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Frequency-dependent oscillatory neural profiles during imitation

View Article: PubMed Central - PubMed

ABSTRACT

Imitation is a complex process that includes higher-order cognitive and motor function. This process requires an observation-execution matching system that transforms an observed action into an identical movement. Although the low-gamma band is thought to reflect higher cognitive processes, no studies have focused on it. Here, we used magnetoencephalography (MEG) to examine the neural oscillatory changes including the low-gamma band during imitation. Twelve healthy, right-handed participants performed a finger task consisting of four conditions (imitation, execution, observation, and rest). During the imitation and execution conditions, significant event-related desynchronizations (ERDs) were observed at the left frontal, central, and parietal MEG sensors in the alpha, beta, and low-gamma bands. Functional connectivity analysis at the sensor level revealed an imitation-related connectivity between a group of frontal sensors and a group of parietal sensors in the low-gamma band. Furthermore, source reconstruction with synthetic aperture magnetometry showed significant ERDs in the low-gamma band in the left sensorimotor area and the middle frontal gyrus (MFG) during the imitation condition when compared with the other three conditions. Our results suggest that the oscillatory neural activities of the low-gamma band at the sensorimotor area and MFG play an important role in the observation-execution matching system related to imitation.

No MeSH data available.


Related in: MedlinePlus

(A) Time-frequency maps for each condition. Ten groups of sensors were defined from the MEG sensors (right). Robust ERDs were observed in the alpha, beta, and low-gamma bands at the left central and parietal areas during the imitation and execution conditions. (B) ERDs in the alpha, beta, and low-gamma bands were averaged across groups of sensors and time (0–1000 ms). ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (*p < 0.05). The beta and low-gamma bands in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (*p < 0.05). Significant differences in ERDs between imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors. Error bars indicate the standard error. (C) An imitation-related functional connectivity map in the low-gamma band calculated using IC. When IC during the imitation condition was compared with that during the execution condition (Imitation > Execution), significant IC was observed between a group of frontal sensors and a group of parietal sensors in the low-gamma band (p < 0.05, FWER-corrected). When IC during the imitation condition was compared with that during the observation condition (Imitation > Observation), significant IC was observed between a group of frontal sensors and a group of parietal sensors, a group of central sensors and a group of occipital sensors, and a group of frontal sensors and a group of central sensors (p < 0.05, FWER-corrected). R = right, L = left, F = frontal, C = central, T = temporal, P = parietal, O = occipital.
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f1: (A) Time-frequency maps for each condition. Ten groups of sensors were defined from the MEG sensors (right). Robust ERDs were observed in the alpha, beta, and low-gamma bands at the left central and parietal areas during the imitation and execution conditions. (B) ERDs in the alpha, beta, and low-gamma bands were averaged across groups of sensors and time (0–1000 ms). ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (*p < 0.05). The beta and low-gamma bands in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (*p < 0.05). Significant differences in ERDs between imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors. Error bars indicate the standard error. (C) An imitation-related functional connectivity map in the low-gamma band calculated using IC. When IC during the imitation condition was compared with that during the execution condition (Imitation > Execution), significant IC was observed between a group of frontal sensors and a group of parietal sensors in the low-gamma band (p < 0.05, FWER-corrected). When IC during the imitation condition was compared with that during the observation condition (Imitation > Observation), significant IC was observed between a group of frontal sensors and a group of parietal sensors, a group of central sensors and a group of occipital sensors, and a group of frontal sensors and a group of central sensors (p < 0.05, FWER-corrected). R = right, L = left, F = frontal, C = central, T = temporal, P = parietal, O = occipital.

Mentions: In the present study, sensor space analysis was initially performed to examine the time-frequency profiles for each condition from recorded data. Ten groups of sensors were defined from MEG sensors (Fig. 1A right), and power changes at each MEG sensor were averaged across groups of sensors and time (0–1000 ms). The results showed robust ERDs in the alpha, beta, and low-gamma bands in groups of left central and parietal sensors during the imitation and execution conditions (Fig. 1A). In particular, ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (Fig. 1B) (alpha band; F(3, 44) = 5.36, p = 0.0031, beta band; F(3, 44) = 6.42, p = 0.0011, one-way ANOVA). The low-gamma band in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (F(3, 44) = 4.66, p = 0.0065, one-way ANOVA). Significant differences in ERDs between the imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors (F(3, 44) = 3.875 p = 0.0152, one-way ANOVA).


Frequency-dependent oscillatory neural profiles during imitation
(A) Time-frequency maps for each condition. Ten groups of sensors were defined from the MEG sensors (right). Robust ERDs were observed in the alpha, beta, and low-gamma bands at the left central and parietal areas during the imitation and execution conditions. (B) ERDs in the alpha, beta, and low-gamma bands were averaged across groups of sensors and time (0–1000 ms). ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (*p < 0.05). The beta and low-gamma bands in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (*p < 0.05). Significant differences in ERDs between imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors. Error bars indicate the standard error. (C) An imitation-related functional connectivity map in the low-gamma band calculated using IC. When IC during the imitation condition was compared with that during the execution condition (Imitation > Execution), significant IC was observed between a group of frontal sensors and a group of parietal sensors in the low-gamma band (p < 0.05, FWER-corrected). When IC during the imitation condition was compared with that during the observation condition (Imitation > Observation), significant IC was observed between a group of frontal sensors and a group of parietal sensors, a group of central sensors and a group of occipital sensors, and a group of frontal sensors and a group of central sensors (p < 0.05, FWER-corrected). R = right, L = left, F = frontal, C = central, T = temporal, P = parietal, O = occipital.
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f1: (A) Time-frequency maps for each condition. Ten groups of sensors were defined from the MEG sensors (right). Robust ERDs were observed in the alpha, beta, and low-gamma bands at the left central and parietal areas during the imitation and execution conditions. (B) ERDs in the alpha, beta, and low-gamma bands were averaged across groups of sensors and time (0–1000 ms). ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (*p < 0.05). The beta and low-gamma bands in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (*p < 0.05). Significant differences in ERDs between imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors. Error bars indicate the standard error. (C) An imitation-related functional connectivity map in the low-gamma band calculated using IC. When IC during the imitation condition was compared with that during the execution condition (Imitation > Execution), significant IC was observed between a group of frontal sensors and a group of parietal sensors in the low-gamma band (p < 0.05, FWER-corrected). When IC during the imitation condition was compared with that during the observation condition (Imitation > Observation), significant IC was observed between a group of frontal sensors and a group of parietal sensors, a group of central sensors and a group of occipital sensors, and a group of frontal sensors and a group of central sensors (p < 0.05, FWER-corrected). R = right, L = left, F = frontal, C = central, T = temporal, P = parietal, O = occipital.
Mentions: In the present study, sensor space analysis was initially performed to examine the time-frequency profiles for each condition from recorded data. Ten groups of sensors were defined from MEG sensors (Fig. 1A right), and power changes at each MEG sensor were averaged across groups of sensors and time (0–1000 ms). The results showed robust ERDs in the alpha, beta, and low-gamma bands in groups of left central and parietal sensors during the imitation and execution conditions (Fig. 1A). In particular, ERDs in the alpha and beta bands in a group of left central sensors during the imitation and execution conditions were significantly lower than those during the observation and rest conditions (Fig. 1B) (alpha band; F(3, 44) = 5.36, p = 0.0031, beta band; F(3, 44) = 6.42, p = 0.0011, one-way ANOVA). The low-gamma band in a group of left frontal sensors showed significant ERDs during the imitation condition compared to the observation and rest conditions (F(3, 44) = 4.66, p = 0.0065, one-way ANOVA). Significant differences in ERDs between the imitation and execution conditions were observed only in the alpha band in a group of right occipital sensors (F(3, 44) = 3.875 p = 0.0152, one-way ANOVA).

View Article: PubMed Central - PubMed

ABSTRACT

Imitation is a complex process that includes higher-order cognitive and motor function. This process requires an observation-execution matching system that transforms an observed action into an identical movement. Although the low-gamma band is thought to reflect higher cognitive processes, no studies have focused on it. Here, we used magnetoencephalography (MEG) to examine the neural oscillatory changes including the low-gamma band during imitation. Twelve healthy, right-handed participants performed a finger task consisting of four conditions (imitation, execution, observation, and rest). During the imitation and execution conditions, significant event-related desynchronizations (ERDs) were observed at the left frontal, central, and parietal MEG sensors in the alpha, beta, and low-gamma bands. Functional connectivity analysis at the sensor level revealed an imitation-related connectivity between a group of frontal sensors and a group of parietal sensors in the low-gamma band. Furthermore, source reconstruction with synthetic aperture magnetometry showed significant ERDs in the low-gamma band in the left sensorimotor area and the middle frontal gyrus (MFG) during the imitation condition when compared with the other three conditions. Our results suggest that the oscillatory neural activities of the low-gamma band at the sensorimotor area and MFG play an important role in the observation-execution matching system related to imitation.

No MeSH data available.


Related in: MedlinePlus