Multi-timescale measurements of brain responses in visual cortex during functional stimulation using time-resolved spectroscopy

Solomiya Lebid; Raymond O'Neill; Charles Markham; Tomás Ward; Shirley Coyle

doi:10.1117/12.604821

3 June 2005 Multi-timescale measurements of brain responses in visual cortex during functional stimulation using time-resolved spectroscopy

Solomiya Lebid, Raymond O'Neill, Charles Markham, Tomás Ward, Shirley Coyle

Author Affiliations +

Proceedings Volume 5826, Opto-Ireland 2005: Optical Sensing and Spectroscopy; (2005) https://doi.org/10.1117/12.604821
Event: OPTO-Ireland, 2005, Dublin, Ireland

Abstract

Studies of neurovascular coupling (hemodynamic changes and neuronal activation) in the visual cortex using a time-domain single photon counting system have been undertaken. The system operates in near infrared (NIR) range of spectrum and allows functional brain monitoring to be done non-invasively. The detection system employs a photomultiplier and multi-channel scaler to detect and record emerging photons with sub-microsecond resolution (the effective collection time per curve point is ~ 200 ns). Localisation of the visual evoked potentials in the brain was done using knowledge obtained from electroencephalographic (EEG) studies and previous frequency-domain optical NIR spectroscopic systems. The well-known approach of visual stimulation of the human brain, which consists of an alternating black and white checkerboard pattern used previously for the EEG study of neural responses, is applied here. The checkerboard pattern is synchronized with the multi-channel scaler system and allows the analysis of time variation in back-scattered light, at different stimulation frequencies. Slow hemodynamic changes in the human brain due to Hb-HbO₂ changes in the blood flow were observed, which is evidence of the system's capability to monitor these changes. Monocular visual tests were undertaken and compared with those done with an EEG system. In some subjects a fast optical response on a time scale commensurate with the neural activity associated with the visual cortex was detected. Future work will concentrate on improved experimental protocols and apparatus to confirm the existence of this important physiological signal.

Citation Download Citation

Solomiya Lebid, Raymond O'Neill, Charles Markham, Tomás Ward, and Shirley Coyle "Multi-timescale measurements of brain responses in visual cortex during functional stimulation using time-resolved spectroscopy", Proc. SPIE 5826, Opto-Ireland 2005: Optical Sensing and Spectroscopy, (3 June 2005); https://doi.org/10.1117/12.604821

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available