Identification of a novel gene regulating amygdala-mediated fear extinction.

Recent years have seen advances in our understanding of the neural circuits associated with trauma-related disorders, and the development of relevant assays for these behaviors in rodents. Although inherited factors are known to influence individual differences in risk for these disorders, it has been difficult to identify specific genes that moderate circuit functions to affect trauma-related behaviors. Here, we exploited robust inbred mouse strain differences in Pavlovian fear extinction to uncover quantitative trait loci (QTL) associated with this trait. We found these strain differences to be resistant to developmental cross-fostering and associated with anatomical variation in basolateral amygdala (BLA) perineuronal nets, which are developmentally implicated in extinction. Next, by profiling extinction-driven BLA expression of QTL-linked genes, we nominated Ppid (peptidylprolyl isomerase D, a member of the tetratricopeptide repeat (TPR) protein family) as an extinction-related candidate gene. We then showed that Ppid was enriched in excitatory and inhibitory BLA neuronal populations, but at lower levels in the extinction-impaired mouse strain. Using a virus-based approach to directly regulate Ppid function, we demonstrated that downregulating BLA-Ppid impaired extinction, while upregulating BLA-Ppid facilitated extinction and altered in vivo neuronal extinction encoding. Next, we showed that Ppid colocalized with the glucocorticoid receptor (GR) in BLA neurons and found that the extinction-facilitating effects of Ppid upregulation were blocked by a GR antagonist. Collectively, our results identify Ppid as a novel gene involved in regulating extinction via functional actions in the BLA, with possible implications for understanding genetic and pathophysiological mechanisms underlying risk for trauma-related disorders

Reward-Related Behavioral Paradigms for Addiction Research in the Mouse: Performance of Common Inbred Strains

The mouse has emerged as a uniquely valuable species for studying the molecular and genetic basis of complex behaviors and modeling neuropsychiatric disease states. While valid and reliable preclinical assays for reward-related behaviors are critical to understanding addiction-related processes, and various behavioral procedures have been developed and characterized in rats and primates, there have been relatively few studies using operant-based addiction-relevant behavioral paradigms in the mouse. Here we describe the performance of the C57BL/6J inbred mouse strain on three major reward-related paradigms, and replicate the same procedures in two other commonly used inbred strains (DBA/2J, BALB/cJ). We examined Pavlovian-instrumental transfer (PIT) by measuring the ability of an auditory cue associated with food reward to promote an instrumental (lever press) response. In a separate experiment, we assessed the acquisition and extinction of a simple stimulus-reward instrumental behavior on a touchscreen-based task. Reinstatement of this behavior was then examined following either continuous exposure to cues (conditioned reinforcers, CRs) associated with reward, brief reward and CR exposure, or brief reward exposure followed by continuous CR exposure. The third paradigm examined sensitivity of an instrumental (lever press) response to devaluation of food reward (a probe for outcome insensitive, habitual behavior) by repeated pairing with malaise. Results showed that C57BL/6J mice displayed robust PIT, as well as clear extinction and reinstatement, but were insensitive to reinforcer devaluation. DBA/2J mice showed good PIT and (rewarded) reinstatement, but were slow to extinguish and did not show reinforcer devaluation or significant CR-reinstatement. BALB/cJ mice also displayed good PIT, extinction and reinstatement, and retained instrumental responding following devaluation, but, unlike the other strains, demonstrated reduced Pavlovian approach behavior (food magazine head entries). Overall, these assays provide robust paradigms for future studies using the mouse to elucidate the neural, molecular and genetic factors underpinning reward-related behaviors relevant to addiction research

Quantitative trait loci for sensitivity to ethanol intoxication in a C57BL/6J × 129S1/SvImJ inbred mouse cross

Individual variation in sensitivity to acute ethanol (EtOH) challenge is associated with alcohol drinking and is a predictor of alcohol abuse. Previous studies have shown that the C57BL/6J (B6) and 129S1/SvImJ (S1) inbred mouse strains differ in responses on certain measures of acute EtOH intoxication. To gain insight into genetic factors contributing to these differences, we performed quantitative trait locus (QTL) analysis of measures of EtOH-induced ataxia (accelerating rotarod), hypothermia, and loss of righting reflex (LORR) duration in a B6 × S1 F2 population. We confirmed that S1 showed greater EtOH-induced hypothermia (specifically at a high dose) and longer LORR compared to B6. QTL analysis revealed several additive and interacting loci for various phenotypes, as well as examples of genotype interactions with sex. QTLs for different EtOH phenotypes were largely non-overlapping, suggesting separable genetic influences on these behaviors. The most compelling main-effect QTLs were for hypothermia on chromosome 16 and for LORR on chromosomes 4 and 6. Several QTLs overlapped with loci repeatedly linked to EtOH drinking in previous mouse studies. The architecture of the traits we examined was complex but clearly amenable to dissection in future studies. Using integrative genomics strategies, plausible functional and positional candidates may be found. Uncovering candidate genes associated with variation in these phenotypes in this population could ultimately shed light on genetic factors underlying sensitivity to EtOH intoxication and risk for alcoholism in humans

Glycemic treatment deintensification practices in nursing home residents with type 2 diabetes.

BackgroundOlder nursing home (NH) residents with glycemic overtreatment are at significant risk of hypoglycemia and other harms and may benefit from deintensification. However, little is known about deintensification practices in this setting.MethodsWe conducted a cohort study from January 1, 2013 to December 31, 2019 among Veterans Affairs (VA) NH residents. Participants were VA NH residents age ≥65 with type 2 diabetes with a NH length of stay (LOS) ≥ 30 days and an HbA1c result during their NH stay. We defined overtreatment as HbA1c <6.5 with any insulin use, and potential overtreatment as HbA1c <7.5 with any insulin use or HbA1c <6.5 on any glucose-lowering medication (GLM) other than metformin alone. Our primary outcome was continued glycemic overtreatment without deintensification 14 days after HbA1c.ResultsOf the 7422 included residents, 17% of residents met criteria for overtreatment and an additional 23% met criteria for potential overtreatment. Among residents overtreated and potentially overtreated at baseline, 27% and 19%, respectively had medication regimens deintensified (73% and 81%, respectively, continued to be overtreated). Long-acting insulin use and hyperglycemia ≥300 mg/dL before index HbA1c were associated with increased odds of continued overtreatment (odds ratio [OR] 1.37, 95% confidence interval [CI] 1.14-1.65 and OR 1.35, 95% CI 1.10-1.66, respectively). Severe functional impairment (MDS-ADL score ≥ 19) was associated with decreased odds of continued overtreatment (OR 0.72, 95% CI 0.56-0.95). Hypoglycemia was not associated with decreased odds of overtreatment.ConclusionsOvertreatment of diabetes in NH residents is common and a minority of residents have their medication regimens appropriately deintensified. Deprescribing initiatives targeting residents at high risk of harms and with low likelihood of benefit such as those with history of hypoglycemia, or high levels of cognitive or functional impairment are most likely to identify NH residents most likely to benefit from deintensification

Induction of fetal demise before pregnancy termination: practices of family planning providers

ObjectivesOur survey aimed to characterize the practice of inducing fetal demise before pregnancy termination among abortion providers, including its technical aspects and why providers have chosen to adopt it.Study designWe conducted a survey of Family Planning Fellowship-trained or Fellowship-affiliated Family Planning (FP) subspecialists about their practice of inducing fetal demise, including questions regarding the circumstances in which they would induce demise, techniques used and rationales for choosing whether to adopt this practice.ResultsOf the 169 FP subspecialists we surveyed, 105 (62%) responded. About half (52%) of respondents indicated that they routinely induced fetal demise before terminations in the second trimester. Providers' practices varied in the gestations at which they started inducing demise as well as the techniques used. Respondents provided legal, technical and psychological reasons for their decisions to induce demise.ConclusionInducing fetal demise before second-trimester abortions is common among US FP specialists for multiple reasons. The absence of professional guidelines or robust data may contribute to the variance in the current practice patterns of inducing demise.ImplicationsOur study documents the widespread practice of inducing fetal demise before second-trimester abortion and further describes wide variation in providers' methods and rationales for inducing demise. It is important for abortion providers as a professional group to come to a formal consensus on the appropriate use of these techniques and to determine whether such practices should be encouraged, tolerated or even permitted

Reward-related behaviors in the C57BL/6J inbred mouse strain.

<p>(<b>A</b>) Sessions to reach criterion on Pavlovian (PAV) and various schedules of instrumental training prior to the PIT probe (n = 13). (<b>B</b>) During the PIT probe, there were more active lever (AL) presses during the CS+ than the CS− trials, or the ITI periods (*<i>p</i><.05), and more AL presses than inactive lever (IL) presses during the CS+ and CS− trials, and ITI periods (#<i>p</i><.05). There were also more IL presses during the ITI periods than the CS+ (‡<i>p</i><.05). (<b>C</b>) More head entries were made during the CS+ than CS− trials, or ITI periods (*<i>p</i><.05) (n = 12). (<b>D</b>) Training sessions to acquire and extinguish a simple stimulus-reward instrumental response (n = 31). (<b>E</b>) Percent responding across extinction sessions. (<b>F</b>) Reinstatement of operant behavior by the Reward⁶+CR³⁰, CR³⁰ and Reward⁶+CR³⁰ protocols (#<i>p</i><.05 versus responding on last extinction session) (n = 10/condition). (<b>G</b>) Lever press responding across instrumental training session prior to devaluation (n = 17). (<b>H</b>) Pellets eaten prior to trial 1 and 2 of US-LiCl paired (Devalued) or unpaired (Non-devalued group) session in the home cage, during a context generalization test (GEN) in the conditioning chamber and the home cage retention test (RET) (n = 7–10/group). (<b>I</b>) Lever presses and head-entry responses into the magazine did not differ between devalued (D) and non-devalued (ND) groups. FR = fixed ratio, VI = variable interval, RR = random ratio. Data are Means ±SEM.</p

Reward-related behaviors in the BALB/cJ inbred mouse strain.

<p>(<b>A</b>) Sessions to reach criterion on Pavlovian (PAV) and various schedules of instrumental training prior to the PIT probe (n = 12). (<b>B</b>) During the PIT probe, there were more active lever (AL) presses during the CS+ than the CS− or ITI (*<i>p</i><.05), and more AL presses than inactive lever (IL) presses during the CS+, CS− and ITI (#<i>p</i><.05). There were also more IL presses during the ITI than the CS+ and CS− (‡<i>p</i><.05). (<b>C</b>) More head entries were made during the CS+ than CS− or ITI (*<i>p</i><.05) (n = 12). (<b>D</b>) Sessions to acquire and extinguish a simple stimulus-reward operant behavior (n = 28). (<b>E</b>) Percent responding across extinction sessions. (<b>F</b>) Reinstatement of operant behavior by Reward⁶+CR⁶, CR⁶ and Reward⁶+CR³⁰ (#<i>p</i><.05 versus responding on last extinction session) (n = 9–10/condition). (<b>G</b>) Increasing lever pressing with instrumental training prior to devaluation (n = 16). (<b>H</b>) Pellets eaten prior to trial 1 and 2 of US-sickness pairing, during a context generalization tests (GEN) and a long-term retention test (RET) (n = 8/group). (<b>I</b>) Lever presses and head entries did not differ between devalued (D) and non-devalued (ND) groups. FR = fixed ratio, VI = variable interval, RR = random ratio. Data are Means ±SEM.</p

Cartoon depictions of the main procedural elements of the reward-related paradigms studied.

<p>(<b>A</b>) <u>Pavlovian-instrumental transfer</u>. Mice were first trained to discriminate between one auditory cue (CS+) which was predictive of the delivery of a food reward and a second auditory cue (CS−) not associated with reward. Instrumental training, starting with a continuous schedule of reinforcement, progressed through increasingly sparse variable interval schedules of reinforcement to increase the rate of pressing on the active lever (AL) delivering food reward. Presses on a second, inactive (control) lever (IL) had no programmed consequences. During the PIT probe test, lever presses during presentations of the CS+, CS− and inter-trial interval (ITI) periods were recorded as well as Pavlovian approach behavior (head-entries (HE) into the magazine). (<b>B</b>) <u>Acquisition, extinction and reinstatement of an instrumental response.</u> Mice were trained to respond to a visual stimulus on a touchscreen to obtain a food reward (delivery of which was concomitant with a compound light/tone stimulus to serve as a conditioned reinforcer). During extinction training, responses produced no reward or conditioned reinforcement. Response were subsequently reinstated either by non-contingent delivery of reward and conditioned reinforcers (CR) during the first six of thirty trials (Reward⁶+CR⁶), delivery of the CRs during all thirty trials (CR³⁰), or a combination of these two procedures (Reward⁶+CR³⁰). (<b>C</b>) <u>Malaise-induced reinforcer devaluation</u>. During instrumental training, mice were trained to lever press on a random ratio reinforcement schedule for food reward. Next, on separate session conducted in the home cage, free availability of food pellet was paired with LiCl-induced malaise (Devalued group) or Food and LiCl injections were given unpaired (Non-devalued group). The effect of US-devaluation on lever pressing and magazine head entry was examined in the absence of the primary food reward (i.e. extinction) in the conditioning chambers.</p