TY - JOUR
T1 - Age-related changes across the primary and secondary somatosensory areas
T2 - An analysis of neuromagnetic oscillatory activities
AU - Hagiwara, Koichi
AU - Ogata, Katsuya
AU - Okamoto, Tsuyoshi
AU - Uehara, Taira
AU - Hironaga, Naruhito
AU - Shigeto, Hiroshi
AU - Kira, Jun ichi
AU - Tobimatsu, Shozo
N1 - Funding Information:
This study was supported in part by Grants-in-aid for Scientists, No. 19390242 , No. 22390177 , and No. 25870511 , from the Ministry of Education, Culture, Sports, Science and Technology in Japan .
PY - 2014/5
Y1 - 2014/5
N2 - Objective: Age-related changes are well documented in the primary somatosensory cortex (SI). Based on previous somatosensory evoked potential studies, the amplitude of N20 typically increases with age probably due to cortical disinhibition. However, less is known about age-related change in the secondary somatosensory cortex (SII). The current study quantified age-related changes across SI and SII mainly based on oscillatory activity indices measured with magnetoencephalography. Methods: We recorded somatosensory evoked magnetic fields (SEFs) to right median nerve stimulation in healthy young and old subjects and assessed major SEF components. Then, we evaluated the phase-locking factor (PLF) for local field synchrony on neural oscillations and the weighted phase-lag index (wPLI) for cortico-cortical synchrony between SI and SII. Results: PLF was significantly increased in SI along with the increased amplitude of N20m in the old subjects. PLF was also increased in SII associated with a shortened peak latency of SEFs. wPLI analysis revealed the increased coherent activity between SI and SII. Conclusions: Our results suggest that the functional coupling between SI and SII is influenced by the cortical disinhibition due to normal aging. Significance: We provide the first electrophysiological evidence for age-related changes in oscillatory neural activities across the somatosensory areas.
AB - Objective: Age-related changes are well documented in the primary somatosensory cortex (SI). Based on previous somatosensory evoked potential studies, the amplitude of N20 typically increases with age probably due to cortical disinhibition. However, less is known about age-related change in the secondary somatosensory cortex (SII). The current study quantified age-related changes across SI and SII mainly based on oscillatory activity indices measured with magnetoencephalography. Methods: We recorded somatosensory evoked magnetic fields (SEFs) to right median nerve stimulation in healthy young and old subjects and assessed major SEF components. Then, we evaluated the phase-locking factor (PLF) for local field synchrony on neural oscillations and the weighted phase-lag index (wPLI) for cortico-cortical synchrony between SI and SII. Results: PLF was significantly increased in SI along with the increased amplitude of N20m in the old subjects. PLF was also increased in SII associated with a shortened peak latency of SEFs. wPLI analysis revealed the increased coherent activity between SI and SII. Conclusions: Our results suggest that the functional coupling between SI and SII is influenced by the cortical disinhibition due to normal aging. Significance: We provide the first electrophysiological evidence for age-related changes in oscillatory neural activities across the somatosensory areas.
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U2 - 10.1016/j.clinph.2013.10.005
DO - 10.1016/j.clinph.2013.10.005
M3 - Article
C2 - 24189210
AN - SCOPUS:84897495834
SN - 1388-2457
VL - 125
SP - 1021
EP - 1029
JO - Electroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
JF - Electroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
IS - 5
ER -