1 / 27

Prenatal Nicotine Exposure Effects on Impulsivity & mPFC Activity in ADHD Research

Explore the impact of prenatal nicotine exposure on impulsivity and neural activity in the medial prefrontal cortex in relation to ADHD. The study investigates behavioral and neurophysiological disturbances after PNE and the correlation between disrupted neural firing and increased impulsivity. Findings suggest altered neurophysiological pathways hindering impulse control in PNE rats. Future directions include data analysis completion, conference presentations, and exploring alternative research approaches.

morganabrown
Download Presentation

Prenatal Nicotine Exposure Effects on Impulsivity & mPFC Activity in ADHD Research

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Impact of prenatal nicotine exposure on impulsivity and neural activity in medial prefrontal cortex Team RITALIN: Research in Testing ADHD's Link to Impulsivity in Neuroscience 13 June 2013

  2. Introduction Introduction Prenatal Nicotine Exposure (PNE) • PNE is linked to many psychiatric disorders • Women who smoke during pregnancy are three times as likely to have children diagnosed with ADHD • 1 in 5 women still smoke during pregnancy • Nicotine causes changes in the development that alters dopaminergic & noradrenergic pathways in the brain • Several studies show behavioral, neuroanatomical, & neurochemical disturbances after PNE • Benefits of methylphenidate, a common ADHD drug, point to PNE as a valuable animal model of impulsivity

  3. Introduction Attention Deficit Hyperactivity Disorder (ADHD) • Symptoms: impulsivity, hyperactivity, & inattention • Affects 5-10% of all school age children • Twentyfold increase in prescription of ADHD drugs in the past 30 years • Diagnoses based on qualitative observations • Limited research on the neurobiology of the disorder • ADHD drugs are addictive stimulants • Fetal nicotine rats and humans with ADHD have similar deficits on behavioral tasks for hyperactivity & impulsivity

  4. Introduction Modeling Impulsivity • Animal model validity • Face validity • Conduct validity • Predictive validity • What areas or circuits are involved? • How can we uncover more about the neurobiology?

  5. Introduction Medial Prefrontal Cortex (mPFC)

  6. Introduction Stop Signal Task (SST)

  7. Introduction Research Questions • Is there a correlation between neural firing in the mPFC cortex and impulsivity in control rats? • Is neural firing in the mPFC cortex disrupted and impulsivity increased in fetal nicotine rats? • Is there a correlation between this disrupted firing and increased impulsivity?

  8. Methodology Phase 1: Rat Breeding & Selection • Significant differences in water consumption & mother weights • No significant differences in pregnancy duration, pups per litter, pup birth weight, or locomotion* • Randomly selected 8 males each from 37 PNE pups (from 3 dams) and 39 control pups (from 3 dams)

  9. Methodology Phase 2: SST Training & Surgery • Compare movement times and percent correct on stop and go trials

  10. Results

  11. Results

  12. Results

  13. Results

  14. Results Post-Surgery Behavior

  15. Methodology Phase 3: Neural Recording & Analysis • 12 rats from the control and PNE groups performed 157 sessions, over which we collected neural firing from 346 cells

  16. Methodology

  17. Results Histograms for Above/Below Baseline Firing

  18. Results Histograms for Preferred/Nonpreferred Stop/Go Trials

  19. Results Distributions for Preferred/Nonpreferred for Go Direction

  20. legend: go ipsi - blue go contra - green stop ipsi - red stop contra - yellow Results Histograms for Contra/Ipsi Stop/Go Trials * legend: go ipsi - blue go contra - green stop ipsi - red stop contra - yellow

  21. Results Subtraction Plots for Preferred/Nonpreferred Stop/Go Trials

  22. Discussion Preliminary Conclusions • Behavior • PNE rats were more impulsive (as measured by SCRT) • However, they were better at basic task procedures (eg responding to spatial cue lights) • Neural recordings • Signals from neurons which encode stopping an already initiated movement were attenuated in PNE rats as compared to controls • Signals from neurons which encode direction towards the correct behavioral response were also attenuated as compared to controls • This points to a neurophysiological pathway disruption in inhibiting impulsivity caused by PNE

  23. Discussion Future Directions • For my team: • Finish collecting data for additional controls • Complete data analysis • Present data at Society for Neuroscience Conference • Write & present our thesis at the Senior Thesis Conference • For someone else: • Try a different task (or SST with different parameters) • Give nicotine postnatally • Administer ADHD drugs to PNE rats and controls

  24. My Team

  25. Questions? Questions?

More Related