Author Archives: Sara M. Freeman

New title: Assistant Professor of Neurobiology at Utah State University

This post is a bit late, but I am thrilled to share that I have started a new position as an Assistant Professor of Neurobiology in the Biology Department at Utah State University!

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I’m about a month in to my first semester so far, and it’s going great! I’m making progress setting up my lab and already have three undergraduate student researchers who are interested in learning about the social brain.

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I am teaching an upper-level, special topics course called ‘Behavioral Neurobiology’, which explores the evolved neural mechanisms of specific animal behaviors across a diverse range of species, such as echolocation in bats, singing in crickets and songbirds, learning and memory in honeybees, and spatial navigation in rats. It’s pretty neat to be teaching this, because I took the same course an undergraduate at the University of Virginia, and it was the reason why I decided to pursue a PhD in Neuroscience! It’s really incredible to come full circle and be teaching this class in my first semester as Assistant Professor.

The first several weeks so far have been beyond busy, of course, but I’ve also been able to connect with a bunch of great folks here at USU, including many other new tenure track Assistant Professors who will be heading along this same journey. The university administration, the higher-ups in the College of Science, and my colleagues in the Biology Department have all been incredibly helpful in getting me oriented here and making me feel supported and welcomed. I am looking forward to this new challenge and all the opportunities ahead of me!  usu_logo_blue

Co-Guest Editor of the Special Issue of the American Journal of Primatology on Oxytocin, Vasopressin, and Primate Behavior

I am proud to report that the special issue of the American Journal of Primatology on Oxytocin, Vasopressin, and Primate Behavior, which I co-guest edited with my postdoc advisor, Karen Bales, is now PUBLISHED!! It came out last month, and it is full of incredible new work, including many original scientific studies as well as some reviews and perspectives pieces. Check it out! There are nearly a dozen papers on these nonapeptides and how they function in the brains and bodies of primates to effect behavior.

For an overview of the contents, you can also read our brief introduction article, which was published along with the special issue:

Sara M Freeman and Karen L Bales. 2018. Oxytocin, vasopressin, and primate behavior: Diversity and insight. American Journal of Primatology. 10.1002/ajp.22919.

I am also very proud of the cover art, which I designed and created myself, completely from publicly available images (Creative Commons licensing info for each one is below).

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The rhesus macaque face (line 1) and human face (line 5) were cropped from original photos that are freely available under the Creative Commons Zero (CC0) license.
The tufted capuchin face (line 2) was cropped from an original photo taken by Tiago Falótico and made available under the Creative Commons Attribution NonCommercial ShareAlike 2.0 Generic (CC BY-NC-SA 2.0) license (
The chimpanzee face (line 3) was cropped from an original photo provided by Afrika Force and licensed under the Creative Commons Attribution 2.0 Generic (CC BY 2.0) license (
The titi monkey face (line 4) was taken by Carlos Villatoro and provided by the California National Primate Research Center.
The common marmoset face (line 6) was cropped from an original photo by and made available under the Creative Commons Attribution 3.0 Unported (CC BY 3.0) (


My first NIH grant as PI: Methods development to advance our understanding of oxytocin receptors

I am proud to announce that on June 22nd, I was awarded an NIH R21 grant, which is a mechanism specifically for exploratory research, such as “high-risk, high-reward studies that may lead to a breakthrough in a particular area, or result in novel techniques, agents, methodologies, models or applications that will impact biomedical, behavioral, or clinical research”. My R21 was awarded from the National Institutes of Mental Health (NIMH), and the project began July 1st and will end in the summer of 2020. For more information, you can look me up on the NIH’s searchable database of grants, RePORTER.

The goal of this two-year project is to develop a new method for the visualization of oxytocin receptors on the cellular level. Currently, the most common technique to accomplish this goal is called immunohistochemistry, which requires the use of antibodies that are very specific to the molecule you’re trying to visualize. Unfortunately, there are no reliable, commercially available antibodies for the oxytocin receptor. So, those of us who study oxytocin receptors are left using the tried-and-true method of receptor autoradiography to visualize the locations of these receptors in tissue.

Despite it’s reliability, autoradiography has some limitations. First and foremost, it only visualizes the distribution of receptors on the gross anatomical level; it does not provide cellular resolution of receptor expression. Second, it doesn’t label the tissue directly, so it’s impossible to perform any double-labeling experiments to see what other features are in, on, or around the oxytocin receptors you’ve identified. And third, it relies on radiation, which is hazardous and cumbersome to use and dispose of, and requires lengthy incubation times on radiosensitive film in order to yield results.

For these reasons, I decided that I would like to dedicate the next two years to the development of an antibody-free, radiation-free method for the visualization of oxytocin receptors on the cellular level. The secondary goal of this grant is to perform a proof-of-principle experiment to show that the technique can be combined with double-labeling for targets in the dopamine system, in order to show that we can better describe oxytocin receptor-expressing neurons in the brain.

My grant will focus on brain tissue from non-mouse organisms, including prairie voles, titi monkeys, and humans, and will use opportunistically collected tissues that have been banked in freezers for later research use. We will not be focusing on mouse brain tissue, because transgenic mice have been developed in which oxytocin receptors can be visualized with fluorescent markers, so the tool I am working to develop would primarily benefit those investigators working outside of mice, in species where transgenic technologies are not available.

I’m very excited to start this new project, especially because this is my first NIH grant as the principal investigator (PI). My postdoc advisor, Dr. Karen Bales, is co-PI on the grant and will be providing her lab and equipment for me to carry out this work. Hopefully, year two of this grant will be carried out in my own lab somewhere, as I will be submitting applications for tenure-track professor positions for this 2018-2019 academic job cycle.

Oxytocin and the neural basis of social behavior in lemurs(!): New collaboration with Dr. Nick Grebe at Duke University

Well, I wanted to write this post back in December, shortly after my trip to Duke ended, but now it’s already February somehow! Better late than never, right?

I am very excited about a new collaboration that I have begun with Dr. Nick Grebe, a postdoc at Duke University in the lab of Dr. Christine Drea. Christine’s lab studies a variety of different species in which the females are the dominant sex, including hyenas, meerkats, and lemurs. They have been able to conduct studies of captive, free-ranging lemurs at the Duke Lemur Center, which is an incredible facility that’s been in operation for over 50 years. They have 15 different species of lemur, as well as two additional prosimian primate species (the pygmy slow loris and the thick-tailed bush baby), which they report is the “largest and most diverse population of lemurs” in the World, outside of their native home of Madagascar.

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This lovely, nocturnal lady is housed in a reverse light cycle, so that her active period (in the dark) occurs during the daytime hours when most of her care staff is on duty. This photo was taken in the last minutes of the light period, when she was first waking up to start her “day” as the lights go out.

This facility promotes research on lemurs in a variety of disciplines with a focus on conservation. I was very happy to learn that I would be able to tour the facility during my visit to Duke, and I was overwhelmingly impressed with their facilities, animals, and staffing expertise. The highlight of the tour was being able to see an Aye-Aye (right), which is an endangered, nocturnal species of lemur that I’ve known about for years (thanks, David Attenborough!), but that I never dreamed I would be able to see up close with my own eyes!

There is a high degree of diversity in the behavior, diet, body size, coat color, and other features of lemurs. Of specific interest to Nick was the fact that some species of lemur are monogamous and form long-lasting bonds between adult male-female pairs, and some species are not. So when he came to start his postdoc at Duke, he wanted to investigate the neurobiological and hormonal basis for this difference in mating structure across lemur species.

There is evidence from other species, especially monogamous and non-monogamous voles, that the social hormones oxytocin and vasopressin are two of the primary biological players in this difference. The distribution of oxytocin and vasopressin receptors in the brain parallel the differences in mating strategy; specifically, the brains of the monogamous species have high levels of these receptors in the regions of the brain that underlie the rewarding properties of stimuli, and the brains of non-monogamous voles do not have receptors in these areas. Behavioral work has followed up on these comparative, neuroanatomical findings to show that receptors in these areas are necessary and sufficient for pair-bonding in monogamous prairie voles. This work from nearly 15 years ago has set a precedent for the patterns of oxytocin and vasopressin receptor expression in the brain to inform our understanding of the behavior of a species, especially when investigating monogamy.

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This figure (adapted from Lim et al. 2004) shows the dense areas of oxytocin and vasopressin receptor expression in the monogamous prairie vole brain (left column), which are reduced or absent in the brain of the non-monogamous meadow vole (right column).

In my career, I have mapped out the distributions of these receptors in brain tissue from four species of primate: rhesus macaques, titi monkeys, and marmosets. There is a great diversity in the behaviors and receptor distributions across these species, and I have dedicated a large part of my research career in describing these differences in and effort to better understand how they contribute to the diversity of primate behavior. Of course, all brain tissue from monkeys is collected opportunistically, when the animals die of natural causes or need to be euthanized at the recommendation of a veterinarian.

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Three coronal blocks of a lemur brain, resting safely on dry ice.

Based on my experience working with this precious tissue and visualizing oxytocin and vasopressin receptors, Nick sought me out to see if I wanted to start a collaboration in order to map out these receptors in brains from monogamous and non-monogamous lemurs. The Duke Lemur Center maintains an extensive brain and tissue bank of postmortem specimens, which are available for research. These tissues are also acquired opportunistically; these animals are NEVER euthanized for research purposes. It’s wonderful that these animals provide researchers with resources for scientific inquiry during their lives AND after they die.

After almost a year of planning, grant writing, and organization, Nick and the Drea lab flew me out to Raleigh-Durham, NC for a week to get this new project off the ground. This project would also not be possible without the generous assistance of Dr. Heather Patisaul at NC State, who provided the lab space and necessary equipment (including the ever precious freezer space!). First, we had to prepare the brain tissues, which were mostly frozen whole, by carefully blocking them into smaller, more manageable pieces. Nick had no previous experience working with brain tissue, so I taught him everything he needed to know in order to carry out this work in my absence, from handling and storage to ultrathin cryosectioning of the brain blocks into slices for neuroanatomical analysis. In one week, we were able to organize and prepare all the tissues and get Nick proficient on sectioning primate brain tissue on the cryostat. It was a busy but enjoyable trip getting a new project off the ground and meeting new people at Duke and NC State.

Sometime later this year, the tissue will be ready and I will return to NC to help them carry out the visualization experiments and start the analysis! Can’t wait for my next trip back!

Bales lab members sweep the 2017 Psychology Conference awards

On Friday, May 5th, the UC-Davis Psychology Department held it’s annual conference, with oral presentations by postdocs, graduate students, and faculty, as well as a poster session, keynote speaker, catered lunch, and reception. It was a wonderful event, held at the Center for Mind and Brain, and it was full of excellent talks and discussion. Each session was judged independently by faculty members in order to determine the winners across three categories: Best Talk by a Postdoc, Best Talk by a Graduate Student, and Best Poster Presentation. This year, members of our lab completely swept the awards! Graduate student Lynea Witczak won Best Poster; graduate student Trent Simmons won Best Talk by a Graduate Student; and I won Best Talk by a Postdoc. Way to go Bales Lab! As John Capitanio said, Karen Bales won a “mentoring hat trick”!


Left to right: Lynea Witczak (Best Poster), Trent Simmons (Best Talk by a Graduate Student), Forrest Rogers (organizer, but NOT involved in judging!), and Dr. Sara Freeman (Best Talk by a Postdoc). All members of Dr. Karen Bales’s lab in the Psychology Department.

Recipient of the 2017 UC Davis Award for Excellence in Postdoctoral Research

I am overwhelmed and proud to share that I received the 2017 Award for Excellence in Postdoctoral Research from UC-Davis! This university-wide award “recognizes the vital role that postdoctoral scholars play in maintaining the reputation of excellent research at UC Davis” and comes with a $1000 prize. Two winners are selected each year by a panel of professors, deans, and officers of the Postdoctoral Scholars Association. There are over 1,000 postdocs at UC-Davis, and this year, 15 postdocs were nominated, and Dr. Kimberly Keil and I were the awardees. (Interesting note: both of us and both of our mentors are all women! #womeninscience)


Left to right: My advisor Dr. Karen Bales, me, the other awardee Dr. Kimberly Keil, and her advisor Dr. Pam Lien.

It is an honor to receive this recognition for my hard work and effort, and I am so thankful to my mentor Dr. Karen Bales for nominating me, and for Dr. John Capitanio (UC Davis) and Dr. Suma Jacob (U of Minnesota) for writing letters in support of my nomination.

I also won Runner-Up for Best Oral Presentation in my session at the 3rd Annual Postdoctoral Research Symposium, held on the same day, for my talk entitled, “What do monogamous monkeys look at? Establishing non-invasive eye-tracking methods for the study of social cognition in nonhuman primates.”2017 Postdoc Excellence Award.png2017 PRS Runner up award.png

Exploring the autistic brain: a short video about my research

Last fall, I attended the annual meeting of the Society for Neuroscience in San Diego, CA. My assistant (Michelle Palumbo) and I presented the results of my research using postmortem human brain tissue to determine whether individuals with autism had changes in the oxytocin receptor compared to typically developing specimens. Oxytocin is a hormone that acts in the brain to modulate social function, and it’s been highly implicated in the biology of autism, although no one has determined whether there are changes in this system in the autistic brain.

I was approached by Rob Percy, the media relations guy for the Allen Brain Institute in Seattle, and he wanted to feature me and my research for a video, because I rely on the Allen Institute’s Human Brain Reference Atlas (it’s an incredible resource; just launched in September). So we did an interview, and a few months later, he put this amazing webisode together! Very proud of it and happy to share! Thanks to my incredible boss Dr. Karen Bales for her support, too, of course.


Michelle Palumbo and I proudly displaying our posters at SFN2016 in San Diego.

Working with titi monkeys: a promotional video!

The administration at the California National Primate Research Center wanted to put together a short informational video to promote awareness of the titi monkeys, which are monkeys that we study in the lab of Dr. Karen Bales. They asked me to be in the video and to discuss the features of the titi monkey colony and the important research we do to investigate the biological basis for social attachment. Enjoy!

For more information about the California National Primate Research Center or the titi monkeys, please visit their website.

Four new publications: a great start to 2016

First, I must say that I cannot believe it’s already mid-April, 2016! I wanted to write this post several weeks ago. Needless to say, I am very happy to share my four(!) most recent publications: two first-author papers from my current postdoctoral research, one first-author perspectives piece/review paper that came out of my PhD research, and a second-
author paper from a collaborative project that I was a part of a few years ago. I am very proud of these papers, which could not have been possible without all the hard work and support from IMG_3656my co-authors, lab mates, and mentors. Please read, enjoy, and share! You can click the titles below for links to the papers.

Meanwhile, I am working on the aims of our (relatively) new, NIH-funded grant to characterize oxytocin receptor expression in the brains of humans and to compare the levels of that expression between individuals who had autism and neurotypically developing individuals. Here’s a recent shot of me in the lab (“in da hood”?) preparing a large amount of solution to counterstain ~270 microscope slides of human brain sections, in order to help us better identify neuroanatomical landmarks during our analysis.

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New grant! Two years of funding to study human brain tissue and oxytocin receptors

I am a few months late on this news, but that doesn’t mean I’m any less excited about it! I am very proud to have received (with my PI, Dr. Karen Bales) an R21 from the NIMH, which provides two years of funding for our project, entitled “Characterization of oxytocin receptors in autism spectrum disorder”. Oxytocin has been implicated in the underlying neurobiology of autism. Oxytocin is also currently an experimental therapeutic for individuals with autism, despite the fact that we don’t know where in the human brain oxytocin acts, nor do we know whether the oxytocin receptor distribution is altered in the brains of individuals with autism compared to neurotypically developing individuals. This grant will answer these questions, as well as characterize the effect of age on oxytocin receptor expression in human brain tissue.

I am co-investigator on the grant (I collected all of the preliminary data last summer with human brainstem tissue). As the primary author of the grant, I am very proud that it was funded on the first try!! This is the first NIH grant I’ve ever written, and I am simply ecstatic that it was funded without revision! Let’s all cross fingers that my grant writing luck continues in the future.

As of last month, I am managing the entire grant, including hiring an assistant(!) to help me section tissue, and running all of the procedures, data collection, experimentation, analysis, and manuscript preparation for publication. It’s going to be an exciting two years. After 5-6 years of working with brain tissue from nonhuman primates, I will be moving forward to study brain tissue from humans! This step is a thrill and a privilege. I feel honored to be in a position to work with such graciously donated and irreplaceable tissue.

For anyone interested in tissue donation, there’s a lot of information on the NIH’s NeuroBioBank website, which is the brain bank that has provided/will be providing tissue for this project.

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