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EFFECTS OF DIETARY PROTEIN AND AEROBIC EXERCISE ON FUNCTIONAL CONNECTIVITY IN BRAIN REWARD CENTERS: A RESTINGSTATE fMRI STUDY By Lexie Buchs A Thesis Submitted in Partial Fulfillment Of the Requirements for an Undergraduate Degree with Honors (Dietetics) The College of Health and Human Sciences Purdue University May 2015 West Lafayette, Indiana Approved by: Reader: Richard Mattes, Ph.D. Reader: Tara Henagan, Ph.D. ___________________________________________________________________ Honors Research Mentor: Wayne Campbell, PhD

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EFFECTS  OF  DIETARY  PROTEIN  AND  AEROBIC  EXERCISE  ON  FUNCTIONAL  CONNECTIVITY  IN  BRAIN  REWARD  CENTERS:  A  RESTING-­‐STATE  fMRI  STUDY  

   

By    

Lexie  Buchs          

A  Thesis  Submitted  in  Partial  Fulfillment  Of  the  Requirements  for  an  Undergraduate  Degree  with  Honors  

(Dietetics)    

The  College  of  Health  and  Human  Sciences  

Purdue  University  

May  2015  

West  Lafayette,  Indiana  

 

           

                           

 

Approved  by:        

Reader:    Richard  Mattes,  Ph.D.  

   

Reader:    Tara  Henagan,  Ph.D.  

 ___________________________________________________________________  

Honors  Research  Mentor:  Wayne  Campbell,  PhD  

 

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ABSTRACT    

The  Salience  Network  (SN)  interprets  internal  and  external  stimuli  for  emotion,  

homeostatic  regulation,  and  reward.  The  Default  Mode  Network  (DMN)  reflects  resting  

state  brain  activity.  Previous  data  have  demonstrated  a  disruption  of  these  networks  in  

obesity.  The  purpose  of  this  study  was  to  examine  the  effects  of  dietary  protein  and  aerobic  

exercise  on  resting  state  activity  in  the  SN  and  DMN  using  functional  Magnetic  Resonance  

Imaging  (fMRI)  in  8  women  ages  18-­‐45  years  old  with  a  BMI  of  30  to  40  kg/m2.  On  testing  

days,  breakfast  and  lunch  were  identical  while  dinner  meals  varied  in  protein  (Normal  

Protein:  15%  vs.  High  Protein:  30%  of  energy  as  protein).  Total  energy  intake  on  testing  

days  was  prescribed  at  approximately  80%  of  the  participants’  estimated  daily  energy  

requirements  to  stimulate  one  day  of  moderate  energy  restriction.  Participants  completed  

a  pre-­‐dinner  scan  five  hours  after  lunch.  After  the  pre  dinner  scan,  subjects  either  rested  or  

exercised  for  30  minutes  at  60%  of  their  estimated  VO2max.  Dinner  was  consumed  

immediately  after  exercise  or  rest.  The  postprandial  fMRI  scan  was  completed  one  hour  

after  dinner.  The  independent  component  analysis  did  not  reveal  a  SN  but  did  reveal  a  

DMN.  However,  DMN  activity  was  not  influenced  by  meal  consumption,  acute  aerobic  

exercise,  or  the  amount  of  protein  at  dinner.  Resting  state  brain  activity  may  not  be  

influenced  by  acute  interventions  and  therefore  long  term  inventions  may  be  necessary  for  

normalizing  resting-­‐state  neural  activity  in  obese  women.    

     

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ACKNOWLEDGEMENTS  

  I  would  like  to  thank  Dr.  Campbell  for  his  guidance  and  support  throughout  this  

project  and  for  giving  me  many  opportunities  to  learn  about  research.  Thank  you  to  Drew  

Sayer  for  patiently  mentoring  me  and  for  all  of  his  help  with  this  project.  Without  your  

guidance  and  direction,  I  would  not  have  been  able  to  complete  the  honors  degree.  Thank  

you  to  Greg  Tamer  for  completing  the  data  analysis  and  for  providing  his  expertise  

throughout  the  study.  I  would  also  like  to  thank  the  study  participants  for  their  dedication  

and  compliance  to  this  study.  This  study  was  funded  by  the  Indiana  CTSI.  

 

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TABLE  OF  CONTENTS    

Abstract  …………………………………………………………………………………………………………..…………….2  

Acknowledgements  ………………………………………………………………………………………..………………3  

List  of  Tables  and  Figures  …………………………………………………………………………….………………...5  

Introduction  ………………..…………………………………………………………………………….………………......6  

Subjects  and  Methods  …………………………………………………………………………..…………………..........9  

Results  ……………………………………………………………………………..............................................................12  

Discussion  ……………………………………………………………………………......................................................13  

References  ……………………………………………………………………………......................................................17  

Appendix  …………………………………………………………………………….........................................................26  

   

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 LIST  OF  TABLES  AND  FIGURES  

Table  1:  Subject  Characteristics.…………………………………………………………………………………….19  

Table  2:  Dinner  (High  Protein  or  Normal  Protein)  …………………………………………………………20  

Figure  1:  Study  Design  …………………………………………………………………………………….……………22  

Figure  2:  Default  Mode  Network  …………………………………………………………………...………………23  

Figure  3.  Pre-­‐Meal  Default  Mode  Network  Activity………………………………………...……………….24  

Figure  4.  1-­‐Hour  Post-­‐Meal  Default  Mode  Network  Activity……………………………………..……..25  

 

 

   

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INTRODUCTION  

Increased  activity  in  a  brain  region  results  in  a  locally  increased  blood  response  in  

that  area  and  also  an  increased  ratio  of  oxygenated  to  deoxygenated  blood.  Functional  

Magnetic  Resonance  Imaging  (fMRI)  scan  detects  the  difference  of  magnetization  in  

oxygen-­‐rich  versus  oxygen-­‐poor  blood  [1].  The  resultant  blood  flow  response  is  detected  

by  the  fMRI  scan  as  an  increase  in  the  blood-­‐oxygen-­‐level-­‐dependent  (BOLD)  contrast,  and  

this  is  used  as  a  marker  of  brain  activity.    

The  human  brain  is  organized  into  networks  and  the  intrinsic  activity  of  these  

networks  can  be  measured  in  the  resting  state  using  fMRI.  These  networks  are  important,  

because  it  is  becoming  increasingly  evident  that  they  are  organizational  features  of  the  

brain  [2].  The  Salience  Network  (SN)  and  the  Default  Mode  Network  (DMN)  are  two  

networks  that  have  been  shown  to  be  associated  with  feeding  behavior.  The  DMN  consists  

of  the  posterior  cingulate  cortex,  cuneus/precuneus,  medial  prefrontal  cortex,  medial  

temporal  lobe,  and  inferior  parietal  cortices.  The  SN  consists  of  the  anterior  cingulate  

cortex  and  insula.  The  DMN  reflects  baseline  brain  function  in  the  resting  state.  The  SN  

reflects  feeding  behavior  and  reward  and  involves  assessing  internal  and  external  stimuli.  

Previous  studies  have  found  activation  of  the  DMN  and  SN  to  be  increased  in  overweight  

and  obese  individuals  in  comparison  to  lean  individuals  [2].  Results  from  previous  studies  

have  led  to  the  idea  that  abnormal  or  increased  activation  in  these  networks  may  

contribute  to  overeating,  and  there  is  also  a  correlation  between  obesity  and  activation  of  

these  networks  [3].  Understanding  these  networks  in  overweight  and  obese  individuals  

and  how  acute  and  long-­‐term  changes  in  network  activity  are  associated  with  food  intake  

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behavior  would  be  helpful  when  strategizing  how  to  normalize  network  activity  to  reduce  

overeating.  

Moderate  increases  in  dietary  protein  [4]  and  exercise  [13]  are  common  strategies  

for  weight  control  and  therefore  may  represent  potential  interventions  for  normalizing  

resting  activity  in  obese  individuals.  For  example,  a  6-­‐month  exercise  intervention  

decreased  resting  state  activity  in  the  DMN  although  the  intervention  did  not  change  

resting  state  activity  in  the  SN  [2].  However,  the  effects  of  acute  exercise  on  the  resting  

state  activity  of  the  SN  and  DMN,  or  whether  dietary  protein  modulates  resting  state  

activity  of  these  networks,  have  not  been  investigated.  The  purpose  of  this  study  is  to  

investigate  the  acute  effects  of  aerobic  exercise  and  dietary  protein  on  the  resting  state  

activity  in  the  SN  and  DMN.    

The  broad  aim  of  the  study  is  to  determine  the  acute  effects  of  dietary  protein  intake  

and  aerobic  exercise  on  resting  state  activity  in  the  SN  and  DMN  of  obese  women.  Our  

decision  to  include  only  obese  women  was  guided  by  previous  research  demonstrating  

greater  neural  responses  to  visual  food  cues  in  obese  compared  to  healthy-­‐weight  

individuals  [5-­‐10]  and  also  in  women  compared  to  men  [11].  We  hypothesize  that  network  

resting  state  activity  will  be  decreased  1-­‐hour  after  consuming  dinner  compared  to  the  pre  

dinner  assessment.    We  further  hypothesized  that  a  high  protein  dinner  will  elicit  a  greater  

reduction  in  resting  state  activity  compared  to  a  normal  protein  dinner.  Acute  aerobic  

exercise  will  result  in  a  relatively  greater  resting  state  activity  compared  to  rest.      

 

 

 

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The  rank  order  of  resting  state  SN  and  DMN  activity  under  all  conditions  and  time  points  is  

hypothesized  to  be:  

NPEx  >  NPR  >  HPEx  >  HPR  

NPR:  Normal  Protein/Rest  

HPR:  High  Protein/Rest  

NPEx:  Normal  Protein/Exercise  

HPEx:  High  Protein/Exercise  

   

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SUBJECTS  AND  METHODS  

Subjects  

  Potential  participants  were  recruited  from  public  advertisements  (flyers).  Study  

inclusion  was  based  on  the  following  criteria:  1)  Women  ages  18-­‐45  years;  2)  body  mass  

index  between  (BMI)  30-­‐40  km/m2;  3)  non-­‐smoking;  4)  not  diabetic;  5)  not  pregnant  or  

lactating;  6)  weight  stable  (±  3kg)  for  3  months;  7)  not  severely  claustrophobic;  8)  and  

willing  to  eat  study  food.  Due  to  the  use  of  the  MRI  scanner,  participants  with  implanted  

pacemakers  and/or  automated  defibrillators  or  any  ferromagnetic  metal  implanted  in  their  

body  were  excluded  from  the  study.  

  There  were  41  total  contacts,  of  which  11  women  were  screened  for  inclusion  

criteria.  Of  these,  9  women  were  approved  and  began  the  study.  Eight  women  completed  all  

study  procedures.      

  The  Purdue  Biomedical  Institutional  Review  Board  approved  all  study  procedures.  

All  subjects  provided  written  informed  consent  regarding  purpose,  procedures,  and  

potential  risks  of  the  study.  Each  subject  received  monetary  compensation  for  

participation.    

Baseline  Assessments  

  BMI  (kg/m2)  was  determined  by  measuring  the  participants  weight  and  height.  

These  measurements  were  completed  at  the  Clinical  Research  Center  at  Purdue  University.    

  The  YMCA  cycle  sub-­‐maximal  exercise  test  was  used  to  estimate  each  participant’s  

maximal  oxygen  consumption.15    

 

 

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Experimental  Design  and  Procedures  

  The  study  consisted  of  five  testing  days  for  each  participant.  On  the  first  testing  day  

the  sub-­‐maximal  exercise  test  was  completed.  The  remaining  four  testing  days  were  

completed  in  random  order  and  each  testing  day  was  separated  by  at  least  seven  days.  The  

following  four  experimental  conditions  were  evaluated:  normal  dietary  protein  with  rest  

(NPR),  high  dietary  protein  with  rest  (HPR),  normal  dietary  protein  with  exercise  (NPEx),  

and  high  dietary  protein  with  exercise  (HPEx).  On  testing  days,  breakfast  and  lunch  were  

consumed  in  the  metabolic  research  kitchen  and  dinner  consumed  at  the  Purdue  MRI  

Facility.  Breakfast,  lunch,  and  dinner  provided  approximately  20%,  30%,  and  30%  of  the  

participants  estimated  energy  requirement,  respectively.  Total  meals  provided  to  the  

participants  included  approximately  80%  of  the  estimated  daily  energy  requirement  to  

simulate  one  day  of  moderate  energy  restriction.  Breakfast  and  lunch  were  identical  on  all  

testing  days  but  dinner  meals  varied  in  macronutrient  distribution.  The  macronutrient  

distribution  of  breakfast  and  lunch  were  15%  protein,  60%  carbohydrate,  and  25%  fat.  The  

normal  protein  (NP)  dinners  were  15%  protein,  60%  carbohydrate,  and  25%  fat,  while  the  

high  protein  (HP)  dinner  provided  30%  of  energy  as  protein,  45%  carbohydrate,  and  25%  

fat.,    (Table  2)  .  Subjects  were  blinded  to  the  protein  level  of  the  dinner  meals.    Dietary  fat  

intake  was  held  constant  and  carbohydrate  intakes  adjusted  to  offset  differences  in  protein  

intake  for  the  HP  and  NP  dinners.  On  two  of  the  four  testing  days  participants  pedaled  on  a  

cycle  ergometer  for  30  minutes  at  60%  of  their  VO2max.  On  the  other  two  testing  days  

participants  rested  for  30  minutes  in  a  waiting  room  at  the  MRI  facility.  Participants  

arrived  at  the  Purdue  MRI  Facility  on  each  of  the  four  testing  days  at  5  pm.  The  study  

design  is  found  in  Figure  1.    

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Appetite  Questionnaire:  On  testing  days,  participants  rated  their  appetite  (hunger  and  

fullness)  every  hour  from  8am  until  5pm  as  well  as  immediately  before  and  after  1)  

consumption  of  meals,  2)  the  exercise/sedentary  activity,  and  3)  fMRI  scans.  Appetite  was  

rated  using  a  100-­‐mm  quasilogarithmic  visual  analog  scale,  with  descriptors  ranging  from  

“barely  detectable”  to  “strongest  sensation  imaginable  of  any  kind”  [12].  

Brain  Scan  using  fMRI:  Participants  lay  in  a  supine  position  and  closed  their  eyes  with  no  

external  interaction  but  were  instructed  to  stay  awake.  Participants  were  scanned  in  a  3  

Tesla  MRI  scanner  (GE  Signa  HDx).  The  entire  head  was  scanned,  and  the  areas  of  interest  

were  the  SN  and  DMN.  

Statistical  Analysis:  Independent  Component  Analysis  (ICA)  was  utilized  to  identify  

resting  state  networks  (SN  and  DMN).  This  analysis  was  completed  using  the  AFNI  

software  (available  from:  http://afni.nimh.nih.gov/).  Repeated  measure  ANOVA  (Mixed  

Procedure)  was  used  to  examine  main  effects  of  exercise  (exercise  vs.  rest),  protein  (high  

vs.  normal),  time  (before  vs.  60  minutes  after  dinner),  and  all  interactions  on  resting  state  

networks.    These  analyses  were  completed  using  SAS  (Version  9.2).  All  data  are  presented  

as  mean  ±  SEM.  Statistical  significance  was  assigned  when  P  <  0.05  and  Tukey-­‐Kramer  

adjustment  was  used  for  post-­‐hoc  analyses  as  needed.    

   

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RESULTS  

Subject  Characteristics  

According  to  our  inclusion  criteria,  the  8  women  who  completed  the  study  

procedures  were  29  ±  3  years  old  and  had  an  average  BMI  of  35  ±  1.1  kg/m2  (Table  1).      

Salience  Network  

After  analyzing  the  resting  state  scans,  the  ICA  did  not  reveal  a  SN.  

Default  Mode  Network  

The  DMN  was  revealed  and  is  shown  in  Figure  2.  There  was  no  change  in  DMN  

activity  among  interventions  indicating  that  the  high  protein  dinner  versus  normal  protein  

dinner,  aerobic  exercise  versus  rest  did  not  have  independent  or  interactive  effects  on  

network  activities  (Figure  3  and  Figure  4).  The  ANOVA  model  demonstrated  trend  

(unadjusted  p=0.0454,  adjusted  p=0.1134)  for  an  increase  in  DMN  activity  1-­‐hour  after  

eating  when  subjects  rested  before  dinner.  However,  this  was  not  statistically  confirmed  

after  correcting  for  multiple  comparisons.  

 

 

   

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DISCUSSION      

The  present  study  evaluated  the  effects  of  protein  consumption  and  aerobic  exercise  

on  the  acute  activity  of  two  resting-­‐state  reward  networks,  the  SN  and  DMN.  Acute  changes  

in  these  two  networks  have  never  been  studied.  We  hypothesized  there  would  be  a  general  

meal-­‐induced  reduction  in  SN  and  DMN  activity  60  minutes  after  dinner.  We  further  

hypothesized  that  a  high  protein  dinner  would  result  in  a  greater  reduction  in  resting  state  

activity  compared  to  a  normal  protein  dinner.  Acute  aerobic  exercise  would  result  in  a  

relatively  greater  resting  state  activity  compared  to  rest.      

  These  hypotheses  were  based  on  previous  research  showing  dietary  protein  [4]  and  

aerobic  exercise  [5]  influencing  subjective  appetite  sensations.  Previous  research  has  

shown  that  acute  higher  protein  diets  increase  satiety  in  comparison  to  lower  protein  diets  

and  this  results  in  a  decreased  energy  intake  [4].  A  long-­‐term  high  protein  diet  has  been  

shown  to  result  in  weight  loss  [16].  The  relationship  between  dietary  induced  

thermogenesis  and  satiety  [4],  specifically  because  the  thermic  effect  of  protein  is  greater  

then  fat  and  carbohydrate,  may  be  the  reasoning  behind  dietary  protein’s  satiating  effects.    

  Previous  research  has  also  demonstrated  that  aerobic  exercise  influences  subjective  

appetite  and  energy  balance,  though  the  results  are  sometimes  conflicting  [13].  Further,  it  

has  been  suggested  that  exercise  effects  on  appetite  may  differ  in  men  versus  women;  

specifically  exercise  has  a  tendency  to  increase  hunger  in  women  relative  to  men  [13].  

Sensations  of  appetite  may  be  influenced  by  activity  in  DMN  and  SN-­‐related  brain  

structures  [2,14].    Also,  exercise  training  has  previously  been  shown  to  decrease  DMN  

activity  [2].  This  did  not  occur  in  this  study,  but  instead  there  were  no  significant  changes  

in  DMN  activity  after  meal  consumption  and  among  interventions.  These  results  suggest  

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that  acute  interventions  may  not  influence  resting  state  brain  activity  and  therefore  long-­‐

term  inventions  may  be  necessary  for  normalizing  resting-­‐state  neural  activity  in  obese  

women.  Another  possibility  is  that  greater  intensity,  duration,  and  caloric  expenditure  of  

exercise  may  be  necessary  to  elicit  acute  changes  in  brain  activity.    

  Looking  at  Figures  3  and  4,  it  seems  that  primarily  the  high  protein  with  rest  

condition  drove  the  trend  for  an  increase  of  DMN  activity  on  resting  days.  These  results  are  

contrary  to  our  hypothesis  of  a  greater  reduction  of  DMN  activity  with  a  high  protein  meal.  

However,  the  increase  in  DMN  activity  was  not  statistically  confirmed  after  correcting  for  

multiple  comparisons.  The  independent  component  analysis  did  not  reveal  a  SN,  and  

therefore  intervention  effects  on  SN  activity  could  not  be  evaluated.    

  A  previous  study  assessed  the  effects  of  a  6-­‐month  exercise  training  intervention  on  

the  DMN  and  SN  in  overweight  and  obese  males  and  females.  DMN  activity  was  decreased  

following  the  6-­‐month  exercise-­‐training  program  relative  to  baseline.  However,  greater  fat  

mass  loss  was  associated  with  greater  reductions  in  DMN  activity  [2].  This  correlation  

between  fat  loss  and  DMN  activity  cannot  be  used  to  infer  causality.  It  is  possible  that  

exercise  training  and  improvements  in  fitness  reduced  DMN  activity.  Conversely,  exercise  

training  may  decrease  fat  mass,  which  may  also  decrease  DMN  activity.    Our  results  show  

that  acute  aerobic  exercise,  which  did  not  influence  overall  fitness  level  or  fat  mass,  did  not  

influence  DMN  activity.  These  results  suggest  that  modulation  of  resting  state  brain  activity  

may  be  driven  by  adaptations  to  chronic  exercise  training  rather  than  acute  exercise.    

  The  resting  state  SN  and  DMN  are  important  because  they  process  homeostatic  

information.  The  DMN  is  specifically  associated  with  self-­‐monitoring  behavior  [3]  and  is  

more  active  during  interoceptive  processing,  which  is  related  to  processing  of  internal  

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stimuli.  The  SN  is  associated  with  the  reward  system  and  shows  greater  activation  when  an  

individual  is  anticipating  food  consumption  [3].  We  expected  to  observe  a  SN  because  

previous  studies  have  revealed  this  network  using  the  same  standard  techniques  [2,  3,  11].  

However  our  analysis  did  not  reveal  this  network.    

Strengths  and  Limitations  

  The  strengths  of  this  study  include  extensive  dietary  controls  and  supervised  

exercise  sessions  to  ensure  adherence  to  our  diet  and  exercise  interventions.  All  subjects  

were  blinded  to  the  protein  content  of  the  meals,  so  any  cognitive  biases  were  avoided.    

Our  small  homogenous  group  of  subjects,  obese  young  women,  is  a  limitation.  A  

larger  subject  group  may  provide  greater  statistical  power  to  detect  a  SN  and  changes  in  

DMN  activity  among  interventions.  Including  a  more  heterogeneous  group  of  men  and  

various  age  groups  would  increase  the  generalizability  of  these  findings.  Inclusion  of  a  

normal  weight  group  would  enable  comparisons  of  resting  state  brain  activity  in  normal  

weight  versus  obese  women.  Also  this  would  allow  an  investigation  of  whether  weight  

status  influences  acute  effects  of  exercise  and  meal  consumption  on  resting  state  brain  

activity.  In  this  study,  scanning  was  completed  in  the  evenings,  beginning  at  5pm;  whereas  

most  existing  research  completed  resting  state  scanning  in  the  morning.  This  may  have  

influenced  our  results,  however  further  research  is  needed  to  confirm  time  of  day  effects.    

Further  Research  

  Since  this  pilot  study  was  the  first  to  test  and  analyze  the  effect  of  protein  

consumption  and  aerobic  exercise  on  acute  activity  in  these  reward  networks,  further  

research  should  be  done  to  confirm  that  there  is  no  change  in  activity  from  these  

interventions.  Further  research  should  especially  be  done  with  a  larger  subject  group,  

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along  with  both  men  and  women  of  varying  BMI’s.  Previous  research  showed  decreased  

reward  network  activity  in  a  6-­‐month  exercise  training  intervention  [2],  therefore  further  

research  should  be  done  to  determine  at  what  time  point  exercise  training  begins  to  

decrease  network  activity.    

Conclusion  

In  conclusion,  neither  high  protein  meals  nor  aerobic  exercise  had  acute  effects  on  

DMN  activity  in  obese  women  ages  18-­‐45  years  old.  Conclusions  cannot  be  made  regarding  

the  effects  of  dietary  protein  or  exercise  on  SN  activity.  Acute  dietary  protein  and  aerobic  

exercise  may  not  be  modulators  of  resting-­‐state  neural  activity  in  obese  women  and  

therefore  may  not  be  effective  strategies  for  decreasing  resting-­‐state  neural  activity  in  

obese  women.  

   

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REFERENCES      

1.   Huettel,  S.A.,  A.W.  Song,  and  G.  McCarthy,  Functional  magnetic  resonance  imaging.  2nd  ed.  2008,  Sunderland,  Mass.:  Sinauer  Associates.  xvi,  542  p.  

2.   McFadden,  K.L.,  et  al.,  Effects  of  exercise  on  resting-­‐state  default  mode  and  salience  network  activity  in  overweight/obese  adults.  Neuroreport,  2013.  24(15):  p.  866-­‐71.  

3.   Garcia-­‐Garcia,  I.,  et  al.,  Alterations  of  the  salience  network  in  obesity:  A  resting-­‐state  fMRI  study.  Hum  Brain  Mapp,  2012.  

4.   Halton,  T.L.  and  F.B.  Hu,  The  effects  of  high  protein  diets  on  thermogenesis,  satiety  and  weight    loss:  a  critical  review.  J  Am  Coll  Nutr,  2004.  23(5):  p.  373-­‐85.  

5.   Martin,  L.E.,  et  al.,  Neural  mechanisms  associated  with  food  motivation  in  obese  and  healthy  weight  adults.  Obesity  (Silver  Spring),  2010.  18(2):  p.  254-­‐60.  

6.   Karhunen,  L.J.,  et  al.,  Regional  cerebral  blood  flow  during  food  exposure  in  obese  and  normal-­‐  weight  women.  Brain,  1997.  120  (  Pt  9):  p.  1675-­‐84.  

7.   Rothemund,  Y.,  et  al.,  Differential  activation  of  the  dorsal  striatum  by  high-­‐calorie  visual  food    stimuli  in  obese  individuals.  Neuroimage,  2007.  37(2):  p.  410-­‐21.  

8.   Stice,  E.,  et  al.,  Relation  of  reward  from  food  intake  and  anticipated  food  intake  to  obesity:  a    functional  magnetic  resonance  imaging  study.  J  Abnorm  Psychol,  2008.  117(4):  p.  924-­‐35.  

9.   Horstmann,  A.,  et  al.,  Obesity-­‐Related  Differences  between  Women  and  Men  in  Brain  Structure    and  Goal-­‐Directed  Behavior.  Front  Hum  Neurosci,  2011.  5:  p.  58.  

10.   Goldstone,  A.P.,  et  al.,  Fasting  biases  brain  reward  systems  towards  high-­‐calorie  foods.  Eur  J    Neurosci,  2009.  30(8):  p.  1625-­‐35.  

11.   Cornier,  M.A.,  et  al.,  Sex-­‐based  differences  in  the  behavioral  and  neuronal  responses  to  food.    Physiol  Behav,  2010.  99(4):  p.  538-­‐43.  

12.   Stubbs,  R.J.,  et  al.,  The  use  of  visual  analogue  scales  to  assess  motivation  to  eat  in  human  subjects:  a  review  of  their  reliability  and  validity  with  an  evaluation  of  new  hand-­‐held  computerized  systems  for  temporal  tracking  of  appetite  ratings.  Br  J  Nutr,  2000.  84(4):  p.  405-­‐15.  

13.     Stensel,  D.,  Exercise,  appetite  and  appetite-­‐regulating  hormones:  implications  for  food  intake  and  weight  control.  Ann  Nutr  Metab,  2010.  57  Suppl  2:  p.  36-­‐42.  

14.   Tregellas,  J.R.,  et  al.,  Altered  default  network  activity  in  obesity.  Obesity  (Silver  Spring),  2011.  19(12):  p.  2316-­‐21.  

15.     Thompson,  W.R.,  N.F.  Gordon,  and  L.S.  Pescatello,  eds.  ACSM's  Guidelines  for  Exercise  Testing  and  Prescription.  8th  Edition  ed.  2010,  Lippincott  Williams  &  Wilkins:  Philadelphia,  PA.  

16.     Wycherley,  T.P.,  L.J.  Moran,  P.M.  Clifton,  M.  Noakes,  and  G.D.  Brinkworth,  Effects  of  

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  energy-­‐restricted  high-­‐protein,  low-­‐fat  compared  with  standard-­‐protein,  low-­‐fat  diets:     a  meta-­‐analysis  of  randomized  controlled  trials.  Am  J  Clin  Nutr,  2012.  96(6):  p.  1281-­‐   98.        

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TABLES  AND  FIGURES      

Table  1.  Subject  Characteristics        

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Table  2.  Dinner  (High  Protein  or  Normal  Protein)  Macronutrient  Composition1      Property High Protein Meal Normal Protein Meal Total Energy (kcals) 811.9 811.9 Protein (g, % Energy) 60.9, 30% 30.4, 15% Carbohydrate (g, % Energy)

91.3, 45% 121.8, 60%

Fat (g, % Energy) 22.6 25% 22.6, 25%    1All  values  are  mean  ±  SEM.                  

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Figure1:  Study  Design.  Schematic  of  testing  day  procedures.    

 

Figure  2:  Default  Mode  Network.  AFNI  was  used  to  create  statistical  parametric  maps  to  

depict  resting  state  Default  Mode  Network  activity  with  all  sessions  combined  (n=64  total  

sessions).    

 

Figure  3:  Pre-­‐Meal  Default  Mode  Network  Activity.  All  values  are  mean  ±  SEM.  Repeated  

measures  ANOVA  (MIXED  Procedures,  SAS,  version  9.2)  was  used  to  test  for  differences  in  

Default  Mode  Network  Activity  on  the  4  testing  days.  Default  Mode  Activity  was  not  

different  on  these  testing  days.    

Abbreviations:  NPR,  Normal  Protein/Rest;  HPR,  High  Protein/Rest;  NPEx,  Normal  

Protein/Exercise;  HPEx,  High  Protein/Exercise  

 

Figure  4:  Post-­‐Meal  Default  Mode  Network  Activity.  All  values  are  mean  ±  SEM.  Repeated  

measures  ANOVA  (MIXED  Procedures,  SAS,  version  9.2)  was  used  to  test  for  differences  in  

Default  Mode  Network  Activity  on  the  4  testing  days.  Default  Mode  Activity  was  not  

different  on  these  testing  days.    

Abbreviations:  NPR,  Normal  Protein/Rest;  HPR,  High  Protein/Rest;  NPEx,  Normal  

Protein/Exercise;  HPEx,  High  Protein/Exercise  

   

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 Figure  1.  Study  Design    

 

       

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Figure  2.  Default  Mode  Network  

 

     

 

   

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Figure  3.  Pre-­‐Meal  Default  Mode  Network  Activity  

 

   

0  

1  

2  

3  

4  

5  

6  D

MN

Act

ivity

(z-s

core

)

NPR                      HPR                        NPEx                    HPEx  

Pre-­‐Meal  Default  Mode  Network  Activity  

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Figure  4.  1-­‐Hour  Post-­‐Meal  Default  Mode  Network  Activity  

       

                     

   

0  

1  

2  

3  

4  

5  

6    DMN  Activity  (z-­‐score)  

NPR                      HPR                        NPEx                    HPEx  

1-­‐Hour  Post-­‐Meal  Default  Mode  Network  Activity  

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APPENDICES      

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APPENDIX  1    

Recruitment  Flyer  

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Women Ages 18 to 45  

Needed for a Research Study

Prof. Wayne Campbell

Department of Nutrition Science, Purdue University

We are looking for overweight women who would like to volunteer for a research study evaluating whether exercise performed before dinner

affects brain activity in response to viewing pictures of food. Participants will be compensated $200 for completing this study.

INTERESTED VOLUNTEERS SHOULD BE:

ü Female ü Age: 18 to 45 ü Overweight ü Not Smoking ü Not Pregnant

Measurements taken during the study will include brain activity using

functional magnetic resonance imaging, questionnaires about appetite, and a blood draw.

FOR MORE INFORMATION, contact

Drew @ (765) 494-8313 or Email: [email protected] Department of Nutrition Science, Purdue University; West Lafayette,

IN 47907

     

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

    Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

Drew  

[email protected]  

765-­‐494-­‐8313

 

John

ap

olza

n@pu

rdue

.edu

76

5-49

6-64

80

 

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APPENDIX  2    

Consent  Form    

   

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APPENDIX  3    

Appetite  Questionnaire    

   

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APPETITE LOG Study code:___________

Please place one mark on each scale that best reflects your answer to each of the following questions at this time.

1. How strong is your feeling of hunger? 1. ____

Not at all Extremely

2. How strong is your feeling of fullness? 2. ____

Not at all Extremely

3. How strong is your desire to eat? 3. ____

Not at all Extremely

4. How strong is your “urge to eat”? 4. ____

Not at all Extremely

5. How strong is your preoccupation with thoughts of food? 5. ____

Not at all Extremely

6. How strong is your feeling of thirst? 6. ____

Not at all Extremely

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7. How strong is your desire to eat something salty? 7. ____

Not at all Extremely

8. How strong is your desire to eat something fatty? 8. ____

Not at all Extremely

9. How strong is your desire to eat something sweet? 9. ____

Not at all Extremely

10. The shakiness of your hand is… 10. ____

Not at all Extremely

11. How strong is your grip? 11. ____

Not at all Extremely

12. How itchy is your scalp? 12. ____

Not at all Extremely

 

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APPENDIX  4    

YMCA  Submaximal  Protocol          

   

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YMCA  Submaximal  Protocol                  

   

1st  Stage  150  kgm  (0.5  kp)  

HR:  <80  HR:  _____  

750  kgm  (2.5  kp)  

HR:  _____  

900  kgm  (3.0  kp)  

HR:  _____  

1050  kgm  (3.5  kp)  

HR:  _____  

HR:  80-­‐89  HR:  _____  

600  kgm  (2.0  kp)  

HR:  _____  

750  kgm  (2.5  kp)  

HR:  _____  

900  kgm  (3.0  kp)  

HR:  _____  

HR:  90-­‐100  HR:  _____  

450  kgm  (1.5  kp)  

HR:  _____  

600  kgm  (2.0  kp)  

HR:  _____  

750  kgm  (2.5  kp)  

HR:  _____  

HR:  >100  HR:  _____  

300  kgm  (1.0  kp)  

HR:  _____  

450  kgm  (1.5  kp)  

HR:  _____  

600  kgm  (2.0  kp)  

HR:  _____  

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APPENDIX  5    

Resume          

   

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Lexie Buchs Education Purdue University – West Lafayette, IN 10/2011 – Present Bachelor of Science degree with Honors, Major: Dietetics, GPA: 3.40

Study Abroad - Dublin Institute of Technology – Dublin, Ireland 1/2014 – 5/2014

Adult and Child First Aid/CPR/AED Certified Blood Born Pathogen Certified

Work Experience Wiley Dining Court – Purdue University 10/2014 – Present Food Preparation, Food Service, Meal Preparation, Cleaning and Sanitation Campbell Nutrition Science Lab – Purdue University 5/2014 – Present MRI Secondary Operator, Data Entry into Microsoft Excel, Miscellaneous Lab Work Metabolic Kitchen – Purdue University 5/2014 - 8/2014 Data Entry, Food Preparation for scientific research studies Buffalo Wild Wings – Auburn, IN 5/2012 - 8/2012

Waitress, Cashier, Greeter, Cleaning and Sanitation Auburn Community Pool – Auburn, IN 5/10 - 8/10 & 5/11 - 8/11 Lifeguard, Swim Lesson Instructor Brown House Restaurant – Auburn, IN 3/2010 - 7/2010 Cook, Cashier, Food Service, Cleaning and Sanitation

Volunteer Experience Data Collection for a Pantry Study in a Purdue University Nutrition Lab Fall 2014 Completed 24-hour recalls with study participants and entered data into Microsoft Excel Lafayette Soup Kitchen Fall 2014 Serve and Prepare Food Mentor at the Ireland Pre-Departure Meeting 11/20/2014 Assisting students in finding housing, and preparing students to leave for Ireland Mentor at the Study Abroad Fair 9/10/2014 Advocating to interested students about the perks of studying abroad and answering questions Ecuador Medical Mission Trip 12/15/2012 - 12/23/2012 Assisted doctors and nurses in hospitals and visited children in orphanages Delta Zeta Painted Turtle 5K – Benefitting the Starkey Hearing Foundation 4/27/2013 Organized and participated in the race event Delta Zeta Turtle Tug - Benefitting the Painted Turtle Camp 10/2011 & 10/2012 Organized the competition, Team Leader Delta Zeta ‘Bowlarama’ - Benefitting the Starkey Hearing Foundation 4/2011 Organized the tournament, facilitated the event

Organizations & Societies Accomplishments & Awards Academy of Nutrition & Dietetics Honors Society.org Purdue University Nutrition Society Phi Sigma Theta Honors Society Purdue University Caduceus Club National Society of Collegiate Scholars Saint Michael’s Church Parishioner Intel International Science Fair 1st Place Air force Award 2011, Competitor 2010 & 2011

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