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Browsing by Subject "Prefrontal cortex"
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Item Aggression Results in the Phosphorylation of ERK1/2 in the Nucleus Accumbens and the Dephosphorylation of mTOR in the Medial Prefrontal Cortex in Female Syrian Hamsters(MDPI, 2023-01-10) Borland, Johnathan M.; Dempsey, Desarae A.; Peyla, Anna C.; Hall, Megan A. L.; Kohut-Jackson, Abigail L.; Mermelstein, Paul G.; Meisel, Robert L.; Neurology, School of MedicineLike many social behaviors, aggression can be rewarding, leading to behavioral plasticity. One outcome of reward-induced aggression is the long-term increase in the speed in which future aggression-based encounters is initiated. This form of aggression impacts dendritic structure and excitatory synaptic neurotransmission in the nucleus accumbens, a brain region well known to regulate motivated behaviors. Yet, little is known about the intracellular signaling mechanisms that drive these structural/functional changes and long-term changes in aggressive behavior. This study set out to further elucidate the intracellular signaling mechanisms regulating the plasticity in neurophysiology and behavior that underlie the rewarding consequences of aggressive interactions. Female Syrian hamsters experienced zero, two or five aggressive interactions and the phosphorylation of proteins in reward-associated regions was analyzed. We report that aggressive interactions result in a transient increase in the phosphorylation of extracellular-signal related kinase 1/2 (ERK1/2) in the nucleus accumbens. We also report that aggressive interactions result in a transient decrease in the phosphorylation of mammalian target of rapamycin (mTOR) in the medial prefrontal cortex, a major input structure to the nucleus accumbens. Thus, this study identifies ERK1/2 and mTOR as potential signaling pathways for regulating the long-term rewarding consequences of aggressive interactions. Furthermore, the recruitment profile of the ERK1/2 and the mTOR pathways are distinct in different brain regions.Item Encoding of conditioned inhibitors of fear in the infralimbic cortex(Oxford University Press, 2023) Ng, Ka H.; Sangha, Susan; Psychiatry, School of MedicineCues in the environment signaling the absence of threat, i.e. safety, can influence both fear and reward-seeking behaviors. Heightened and maladaptive fear is associated with reduced activity in the medial prefrontal cortex. We have previously shown in male rats that the infralimbic (IL) prefrontal cortex is necessary for suppressing fear during a safety cue. The objective of the present study was to determine if there was safety cue-specific neural activity within the IL using a Pavlovian conditioning paradigm, where a fear cue was paired with shock, a safety cue was paired with no shock, and a reward cue was paired with sucrose. To investigate how safety cues can suppress fear, the fear and safety cues were presented together as a compound fear + safety cue. Single-unit activity showed a large proportion of neurons with excitatory responses to the fear + safety cue specifically, a separate group of neurons with excitatory responses to both the reward and fear + safety cues, and bidirectional neurons with excitation to the fear + safety cue and inhibition to the fear cue. Neural activity was also found to be negatively correlated with freezing during the fear + safety cue. Together, these data implicate the IL in encoding specific aspects of conditioned inhibitors when fear is being actively suppressed.Item Encoding of the Intent to Drink Alcohol by the Prefrontal Cortex Is Blunted in Rats with a Family History of Excessive Drinking(Society for Neuroscience, 2019) Lisenbardt, David N.; Timme, Nicholas M.; Lapish, Christopher C.; Psychology, School of ScienceThe prefrontal cortex (PFC) plays a central role in guiding decision making, and its function is altered by alcohol use and an individual's innate risk for excessive alcohol drinking. The primary goal of this work was to determine how neural activity in the PFC guides the decision to drink. Towards this goal, the within-session changes in neural activity were measured from medial PFC (mPFC) of rats performing a drinking procedure that allowed them to consume or abstain from alcohol in a self-paced manner. Recordings were obtained from rats that either lacked or expressed an innate risk for excessive alcohol intake, Wistar or alcohol-preferring (P) rats, respectively. Wistar rats exhibited patterns of neural activity consistent with the intention to drink or abstain from drinking, whereas these patterns were blunted or absent in P rats. Collectively, these data indicate that neural activity patterns in mPFC associated with the intention to drink alcohol are influenced by innate risk for excessive alcohol drinking. This observation may indicate a lack of control over the decision to drink by this otherwise well-validated supervisory brain region.Item Habitual Behavior Is Mediated by a Shift in Response-Outcome Encoding by Infralimbic Cortex(Society for Neuroscience, 2018-01-03) Barker, Jacqueline M.; Glen, W. Bailey; Linsenbardt, David N.; Lapish, Christopher C.; Chandler, L. Judson; Psychology, School of ScienceThe ability to flexibly switch between goal-directed actions and habits is critical for adaptive behavior. The infralimbic prefrontal cortex (IfL-C) has been consistently identified as a crucial structure for the regulation of response strategies. To investigate the role of the IfL-C, the present study employed two validated reinforcement schedules that either promote habits or goal-directed actions in mice. The results reveal that information about action-outcome relationships is differentially encoded in the IfL-C during actions and habits as evidenced by encoding of behavioral outcomes during goal-directed actions that is lost during habits. Optogenetic inhibition of the IfL-C selectively at press during habitual behavior (when firing rates are reduced during unreinforced goal-directed actions) resulted in restoration of sensitivity to change of action-outcome contingency. These results reveal a novel functional mechanism by which IfL-C promotes habitual behavior, and provide insight into strategies for the treatment and prevention of pathological, inflexible behavior common in neuropsychiatric illness.Item Investigating the role of extrasynaptic GABAA receptors located in the infralimbic cortex in the binge-like alcohol intake of male C57BL/6J mice(2013-11-20) Fritz, Brandon Michael; Boehm, Stephen; Czachowsk, Cristine; Grahame, Nicholas J.Extrasynaptic GABAA receptors, often identified as those containing both α4 and δ subunits, appear to be a target for the actions of alcohol (ethanol) at relatively low concentrations, perhaps suppressing the activity of GABAergic interneurons which regulate activity in the mesolimbocortical circuit. Pharmacological studies in rodents using the δ-subunit selective agonist Gaboxadol (THIP) have found both promotional and inhibitory effects on alcohol consumption. The goal of this project was to determine the role of extrasynaptic GABAA receptors located in the infralimbic cortex (ILC) in the binge-like alcohol intake of male C57BL/6J (B6) mice. The ILC is of interest due to its demonstrated involvement in stress reactivity and alcohol exposure has been shown to interfere with extinction learning; impairments of which may be related to inflexible behavior (i.e. problematic alcohol consumption). Adult male B6 mice were bilaterally implanted with stainless steel guide cannulae aimed at the ILC and were offered limited access to 20% ethanol or 5% sucrose for 6 days. On day 7, mice were bilaterally injected with 50 or 100 ng THIP (25 or 50 ng per side respectively) or saline vehicle into the ILC. It was found that the highest dose of THIP (100 ng/mouse) increased alcohol intake relative to vehicle controls, although control animals consumed relatively little ethanol following infusion. Furthermore, THIP had no effect on sucrose consumption (p > 0.05), suggesting that the effect of THIP was selective for ethanol consumption. Together, these findings suggest that the mice that consumed ethanol may have been particularly reactive to the microinfusion process relative to animals that consumed sucrose, perhaps because ethanol consumption was not as reinforcing as sucrose consumption. In addition, the observation that THIP effectively prevented the decrease in ethanol intake on day 7 induced by the microinjection process may be related to a role for the ILC in adaptive learning processes, which in turn, promote behavioral flexibility.Item Left prefrontal transcranial magnetic stimulation for treatment-resistant depression in adolescents: a double-blind, randomized, sham-controlled trial(Springer Nature, 2021) Croarkin, Paul E.; Elmaadawi, Ahmed Z.; Aaronson, Scott T.; Schrodt, G. Randolph, Jr.; Holbert, Richard C.; Verdoliva, Sarah; Heart, Karen L.; Demitrack, Mark A.; Strawn, Jeffrey R.; Psychiatry, School of MedicineTreatment-resistant depression (TRD) is prevalent and associated with a substantial psychosocial burden and mortality. There are few prior studies of interventions for TRD in adolescents. This was the largest study to date examining the feasibility, safety, and efficacy of 10-Hz transcranial magnetic stimulation (TMS) for adolescents with TRD. Adolescents with TRD (aged 12-21 years) were enrolled in a randomized, sham-controlled trial of TMS across 13 sites. Treatment resistance was defined as an antidepressant treatment record level of 1 to 4 in a current episode of depression. Intention-to-treat patients (n = 103) included those randomly assigned to active NeuroStar TMS monotherapy (n = 48) or sham TMS (n = 55) for 30 daily treatments over 6 weeks. The primary outcome measure was change in the Hamilton Depression Rating Scale (HAM-D-24) score. After 6 weeks of blinded treatment, improvement in the least-squares mean (SE) HAM-D-24 scores were similar between the active (-11.1 [2.03]) and sham groups (-10.6 [2.00]; P = 0.8; difference [95% CI], - 0.5 [-4.2 to 3.3]). Response rates were 41.7% in the active group and 36.4% in the sham group (P = 0.6). Remission rates were 29.2% in the active group and 29.0% in the sham group (P = 0.95). There were no new tolerability or safety signals in adolescents. Although TMS treatment produced a clinically meaningful change in depressive symptom severity, this did not differ from sham treatment. Future studies should focus on strategies to reduce the placebo response and examine the optimal dosing of TMS for adolescents with TRD.Item Neural activation during risky decision-making in youth at high risk for substance use disorders(Elsevier, 2015-08-30) Hulvershorn, Leslie A.; Hummer, Tom A.; Fukunaga, Rena; Leibenluft, Ellen; Finn, Peter; Cyders, Melissa A.; Anand, Amit; Overhage, Lauren; Dir, Allyson; Brown, Joshua; Department of Psychiatry, IU School of MedicineRisky decision-making, particularly in the context of reward-seeking behavior, is strongly associated with the presence of substance use disorders (SUDs). However, there has been little research on the neural substrates underlying reward-related decision-making in drug-naïve youth who are at elevated risk for SUDs. Participants comprised 23 high-risk (HR) youth with a well-established SUD risk phenotype and 27 low-risk healthy comparison (HC) youth, aged 10-14. Participants completed the balloon analog risk task (BART), a task designed to examine risky decision-making, during functional magnetic resonance imaging. The HR group had faster reaction times, but otherwise showed no behavioral differences from the HC group. HR youth experienced greater activation when processing outcome, as the chances of balloon explosion increased, relative to HC youth, in ventromedial prefrontal cortex (vmPFC). As explosion probability increased, group-by-condition interactions in the ventral striatum/anterior cingulate and the anterior insula showed increasing activation in HR youth, specifically on trials when explosions occurred. Thus, atypical activation increased with increasing risk of negative outcome (i.e., balloon explosion) in a cortico-striatal network in the HR group. These findings identify candidate neurobiological markers of addiction risk in youth at high familial and phenotypic risk for SUDs.Item Nf1-DEFICIENT MICE DISPLAY SOCIAL LEARNING DEFICITS THAT ARE RESCUED BY THE DELETION OF PAK1 GENE(2011-03-16) Spence, John Paul; Shekhar, Anantha, 1957-; Clapp, D. Wade; Johnson, Philip L.; Yang, Feng-ChunNeurofibromatosis type 1 (NF1) is a neurocutaneous disorder that affects roughly 1 in 3500 individuals. In addition to physical features (e.g., neurofibromas), developmental disorders are also common that can affect cognition, learning, attention and social function. The NF1 gene encodes neurofibromin, a GTPase activating protein (GAP)-like protein that negatively regulates Ras GTPase activation. Mutation at the NF1 locus increases the output of MAPK and PI3K signal transduction from the cellular membrane to the nucleus. Similar to humans, Nf1+/- mice show spatial learning abnormalities that are potentially correlated with increases in GABA-mediated inhibition and deficits in long-term potentiation in the hippocampus. Here, we demonstrate for the first time that Nf1+/- mice exhibit a selective loss of long-term social learning / memory and increased GABAergic inhibition in the basolateral amygdala, a critical brain region for regulating social behaviors. Next, utilizing a genetic intercross, we show that the co-deletion of p21-activated kinase type 1 (Pak1-/-), which positively regulates MAPK activation, restores Nf1+/--dependent MAPK hyperactivation in neurons cultured from the frontal cortex. We found that the co-deletion of Pak1 in Nf1+/- mice (Nf1+/- / Pak1-/-) also restores the deficits in long-term social learning / memory seen in Nf1+/- mice and normalizes the increases in GABA-mediated inhibition in the BLA, as compared to Nf1+/- mice. Together, these findings establish a role for Nf1 and Pak1 genes in the regulation of social learning in Nf1-deficient mice. Furthermore, proteomic studies identify dysregulation of F-actin and microtubule dynamics in the prefrontal cortex, and implicate proteins associated with vesicular release as well as neurite formation and outgrowth (e.g., LSAMP, STXBP1, DREB). In the BLA, disintegrin and metalloproteinase domain-containing protein 22 (ADAM22) was identified, and ADAM22 may play a role in the regulation of AMPA receptors. Finally, due to the increased co-occurrence of NF1 and autism, these findings may also have important implications for the pathology and treatment of NF1-related social deficits and some forms of autism.Item Presence of ethanol-sensitive and ethanol-insensitive glycine receptors in the ventral tegmental area and prefrontal cortex in mice(Wiley, 2021) Araya, Anibal; Gallegos, Scarlet; Viveros, Rodrigo; San Martin, Loreto; Muñoz, Braulio; Harvey, Robert J.; Zeilhofer, Hanns U.; Aguayo, Luis G.; Pharmacology and Toxicology, School of MedicineBackground and purpose: Glycine receptors composed of α1 and β subunits are primarily found in the spinal cord and brainstem and are potentiated by ethanol (10-100 mM). However, much less is known about the presence, composition and ethanol sensitivity of these receptors in higher CNS regions. Here, we examined two regions of the brain reward system, the ventral tegmental area (VTA) and the prefrontal cortex (PFC), to determine their glycine receptor subunit composition and sensitivity to ethanol. Experimental approach: We used Western blot, immunohistochemistry and electrophysiological techniques in three different models: wild-type C57BL/6, glycine receptor subunit α1 knock-in and glycine receptor subunit α2 knockout mice. Key results: Similar levels of α and β receptor subunits were detected in both brain regions, and electrophysiological recordings demonstrated the presence of glycine-activated currents in both areas. Sensitivity of glycine receptors to glycine was lower in the PFC compared with VTA. Picrotoxin only partly blocked the glycine-activated current in the PFC and VTA, indicating that both regions express heteromeric αβ receptors. Glycine receptors in VTA neurons, but not in PFC neurons, were potentiated by ethanol. Conclusion and implications: Glycine receptors in VTA neurons from WT and α2 KO mice were potentiated by ethanol, but not in neurons from the α1 KI mice, supporting the conclusion that α1 glycine receptors are predominantly expressed in the VTA. By contrast, glycine receptors in PFC neurons were not potentiated in any of the mouse models studied, suggesting the presence of α2/α3/α4, rather than α1 glycine receptor subunits.Item Proactive Versus Reactive Control Strategies Differentially Mediate Alcohol Drinking in Male Wistars and P Rats(Society for Neuroscience, 2024-03-27) Morningstar, M. D.; Timme, N. M.; Ma, B.; Cornwell, E.; Galbari, T.; Lapish, C. C.; Psychology, School of ScienceProblematic alcohol consumption is associated with deficits in decision-making and alterations in prefrontal cortex neural activity likely contribute. We hypothesized that the differences in cognitive control would be evident between male Wistars and a model of genetic risk: alcohol-preferring P rats. Cognitive control is split into proactive and reactive components. Proactive control maintains goal-directed behavior independent of a stimulus, whereas reactive control elicits goal-directed behavior at the time of a stimulus. We hypothesized that Wistars would show proactive control over alcohol seeking whereas P rats would show reactive control over alcohol seeking. Neural activity was recorded from the prefrontal cortex during an alcohol seeking task with two session types. On congruent sessions, the conditioned stimulus (CS+) was on the same side as alcohol access. Incongruent sessions presented alcohol opposite the CS+. Wistars, but not P rats, made more incorrect approaches during incongruent sessions, suggesting that Wistars utilized the previously learned rule. This motivated the hypothesis that neural activity reflecting proactive control would be observable in Wistars but not P rats. While P rats showed differences in neural activity at times of alcohol access, Wistars showed differences prior to approaching the sipper. These results support our hypothesis that Wistars are more likely to engage in proactive cognitive control strategies whereas P rats are more likely to engage in reactive cognitive control strategies. Although P rats were bred to prefer alcohol, the differences in cognitive control may reflect a sequela of behaviors that mirror those in humans at risk for an AUD.