Biology subjects

Jacobs, D. S.

Publications and source records attributed to Jacobs, D. S..

4 recordsLinked to original sources

bioRxiv2026

Psilocybin asymmetrically modulates outcome-based choice and cortical processing under uncertainty

Emerging clinical research with psilocybin highlights the value of the psychedelic experience on successful treatment of a multitude of psychiatric disorders. While the psychedelic trip or clinical support procedures cannot be modeled in rodents, neural processes critical to meta-learning and flexible modification of previously learned strategies can be quantified during psilocybin exposure. Here we applied computational modeling and single unit recordings from medial prefrontal cortex to characterize the effect of psilocybin using a value-based probabilistic choice task. Psilocybin improved choice selection in uncertain contexts and shifted reinforcement learning rate bidirectionally, enhancing updating from rewarded, while reducing updating from unrewarded, actions. These behavioral changes coincided with selective shifts in the neural encoding of task features including enhanced neural representation of rewarded, and diminished representation of unrewarded, outcomes. Collectively these data indicate that psilocybin improves choice selection in uncertain contexts by reweighing cortical coding in a way that favors learning from positive new information over prospective actions.

neuroscience↗

bioRxiv2024

Reductions of Grin2a in adolescent dopamine neurons confers aberrant salience and related psychosis phenotype

Psychosis is a hallmark of schizophrenia. It involves a collection of symptoms that are typically associated with disrupted dopamine signaling and emerges during adolescence or early adulthood. Most schizophrenia-associated genes, however, involve glutamatergic or other ubiquitous targets that do not explain the latent expression of psychosis or dopaminergic abnormalities. Here, we describe an etiologically relevant model for the adolescent onset of dopamine-related dysfunction in schizophrenia. We focused on GRIN2A, the gene encoding the GluN2A subunit of the NMDA receptor, as both the common loss-of-function variants and the rare missense variants in this gene are risk factors for schizophrenia. We find that GluN2A levels distinctly decline in dopamine neuron-containing regions throughout adolescence while remaining stable in other regions. This suggested that adolescent dopamine neurons may be particularly vulnerable to further reductions in GluN2A caused by a damaging variant of GRIN2A. Consistent with this idea, we find that selective knockout of Grin2a in adolescent rat dopamine neurons results in a psychosis-relevant behavioral phenotype. This manipulation also reduced dopamine release in response to unexpected outcomes in young adults, reflective of prediction error signaling abnormalities observed in the clinical population. These data provide mechanistic insight into how GRIN2A mutations may contribute to the delayed onset of dopamine-related symptoms and provide a model for identifying course altering treatments for schizophrenia.

neuroscience↗

bioRxiv2023

Complementary roles of orbitofrontal and prelimbic cortices in adaption of reward motivated actions to learned anxiety.

BackgroundAnxiety is a common symptom of several mental health disorders and adversely affects motivated behaviors. Anxiety can emerge from associating risk of future harm while engaged in goal-guided actions. Using a recently developed behavioral paradigm to model this aspect of anxiety, we investigated the role of two cortical subregions, the prelimbic medial frontal cortex (PL) and lateral orbitofrontal cortex (lOFC), which have been implicated in anxiety and outcome expectation, in flexible representation of actions associated with harm risk. MethodsA seek-take reward-guided instrumental task design was used to train animals to associate the seek action with a variable risk of punishment. After learning, animals underwent extinction training for this association. Fiber photometry was used to measure and compare neuronal activity in PL and lOFC during learning and extinction. ResultsAnimals increased action suppression in response to punishment contingencies. This increase dissipated after extinction training. These behavioral changes were associated with region specific changes in neuronal activity. PL neuronal activity preferentially adapted to threat of punishment whereas lOFC activity adapted to safe aspects of the task. Moreover, correlated activity between these regions was suppressed during actions associated with harm risk suggesting that these regions may guide behavior independently under anxiety. ConclusionsThese findings suggest the PL and lOFC serve distinct but complementary roles in the representation of learned anxiety. This dissociation may provide a mechanism for how overlapping cortical systems are implicated in reward-guided action execution during anxiety.

neuroscience↗

bioRxiv2022

Learning of probabilistic punishment as a model of anxiety produces changes in action but not punishment encoding in the dmPFC and VTA

Previously, we developed a novel model for anxiety during motivated behavior by training rats to perform a task where actions executed to obtain a reward were probabilistically punished and observed that after learning, neuronal activity in the ventral tegmental area (VTA) and dorsomedial prefrontal cortex (dmPFC) encode the relationship between action and punishment risk (Park & Moghaddam, 2017). Here we used male and female rats to expand on the previous work by focusing on neural changes in the dmPFC and VTA that were associated with the learning of probabilistic punishment, and with anxiolytic treatment with diazepam after learning. We find that adaptive neural responses of dmPFC and VTA during the learning of anxiogenic contingencies are independent from the punishment experience and occur primarily during the peri-action period. Our results further identify peri-action ramping of VTA neural activity, and VTA-dmPFC correlated activity, as potential markers for the anxiolytic properties of diazepam.

neuroscience↗