TY - JOUR
T1 - Accurate motor mapping in awake common marmosets using micro-electrocorticographical stimulation and stochastic threshold estimation
AU - Kosugi, Akito
AU - Takemi, Mitsuaki
AU - Tia, Banty
AU - Castagnola, Elisa
AU - Ansaldo, Alberto
AU - Sato, Kenta
AU - Awiszus, Friedemann
AU - Seki, Kazuhiko
AU - Ricci, Davide
AU - Fadiga, Luciano
AU - Iriki, Atsushi
AU - Ushiba, Junichi
N1 - Funding Information:
This work was supported by Grants-in-Aid for JSPS Research Fellow to AK (#15J05875) and MT (#14J00630), the Brain/ MINDS project from AMED, Japan to AI and grants from the Italian Ministry of the University and Research to LF.
Publisher Copyright:
© 2018 IOP Publishing Ltd.
PY - 2018/4/6
Y1 - 2018/4/6
N2 - Objective. Motor map has been widely used as an indicator of motor skills and learning, cortical injury, plasticity, and functional recovery. Cortical stimulation mapping using epidural electrodes is recently adopted for animal studies. However, several technical limitations still remain. Test-retest reliability of epidural cortical stimulation (ECS) mapping has not been examined in detail. Many previous studies defined evoked movements and motor thresholds by visual inspection, and thus, lacked quantitative measurements. A reliable and quantitative motor map is important to elucidate the mechanisms of motor cortical reorganization. The objective of the current study was to perform reliable ECS mapping of motor representations based on the motor thresholds, which were stochastically estimated by motor evoked potentials and chronically implanted micro-electrocorticographical (μECoG) electrode arrays, in common marmosets. Approach. ECS was applied using the implanted μECoG electrode arrays in three adult common marmosets under awake conditions. Motor evoked potentials were recorded through electromyographical electrodes implanted in upper limb muscles. The motor threshold was calculated through a modified maximum likelihood threshold-hunting algorithm fitted with the recorded data from marmosets. Further, a computer simulation confirmed reliability of the algorithm. Main results. Computer simulation suggested that the modified maximum likelihood threshold-hunting algorithm enabled to estimate motor threshold with acceptable precision. In vivo ECS mapping showed high test-retest reliability with respect to the excitability and location of the cortical forelimb motor representations. Significance. Using implanted μECoG electrode arrays and a modified motor threshold-hunting algorithm, we were able to achieve reliable motor mapping in common marmosets with the ECS system.
AB - Objective. Motor map has been widely used as an indicator of motor skills and learning, cortical injury, plasticity, and functional recovery. Cortical stimulation mapping using epidural electrodes is recently adopted for animal studies. However, several technical limitations still remain. Test-retest reliability of epidural cortical stimulation (ECS) mapping has not been examined in detail. Many previous studies defined evoked movements and motor thresholds by visual inspection, and thus, lacked quantitative measurements. A reliable and quantitative motor map is important to elucidate the mechanisms of motor cortical reorganization. The objective of the current study was to perform reliable ECS mapping of motor representations based on the motor thresholds, which were stochastically estimated by motor evoked potentials and chronically implanted micro-electrocorticographical (μECoG) electrode arrays, in common marmosets. Approach. ECS was applied using the implanted μECoG electrode arrays in three adult common marmosets under awake conditions. Motor evoked potentials were recorded through electromyographical electrodes implanted in upper limb muscles. The motor threshold was calculated through a modified maximum likelihood threshold-hunting algorithm fitted with the recorded data from marmosets. Further, a computer simulation confirmed reliability of the algorithm. Main results. Computer simulation suggested that the modified maximum likelihood threshold-hunting algorithm enabled to estimate motor threshold with acceptable precision. In vivo ECS mapping showed high test-retest reliability with respect to the excitability and location of the cortical forelimb motor representations. Significance. Using implanted μECoG electrode arrays and a modified motor threshold-hunting algorithm, we were able to achieve reliable motor mapping in common marmosets with the ECS system.
KW - ECoG
KW - adaptive threshold hunting
KW - cortical stimulation mapping
KW - motor representation
KW - motor threshold
KW - test-retest reliability
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U2 - 10.1088/1741-2552/aab307
DO - 10.1088/1741-2552/aab307
M3 - Article
C2 - 29491189
AN - SCOPUS:85047482460
VL - 15
JO - Journal of Neural Engineering
JF - Journal of Neural Engineering
SN - 1741-2560
IS - 3
M1 - 036019
ER -