Faculty Collaboration Database

Digit tapping model of functional activation in the rat somatosensory cortex. J Neurosci Methods 2006 Oct 15;157(1):48-53

Date

05/10/2006

Pubmed ID

16682081

DOI

10.1016/j.jneumeth.2006.03.021

Scopus ID

2-s2.0-33747833110 (requires institutional sign-in at Scopus site)   2 Citations

Abstract

To establish a non-invasive model for functional activation of the rat somatosensory cortex, the forepaw digits of halothane-anesthetized rats were tapped while the blood flow (laser-Doppler flow, LDF) and somatosensory evoked potential (SSEP) responses in the forelimb area of the somatosensory cortex (S1FL) were measured. The distal phalanges of the forepaw digits were lightly tapped for 10s with an aluminum bar at frequencies between 1 and 40 Hz, with 0.4 cm total bar displacement. The LDF signal was normalized to the baseline preceding each stimulus block and averaged. The LDF response to digit tapping in the contralateral, but not ipsilateral S1FL, commenced within 1s, peaked at 11+/-0.5% (S.E.M.) above baseline within 2-3s, decreased to a plateau of 5+/-0.3% for the duration of the stimulation, and returned to baseline within 5-10s following tapping cessation. The LDF peak and plateau were not significantly different at different tapping frequencies. In the contralateral, but not ipsilateral, S1FLs, tapping produced an SSEP with positive (P1) and negative (N1) peaks at 27+/-0.5 and 47+/-0.2m s, respectively, after onset of the tap stimulation. As the tapping frequency increased from 1 to 20 Hz, the P1-N1 peak-to-peak amplitude decreased. At 30 and 40 Hz, the shortened interstimulus interval entrained the individual SSEPs into a steady-state evoked response. This study demonstrates that a robust functional activation of the forelimb region of primary somatosensory cortex of halothane-anesthetized rats can be produced by non-invasively tapping the forepaw digits and quantified with LDF and SSEP.

Author List

Schulte ML, Li SJ, Hyde JS, Hudetz AG

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

Analysis of Variance
Animals
Behavior, Animal
Blood Flow Velocity
Dose-Response Relationship, Radiation
Evoked Potentials, Somatosensory
Extremities
Functional Laterality
Laser-Doppler Flowmetry
Male
Models, Biological
Physical Stimulation
Rats
Rats, Sprague-Dawley
Somatosensory Cortex