Faculty Collaboration Database

Intracranial microprobe for evaluating neuro-hemodynamic coupling in unanesthetized human neocortex. J Neurosci Methods 2009 May 15;179(2):208-18

Date

05/12/2009

Pubmed ID

19428529

Pubmed Central ID

PMC2680793

DOI

10.1016/j.jneumeth.2009.01.036

Scopus ID

2-s2.0-63049090889 (requires institutional sign-in at Scopus site)   17 Citations

Abstract

Measurement of the blood-oxygen-level dependent (BOLD) response with fMRI has revolutionized cognitive neuroscience and is increasingly important in clinical care. The BOLD response reflects changes in deoxy-hemoglobin concentration, blood volume, and blood flow. These hemodynamic changes ultimately result from neuronal firing and synaptic activity, but the linkage between these domains is complex, poorly understood, and may differ across species, cortical areas, diseases, and cognitive states. We describe here a technique that can measure neural and hemodynamic changes simultaneously from cortical microdomains in waking humans. We utilize a "laminar optode," a linear array of microelectrodes for electrophysiological measures paired with a micro-optical device for hemodynamic measurements. Optical measurements include laser Doppler to estimate cerebral blood flow as well as point spectroscopy to estimate oxy- and deoxy-hemoglobin concentrations. The microelectrode array records local field potential gradients (PG) and multi-unit activity (MUA) at 24 locations spanning the cortical depth, permitting estimation of population trans-membrane current flows (Current Source Density, CSD) and population cell firing in each cortical lamina. Comparison of the laminar CSD/MUA profile with the origins and terminations of cortical circuits allows activity in specific neuronal circuits to be inferred and then directly compared to hemodynamics. Access is obtained in epileptic patients during diagnostic evaluation for surgical therapy. Validation tests with relatively well-understood manipulations (EKG, breath-holding, cortical electrical stimulation) demonstrate the expected responses. This device can provide a new and robust means for obtaining detailed, quantitative data for defining neurovascular coupling in awake humans.

Author List

Keller CJ, Cash SS, Narayanan S, Wang C, Kuzniecky R, Carlson C, Devinsky O, Thesen T, Doyle W, Sassaroli A, Boas DA, Ulbert I, Halgren E

Author

Chad Carlson MD Professor in the Neurology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Action Potentials
Adult
Cell Membrane
Cerebrovascular Circulation
Electric Stimulation
Electrocardiography
Electrophysiology
Female
Hemodynamics
Hemoglobins
Humans
Laser-Doppler Flowmetry
Male
Membrane Potentials
Microelectrodes
Neocortex
Neural Pathways
Neurons
Optics and Photonics
Oxygen Consumption
Oxyhemoglobins
Spectrum Analysis
Young Adult