PDMS–Parylene Hybrid, Flexible Micro-ECoG Electrode Array for Spatiotemporal Mapping of Epileptic Electrophysiological Activity from Multicortical Brain Regions

AbstractThe cochlear implant is one of the most successful medical prostheses, allowing deaf and severely hearing-impaired persons to hear again by electrically stimulating the auditory nerve. A trained audiologist adjusts the stimulation settings for good speech understanding, known as “fitting” the implant. This process is based on subjective feedback from the user, making it time-consuming and challenging, especially in paediatric or communication-impaired populations. Furthermore, fittings only happen during infrequent sessions at a clinic, and therefore cannot take into account variable factors that affect the user’s hearing, such as physiological changes and different listening environments. Objective audiometry, in which brain responses evoked by auditory stimulation are collected and analysed, removes the need for active patient participation. However, recording of brain responses still requires expensive equipment that is cumbersome to use. An elegant solution is to record the neural signals using the implant itself. We demonstrate for the first time the recording of continuous electroencephalographic (EEG) signals from the implanted intracochlear electrode array in human subjects, using auditory evoked potentials originating from different brain regions. This was done using a temporary recording set-up with a percutaneous connector used for research purposes. Furthermore, we show that the response morphologies and amplitudes depend crucially on the recording electrode configuration. The integration of an EEG system into cochlear implants paves the way towards chronic neuro-monitoring of hearing-impaired patients in their everyday environment, and neuro-steered hearing prostheses, which can autonomously adjust their output based on neural feedback.

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Effect of Perospirone on p300 Electrophysiological Activity and Social Cognition in Schizophrenia: A Three-dimensional Analysis with (s)loreta

European Psychiatry ◽

10.1016/s0924-9338(09)71436-1 ◽

2009 ◽

Vol 24 (S1) ◽

pp. 1-1

Author(s):

T. Sumiyoshi ◽

Y. Higuchi ◽

T. Itoh ◽

M. Matsui ◽

H. Arai ◽

...

Keyword(s):

Social Cognition ◽

Partial Agonist ◽

Verbal Learning ◽

Current Source ◽

Three Dimensional ◽

Event Related Potentials ◽

Brain Regions ◽

Electrophysiological Activity ◽

Before And After ◽

Related Potentials

The purpose of this study was to determine if perospirone, a second generation antipsychotic drug and partial agonist at serotonin-5-HT1A receptors, enhances electrophysiological activity, such as event-related potentials (ERPs), in frontal brain regions, as well as cognitive function in subjects with schizophrenia. P300 current source images were obtained by means of standardized low resolution brain electromagnetic tomography (sLORETA) before and after treatment with perospirone for 6 months. Perospirone significantly increased P300 current source density in the left superior frontal gyrus, and improved positive symptoms and performance on the script tasks, a measure of verbal social cognition. Perospirone also tended to enhance verbal learning memory in patients with schizophrenia. There was a significant correlation between the changes in P300 amplitudes on the left frontal lead and those in social cognition. These results suggest the changes in three-dimensional distribution of cortical activity, as demonstrated by sLORETA, may mediate some of the actions of antipsychotic drugs. the distinct cognition-enhancing profile of perospirone may be related to its actions on 5-HT1A receptors.

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EEG-based diagnostics of the auditory system using cochlear implant electrodes as sensors

10.1101/2020.07.16.206250 ◽

2020 ◽

Author(s):

Ben Somers ◽

Christopher J. Long ◽

Tom Francart

Keyword(s):

Cochlear Implant ◽

Auditory Evoked Potentials ◽

Human Subjects ◽

Electrode Array ◽

Brain Regions ◽

Hearing Impaired ◽

Brain Responses ◽

Listening Environments ◽

Objective Audiometry ◽

Neural Feedback

AbstractThe cochlear implant is one of the most successful medical prostheses, allowing deaf and severely hearing-impaired persons to hear again by electrically stimulating the auditory nerve. A trained audiologist adjusts the stimulation settings for good speech understanding, known as “fitting” the implant. This process is based on subjective feedback from the user, making it time-consuming and challenging, especially in paediatric or communication-impaired populations. Furthermore, fittings only happen during infrequent sessions at a clinic, and therefore cannot take into account variable factors that affect the user’s hearing, such as physiological changes and different listening environments. Objective audiometry, in which brain responses evoked by auditory stimulation are collected and analysed, removes the need for active patient participation. However, recording of brain responses still requires expensive equipment that is cumbersome to use. An elegant solution is to record the neural signals using the implant itself. We demonstrate for the first time the recording of continuous electroencephalographic (EEG) signals from the implanted intracochlear electrode array in human subjects, using auditory evoked potentials originating from different brain regions. Furthermore, we show that the response morphologies and amplitudes depend crucially on the recording electrode configuration. The integration of an EEG system into cochlear implants paves the way towards chronic neuro-monitoring of hearing-impaired patients in their everyday environment, and neuro-steered hearing prostheses, which can autonomously adjust their output based on neural feedback.

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Different types of theta rhythmicity are induced by social and fearful stimuli in a network associated with social memory

eLife ◽

10.7554/elife.03614 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 30

Author(s):

Alex Tendler ◽

Shlomo Wagner

Keyword(s):

Rhythmic Activity ◽

Brain Regions ◽

Brain State ◽

Social Stimuli ◽

Brain Areas ◽

Neuronal Communication ◽

Electrophysiological Activity ◽

Different Types ◽

Social Encounters ◽

Theta Range

Rhythmic activity in the theta range is thought to promote neuronal communication between brain regions. In this study, we performed chronic telemetric recordings in socially behaving rats to monitor electrophysiological activity in limbic brain regions linked to social behavior. Social encounters were associated with increased rhythmicity in the high theta range (7–10 Hz) that was proportional to the stimulus degree of novelty. This modulation of theta rhythmicity, which was specific for social stimuli, appeared to reflect a brain-state of social arousal. In contrast, the same network responded to a fearful stimulus by enhancement of rhythmicity in the low theta range (3–7 Hz). Moreover, theta rhythmicity showed different pattern of coherence between the distinct brain regions in response to social and fearful stimuli. We suggest that the two types of stimuli induce distinct arousal states that elicit different patterns of theta rhythmicity, which cause the same brain areas to communicate in different modes.

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A novel scalable electrode array and system for non-invasively assessing gastric function using flexible electronics

10.21203/rs.3.rs-1233270/v1 ◽

2022 ◽

Author(s):

Armen Gharibans ◽

Tommy Hayes ◽

Daniel Carson ◽

Stefan Calder ◽

Chris Varghese ◽

...

Keyword(s):

Body Surface ◽

Flexible Electronics ◽

Electrode Array ◽

Performance Testing ◽

Automated Analysis ◽

The Body ◽

Data Logger ◽

Gastric Function ◽

Spatiotemporal Mapping ◽

Visualization Algorithms

Abstract Disorders of gastric function are highly prevalent, but diagnosis often remains symptom-based and inconclusive. Body surface gastric mapping is an emerging diagnostic solution, but current approaches lack scalability and are cumbersome and clinically impractical. We present a novel scalable system for non-invasively mapping gastric electrophysiology in high-resolution (HR) at the body-surface. The system comprises a custom-designed flexible HR sensor array and portable data-logger synchronized to an App, with automated analysis and visualization algorithms. The novel system underwent performance testing then validation in 24 healthy subjects. In all subjects, gastric electrophysiology and meal responses were successfully captured and mapped non-invasively (mean frequency 2.9 ± 0.3 cycles per minute; peak amplitude at mean 60 m postprandially with return to baseline in <4 h). Spatiotemporal mapping showed regular and consistent wave activity of mean direction 182.7°±73 (74.7% antegrade, 7.8% retrograde, 17.5% indeterminate). The presented system is a new diagnostic tool for assessing gastric function that is scalable, validated, and ready for clinical applications, offering several biomarkers that are new to gastroenterology practice.

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