Face to face communication is interactive, and involves continuous feedforward and feedback of information, thoughts, and feelings to the opposite party. To accurately assess the neural processing underlying these interactions, synchronous and simultaneous recording of the brain activity from both parties is needed, a method known as hyperscanning. Here, we investigated the neural processing underlying nonverbal face-to-face communication using a magnetoencephalographic (MEG) hyperscanning system, comprising two fiber optically connected MEGs. Eight pairs of subjects participated. Each individual in each pair viewed a combined 80 randomized 20 s trials of 40 real-time and 40 recorded (hereafter, real and simulated, respectively) videos of the opposite party's face. Non-verbal communication through actions such as gaze, eye blinks, and facial expression was intrinsically only possible during real videos. After each trial, subjects individually subjectively discriminated whether the viewed video was real or simulated. Overall subjective discrimination accuracies were slightly but significantly above chance level. Statistical analysis of brain activity revealed a significant three way interaction between theta-band rhythm amplitude, video type, and subjective discrimination response in the right frontal cortex. Additionally, when subjects responded that videos were simulated, theta activity was significantly lower for real videos compared with simulated videos (p = 0.01). This result not only demonstrates the importance of right frontal theta activity during non-verbal communication, but also indicates the existence of unconscious, semi-automated neural processing during non-verbal communication that underlies one's ability to subjectively discriminate whether or not the opposite party is real.Understanding the fundamental roles of brainstem function resulting in proper motor control is critical to motor-rehabilitation after brain injuries. In particular, vestibular and reticular formation nuclei are thought to be associated with spasticity in chronic stroke patients. We used two kinds of stimuli in 10 healthy subjects to activate these nuclei while collecting high-resolution (1.5-mm) fMRI across the majority of brainstem. Optokinetic stimuli evoked illusory self-motion to activate the vestibular nuclei. Acoustic-startle stimuli were sets of loud tones designed to activate of the reticular formation. We summarized the response represented in a form of activation volume, mean percent signal change, and the phase delay (time lag) following the stimulus. We observed patterns of significant activations in the brainstem but did not find significant differences between the stimulus. We conclude that more sensitive measurement techniques are needed to reliably detect vestibular and reticular formation nuclei responses.Human Machine Interfaces (HMIs) can provide critical support and improve daily task functionality for prosthesis users or social interaction for patients with locked-in syndrome using an assistive communication device. One goal in the development of sophisticated HMIs is to reduce the cognitive load (CL) they place on the user to promote the use of the technology. Electroencephalogram (EEG)-derived measures collected with wired wet-electrode systems have been used to assess CL in laboratory environments and have demonstrated acceptable test-retest reliability. Assessment of CL during real-world unconstrained HMI operation, however, requires the use of a wireless dry-electrode EEG system which provides easier electrode application and untethered movement. However, the test-retest reliability of wireless dry-electrode systems to quantify CL has not been explored. Ensuring the consistent capture of CL-related signals across multiple sessions is critical if these devices are to be used to assess how improvements logy developers in their design of future HMIs.Lack of sensory feedback is one of the main issues contributing to lack of control and embodiment for upper-limb prostheses. Noninvasive nerve stimulation may help amputees overcome such limitations by providing a degree of somatotopic feedback, however its neural correlates have been only partly characterized so far. While the effects of median nerve stimulation have been studied, little attention has been given to ulnar nerve and bipolar stimulation, which might provide a finer modulation of the somatotopic sensation. Here, monopolar and bipolar transcutaneous electrical nerve stimulation (TENS) is repeatedly applied to the ulnar and median nerves and elicited Somatosensory Evoked Potentials (SEPs) are characterized by means of electroencephalography (EEG). Clear P50, P150 and P270 SEPs were outlined, with significantly different amplitudes between configurations. In each case scalp topographies showed a strong contralateral activation in the early phase after the stimulus onset (40-100 ms), compatible with generators in the somatosensory cortex and in accordance to previous literature on actual tactile stimuli, which gives way to a frontal-central distribution at long latencies (130-190 ms). These findings, although needing further validation with a larger pool of subjects, show that bipolar TENS could have potential applications in improving prosthesis control with tactile feedback.Error-related potentials (ErrPs) can reflect the brain's response to errors. Recently, it has been used in the studies on neural mechanisms of human cognition, such as error detection and conflict monitoring. Moreover, ErrPs have provided technical support for the development of brain-computer interface (BCI). However, the different effects of visual stimulation modes (dynamic or static) on ErrPs have not been revealed. This may seriously affect the recognition accuracy of the ErrPs in practical applications. Therefore, the aim of this study was to investigate how people respond to different types of visual stimulations. Nineteen participants were recruited in the ErrPs-based tasks with two visual stimulation modes (dynamic and static). https://www.selleckchem.com/products/salinosporamide-a-npi-0052-marizomib.html The ErrPs were analyzed and the feature values (N1, P2, P3, N6 and P8, named by the occurrence time) were statistically compared. The results showed that the difference between correctness and error was reflected in P3, N6, P8 in dynamic stimulation; and N1, P3, N6 and P8 in static stimulation.
Face to face communication is interactive, and involves continuous feedforward and feedback of information, thoughts, and feelings to the opposite party. To accurately assess the neural processing underlying these interactions, synchronous and simultaneous recording of the brain activity from both parties is needed, a method known as hyperscanning. Here, we investigated the neural processing underlying nonverbal face-to-face communication using a magnetoencephalographic (MEG) hyperscanning system, comprising two fiber optically connected MEGs. Eight pairs of subjects participated. Each individual in each pair viewed a combined 80 randomized 20 s trials of 40 real-time and 40 recorded (hereafter, real and simulated, respectively) videos of the opposite party's face. Non-verbal communication through actions such as gaze, eye blinks, and facial expression was intrinsically only possible during real videos. After each trial, subjects individually subjectively discriminated whether the viewed video was real or simulated. Overall subjective discrimination accuracies were slightly but significantly above chance level. Statistical analysis of brain activity revealed a significant three way interaction between theta-band rhythm amplitude, video type, and subjective discrimination response in the right frontal cortex. Additionally, when subjects responded that videos were simulated, theta activity was significantly lower for real videos compared with simulated videos (p = 0.01). This result not only demonstrates the importance of right frontal theta activity during non-verbal communication, but also indicates the existence of unconscious, semi-automated neural processing during non-verbal communication that underlies one's ability to subjectively discriminate whether or not the opposite party is real.Understanding the fundamental roles of brainstem function resulting in proper motor control is critical to motor-rehabilitation after brain injuries. In particular, vestibular and reticular formation nuclei are thought to be associated with spasticity in chronic stroke patients. We used two kinds of stimuli in 10 healthy subjects to activate these nuclei while collecting high-resolution (1.5-mm) fMRI across the majority of brainstem. Optokinetic stimuli evoked illusory self-motion to activate the vestibular nuclei. Acoustic-startle stimuli were sets of loud tones designed to activate of the reticular formation. We summarized the response represented in a form of activation volume, mean percent signal change, and the phase delay (time lag) following the stimulus. We observed patterns of significant activations in the brainstem but did not find significant differences between the stimulus. We conclude that more sensitive measurement techniques are needed to reliably detect vestibular and reticular formation nuclei responses.Human Machine Interfaces (HMIs) can provide critical support and improve daily task functionality for prosthesis users or social interaction for patients with locked-in syndrome using an assistive communication device. One goal in the development of sophisticated HMIs is to reduce the cognitive load (CL) they place on the user to promote the use of the technology. Electroencephalogram (EEG)-derived measures collected with wired wet-electrode systems have been used to assess CL in laboratory environments and have demonstrated acceptable test-retest reliability. Assessment of CL during real-world unconstrained HMI operation, however, requires the use of a wireless dry-electrode EEG system which provides easier electrode application and untethered movement. However, the test-retest reliability of wireless dry-electrode systems to quantify CL has not been explored. Ensuring the consistent capture of CL-related signals across multiple sessions is critical if these devices are to be used to assess how improvements logy developers in their design of future HMIs.Lack of sensory feedback is one of the main issues contributing to lack of control and embodiment for upper-limb prostheses. Noninvasive nerve stimulation may help amputees overcome such limitations by providing a degree of somatotopic feedback, however its neural correlates have been only partly characterized so far. While the effects of median nerve stimulation have been studied, little attention has been given to ulnar nerve and bipolar stimulation, which might provide a finer modulation of the somatotopic sensation. Here, monopolar and bipolar transcutaneous electrical nerve stimulation (TENS) is repeatedly applied to the ulnar and median nerves and elicited Somatosensory Evoked Potentials (SEPs) are characterized by means of electroencephalography (EEG). Clear P50, P150 and P270 SEPs were outlined, with significantly different amplitudes between configurations. In each case scalp topographies showed a strong contralateral activation in the early phase after the stimulus onset (40-100 ms), compatible with generators in the somatosensory cortex and in accordance to previous literature on actual tactile stimuli, which gives way to a frontal-central distribution at long latencies (130-190 ms). These findings, although needing further validation with a larger pool of subjects, show that bipolar TENS could have potential applications in improving prosthesis control with tactile feedback.Error-related potentials (ErrPs) can reflect the brain's response to errors. Recently, it has been used in the studies on neural mechanisms of human cognition, such as error detection and conflict monitoring. Moreover, ErrPs have provided technical support for the development of brain-computer interface (BCI). However, the different effects of visual stimulation modes (dynamic or static) on ErrPs have not been revealed. This may seriously affect the recognition accuracy of the ErrPs in practical applications. Therefore, the aim of this study was to investigate how people respond to different types of visual stimulations. Nineteen participants were recruited in the ErrPs-based tasks with two visual stimulation modes (dynamic and static). https://www.selleckchem.com/products/salinosporamide-a-npi-0052-marizomib.html The ErrPs were analyzed and the feature values (N1, P2, P3, N6 and P8, named by the occurrence time) were statistically compared. The results showed that the difference between correctness and error was reflected in P3, N6, P8 in dynamic stimulation; and N1, P3, N6 and P8 in static stimulation.
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