Aging changes and gender differences in response to median nerve stimulation measured with MEG.
OBJECTIVE
The current study uses magnetoencephalography (MEG) to characterize age-related changes and gender differences in the amplitudes and timing of cortical sources evoked by median nerve stimulation.


METHODS
Thirty-four healthy subjects from two age groups: 20-29 and >64 years of age were examined. After measuring the MEG responses, we modeled the data using a spatio-temporal multi-dipole modeling approach to determine the source locations and their associated timecourses.


RESULTS
We found early, large amplitude responses in the elderly in primary somatosensory (approximately 20 ms) and pre-central sulcus timecourses (approximately 22 ms) and lower amplitude responses in the elderly later in primary somatosensory (approximately 32 ms) and contralateral secondary somatosensory timecourses (approximately 90 ms). In addition, females had larger peak amplitude responses than males in the contralateral secondary somatosensory timecourse (approximately 28 and 51 ms).


CONCLUSIONS
These results show that the median nerve stimulation paradigm provides considerable sensitivity to age- and gender-related differences. The results are consistent with the theory that increased amplitudes identified in the elderly may be associated with decreased inhibition.


CONCLUSIONS
The results emphasize that an examination of two discrete age groups, collapsed across gender, cannot provide a complete understanding of the fundamental changes that occur in the brain across the lifetime.
Stephen
Julia M
JM
Department of Radiology, MSC10 5530, 1 University of New Mexico SOM, Albuquerque, NM 87131, USA. jstephen@unm.edu
Ranken
Doug
D
Best
Elaine
E
Adair
John
J
Knoefel
Janice
J
Kovacevic
Sanja
S
Padilla
Denise
D
Hart
Blaine
B
Aine
Cheryl J
CJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology / Q000528:radiation effects*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D008959:Models, Neurological; D011930:Reaction Time / Q000502:physiology / Q000528:radiation effects; D012727:Sex Characteristics