Accession Number : AD0682239

Title :   SPECIFIC IMPEDANCE OF THE CEREBRAL CORTEX AT VARIOUS DEPTHS DURING SPREADING DEPRESSION.

Descriptive Note : Scientific rept.,

Corporate Author : PURDUE UNIV LAFAYETTE IND SCHOOL OF ELECTRICAL ENGINEERING

Personal Author(s) : Hoffman,C. J. ; Clark,F. J.

Report Date : DEC 1968

Pagination or Media Count : 166

Abstract : Specific impedance at various depths in the cerebral cortex was measured at 1.6 kHz using a novel thin film coaxial microelectrode technique which permitted measurement of the impedance of very small volumes of tissue (0.01 cubic mm.). Experiments using rats indicated that spreading depression produces increases in specific impedance 3 - 4 times the resting level, increases which are more than 10 times greater than changes previously reported. The impedance locus in the complex plane was loop shaped, very similar to the cross-section of an airfoil. Significant changes in specific impedance were also produced by asphyxia and by releasing cerebospinal fluid pressure. (Author)

Descriptors :   (*CEREBRAL CORTEX, ELECTRICAL IMPEDANCE), MEASUREMENT, TEST METHODS, ELECTRODES, CIRCUITS, CONTROL SYSTEMS, CALIBRATION, THEORY, ANATOMICAL MODELS, MATHEMATICAL ANALYSIS, LABORATORY ANIMALS, INSTRUMENTATION

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE