title: Neural pattern similarity between contra- and ipsilateral movements in high-frequency band of human electrocorticograms.
abstract: The cortical motor areas are activated not only during contralateral limb movements but also during ipsilateral limb movements. Although these ipsilateral activities have been observed in several brain imaging studies, their functional role is poorly understood. Due to its high temporal resolution and low susceptibility to artifacts from body movements, the electrocorticogram (ECoG) is an advantageous measurement method for assessing the human brain function of motor behaviors. Here, we demonstrate that contra- and ipsilateral movements share a similarity in the high-frequency band of human ECoG signals. The ECoG signals were measured from the unilateral sensorimotor cortex while patients conducted self-paced movements of different body parts, contra- or ipsilateral to the measurement side. The movement categories (wrist, shoulder, or ankle) of ipsilateral movements were decoded as accurately as those of contralateral movements from spatial patterns of the high-frequency band of the precentral motor area (the primary motor and premotor areas). The decoder, trained in the high-frequency band of ipsilateral movements generalized to contralateral movements, and vice versa, confirmed that the activity patterns related to ipsilateral limb movements were similar to contralateral ones in the precentral motor area. Our results suggest that the high-frequency band activity patterns of ipsilateral and contralateral movements might be functionally coupled to control limbs, even during unilateral movements.
authors.affiliation: ATR Neural Information Analysis Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan. Electronic address: fujiwara.yusuke02@is.naist.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto, 606-8507. Electronic address: matsumot@kuhp.kyoto-u.ac.jp.
authors.forename: Riki
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Nakae
authors.affiliation: Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto, 606-8507.
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Usami
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Matsuhashi
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Neurosurgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon City 791-0295, Ehime, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Kunieda
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan; Graduate School of Core Ethics and Frontier Sciences. Ritsumeikan University, 56-1 Toji-in Kitamachi, Kita-ku, Kyoto 603-8577, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Mima
authors.affiliation: Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, 54 Shogoin-kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: ATR Computational Neuroscience Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Osu
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D058256:Brain Waves / Q000502:physiology*; D000069280:Electrocorticography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009044:Motor Cortex / Q000502:physiology*; D012782:Shoulder / Q000502:physiology; D014953:Wrist / Q000502:physiology
keywords: Decoding; ECoG; High gamma; Ipsilateral movement; Precentral motor cortex