Ahmad R. Hariri, Ph.D. Developmental Imaging Genomics Program Department of Psychiatry

1. Functional Neuroimaging of Genetically Driven Variation in Brain Function:Towards a Biological Understanding of Individual Differences in Behavior Ahmad R. Hariri, Ph.D. Developmental Imaging Genomics Program Department of Psychiatry University of Pittsburgh School of Medicine

3. Why study genes? • Various aspects of cognition, temperament, and personality are highly heritable (40-70%) • Account for the lionshare of susceptibility to major psychiatric disorders • Transcend phenomenological diagnosis, and represent mechanisms of disease • Offer the potential to identify at-risk individuals and biological pathways for the development of new treatments Deshaies 02 — DNA Man #1

4. How do we get from here to there? Behavior: complex functional interactions and emergent phenomena Genes: multiple susceptibility alleles each of small effect

5. IMAGING GENOMICS Behavior: complex functional interactions and emergent phenomena Cells: Subtle molecular alterations Systems: response bias to environmental cues The path from here to there… Genes: multiple susceptibility alleles each of small effect

6. Imaging Genomics:Basic Principles

7. Imaging Genomics: Basic Principles 1) Selection of candidate genes • Well defined functional polymorphisms, associated with specific physiological effects at the cellular level in distinct brain circuits • Genes with identified SNPs or other allele variants with likely functional implications involving circumscribed neuroanatomical systems

8. Imaging Genomics: Basic Principles 2) Control for non-genetic factors • Systematic differences between genotype groups could either obscure a true gene effect or masquerade for one • Age, gender, IQ, population stratification • Environmental factors such as illness, injury, or substance abuse • Task performance • Linked pari passu with BOLD response • Match or consider variability

9. Imaging Genomics: Basic Principles 3) Task selection • Imaging tasks must maximize sensitivity and inferential value, as the interpretation of potential gene effects depends on the validity of the information processing paradigm • Engage circumscribed brain circuits • Produce robust signals in all subjects • Show variance across subjects

10. Imaging Genomics: Applications

11. Central serotonergic system Slide courtesy of K.P. Lesch

12. Typical 5-HT neuron and target synapse Figure courtesy of K.P. Lesch

13. 5-HT Transporter Promoter Variant (5-HTTLPR) Figure courtesy of K.P. Lesch

14. Harm avoidance, Neuroticism, Depression, Anxiety Genes: Short and long allele variants Cells: Alterations in synaptic 5-HT The 5-HTTLPR

15. IMAGING GENOMICS Harm avoidance, Neuroticism, Depression, Anxiety Systems: amygdala bias to environmental cues Genes: Short and long allele variants Cells: Alterations in synaptic 5-HT 5-HTTLPR and temperament

16. The Amygdala

19. fMRI amygdala reactivity paradigm(A.K.A. Hariri’s Hammer)

20. 5-HTTLPR S allele driven amygdalahyper-reactivity to environmental cues Hariri et al., Science 2002 P < 0.05, corrected

21. S allele driven amygdala hyper-reactivity

22. R=0.6, p<0.005 LL LS SS Berlin replication in healthy adults Heinz et al., Nature Neuroscience 2005

23. S carriers > L/L P < 0.05, corrected Italian replication in healthy adults Bertolino et al., Biological Psychiatry 2005

24. Pittsburgh replication in healthy adults Sample Demographics: LL: 8♀/4♂; Mean age = 46.1 S carrier: 9♀/7♂;Mean age 47.5 5-HTTLPR S carrier > LL (P < 0.05, uncorrected)

25. Swedish replication in social phobics Furmark et al., Neuroscience Letters 2004

26. NIMH replication in healthy adults N = 92 Hariri et al., Archives (2005)

27. Elaboration: S allele load and sex effects Hariri et al., Archives (2005)

28. IMAGING GENOMICS ????????? Systems: amygdala bias to environmental cues Genes: Short allele variant Cells: Increased synaptic 5-HT 5-HTTLPR and temperament

29. Amygdala reactivity and harm avoidance * No correlation between amygdala reactivity and HA

30. Prefrontal-Amygdala Dynamics Wood & Grafman 2003

37. Overall Coupling 5-HTTLPR Effects left right Reduced functional coupling of the amygdala and prefrontal cortex in S allele carriers Pezawas et al. Nature Neuroscience 2005

38. Amygdala-Prefrontal connectivity predicts HA

39. Functional circuitry is key for understanding complex emergent phenomena

40. 5-HTTLPR biases corticolimbic information processing related to temperament Hamann Nature Neuroscience 2005

41. Subgenual PFC 5-HT1A and 5-HT2A binding predict amygdala reactivity

42. sgPFC 1A/2A ratio predicts amygdala reactivity

43. DRN 5-HT1A predicts amygdala reactivity

44. Typical 5-HT neuron and target synapse Figure courtesy of K.P. Lesch

45. hTPH2 G(-844)T polymorphism • Relatively high minor allele frequency (T allele = 38%) • Located within 1 Kb (844 bp upstream) of the transcription initiation site of hTPH2 and is likely a constituent of the proximal promoter of the gene • Regulatory variants often produce functional changes in gene expression • Transcriptional regulatory databases indicate transcription factor recognition sequence homology surrounding the -844 promoter variant (http://www.genomatix.de) • In silico evidence that the G to T allele substitution potentially modifies the binding of several transcription factors including octamer-binding factor 6, special AT-rich sequence-binding protein 1 as well as homeodomain proteins MSX-1 and MSX-2

46. Right amygdala activity (in arbitrary units) T carriers > G/G G/G T carrier hTPH2 genotype hTPH2 G(-844)T biases amygdala reactivity Brown et al., Molecular Psychiatry (in press)

47. Cells: 5-HT synthesis? hTPH2 G(-844)T biases amygdala reactivity Emotional Behaviors? Systems: amygdala bias to environmental cues Genes: hTPH2 expression?

48. University of Pittsburgh Steve Manuck Bob Ferrell Carolyn Meltzer Sarah Brown Patrick Fisher Scott Kurdilla NIMH - GeCaP Danny Weinberger Emily Drabant Karen Munoz Anand Mattay Lukas Pezawas Andreas Meyer-Lindenberg Acknowledgments " " Support: NIMH P01MH041712-18, R24MH067346-03, R01MH061596-04; NIDA R01DA018910-01; NARSAD