University of Southern California

USC Neuroscience

Richard Simerly

Pediatrics, Keck School of Medicine
Neurobiology, Biological Sciences
Director, Saban Neuroscience Program

Research Topics

  1. Axon targeting in limbic and hypothalamic neural pathways
  2. Leptin receptor signaling in developing hypothalamic circuitry
  3. Development of sexually dimorphic forebrain regions

Research Overview

The development of the brain depends on complex interactions between genetic factors and environmental influences, such as neuronal activity, growth factors and circulating hormones. Hormones secreted by peripheral organs can determine the number and chemical phenotype of specific sets of neurons during development, as well as direct formation of connections with other parts of the brain. Currently, we are studying the organization and development of forebrain pathways that regulate feeding and energy homeostasis. Recent findings indicate that these neural pathways develop under the influence of the adipocyte derived hormone leptin during discrete temporal domains, suggesting that there are region-specific, hormonally directed mechanisms governing the assembly of homeostatic circuits. Using axonal labeling methods and both in vitro and in vivo experimental approaches, we are determining if manipulations of genes known to participate in leptin signaling in mature animals also influence the development of the pathways that mediate hypothalamic responses to changes in energy balance. The results of this work indicate that leptin is indeed a major developmental factor that may mediate the developmental effects of a variety of environmental factors including nutrition.

Contact Information

Mailing Address:
The Saban Research Institute of Childrens Hospital LA
4650 Sunset Blvd., Mailstop #135
Los Angeles, CA 90027
Office Location:
The Saban Research Institute
Office Phone:
(323) 361-8608
Lab Location:
Third floor, Saban Res Inst.
Lab Phone:
(323) 361-8533
(323) 361-1549


  • University of California, Berkeley, AB, 1976
  • University of California, Los Angeles, PhD, 1984
  • The Salk Institute for Biological Research , 1984 - 1986

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Selected Publications

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Bouyer K and RB Simerly. (2013) Neonatal leptin exposure specifies innervation of presympathetic hypothalamic neurons and improves the metabolic status of leptin-deficient mice. J. Neurosci. 33(2):840-5

-PubMed -Link

Bouret SG, Bates SH, Chen S, Myers MG, and RB Simerly (2012) Distinct roles for specific leptin receptor signals in the development of hypothalamic feeding circuits. J. Neurosci. 32(4):1244-52. -PubMed -Link

Waters EM and RB Simerly. (2009) Estrogen induces caspase-dependent cell death during hypothalamic development. J. Neurosci 29(31):9714-8. -PubMed -Link

Simerly RB. (2008) Hypothalamic substrates of metabolic imprinting. Physiol Behav. 94(1):79-89. -PubMed

Bouret SG, Gorski JN, Patterson CM, Chen S, Levin BE, Simerly RB. (2008) Hypothalamic neural projections are permanently disrupted in diet-induced obese rats. Cell Metab. 7(2):179-185. -PubMed

Polston E.K. and R.B. Simerly. (2006) Ontogeny of projections from the anteroventral periventricular nucleus of the hypothalamus in the female rat. J. Comp. Neurology 495:122-132. -PubMed

Cooke B.M. and R.B. Simerly. (2005) Ontogeny of bidirectional connections between the medial nucleus of the amygdala and the principal bed nucleus of the stria terminalis in the rat. J. Comp Neurol. 489:42-58. -PubMed

Simerly, R.B. (2005) Getting Wired on Hormones: Endocrine Regulation of Hypothalamic Development. Curr. Op. Neurobiol, 15:81-85. -PubMed

Bouret SG, Draper SJ, Simerly RB. (2004) Trophic action of leptin on hypothalamic neurons that regulate feeding. Science. 304(5667):108-110. -PubMed