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

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

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

6. Imaging Genomics: Basic Principles

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

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

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

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

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

16. The Amygdala

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

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

21. S allele driven amygdala hyper-reactivity

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

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

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

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

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

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

30. Prefrontal-Amygdala Dynamics Wood & Grafman 2003

37. Reduced functional coupling of the amygdala and prefrontal cortex in S allele carriers Pezawas et al. Nature Neuroscience 2005 right left Overall Coupling5-HTTLPR Effects

38. Amygdala-Prefrontal connectivity predicts HA

39. Functional circuitry is key for understanding complex emergent phenomena

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

41. Subgenual PFC 5-HT 1A and 5-HT 2A binding predict amygdala reactivity

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

43. DRN 5-HT 1A predicts amygdala reactivity

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

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

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

48. " " Acknowledgments 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 Support: NIMH P01MH041712-18, R24MH067346-03, R01MH061596-04; NIDA R01DA018910-01; NARSAD