A mutation in the transcription factor zinc finger E-box-binding homeobox 2 (ZEB2) in humans is linked with Mowat-Wilson Syndrome, a neurodevelopmental disorder associated with severe speech impairment. Despite this, little is known about the neural basis of how ZEB2 affects language. To study the molecular and neural mechanisms, zebra finches, a species of songbird, serve as a strong model animal due to their ability to learn song and the similarities in human and zebra finch brains. More specifically, the zebra finch’s robust nucleus of the arcopallium (RA), a key component of the bird’s song circuit, is functionally analogous to the human laryngeal motor cortex, a region associated with speech control. Given that male zebra finches engage in song learning during developmental periods while females do not, creating a timeline of ZEB2 protein expression in zebra finch RA between the two sexes would aid in understanding the protein’s role in developing both song circuitry and production. To accomplish this, brains collected at key developmental time points are cryosectioned and stained using fluorescent antibodies to quantify ZEB2 protein expression levels. Results are expected to suggest a sex-specific upregulation of ZEB2 during the critical period for vocal learning in the RA of male zebra finches compared to females. These projected findings suggest ZEB2’s importance in song circuitry, with a potential translation to the development of analogous structures in humans.

Gonadotropin-releasing hormone (GnRH) stimulates the production of gonadotropins, which are necessary for producing the sex hormones that regulate reproductive functions. Androgens are known to influence GnRH neuron size, quantity, and neurogenesis, but the role of androgen receptor alpha (ARα) in regulating these neurons remains unclear. In the Astatotilapia burtoni model, ARα knockout (KO) males have altered reproductive phenotypes, differences in aggression/courtship, and disrupted GnRH1 expression, a key mediator of the HPG reproductive axis. To study how ARα affects the number and size of GnRH1 neurons in dominant fish, GnRH1-expressing neurons were imaged in the preoptic area (POA), a key node in the social behavior network where ARα is expressed. Ongoing analysis shows that ARα KOs have increased GnRH signaling, indicated by more GnRH neurons in the POA. This suggests potential dysregulation of the HPG axis due to loss of androgen-dependent negative feedback, where the absence of ARα prevents proper detection of circulating androgens and disrupts normal inhibition of GnRH activity. This project expands our understanding of AR signaling in the HPG axis, providing insight into how androgen feedback disruption contributes to human reproductive and neuroendocrine disorders.

Everyday decisions rely on prior experiences with environmental cues to predict rewards. We learn to distinguish the identity of rewards through formation and use of cue-reward memories. This process relies on interactions between lateral orbitofrontal cortex (lOFC) and basolateral amygdala (BLA). Prior work in our lab shows BLA is necessary to form identity-specific cue-reward memories. BLA sends direct projections to lOFC, which mediates the use of the identity of predicted rewards for decisions. Unknown is how BLA-lOFC supports cue-reward Pavlovian learning. We hypothesized that BLA-lOFC supports encoding of identity-specific cue-reward memories that guide adaptive decisions. To test this, we first conducted instrumental conditioning to establish action-reward associations and then Pavlovian conditioning while optogenetically inhibiting BLA-lOFC at reward. We used the Pavlovian-to-Instrumental Transfer (PIT) test to assess the ability of cues to bias an action known to earn the same reward. If BLA-lOFC projections support encoding and use of identity-specific cue-reward memories, inhibition will disrupt the ability of cues to selectively bias choice during PIT. Our preliminary data show inhibiting BLA-lOFC during Pavlovian learning disrupts encoding of cue-reward memories that bias decisions during PIT. These results can elucidate the neural circuit supporting associative learning and adaptive decision making, and hence improve understanding of psychiatric diseases that arise from malfunctioning of this neural circuit.

Opioid tolerance is a contextually-associated learned response. This is especially relevant when discussing opioid overdoses as administration in a novel context can attenuate respiratory depression tolerance, thereby resulting in overdose. Endocannabinoids (eCBs) have been found to enhance analgesia, alter opioid tolerance, and play a role in contextual learning. Yet, the role of the eCB system in the development of contextual opioid analgesic tolerance (COAT) is not established. This study aims to design an experiment to establish the paradigm of COAT so that future studies can elucidate the role of the endocannabinoid system. To evaluate analgesic tolerance, a hot plate (HP) assay was used to measure mouse paw withdrawal latency (PWL). A smaller PWL indicated less analgesia and more tolerance. After recording baseline PWL, all animals (n=4, M) received morphine for 9 consecutive days followed by HP testing. On the 9th day, testing was performed in a novel context (NC) with distinct contextual cues. There were no significant baseline differences in HP PWL between animals. Opioid analgesic tolerance was observed by a significant decrease in HP PWL between the 1st and 7th day of morphine administration. Additionally, testing in a NC on day 8 significantly increased PWL compared to day 7 HP PWL. We predict future experiments will continue to support this data. Preliminary data from this cohort supports the idea that the development of opioid analgesic tolerance is associated with the contextual cues of the environment.

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is frequently refractory to treatment. Epileptogenesis is believed to be initiated by a precipitating injury, such as status epilepticus (SE), followed by maladaptive cellular and circuit remodeling. Yet, the cellular mechanisms underlying these long-term changes remain poorly understood, and no therapies currently exist to prevent epileptogenesis. In previous work, we used a post SE pilocarpine-induced mouse model to perform single-nucleus RNA sequencing of dorsal hippocampal tissue, supported by histological analyses. We discovered a distinct microglial subpopulation enriched for IGF1 and MYO1E, abundant in epileptic but not in control hippocampi, with features of a heightened phagocytic and metabolic activity. These epilepsy-associated microglia may drive pathological remodeling and offer a potential therapeutic target to prevent epileptogenesis. We seek to standardize the epileptogenesis model by ensuring consistent SE induction; however, variability in pilocarpine responsiveness across transgenic mice poses a key challenge. This project aims to optimize pilocarpine dosing protocols to reliably induce SE in transgenic mice with inducible knockouts of floxed IGF1 and MYO1E in microglia tagged to the Cx3cr1 promoter. We are targeting high levels of SE incidence with low levels of mortality. The end goal is to consistently generate a method to model for TLE and future experiments elucidating mechanisms underlying epileptogenesis.