Measuring the bulk impedance of brain tissue in vitro

Wilson, Marcus T.; Lin, Oliver D.; Voss, L.J.; Jones, K.

Measuring the bulk impedance of brain tissue in vitro

dc.contributor.author	Wilson, Marcus T.	en_NZ
dc.contributor.author	Lin, Oliver D.	en_NZ
dc.contributor.author	Voss, L.J.	en_NZ
dc.contributor.author	Jones, K.	en_NZ
dc.date.accessioned	2015-12-02T00:50:48Z
dc.date.available	2015	en_NZ
dc.date.available	2015-12-02T00:50:48Z
dc.date.issued	2015	en_NZ
dc.description.abstract	Theoretical and numerical models of brain activity suggest a link between seizures and electrical connectivity. We have therefore been motivated to measure electrical conductivity in brain tissue. Such measurements in vitro are difficult; it is necessary to use a conductive inorganic salt solution, artificial cerebrospinal fluid (ACSF), to keep the tissue alive. We have attempted to provide a robust method to make such measurements. Mouse brain tissue was sliced (400 μm) using established methods. Half the slices were placed in standard ACSF; half were placed in ACSF devoid of magnesium ions. The latter case promotes seizure activity. Electrical activity was measured with a tungsten electrode at various places on the slices. Sixty-nine samples of cortex (2 mm × 2 mm) were cut with a razor. Their areas were measured with a calibrated microscope. Each sample was placed between two flat Ag/AgCl electrodes in a Perspex sandwich. Excess ACSF was removed with filter paper. The impedance was measured at 25°C from 20 Hz to 2 MHz with an Agilent E4980A four-point impedance meter in a shielded room, using a low current. Between 1 kHz and 100 kHz the conductivity was approximately 0.2 S m⁻¹; outside this range dispersion occurred. Samples prepared in the magnesium-free ACSF had a conductivity about 10% lower. The Cole-Cole model of conductivity was fitted. There were few significant differences between the parameters for the different groups measured.	en_NZ
dc.format.mimetype	application/pdf
dc.identifier.citation	Wilson, M. T., Lin, O. D., Voss, L. J., & Jones, K. (2015). Measuring the bulk impedance of brain tissue in vitro. In Metrology Society of Australasia Conference, MSA Conference, Queenstown, New Zealand, October 14-16, 2015	en
dc.identifier.uri	https://hdl.handle.net/10289/9781
dc.language.iso	en
dc.relation.isPartOf	Metrology Society of Australasia Conference	en_NZ
dc.rights	© This work is licensed under a Creative Commons Attribution - No Derivatives 4.0 International License.
dc.source	Metrology Society of Australasia Conference	en_NZ
dc.title	Measuring the bulk impedance of brain tissue in vitro	en_NZ
dc.type	Conference Contribution
pubs.elements-id	134058
pubs.finish-date	2015-10-16	en_NZ
pubs.organisational-group	/Waikato
pubs.organisational-group	/Waikato/FSEN
pubs.organisational-group	/Waikato/FSEN/Engineering
pubs.publisher-url	http://www.metrology.asn.au/msaconnected/conference-home	en_NZ
pubs.start-date	2015-10-14	en_NZ