Biology subjects

Freeman, S. M.

Publications and source records attributed to Freeman, S. M..

3 recordsLinked to original sources

bioRxiv2026

Oxytocin and Vasopressin at Birth Prevent Hypoactivity and Excess Weight Gain in Vole Offspring Delivered by Cesarean Section

Birth occurs during a sensitive period in brain development wherein hormones facilitate the dramatic shift in physiology that accomplishes the transition to extrauterine homeostasis. The surge in birth signaling hormones is abridged in cases of delivery by cesarean section (CS), which accounts for 32% of all births in the U.S. Epidemiological studies have associated birth via CS with increased risk of obesity in later life. Here, we sought to investigate this association using an experimental preclinical animal model, the prairie vole. Subjects were delivered either via vaginal delivery (VD) or CS and then cross-fostered. CS delivery led to increased body weight across development, which could be prevented with hormone rescue of oxytocin (OXT) and arginine vasopressin (AVP), delivered to neonates immediately after CS. This weight gain could not be attributed to differences in birth weight, parenting, food consumption, or thermoregulation; however, CS subjects moved slower than VD subjects, which hormone rescue reversed. Hormone rescue also reduced adiposity in adulthood among CS subjects. The dopamine system was dysregulated in the caudate/putamen of CS offspring, suggesting a neural mechanism for the decreased locomotion. Hormone rescue of CS neonates restored dopamine synthesis in the caudate/putamen and increased spontaneous locomotor activity. These findings suggest CS can lead to increased weight gain in part through a reduction of locomotion driven by long-lasting changes in striatal dopamine regulation, all of which can be prevented by treating CS neonates with a single peripheral administration of two birth-signaling hormones, OXT and AVP.

neuroscience↗

bioRxiv2024

Oxtyocin and vasopressin 1a receptor alterations in the superior temporal sulcus and hypothalamus in schizophrenia

Schizophrenia is a chronic, severe psychiatric condition characterized in part by social impairments. As social cognitive functioning is a major predictor of successful life outcomes in schizophrenia, there is a critical need to determine the neurobiological basis of social impairments in schizophrenia. The current study used receptor autoradiography to examine vasopressin 1a (AVPR1a) and oxytocin receptor (OXTR) densities in the postmortem brain tissue of individuals who had schizophrenia (N=23) relative to unaffected matched controls (N=18). We analyzed the superior temporal sulcus, a brain region that is highly implicated in social perception and shows aberrant functioning in schizophrenia. GreaterAVPR1a binding densities were observed relative to OXTR. Increases in AVPR1a densities with advanced age in females who had schizophrenia were also observed. This finding in the superior temporal sulcus may explain a shift in positive symptom severity(paranoia/suspiciousness) that has been observed with advanced age in women with schizophrenia. In addition, increased OXTR and a trend toward increased AVPR1a densities were observed in the hypothalamus in schizophrenia. The hypothalamus synthesizes oxytocin and vasopressin in the brain and is the initiator of the hypothalamic-pituitary-adrenal axis, which facilitates the fight or flight stress response. These receptor systems may be upregulated to compensate for possibly low exogenous oxytocin and vasopressin release from the hypothalamus in schizophrenia. Our findings show age- and sex-dependent effects on nonapeptide receptor binding that shed light onto the neurobiology of the social brain in the progression of schizophrenia.

neuroscience↗

bioRxiv2021

OpenMonkeyChallenge: Dataset and Benchmark Challenges for Pose Tracking of Non-human Primates

The ability to automatically track non-human primates as they move through the world is important for several subfields in biology and biomedicine. Inspired by the recent success of computer vision models enabled by benchmark challenges (e.g., object detection), we propose a new benchmark challenge called OpenMonkeyChallenge that facilitates collective community efforts through an annual competition to build generalizable non- human primate pose tracking models. To host the benchmark challenge, we provide a new public dataset consisting of 111,529 annotated (17 body landmarks) photographs of non-human primates in naturalistic contexts obtained from various sources including the internet, three National Primate Research Centers, and the Minnesota Zoo. Such annotated datasets will be used for the training and testing datasets to develop generalizable models with standardized evaluation metrics. We demonstrate the effectiveness of our dataset quantitatively by comparing it with existing datasets based on seven state-of-the-art pose tracking models.

animal behavior and cognition↗