Letter | Published:

Oxytocin-dependent reopening of a social reward learning critical period with MDMA

Nature (2019) | Download Citation

Abstract

A critical period is a developmental epoch during which the nervous system is expressly sensitive to specific environmental stimuli that are required for proper circuit organization and learning. Mechanistic characterization of critical periods has revealed an important role for exuberant brain plasticity during early development, and for constraints that are imposed on these mechanisms as the brain matures1. In disease states, closure of critical periods limits the ability of the brain to adapt even when optimal conditions are restored. Thus, identification of manipulations that reopen critical periods has been a priority for translational neuroscience2. Here we provide evidence that developmental regulation of oxytocin-mediated synaptic plasticity (long-term depression) in the nucleus accumbens establishes a critical period for social reward learning. Furthermore, we show that a single dose of (+/−)-3,4-methylendioxymethamphetamine (MDMA) reopens the critical period for social reward learning and leads to a metaplastic upregulation of oxytocin-dependent long-term depression. MDMA-induced reopening of this critical period requires activation of oxytocin receptors in the nucleus accumbens, and is recapitulated by stimulation of oxytocin terminals in the nucleus accumbens. These findings have important implications for understanding the pathogenesis of neurodevelopmental diseases that are characterized by social impairments and of disorders that respond to social influence or are the result of social injury3.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Data availability

The pAAV-CAG-FonChronos-TdTomato construct has been deposited on Addgene (accession number 105834). Oxytocin-2A-Flp optimized knock-in mice, and data sets are available from the corresponding author upon request.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

  1. 1.

    Hübener, M. & Bonhoeffer, T. Neuronal plasticity: beyond the critical period. Cell 159, 727–737 (2014).

  2. 2.

    Patton, M. H., Blundon, J. A. & Zakharenko, S. S. Rejuvenation of plasticity in the brain: opening the critical period. Curr. Opin. Neurobiol. 54, 83–89 (2019).

  3. 3.

    Yazar-Klosinski, B. B. & Mithoefer, M. C. Potential psychiatric uses for MDMA. Clin. Pharmacol. Ther. 101, 194–196 (2017).

  4. 4.

    Dölen, G., Darvishzadeh, A., Huang, K. W. & Malenka, R. C. Social reward requires coordinated activity of nucleus accumbens oxytocin and serotonin. Nature 501, 179–184 (2013).

  5. 5.

    McEwen, B. B. Brain-fluid barriers: relevance for theoretical controversies regarding vasopressin and oxytocin memory research. Adv. Pharmacol. 50, 531–592, 655–708 (2004).

  6. 6.

    Lee, M. R. et al. Oxytocin by intranasal and intravenous routes reaches the cerebrospinal fluid in rhesus macaques: determination using a novel oxytocin assay. Mol. Psychiatry 23, 115–122 (2018).

  7. 7.

    Thompson, M. R., Callaghan, P. D., Hunt, G. E., Cornish, J. L. & McGregor, I. S. A role for oxytocin and 5-HT(1A) receptors in the prosocial effects of 3,4 methylenedioxymethamphetamine (“ecstasy”). Neuroscience 146, 509–514 (2007).

  8. 8.

    Hunt, G. E., McGregor, I. S., Cornish, J. L. & Callaghan, P. D. MDMA-induced c-Fos expression in oxytocin-containing neurons is blocked by pretreatment with the 5-HT-1A receptor antagonist WAY 100635. Brain Res. Bull. 86, 65–73 (2011).

  9. 9.

    Forsling, M. L. et al. The effect of 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) and its metabolites on neurohypophysial hormone release from the isolated rat hypothalamus. Br. J. Pharmacol. 135, 649–656 (2002).

  10. 10.

    Shulgin, A. A. T. & Nichols, D. E. Characterization of three new psychotomimetics. Psychopharmacol. Hallucinog. 2, 74–83 (1978).

  11. 11.

    Rudnick, G. & Wall, S. C. The molecular mechanism of “ecstasy” [3,4-methylenedioxy-methamphetamine (MDMA)]: serotonin transporters are targets for MDMA-induced serotonin release. Proc. Natl Acad. Sci. USA 89, 1817–1821 (1992).

  12. 12.

    Field, J. R., Henry, L. K. & Blakely, R. D. Transmembrane domain 6 of the human serotonin transporter contributes to an aqueously accessible binding pocket for serotonin and the psychostimulant 3,4-methylene dioxymethamphetamine. J. Biol. Chem. 285, 11270–11280 (2010).

  13. 13.

    Edsinger, E. & Dölen, G. A conserved role for serotonergic neurotransmission in mediating social behavior in octopus. Curr. Biol. 28, 3136–3142.e4 (2018).

  14. 14.

    Simmler, L. D. et al. Pharmacological characterization of designer cathinones in vitro. Br. J. Pharmacol. 168, 458–470 (2013).

  15. 15.

    Jørgensen, H., Riis, M., Knigge, U., Kjaer, A. & Warberg, J. Serotonin receptors involved in vasopressin and oxytocin secretion. J. Neuroendocrinol. 15, 242–249 (2003).

  16. 16.

    Trigo, J. M. et al. 3,4-Methylenedioxymethamphetamine self-administration is abolished in serotonin transporter knockout mice. Biol. Psychiatry 62, 669–679 (2007).

  17. 17.

    Abraham, W. C. & Bear, M. F. Metaplasticity: the plasticity of synaptic plasticity. Trends Neurosci. 19, 126–130 (1996).

  18. 18.

    Klapoetke, N. C. et al. Independent optical excitation of distinct neural populations. Nat. Methods 11, 338–346 (2014).

  19. 19.

    Blakemore, S.-J. & Mills, K. L. Is adolescence a sensitive period for sociocultural processing? Annu. Rev. Psychol. 65, 187–207 (2014).

  20. 20.

    Nelson, E. E., Jarcho, J. M. & Guyer, A. E. Social re-orientation and brain development: an expanded and updated view. Dev. Cogn. Neurosci. 17, 118–127 (2016).

  21. 21.

    Pedersen, C. A. Biological aspects of social bonding and the roots of human violence. Ann. NY Acad. Sci. 1036, 106–127 (2004).

  22. 22.

    Leung, R. K., Toumbourou, J. W. & Hemphill, S. A. The effect of peer influence and selection processes on adolescent alcohol use: a systematic review of longitudinal studies. Health Psychol. Rev. 8, 426–457 (2014).

  23. 23.

    Nicolaisen, M. & Thorsen, K. Who are lonely? Loneliness in different age groups (18–81 years old), using two measures of loneliness. Int. J. Aging Hum. Dev. 78, 229–257 (2014).

  24. 24.

    Shapiro, L. E. & Insel, T. R. Ontogeny of oxytocin receptors in rat forebrain: a quantitative study. Synapse 4, 259–266 (1989).

  25. 25.

    Lüscher, C. & Malenka, R. C. Drug-evoked synaptic plasticity in addiction: from molecular changes to circuit remodeling. Neuron 69, 650–663 (2011).

  26. 26.

    Nair, S. G. & Gudelsky, G. A. 3,4-Methylenedioxymethamphetamine (MDMA) enhances the release of acetylcholine by 5-HT4 and D1 receptor mechanisms in the rat prefrontal cortex. Synapse 58, 229–235 (2005).

  27. 27.

    Hagena, H. & Manahan-Vaughan, D. The serotonergic 5-HT4 receptor: A unique modulator of hippocampal synaptic information processing and cognition. Neurobiol. Learn. Mem. 138, 145–153 (2017).

  28. 28.

    Melroy-Greif, W. E., Stitzel, J. A. & Ehringer, M. A. Nicotinic acetylcholine receptors: upregulation, age-related effects and associations with drug use. Genes Brain Behav. 15, 89–107 (2016).

  29. 29.

    Mithoefer, M. C. et al. 3,4-Methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for post-traumatic stress disorder in military veterans, firefighters, and police officers: a randomised, double-blind, dose-response, phase 2 clinical trial. Lancet Psychiatry 5, 486–497 (2018).

  30. 30.

    Young, M. B. et al. Inhibition of serotonin transporters disrupts the enhancement of fear memory extinction by 3,4-methylenedioxymethamphetamine (MDMA). Psychopharmacology (Berl.) 234, 2883–2895 (2017).

  31. 31.

    Wu, Z. et al. An obligate role of oxytocin neurons in diet induced energy expenditure. PLoS One 7, e45167 (2012).

  32. 32.

    Furler, S., Paterna, J. C., Weibel, M. & Büeler, H. Recombinant AAV vectors containing the foot and mouth disease virus 2A sequence confer efficient bicistronic gene expression in cultured cells and rat substantia nigra neurons. Gene Ther. 8, 864–873 (2001).

  33. 33.

    Chan, H. Y. et al. Comparison of IRES and F2A-based locus-specific multicistronic expression in stable mouse lines. PLoS One 6, e28885 (2011).

  34. 34.

    Douglas, L. A., Varlinskaya, E. I. & Spear, L. P. Rewarding properties of social interactions in adolescent and adult male and female rats: impact of social versus isolate housing of subjects and partners. Dev. Psychobiol. 45, 153–162 (2004).

  35. 35.

    Panksepp, J. B. & Lahvis, G. P. Social reward among juvenile mice. Genes Brain Behav. 6, 661–671 (2007).

  36. 36.

    Silverman, J. L., Yang, M., Lord, C. & Crawley, J. N. Behavioural phenotyping assays for mouse models of autism. Nat. Rev. Neurosci. 11, 490–502 (2010).

  37. 37.

    Mathur, B. N., Capik, N. A., Alvarez, V. A. & Lovinger, D. M. Serotonin induces long-term depression at corticostriatal synapses. J. Neurosci. 31, 7402–7411 (2011).

  38. 38.

    Whitnall, M. H., Key, S., Ben-Barak, Y., Ozato, K. & Gainer, H. Neurophysin in the hypothalamo-neurohypophysial system. II. Immunocytochemical studies of the ontogeny of oxytocinergic and vasopressinergic neurons. J. Neurosci. 5, 98–109 (1985).

  39. 39.

    Ben-Barak, Y., Russell, J. T., Whitnall, M. H., Ozato, K. & Gainer, H. Neurophysin in the hypothalamo-neurohypophysial system. I. Production and characterization of monoclonal antibodies. J. Neurosci. 5, 81–97 (1985).

  40. 40.

    Dölen, G. Oxytocin: parallel processing in the social brain? J. Neuroendocrinol. 27, 516–535 (2015).

Download references

Acknowledgements

We thank members of the Dölen laboratory, I. Wickersham and J. Cohen for comments, and M. Pucak and the NINDS Multiphoton Imaging Core (supported by National Institute of Health grant NS050274) for assistance in acquiring and interpreting confocal images. The OT-NP antibody was a gift from H. Gainer. MDMA was a gift from the National Institute on Drug Abuse (NIDA) and R. Doblin, Multidisciplinary Association for Psychedelic Studies (MAPS). This work was supported by grants from the Kinship Foundation, Hartwell Foundation, Klingenstein-Simons Foundation, and NIH 5 R56 MH115177-0 (G.D.) and the New York Stem Cell Foundation-Robertson Award, NIH Director’s Pioneer Award 1DP1NS087724 and NIH 1R01NS075421 (E.B.).

Reviewer information

Nature thanks William Wetzel and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Affiliations

  1. The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA

    • Romain Nardou
    • , Eastman M. Lewis
    • , Rebecca Rothhaas
    •  & Gül Dölen
  2. The Solomon H. Snyder Department of Neuroscience, Wendy Klag Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA

    • Romain Nardou
    • , Eastman M. Lewis
    • , Rebecca Rothhaas
    •  & Gül Dölen
  3. The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA

    • Romain Nardou
    • , Eastman M. Lewis
    • , Rebecca Rothhaas
    •  & Gül Dölen
  4. Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA

    • Ran Xu
    • , Aimei Yang
    •  & Edward Boyden
  5. McGovern Institute, MIT, Cambridge, MA, USA

    • Ran Xu
    • , Aimei Yang
    •  & Edward Boyden
  6. Department of Biological Engineering, Media Laboratory, Koch Institute, MIT, Cambridge, MA, USA

    • Aimei Yang
    •  & Edward Boyden

Authors

  1. Search for Romain Nardou in:

  2. Search for Eastman M. Lewis in:

  3. Search for Rebecca Rothhaas in:

  4. Search for Ran Xu in:

  5. Search for Aimei Yang in:

  6. Search for Edward Boyden in:

  7. Search for Gül Dölen in:

Contributions

G.D. and R.N. designed the study, interpreted results and wrote the paper. R.N. performed and analysed behavioural experiments, electrophysiology and optogenetics. R.N., E.M.L. and R.R. performed stereotaxic injections, performed and analysed immunohistochemistry experiments. R.N. and E.M.L. validated Chronos function in OT neurons. G.D. designed the OT-2A-Flp KI mouse construct. A.Y., R.X. and E.B. designed the AAV-CAG-FonChronos-TdTomato viral construct. All authors edited the paper.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Gül Dölen.

Extended data figures and tables

  1. Extended Data Fig. 1 Social reward learning is constrained by a critical period in female mice.

    an, Individual (top) and average (bottom) responses of female mice from P21 to P112. o, Comparison across ages using the normalized social preference score reveals a developmental decline in the magnitude of social CPP in females. One-way ANOVA (F(13,248) = 1.867, P = 0.034). P21, n = 13; t(12) = −3.146, P = 0.008; P28, n = 20; t(19) = −2.097, P = 0.049; P35, n = 17; t(16) = −3.226, P = 0.005; P42, n = 22; t(21) = −1.773, P = 0.910; P49, n = 19; t(18) = −6.35, P ≤ 0.001; P56, n = 9; t(8) = −4.938, P = 0.001; P63, n = 17; t(16) = −2.659, P = 0.017; P70, n = 19; t(18) = −2.51, P = 0.022; P77, n = 25; t(24) = −2.551, P = 0.018; P84, n = 15; t(14) = −0.777, P = 0.45; P91, n = 18; t(17) = −2.027, P = 0.059; P98, n = 23; t(22) = −0.62, P = 0.5420; P105, n = 19; t(18) = −0.155, P = 0.8790; P112, n = 17; t(16) = −1.223, P = 0.2390; n is the number of mice; two-tailed paired t-test pre versus post. p, Comparison across ages using the subtracted social preference score reveals a similar trend. One-way ANOVA (F(13,248) = 1.625, P = 0.079). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  2. Extended Data Fig. 2 Locomotor activity during social CPP is similar in juvenile and adult mice.

    ah, MANOVA (F(8,36) = 8.022, P < 0.001). Ambulatory time (F(1,43) = 2.234, P = 0.142) (a), ambulatory counts (F(1,43) = 0.030, P = 0.864) (b), stereotypic time (F(1,43) = 1.659, P = 0.205) (c), stereotypic counts (F(1,43) = 0.497, P = 0.485) (d), vertical counts (F(1,43) = 0.077, P = 0.783) (f) and resting time (F(1,43) = 0.023, P = 0.879) (g) are not different between P42 (n = 26 animals) and P98 (n = 19 animals). Vertical time (e) is increased (F(1,43) = 6.803, P = 0.012) and number of transitions (h) is decreased (F(1,43) = 12.418, P = 0.001) in adult compared to juvenile mice. ip, None of the eight variables normalized (post/pre) are different between P42 and P98 (MANOVA (F(8,36) = 3.174, P = 0.008); normalized ambulatory time (F(1,43) = 3.443, P = 0.070) (i), normalized ambulatory counts (F(1,43) = 3.937, P = 0.054) (j), normalized stereotypic time (F(1,43) = 0.610, P = 0.439) (k), normalized stereotypic counts (F(1,43) = 0.086, P = 0.771) (l), normalized vertical time (F(1,43) = 0.071, P = 0.791) (m), normalized vertical counts (F(1,43) = 0.441, P = 0.510) (n), normalized resting time (F(1,43) = 0.077, P = 0.783) (o) and normalized number of transitions (F(1,43) = 0.279, P = 0.600) (p). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  3. Extended Data Fig. 3 The number of OT neurons projecting to the NAc does not decline during development.

    a, Injection and labelling strategy in C57BL/6 wild-type mice. b, Image showing successful targeting of NAc with retrobeads (RtBs). Scale bar, 500 μm. c, Quantification of RtB–OT antibody double-labelled cells across ages in the PVN (juvenile n = 7 animals; adult n = 6 animals; t(11) = −2.378, P = 0.037; two-tailed unpaired t-test). d, Number of OT neurons innervating the NAc normalized to the total number of PVN neurons innervating the NAc shows that the developmental increase across ages is not restricted to OT projecting neurons (juvenile n = 4 animals; adult n = 3 animals; t(5) = −1.284, P = 0.256; two tailed unpaired t-test). e, f, Images of the PVN labelled with OT antibodies (left) or RtB (centre) and merged (right) showing the presence of RtBs in OT neurons in both juvenile (e) and adult (f) mice. Scale bar, 50 μm. aca, anterior commissure; AcbSh, nucleus accumbens shell; CPu, caudate putamen; NAcc, nucleus accumbens core; PVN, paraventricular nucleus of the hypothalamus. Data are presented as mean ± s.e.m. *P < 0.05.

  4. Extended Data Fig. 4 Cocaine CPP (cCPP) is not different across the ages at lower doses of cocaine.

    a, Experimental time course of i.p. injections during cCPP experiments in bg. b, c, Individual (top) and average (bottom) time spent in the cocaine-paired context indicates a significantly increased preference for the cocaine context after conditioning with 5 mg kg−1 cocaine (P42, n = 20 animals, t(19) = −3.701, P = 0.002; P98, n = 24 animals, t(23) = −2.496, P = 0.020; two-tailed paired t-test). d, Comparisons between P42 and P98 reveal no difference in normalized cocaine preference (top, t(42) = −0.029, P = 0.977) and subtracted cocaine preference (bottom, t(42) = 0.121, P = 0.904) with 5 mg kg−1 cocaine (two-tailed unpaired t-test). e, f, Individual (top) and average (bottom) time spent in the cocaine-paired context indicates a significantly increased preference for the cocaine context after conditioning with 10 mg kg−1 cocaine (P42, n = 10 animals, t(9) = −2.469, P = 0.036; P98, n = 10 animals, t(9) = −7.411, P < 0.0001; two-tailed paired t-test). g, Comparisons between P42 and P98 reveal no difference in normalized cocaine preference (top, t(18) = −1.698, P = 0.107) and subtracted cocaine preference (bottom, t(18) = −2.07, P = 0.053) with 10 mg kg−1 cocaine (two-tailed unpaired t-test). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  5. Extended Data Fig. 5 Intraperitoneal OT does not reopen the critical period for social reward learning.

    ae, Social CPP in adult animals following pretreatment with i.p. OT (0.5 mg kg−1) or saline. a, Experimental time course. b, c, Individual (top) and average (bottom) preference for the social context in animals receiving i.p. pretreatment with saline (b, n = 10 animals, t(9) = −1.049, P = 0.321) or OT (c, n = 9 animals, t(8) = 0.126, P = 0.903) (two-tailed paired t-test). d, Comparisons of the normalized (top, t(17) = 0.706, P = 0.49) and subtracted (bottom, t(17) = 0.852, P = 0.406) social preference reveal no difference between i.p. OT and saline pretreatment groups (two-tailed unpaired t-test). e, Normalized social preference in mice pretreated with i.p. OT or saline plotted against the developmental time course of normalized social preference scores of untreated male mice (replotted from Fig. 1q). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  6. Extended Data Fig. 6 MDMA-induced LTD in the NAc requires OTR, SERT, and 5HTR4 activation.

    ai, Representative traces (a, d, g), summary time course (b, e, h), and average post-treatment magnitude comparisons (c, f, i) reveal that OT-LTD occludes MDMA-induced LTD (ac, n = 7 cells, t(6) = 1.639, P = 0.152; two-tailed paired t-test). The SERT antagonist fluoxetine (10 µM) blocks MDMA-induced but not OT-induced LTD (df, MDMA (n = 6 cells), OT (n = 4 cells), t(8) = 2.429, P = 0.041; two-tailed unpaired t-test). The 5HTR4 antagonist SB203186 (10 µM) blocks MDMA-LTD but not OT-LTD (gi, n = 7 cells, t(12) = 3.818, P = 0.002; two tailed unpaired t-test). *P < 0.05; n.s., comparisons not significant (P > 0.05).

  7. Extended Data Fig. 7 Dose, time course and social context of MDMA-induced reinstatement of social CPP in adult mice.

    a, f, k, Experimental time course of i.p. pretreatment in social CPP. ae, Social CPP following pretreatment with i.p. MDMA at 5 mg kg−1 or 20 mg kg−1 shows that neither 5 mg kg−1 (b, n = 9 animals, t(8) = −0.61, P = 0.559) nor 20 mg kg−1 (c, n = 19 animals, t(18) = −1.071, P = 0.298) reopens the critical period for social reward learning (individual data, top; group average, bottom; two-tailed unpaired t-test). Comparisons of the normalized (top) and subtracted (bottom) social preference scores reveal no difference between 5 mg kg−1 and 20 mg kg−1 MDMA pretreatment groups (d, normalized, t(26) = −0.736, P = 0.468; subtracted, t(26) = −0.384, P = 0.704; two-tailed paired t-test). e, Normalized social preference in groups pretreated with MDMA (5 mg kg−1 or 20 mg kg−1) plotted against the developmental time course of normalized social preference scores of untreated male mice (replotted from Fig. 1q). fj, i.p. MDMA injection followed by 3 h in social or isolate context shows that MDMA pretreatment reinstates social CPP when given in a social (g, n = 26 animals, t(25) = −4.116, P < 0.0004) but not isolate (h, n = 29 animals, t(28) = −1.97, P = 0.059) context. The social preference score following MDMA + 3 h isolation is lower than that following MDMA + 3 h social (i, normalized, t(53) = 2.239, P = 0.029; subtracted, t(53) = 2.185, P = 0.033; two-tailed unpaired t-test). j, Normalized social preference in groups pretreated with MDMA followed by 3 h isolation or 3 h social setting plotted against the developmental time course of normalized social preference scores of untreated male mice (replotted from Fig. 1q). kr, Following pretreatment with i.p. MDMA, reinstatement of social CPP is apparent after 6 h (l, n = 19, t(18) = −2.266, P = 0.036), lasts at least 2 weeks (m, n = 25, t(24) = −4.421, P < 0.0001) and returns to saline-pretreated levels by 4 weeks following MDMA pretreatment (o, MDMA, n = 19, t(18) = −0.319, P = 0.753; p, saline n = 9, t(8) = 0.098, P = 0.924) (two-tailed paired t-test). There is no difference between the 6-h and 2-week MDMA pretreatment groups (n, normalized (t(42) = −1.611, P = 0.115; subtracted, t(42) = −1.011, P = 0.318) or the MDMA and saline pretreatment groups 4 weeks after treatment (q, normalized, t(26) = 0.701, P = 0.49; subtracted, t(26) = 0.258, P = 0.799) (two-tailed unpaired t-test). r, Normalized social preference in groups pretreated with MDMA (6 h, 2 and 4 weeks) and saline (4 weeks) plotted against the developmental time course of normalized social preference scores of untreated male mice (replotted from Fig. 1q). sv, cCPP following pretreatment with i.p. MDMA. s, Experimental time course of i.p. injections before and during cCPP experiments in tv. t, u, Individual (top) and average (bottom) time spent in the cocaine-paired context indicates a significantly increased preference for the cocaine (20 mg kg−1) context after conditioning (saline, n = 10 animals, t(9) = −3.562, P = 0.006; MDMA, n = 16 animals, t(15) = −5.477, P < 0.0001, two-tailed paired t-test). v, Comparisons between mice pretreated with saline and MDMA 2 days before cCPP reveals no difference in normalized cocaine preference (t(24) = −0.322, P = 0.75) or subtracted cocaine preference (t(24) = −0.001, P = 0.999) (two-tailed unpaired t-test). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  8. Extended Data Fig. 8 OT receptor antagonist prevents the reopening of the critical period for social reward learning by MDMA.

    ae, Social CPP in adult mice following pretreatment with i.p. MDMA or MDMA + OTR-A. fj, Social CPP in adult mice following pretreatment with OTR-A or saline. a, f, Experimental time course of intraperitoneal (i.p.) pretreatment in social CPP. b, c, g, h, Individual (top) and average (bottom) responses to social CPP in mice pretreated with i.p. MDMA (b), MDMA + OTR-A (c), saline (g) or OTR-A (h). b, The reopening of the critical period for social reward learning by MDMA (n = 18 animals, t(17) = −5.182, P < 0.0001) is abolished in the presence of OTR-A (c, n = 9 animals, t(8) = −0.837, P = 0.427) (two-tailed paired t-test). g, h, There is no difference in time spent in social bedding cue following conditioning between animals pretreated with i.p. saline (g, n = 10 animals, t(9) = −0.057, P = 0.956) or OTR-A (h, n = 10 animals, t(9) = −0.81, P = 0.439) (two-tailed paired t-test). d, i, Comparisons of the normalized (top) and subtracted (bottom) social preference scores between treatment groups reveal a decrease following MDMA + OTR-A versus MDMA alone (d, normalized, t(25) = 2.106, P = 0.045; subtracted, t(25) = 2.410, P = 0.024) but no difference in OTR-A versus saline (i, normalized, t(18) = −0.587, P = 0.564; subtracted, t(18) = −0.479, P = 0.638) (two-tailed unpaired t-test). e, j, Normalized social preference in mice pretreated with MDMA or MDMA + OTR-A (e) and OTR-A or saline (j) plotted against the developmental time course of normalized social preference scores of untreated male mice (re-plotted from Fig. 1q). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  9. Extended Data Fig. 9 Generation and validation of OT-2A-Flp knock-in mice and validation of optogenetic targeting strategy.

    a, Targeting strategy for generating an OT-2A-Flp knock-in (KI) mouse. bd, i, The OT-2A-Flp::FonGFP cross efficiently labels OT neurons in the PVN of adult male mice. b, Breeding strategy for OT-2A-Flp driver mice crossed to FonGFP reporter mice. c, d, Representative image of the PVN labelled with OT antibody (OT-Ab, magenta, left), OT-2A-Flp::FonGFP (OT-mRP, cyan, centre), and merged (right) at low magnification (scale bar, 200 μm) and high magnification (scale bar, 50 μm). GFP expression (OT-mRp) under the OT promoter is co-localized with OT-Ab labelling in the PVN. i, In the PVN, OT-mRp is expressed in 94% of OT-Ab-labelled neurons (n = 2 animals; 714 ± 142 OT neurons per animal). eh, j, Confirmation of viral expression, OT neuronal specificity, and probe placement in AAV-CAG-FonChronos-TdTomato (OT-vRp)/OT-2A-Flp KI mouse. e, Anatomical validation of optogenetic targeting strategy. Left, cell type specification and projection targeting strategy (adapted from ref. 40 with permission: https://creativecommons.org/licenses/by-nc-nd/4.0/). Right, DAPI staining to confirm optical probe placement above the NAc (scale bar, 1 mm). f, OT-Ab labelling (magenta, left) and Chronos-TdTomato expression (OT-vRp, cyan, middle) are co-localized (right) in axons in the NAc. g, h, OT-Ab labelling (magenta, left) and Chronos-TdTomato expression (OT-vRp, cyan, middle) are co-localized (right) in the PVN at low magnification (c, scale bar, 200 µm) and high magnification (d, scale bar, 50 µm). j, In the PVN, 87% of OT-vRp positive neurons are labelled by OT-Ab (n = 3 animals; 492 ± 112 OT neurons per animal). 3V, third ventricle.

  10. Extended Data Fig. 10 Working model.

    a, In juvenile animals, OT-producing neurons from the PVN release OT into the NAc. Activation of OTRs on presynaptic terminals of 5-HT neurons from the dorsal raphe nucleus (dRph) causes the release of 5-HT into the NAc. Activation of 5HT1b receptors on glutamatergic terminals from various brain regions (cortex, amygdala, thalamus) decreases the probability of glutamate release, which is recorded in MSNs as LTD of excitatory synaptic transmission. b, In adult mice, OTRs are downregulated in the NAc, decreasing the magnitude of social CPP and OT-LTD induced at excitatory synapses onto MSNs. c, Binding of MDMA to the SERT transporter causes efflux of 5-HT, which activates 5HT4 receptors on OT terminals, causing the release of OT. In turn, increased synaptic OT induces metaplastic upregulation of OTRs, reinstating social CPP and induction of OT-LTD at excitatory synapses. d, Optogenetic stimulation of OT terminals causes direct release of OT in the NAc, inducing metaplastic upregulation of OTRs and recapitulating the effects of MDMA.

  11. Extended Data Fig. 11 Pair housing does not alter social reward learning in adults.

    a, Experimental time course for mice socially housed in groups of five versus pair housed (dyads) before social CPP. b, c, Individual (top) and average (bottom) responses in groups of five mice (b) versus dyads (c). Mice housed in groups of five or two show similar social preferences at P98 (group of five, n = 10 animals, t(9) = −1.472, P = 0.175; dyad, n = 14 animals, t(13) = −0.742, P = 0.471; two-tailed paired t-test). d, Comparisons between housing groups reveal no difference in normalized (top, t(22) = 0.502, P = 0.62) or subtracted (bottom, t(22) = 0.595, P = 0.558) social preference scores (two-tailed unpaired t-test). Data are presented as mean ± s.e.m. *P < 0.05; n.s., comparisons not significant (P > 0.05).

  12. Extended Data Table 1 Social reward learning across development in male mice

Supplementary information

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/s41586-019-1075-9

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.