Measurement of brain activity by near-infrared light

Abstract

Abstract. We review our most recent results on near-IR studies of human brain activity, which have been evolving in two directions: detection of neuronal signals and measurements of functional hemodynamics. We discuss results obtained so far, describing in detail the techniques we developed for detecting neuronal activity, and presenting results of a study that, as we believe, confirms the feasibility of neuronal signal detection. We review our results on near-IR measurements of cerebral hemodynamics, which are performed simultaneously with functional magnetic resonance imaging (MRI) These results confirm the cerebral origin of hemodynamic signals measured by optical techniques on the surface of the head. We also show how near-IR methods can be used to study the underlying physiology of functional MRI signals.

Detection of cerebral ischemia in neurovascular surgery using quantitative frequency-domain near-infrared spectroscopy

“…The use of multiple probes may reduce this particular limitation, but does not currently address the lack of monitoring for deep tissues. Although the accuracy of Q-NIRS recordings is independent of the skull and scalp, 5,13,[37][38][39][43][44][45] increased skull thickness reduces the breadth and depth by which the near-infrared light travels into the brain tissues, thus reducing the area of tissue measured by this method. In the future, advances in Q-NIRS technology that allow the ability to monitor deeper tissues over a larger area would be optimal.…”

A spatial and temporal comparison of hemodynamic signals measured using optical and functional magnetic resonance imaging during activation in the human primary visual cortex

“…These measures can be related to changes in physiological parameters such as cerebral blood flow (CBF), cerebral blood volume (CBV) and the cerebral metabolic rate of oxygen (CMRO 2 ). A current search of scientific reference engines using the keywords "near infrared" and "brain" returns more than 600 references, including about 70 review papers (for the most recent reviews see Gibson et al, 2005;Gratton et al, 2005). However, the majority of these works use near infrared spectroscopy (NIRS) to study the human brain with little spatial resolution beyond the location of the optical probe (Strangman et al, 2003;Toronov et al, 2003b).…”

Neurochemistry in the Pathophysiology of Septic Encephalopathy

“…Near infrared spectroscopy (NIRS) uses near infra-red region (800-2500nm) of light. Since the light in near infra -red range can pass through the skull, reach to the surface of the brain and coincide with the fast event-related responses in human recorded by electroencephalograms (Medvedev AV et al, 2010), it has been used to track cerebral hemodynamics (Gratton E et al, 2005) and human brain activity (Perrey S, 2008). On the other hand, trials to apply q-dots to the molecules associated with pathological states are performed in neurosurgery (Taghva A et al, 2010) and brain tumor (Popescu MA & Toms SA, 2006).…”