spatio-temporal-dynamics
KW - Speech
KW - Subdural EEG
KW - Time-frequency analysis
UR - http://www.scopus.com/inward/record.url?scp=84917682536&partnerID=8YFLogxK
U2 - 10.1016/j.clinph.2014.04.015
DO - 10.1016/j.clinph.2014.04.015
M3 - Article
C2 - 24877680
AN - SCOPUS:84917682536
SN - 1388-2457
VL - 126
SP - 39
EP - 46
JO - Clinical Neurophysiology
JF - Clinical Neurophysiology
IS - 1
ER -