The effects of motor imagery on the Hoffmann Reflex and presynaptic inhibition
by Hale, Brendon S., Ph.D., INDIANA UNIVERSITY, 2007, 66 pages; 3274271

Abstract:

Mental imagery of a motor task may influence the amplitude of the Hoffmann reflex (H-reflex) (Hale et al. 2003, Oishi et al. 1995) these investigations have not examined the potential influence that presynaptic inhibition might have on the H-reflex during mental imagery of a motor task.

Purpose. The purpose of this project was to investigate the effects of mental imagery of a motor task on the H-reflex and on presynaptic inhibition of the H-reflex.

Methods. In this study 25 adult participants (M=22.8 years, SD=5.4; 15 Females, 10 Males) were examined on one day of testing. The participants mentally imaged a simple plantar flexion movement of the right foot at two intensities: 20 and 60% of maximum voluntary contraction after completing a series of practice trials of actual contractions at these intensities. Five participants served as control subjects who completed the entire testing protocol but did not perform mental imagery. The dependent measures were peak-to-peak amplitude of the H-reflex and the peak to peak amplitude of the conditioned H-reflex. Data analysis was conducted using a 2X2 ANOVA to determine if any changes in H-reflex amplitude occurred from rest and imagery percentage. Additionally, a One-way ANOVA was conducted to determine if any changes in presynaptic inhibition were noted during the imagery trials.

Results. Repeated measures ANOVA revealed a significant (p<0.05) condition effect for H-reflex amplitude during imagery trials. Specifically, H-reflex amplitude increased between 6 and 15% during imagery trials above rest. Additionally, a significant (p<0.05) difference was also observed between percent of contraction imagined. A significant (p<0.05) difference was observed in presynaptic inhibition between percent of imagined contraction. Control subjects demonstrated no significant difference for H-reflex or presynaptic inhibition.

Conclusion. These findings indicate that the amplitude of the H-reflex is increased while performing mental imagery of plantar flexion. Additionally, the measured differences in the conditioned H-reflex indicate that presynaptic inhibition might influence H-reflex response during mental imagery.

 
AdviserJohn S. Raglin
SchoolINDIANA UNIVERSITY
SourceDAI/B 68-07, p. , Nov 2007
Source TypeDissertation
SubjectsMorphology; Psychobiology
Publication Number3274271
Adobe PDF Access the complete dissertation:
 

» Find an electronic copy at your library.
  Use the link below to access a full citation record of this graduate work:
  http://gateway.proquest.com/openurl%3furl_ver=Z39.88-2004%26res_dat=xri:pqdiss%26rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation%26rft_dat=xri:pqdiss:3274271
  If your library subscribes to the ProQuest Dissertations & Theses (PQDT) database, you may be entitled to a free electronic version of this graduate work. If not, you will have the option to purchase one, and access a 24 page preview for free (if available).

About ProQuest Dissertations & Theses
With over 2.3 million records, the ProQuest Dissertations & Theses (PQDT) database is the most comprehensive collection of dissertations and theses in the world. It is the database of record for graduate research.

The database includes citations of graduate works ranging from the first U.S. dissertation, accepted in 1861, to those accepted as recently as last semester. Of the 2.3 million graduate works included in the database, ProQuest offers more than 1.9 million in full text formats. Of those, over 860,000 are available in PDF format. More than 60,000 dissertations and theses are added to the database each year.

If you have questions, please feel free to visit the ProQuest Web site - http://www.proquest.com - or call ProQuest Hotline Customer Support at 1-800-521-3042.