About

Ryan Freedman is an Adjunct Associate Professor of the Practice of Environmental Studies at USC Dornsife. His role involves engaging with environmental studies through practical application and teaching. As part of the USC Dornsife faculty, he contributes to the academic community by integrating environmental issues into the broader spectrum of research and education. His work supports the university's mission to serve as a dynamic intellectual resource woven into the fabric of local communities, emphasizing the importance of environmental understanding and sustainability.

Research topics

• Medicine
• Biology
• Dermatology
• Neuroscience
• Internal medicine

Selected publications

• Contents, Vol. 29, 1994

  Neuropsychobiology · 2008-02-22

  articleOpen access
  PublisherOA PDFDOI

• Long-Term Effects of Early Genetic Influences on Behavior

  New England Journal of Medicine · 2002-07-18 · 7 citations

  review1st authorCorresponding

  In a recently published study, investigators at Columbia University reported on a mouse model in which the forebrain serotonin-1A receptor was knocked out. The mice demonstrated inhibition of certain aspects of behavior. For example, when placed in an open area the affected mice were less likely to explore than normal mice. In this commentary, Dr. Freedman discusses the implications of this provocative research for the genetic control of human behavior.

  PublisherDOI

• NURR1 Mutations in cases of schizophrenia and manic-depressive disorder

  American Journal of Medical Genetics · 2000-01-01 · 150 citations

  article

  Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.

  PublisherDOI

• Nicotinic Receptors, Smoking and Schizophrenia

  Restorative Neurology and Neuroscience · 1998-01-01 · 60 citations

  articleSenior author

  Neuronal nicotinic acetylcholine receptor expression was examined in schizophrenia. The incidence of smoking in schizophrenia is remarkably high and nicotine has been found to normalize an auditory evoked potential deficit seen in most subjects who suffer from this disease. Antagonists and agonists of a specific subset of this receptor family, the alpha7 nicotinic receptor, were found to regulate the gating of filtering of auditory information in both humans and in an animal model. The alpha7 gene has been cloned and a polymorphic dinucleotide repeat near the gene was used for linkage analysis, showing the alpha7 locus to be linked to the P50 deficit. Expression of the alpha7 receptor, which binds nicotine with low affinity, is reduced in the hippocampus of schizophrenics. [3H]-nicotine binding, a measure of the high affinity nicotinic receptors, was also decreased in schizophrenics and does not increase in response to tobacco use, as is seen in control subjects. The results of these studies suggest the presence of abnormal expression and function of the neuronal nicotinic receptor gene family in schizophrenia.

  PublisherDOI

• Localization of alphabungarotoxin binding to chemically-identified subtypes of rat hippocampal neurons

  Schizophrenia Research · 1995-04-01

  articleSenior author
  PublisherDOI

• Neuronal development in embryonic brain tissue derived from schizophrenic women and grafted to animal hosts

  Schizophrenia Research · 1994-10-01 · 13 citations

  article1st authorCorresponding
  PublisherDOI

• Significant reductions in synapsin but not synaptophysin specific activity in the brains of some schizophrenics

  Biological Psychiatry · 1993-10-01 · 154 citations

  articleSenior author
  PublisherDOI

• Eighteen-month course of two patients with grafts of fetal dopamine neurons for severe Parkinson's disease

  Experimental Neurology · 1992-12-01 · 71 citations

  articleSenior author
  PublisherDOI

• Sensory gating deficits in psychiatric impatients: Relation to catecholamine metabolites in different diagnostic groups

  Biological Psychiatry · 1990-03-01 · 114 citations

  articleSenior author
  PublisherDOI

• Stability of plasma catecholamine metabolites in outpatient schizophrenics

  Biological Psychiatry · 1989-04-01

  articleSenior author
  PublisherDOI

Recent grants

• NIH Grant R37MH038321

  NIH · $3.4M · 2000

• NIH Grant R01MH038321

  NIH · $3.2M · 2006

• NIH Grant P50MH044212

  NIH · $3.2M · 1999

Frequent coauthors

• Sherry Leonard

  Edward Via College of Osteopathic Medicine

  14 shared

• Norman E. Levan

  Shaare Zedek Medical Center

  12 shared

• Randal G. Ross

  University of Colorado Denver

  9 shared

• Maria Anvret

  Karolinska University Hospital

  6 shared

• Mariette Arvidsson

  Ludwig Cancer Research

  6 shared

• Olof Sydow

  Karolinska Institutet

  6 shared

• Henry H. Henstell

  6 shared

• Zhiping Zhang

  Alibaba Group (United States)

  6 shared