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An Internet-Based Real-Time Audiovisual Link for Dual MEG Recordings.

Zhdanov A, Nurminen J, Baess P, Hirvenkari L, Jousmäki V, Mäkelä JP, Mandel A, Meronen L, Hari R, Parkkonen L - PLoS ONE (2015)

Bottom Line: All the nine pairs were able to synchronize their behavior.In addition to the video, we captured the subjects' movements with accelerometers attached to their index fingers; we determined from these signals that the average synchronization accuracy was 215 ms.In one subject pair we demonstrate inter-subject coherence patterns of the MEG signals that peak over the sensorimotor areas contralateral to the hand used in the task.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; MEG Core, Aalto Neuroimaging, Aalto University, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

ABSTRACT

Hyperscanning: Most neuroimaging studies of human social cognition have focused on brain activity of single subjects. More recently, "two-person neuroimaging" has been introduced, with simultaneous recordings of brain signals from two subjects involved in social interaction. These simultaneous "hyperscanning" recordings have already been carried out with a spectrum of neuroimaging modalities, such as functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and functional near-infrared spectroscopy (fNIRS).

Dual meg setup: We have recently developed a setup for simultaneous magnetoencephalographic (MEG) recordings of two subjects that communicate in real time over an audio link between two geographically separated MEG laboratories. Here we present an extended version of the setup, where we have added a video connection and replaced the telephone-landline-based link with an Internet connection. Our setup enabled transmission of video and audio streams between the sites with a one-way communication latency of about 130 ms. Our software that allows reproducing the setup is publicly available.

Validation: We demonstrate that the audiovisual Internet-based link can mediate real-time interaction between two subjects who try to mirror each others' hand movements that they can see via the video link. All the nine pairs were able to synchronize their behavior. In addition to the video, we captured the subjects' movements with accelerometers attached to their index fingers; we determined from these signals that the average synchronization accuracy was 215 ms. In one subject pair we demonstrate inter-subject coherence patterns of the MEG signals that peak over the sensorimotor areas contralateral to the hand used in the task.

No MeSH data available.


Related in: MedlinePlus

Accelerometer signals.The upper box shows the first principal components from the two sites. The plot depicts the original, unfiltered signals (grey) and the same signals low-pass filtered at 3 Hz (red—HUCH, blue—Aalto). The detected events are marked by vertical lines. The lower nine boxes depict segmented first PC for the nine subject pairs. Grey lines denote individual movement cycles time-locked to the events detected at Aalto. The upper traces are from Aalto, the lower from HUCH. The thick blue and red curves show the averages for Aalto and HUCH, respectively.
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pone.0128485.g005: Accelerometer signals.The upper box shows the first principal components from the two sites. The plot depicts the original, unfiltered signals (grey) and the same signals low-pass filtered at 3 Hz (red—HUCH, blue—Aalto). The detected events are marked by vertical lines. The lower nine boxes depict segmented first PC for the nine subject pairs. Grey lines denote individual movement cycles time-locked to the events detected at Aalto. The upper traces are from Aalto, the lower from HUCH. The thick blue and red curves show the averages for Aalto and HUCH, respectively.

Mentions: The upper box of Fig 5 provides a characteristic example of PC1 from the two subjects and the corresponding events (red and blue vertical markers). The rising zero-crossings were reliably detected and matched between the sites. We quantified the behavioral synchronization accuracy in two ways: (1) Segmenting and averaging the full-bandwidth accelerometer signals at one site time-locked to the events detected on the other (time window from –1 to 3 s around the trigger; no baseline correction), and (2) computing time differences between matching events between the two sites.


An Internet-Based Real-Time Audiovisual Link for Dual MEG Recordings.

Zhdanov A, Nurminen J, Baess P, Hirvenkari L, Jousmäki V, Mäkelä JP, Mandel A, Meronen L, Hari R, Parkkonen L - PLoS ONE (2015)

Accelerometer signals.The upper box shows the first principal components from the two sites. The plot depicts the original, unfiltered signals (grey) and the same signals low-pass filtered at 3 Hz (red—HUCH, blue—Aalto). The detected events are marked by vertical lines. The lower nine boxes depict segmented first PC for the nine subject pairs. Grey lines denote individual movement cycles time-locked to the events detected at Aalto. The upper traces are from Aalto, the lower from HUCH. The thick blue and red curves show the averages for Aalto and HUCH, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476621&req=5

pone.0128485.g005: Accelerometer signals.The upper box shows the first principal components from the two sites. The plot depicts the original, unfiltered signals (grey) and the same signals low-pass filtered at 3 Hz (red—HUCH, blue—Aalto). The detected events are marked by vertical lines. The lower nine boxes depict segmented first PC for the nine subject pairs. Grey lines denote individual movement cycles time-locked to the events detected at Aalto. The upper traces are from Aalto, the lower from HUCH. The thick blue and red curves show the averages for Aalto and HUCH, respectively.
Mentions: The upper box of Fig 5 provides a characteristic example of PC1 from the two subjects and the corresponding events (red and blue vertical markers). The rising zero-crossings were reliably detected and matched between the sites. We quantified the behavioral synchronization accuracy in two ways: (1) Segmenting and averaging the full-bandwidth accelerometer signals at one site time-locked to the events detected on the other (time window from –1 to 3 s around the trigger; no baseline correction), and (2) computing time differences between matching events between the two sites.

Bottom Line: All the nine pairs were able to synchronize their behavior.In addition to the video, we captured the subjects' movements with accelerometers attached to their index fingers; we determined from these signals that the average synchronization accuracy was 215 ms.In one subject pair we demonstrate inter-subject coherence patterns of the MEG signals that peak over the sensorimotor areas contralateral to the hand used in the task.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; MEG Core, Aalto Neuroimaging, Aalto University, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

ABSTRACT

Hyperscanning: Most neuroimaging studies of human social cognition have focused on brain activity of single subjects. More recently, "two-person neuroimaging" has been introduced, with simultaneous recordings of brain signals from two subjects involved in social interaction. These simultaneous "hyperscanning" recordings have already been carried out with a spectrum of neuroimaging modalities, such as functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and functional near-infrared spectroscopy (fNIRS).

Dual meg setup: We have recently developed a setup for simultaneous magnetoencephalographic (MEG) recordings of two subjects that communicate in real time over an audio link between two geographically separated MEG laboratories. Here we present an extended version of the setup, where we have added a video connection and replaced the telephone-landline-based link with an Internet connection. Our setup enabled transmission of video and audio streams between the sites with a one-way communication latency of about 130 ms. Our software that allows reproducing the setup is publicly available.

Validation: We demonstrate that the audiovisual Internet-based link can mediate real-time interaction between two subjects who try to mirror each others' hand movements that they can see via the video link. All the nine pairs were able to synchronize their behavior. In addition to the video, we captured the subjects' movements with accelerometers attached to their index fingers; we determined from these signals that the average synchronization accuracy was 215 ms. In one subject pair we demonstrate inter-subject coherence patterns of the MEG signals that peak over the sensorimotor areas contralateral to the hand used in the task.

No MeSH data available.


Related in: MedlinePlus