The neural correlates of habituation of response to startling tactile stimuli presented in a functional magnetic resonance imaging environment

McDowell, Jennifer E.; Brown, Gregory G.; Lazar, Nicole; Camchong, Jazmin; Sharp, Richard; Krebs-Thomson, Kirsten; Eyler, Lisa T.; Braff, David L.; Geyer, Mark A.

doi:10.1016/j.pscychresns.2006.05.008

« Previous Next »Psychiatry Research: Neuroimaging
Volume 148, Issue 1 , Pages 1-10, 22 November 2006

The neural correlates of habituation of response to startling tactile stimuli presented in a functional magnetic resonance imaging environment

Jennifer E. McDowell
- Department of Psychology, University of Georgia, Athens, GA 30602, USA
- Corresponding author. Tel.: +1 706 542 3075; fax: +1 706 542 3275.
Gregory G. Brown
- Department of Psychiatry, University of California, San Diego, CA, USA
- Veterans Affairs, San Diego Healthcare System, San Diego, CA, USA
Nicole Lazar
- Department of Statistics, University of Georgia, Athens, GA, USA
Jazmin Camchong
- Department of Psychology, University of Georgia, Athens, GA 30602, USA
Richard Sharp
- Department of Psychiatry, University of California, San Diego, CA, USA
Kirsten Krebs-Thomson
- Department of Psychiatry, University of California, San Diego, CA, USA
Lisa T. Eyler
- Veterans Affairs, San Diego Healthcare System, San Diego, CA, USA
David L. Braff
- Department of Psychiatry, University of California, San Diego, CA, USA
Mark A. Geyer
- Department of Psychiatry, University of California, San Diego, CA, USA

Received 10 February 2006; received in revised form 17 May 2006; accepted 23 May 2006.

Abstract

Functional magnetic resonance imaging (fMRI) provides a means of identifying neural circuitry associated with startle and its modulation in humans. Twelve subjects who demonstrated eyeblink startle in the laboratory were recruited for an fMRI study in which they were scanned while presented with two identical runs consisting of alternating blocks of no stimuli and startling tactile stimuli. Together, behavioral and imaging data are consistent with a pattern of general cortical and thalamic activation induced by startling stimuli that shows habituation both across and within runs. From Run 1 to Run 2, both the eyeblink amplitude and the fMRI signal decreased. Within Run 1, there was a graded decrease in eyeblink amplitude and whole-brain fMRI signal across blocks of startling stimuli. A similar graded decrease was observed in the thalamus signal, as well. Thus, startling tactile stimuli initially induce widespread cortical and thalamic activity, perhaps mediated by the reticular activating system. The activity then habituates in a graded fashion with repeated presentations of the stimuli.

Keywords: Startle, fMRI, Thalamus, Eyeblink, Habituation