EXERCISE AND THE AGING BRAIN

93 Pages·2003·0.58 MB·English

ABSTRACT
Title of Thesis: EXERCISE AND THE AGING BRAIN: A NEUROIMAGING
STUDY OF FRONTAL LOBE FUNCTION DURING
EXECUTIVE CHALLENGE IN OLDER MEN AND WOMEN
WHO VARIED IN PHYSICAL ACTIVITY PARTICIPATION
Holly Sue Stover, Master of Arts, 2003
Thesis directed by: Professor Bradley D. Hatfield
Department of Kinesiology
Physical activity preserves neurocognitive functioning in older adults by
increasing brain blood flow and preserving neurotransmitter activity. Because the frontal
lobes show the greatest decline, the most apparent difference was expected between
physically inactive versus active individuals when performing tasks that challenge frontal
lobes. Adults (66-92 years) with varied physical activity levels were administered
binaural auditory oddball and go-nogo tasks. The nogo trials challenged executive
processes through response inhibition. Physical activity was indexed with the Yale
Physical Activity Survey. EEG was recorded from frontal, central, and parietal sites.
Multiple regression analysis revealed that the overall relationship of P300 amplitude to
age and physical activity was significant during nogo trials at site F3, F (2, 75) = 3.61, p
= .032 and at site FZ, F (2, 75) = 6.26, p = .003. In summary, physical activity is
associated with a specific effect on the aging brain revealed during executive challenge.
EXERCISE AND THE AGING BRAIN: A NEUROIMAGING STUDY OF
FRONTAL LOBE FUNCTION DURING EXECUTIVE CHALLENGE IN
OLDER MEN AND WOMEN WHO VARIED IN PHYSICAL ACTIVITY
by
Holly Sue Stover
Thesis submitted to the Faculty of the Graduate School of
the University of Maryland, College Park in partial fulfillment
of the requirements for the degree of
Master of Arts
2003
Advisory Committee:
Professor Bradley D. Hatfield, Chair
Dr. Jose Contreras-Vidal
Dr. Amy Haufler
©Copyright by
Holly Sue Stover
2003
DEDICATION
I dedicate this thesis to my father, Thomas Joseph Stover. Although you can not
be here to witness the hard work and happiness that went into completing my degree, I
know you are always with me. Your encouragement to enter the realm of Sport
Psychology led me to more than I ever hoped for. There is not a day that goes by that I
don’t stop and think of you. Your love and support are what carried me through and
helped me to believe in myself.
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ACKNOWLEDGEMENT
I would like to thank Dr. Brad Hatfield for your guidance and support. You
continued to challenge me every step of the way to be a more creative and more exacting
writer. I appreciated the opportunity to work with you and hope to do so in the future.
I would also like to thank Dr. Amy Haufler and Dr. Jose Contreras-Vidal for
your time and participation as committee members.
To my family, thank you for supporting me throughout my education. Your love
enabled me to keep my head up during trying times.
To my husband Michael, thank you for your smiles and words of kindness. Your
love and support helped me to keep going and not give up along the way.
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TABLE OF CONTENTS
Dedication........................................................................................................................ii
Acknowledgement..........................................................................................................iii
List of Tables...................................................................................................................vi
List of Figures................................................................................................................vii
Chapter I: Introduction..................................................................................................1
Statement of Problem............................................................................................7
Hypotheses............................................................................................................8
Definition of terms................................................................................................9
Delimitations.......................................................................................................10
Limitations..........................................................................................................10
Chapter II: Review of Literature.................................................................................11
The Aging Brain.................................................................................................11
The P300 Component of the Event-Related Potential........................................13
P300 and Age......................................................................................................17
Physical Activity and Cognitive Function..........................................................18
Exercise and Central Nervous System Effects in Animals.................................19
Exercise, Aging, and Central Nervous System Function....................................20
Effect of Exercise on P300.................................................................................21
Chapter III: Methods and Procedures.........................................................................24
Participants..........................................................................................................24
Behavioral Challenges........................................................................................25
Measures.............................................................................................................26
Physical Activity.....................................................................................26
EEG.........................................................................................................27
Testing Procedures..............................................................................................28
Statistical Analysis..............................................................................................30
Chapter IV: Results and Discussion...........................................................................32
Overview.............................................................................................................32
Results.................................................................................................................32
Hypothesis One.......................................................................................33
Hypothesis Two......................................................................................38
Reaction Time Results............................................................................45
Discussion...........................................................................................................46
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Chapter V: Summary and Conclusions.......................................................................52
Summary.............................................................................................................52
Conclusions.........................................................................................................53
Directions for Future Research...........................................................................53
Appendix A: Regression Analysis of P300 Amplitude on Age and Vigorous Exercise:
Overall Summary of Results for Amplitudes and Latencies Elicited at All
Recording Sites During Target Oddball and Nogo Trials……………...55
Appendix B: Task Instructions- Oddball task...............................................................56
Appendix C: Task Instructions- Go-nogo task.............................................................57
Appendix D: Yale Physical Activity Survey................................................................58
Appendix E: Mini Mental State Exam.........................................................................67
References.......................................................................................................................69
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LIST OF TABLES
1. Means and standard deviations of participant characteristics................................25
2. Regression analysis of P300 amplitude on age and physical activity: Overall
summary of results for amplitudes elicited at all remaining sites during nogo
trials........................................................................................................................38
3. Regression analysis of P300 latency on age and physical activity: Overall
summary of results for latencies elicited at all remaining sites during nogo
trials........................................................................................................................40
4. Regression Analysis of P300 amplitude on age and physical activity: Overall
summary of results for amplitudes elicited at all remaining sites during rare
oddball trials...........................................................................................................43
5. Regression Analysis of P300 latency on age and physical activity: Overall
summary of results for latencies elicited at all remaining sites during rare oddball
trials........................................................................................................................44
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LIST OF FIGURES
1. Scatterplot of P300 amplitude at site F3 during nogo trials regressed on physical
activity....................................................................................................................34
2. Grand average waveforms of extreme contrast between high vs. low physical
activity groups during nogo trials..........................................................................35
3. Scatterplot of P300 amplitude at site Fz during nogo trials regressed on physical
activity...................................................................................................................36
4. Scatterplot of P300 amplitude at site C4 during nogo trials regressed on physical
activity....................................................................................................................37
5. Scatterplot of P300 latency at site P4 during nogo trials regressed on physical
activity....................................................................................................................41
6. Scatterplot of P300 latency at site Pz during nogo trials regressed on
age..........................................................................................................................42
7. Scatterplot of P300 latency at site C3 during rare oddball trials regressed
on age ....................................................................................................................45
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CHAPTER I
INTRODUCTION
As we age, our physical and mental abilities change considerably. Similarly,
central nervous system functioning also changes as we get older. The body and brain
mature rapidly during the early years of life, enabling us to gain mastery of our
surroundings. As we mature into the second decade, most physical and central nervous
systems are matured, and maintained for a short time (Roberts, 1972). Starting in the
40’s, and continuing during the remainder of life, a gradual deterioration of behavioral
and biological functioning occurs within the brain and body. There is much variability
however, in the loss of functionality that occurs with aging. Many are able to maintain
their physical and mental prowess, while others struggle to think clearly and perform
daily activities. Recent investigations have suggested that physical activity may benefit
not only our physical bodies, but our mental functioning as well. A case has been made
for the slowing of the cognitive aging process through physical activity. The following
study will examine the relationship of cognitive function in an elderly population with
physical activity from a neurobiological perspective.
It is estimated that by 2025 25% of Americans will be over the age of 65. It is
also predicted that in 2025, over eight million Americans will be 85 years of age or older
(U.S. Census Bureau, 1990). Cognitive function and emotional well-being are imperative
to the quality of life in older adults. Unfortunately, dementia and depressive disorders are
prevalent in this population. One factor that has been demonstrated empirically to
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