Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Substance Exposure and Adverse Neonatal Outcomes: A Population-Based Cohort Study

OBJECTIVE

To estimate the independent and combined effects of in utero exposures on birth outcomes in a rural population.

STUDY DESIGN

The study used population-level data (2020-2022) from a state-wide surveillance tool (Working in Appalachia to identify at-risk infants, Critical congenital heart disease, and Hearing loss) in West Virginia. Outcomes included low birth weight, preterm birth, small for gestational age, and birth weight in grams. Exposure included a composite variable with 8 levels of 3 exposure (opioids, stimulants, and cannabis) categories. Analyses were adjusted for sociodemographic covariates using multiple logistic and linear regression analyses.

RESULTS

Of the 34 412 singleton live births, 1 in 8 newborns (12.2%) had in utero exposure(s) to opioids, stimulants, and/or cannabis, 11.5% were preterm, 7.9% had low birthweight, 9.6% were small for gestational age, and mean birth weight was 3249 ± 563.6 g. Preterm birth was associated with stimulant alone exposure (aOR, 1.40; 95% CI, 1.03-1.89) and stimulant and cannabis concurrent exposure (aOR, 1.69; 95% CI, 1.16, 2.47). Low birthweight was associated with opioids alone (aOR, 1.34; 95% CI, 1.10, 1.63), cannabis alone (aOR, 1.31; 95% CI, 1.13 to -1.52), opioid and cannabis (aOR, 1.61; 95% CI, 1.12 to -2.31), and opioids, stimulants, and cannabis concurrent exposures (aOR, 2.27; 95% CI, 1.43-3.61). Five exposure categories were associated with lower birth weights (adjusted mean difference range. -72 to -211 g). Small for gestational age was associated with opioids alone (aOR, 1.48; 95% CI, 1.24-1.78), cannabis alone (aOR, 1.49; 95% CI, 1.31-1.69), and opioids and cannabis concurrent exposures (aOR, 1.91; 95% CI, 1.36-2.67).

CONCLUSIONS

We showed complex associations between in utero substance exposures, preterm birth, birth weight, and sociodemographic factors in a rural population. The results may inform policy efforts to improve maternal and child health in socioeconomically disadvantaged and underserved rural populations.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

984 ADVANCE CARE PLANNING ON THE COMPLEX CARE WARDS AT ROYAL BOLTON HOSPITAL

Introduction

Advance care planning (ACP) is an important aspect of geriatric medicine, giving patients the opportunity to express their wishes and identify their preferred place of care and death whilst reducing unwanted hospital admissions. At Royal Bolton Hospital we reviewed the Complex Care department’s performance in engaging with ACP discussions with appropriate patients and considered how this could be improved.

Method

In October 2020, patients were identified from the current inpatients on the Complex Care wards using the following criteria: nursing home resident, clinical frailty score (CFS) 7 or above, or CFS 6 with 3 or more hospital admissions in the last 6 months. We reviewed the patient notes to ascertain whether any ACP had occurred and then followed the patients up at 6 and 12 months. At 6 and 12 months we identified the mortality and readmission rates to quantify whether the patients had been appropriate for ACP.

Results

35 patients identified as appropriate for ACP. ACP had been conducted in 10 patients. At 6 months, 13 patients had died and 17 had had hospital readmissions, totalling 196 readmission days. At 12 months, 8 patients had died, and 8 patients had been readmitted to hospital, totalling 85 readmission days. Combining the data for the 6- and 12-month results revealed 21 patients had died and 25 had been readmitted to hospital, totalling 281 readmission days. Only 4 of the 35 patients had neither died nor been readmitted to hospital.

Conclusion

Appropriate patients were accurately identified for ACP as confirmed by their subsequent mortality and readmission rates. However, there is scope for improving the quantity of ACP discussions by the Complex Care department in these patients. Further education for the medical staff, a patient leaflet and poster aimed at the ward juniors will be introduced with the aim of doing this.

The association between area-level residential instability and gray matter volume changes

Introduction

Area-level residential instability (ARI), an index of social fragmentation, has been shown to explain the association between urbanicity and psychosis. Urban upbringing has been shown to be associated with decreased gray matter volumes (GMV)s of brain regions corresponding to the right caudal middle frontal gyrus (CMFG) and rostral anterior cingulate cortex (rACC).

Objectives

We hypothesize that greater ARI will be associated with reduced right posterior CMFG and rACC GMVs.

Methods

Data were collected at baseline as part of the North American Prodrome Longitudinal Study. Counties where participants resided during childhood were geographically coded using the US Censuses to area-level factors. ARI was defined as the percentage of residents living in a different house five years ago. Generalized linear mixed models tested associations between ARI and GMVs.

Results

This study included 29 HC and 64 CHR-P individuals who were aged 12 to 24 years, had remained in their baseline residential area, and had magnetic resonance imaging scans. ARI was associated with reduced right CMFG (adjusted β = -0.258; 95% CI = -0.502 – -0.015) and right rACC volumes (adjusted β = -0.318; 95% CI = -0.612 – -0.023). The interaction terms (ARI X diagnostic group) in the prediction of both brain regions were not significant, indicating that the relationships between ARI and regional brain volumes held for both CHR-P and HCs.

Conclusions

Like urban upbringing, ARI may be an important social environmental characteristic that adversely impacts brain regions related to schizophrenia.

Disclosure

No significant relationships.

675 IMPROVING RECOGNITION OF DELIRIUM IN CRITICAL CARE PATIENTS

Introduction

Delirium is more prevalent in patients admitted to the critical care environment, those over 65 years old and living with frailty. By increasing the recognition of delirium we can improve management of patients and therefore reduce associated morbidity. Initial audit of this patient group highlighted that we are missing opportunities to screen for, diagnose and document the presence of delirium. This Quality Improvement project aimed to improve delirium screening, and therefore recognition, on the critical care unit at The Royal Bolton Hospital.

Method

A retrospective analysis of patients aged ≥65 years or with a CFS ≥5 admitted to critical care at The Royal Bolton Hospital over a 2-week period for each PDSA cycle. Three cycles were undertaken. The initial intervention was a local teaching session for medical and nursing staff on critical care. The second intervention was to display delirium information posters throughout critical care which encouraged recognition and screening of delirium.

Results

Prior to intervention 9% of this patient group were assessed for delirium on admission to critical care and 55% were re-assessed at some point during their admission. After the initial intervention these numbers significantly improved to 33% and 80% respectively. After the second intervention 8% were screened on admission and 69% were re-assessed. Missed opportunities to document delirium as a diagnosis remained similar throughout all cycles.

Conclusion

We can improve delirium screening via regular educational sessions for medical and nursing staff on critical care. Information posters do not appear to have as much impact. There is scope to improve documentation of delirium as a diagnosis which would further aid in management and outcomes. We suggest a further PDSA cycle with an intervention to address this.

A review of executive functioning challenges and strengths in autistic adults

Objective: There has been a steady rise in research characterizing executive functioning (EF) impairments in autistic individuals but limited research investigating EF strengths. This review provides a summary of current EF research in autistic adults with a focus on EF challenges and strengths and potential sources of heterogeneity in research findings. New avenues for addressing gaps in our understanding of EF strengths are proposed.Method: A review of the EF literature was conducted. One hundred twenty-four studies of inhibition, working memory, cognitive flexibility, fluency, planning, decision-making, and subjective measures of EF in autistic adults were included.Results: Autistic adults with average intellectual functioning demonstrate difficulties with cognitive flexibility, phonemic fluency, and working memory. Strengths in planning, decision-making, and semantic verbal fluency were evident in some but not all studies. Findings regarding inhibition are inconclusive. Key findings across each EF domain are discussed and sources of potential heterogeneity across studies were evaluated. The type of measure used appears to contribute to heterogeneous findings. Subjective EF measures revealed more consistent findings of deficits in autistic adults than objective EF measures.Conclusions: Research reveals areas of EF weaknesses as well as strengths in autistic adults. Unlike EF challenges, EF strengths are not well understood. Future research identifying EF strengths is needed to improve services and supports for autistic adults. Further investigation of potential factors that interact with or constrain EF such as comorbid disorders, verbal ability, sensory processing, and other factors specific to autism will be critical to move the field forward and increase understanding of how EF is related to everyday functioning in autistic adults.

228 Resilience, Mindset and Burnout of Healthcare Workers During the COVID-19 Pandemic

Introduction

We investigated the impact of the Biopsychosocial challenges associated with the COVID-19 Pandemic on the Healthcare Workforce, exploring the impact on and relationship between Healthcare Workers’ Mindset, Resilience and Burnout.

Method

An electronic survey was distributed to Healthcare Workers through Professional Associations' websites and social media. The survey contained demographic questions, a Burnout Inventory, a General Resilience scale, a scale to assess for Resilience during the Pandemic, as well as an Adapted Dweck Mindset instrument to measure Mindset as related to Workplace Environment and Resilience. Univariate and multivariate analysis was undertaken to examine the relationship between these factors.

Results

1,370 healthcare workers completed the questionnaire. 58.5%, 25.4%, 28.5% reported having Burnout, Low General Resilience and Low COVID Resilience, respectively. Burnout was significantly associated with Fixed Mindset, Low General Resilience and Low COVID Resilience. Resilience Training was found to be protective for Burnout.

Conclusions

The COVID-19 Pandemic has led to a higher proportion of HCWs experiencing Burnout than previously reported. Our findings demonstrate that HCWs with Low Resilience and Fixed Mindsets are more likely to experience Burnout, suggesting that, in combination with improved institutional support, there is a role for personalised Resilience and Mindset Training, in helping reduce the proportion of HCW Burnout.

Impact of intra-operative hypotension on mortality rates and post-operative complications in dogs undergoing cholecystectomy

OBJECTIVES

To report the mortality rate within a cohort of dogs undergoing cholecystectomy and investigate the impact of intra-operative hypotension on mortality.

MATERIALS AND METHODS

Clinical records at five UK referral centres were reviewed for dogs undergoing cholecystectomy. Data collected included presenting signs, pre-operative blood test results, intra-operative data including frequency and duration of hypotension and the incidence and type of post-operative complications.

RESULTS

Data from 119 dogs were included. Sixteen dogs (13%) died before discharge and by 28 days after surgery the total mortality was 19 dogs (17%). Hypotension lasting over 10 minutes during general anaesthesia occurred in 65 dogs (54.6%), with a mean ± sd duration of 36.1 ± 30.0 minutes. Intra-operative hypotension or the number of hypotensive episodes did not appear to be associated with in-hospital or 28-day mortality. American Society of Anaesthesiologists grade (of fitness for surgery) was significantly associated with both in-hospital and 28-day mortality on univariable analysis, as were post-operative hypoproteinaemia, ileus and pancreatitis. However on multivariable analysis, only ileus and pancreatitis were found to significantly impact mortality.

CLINICAL SIGNIFICANCE

Dogs presenting with a higher American Society of Anaesthesiologists grade appear to have a higher risk of mortality, although intra-operative hypotension did not appear to be part of this risk.

Long-term clinical outcomes following surgery for spontaneous pneumothorax caused by pulmonary blebs and bullae in dogs - a multicentre (AVSTS Research Cooperative) retrospective study

OBJECTIVES

To report the clinical characteristics and recurrence rate of spontaneous pneumothorax secondary to pulmonary blebs and bullae following surgical management in a large cohort of dogs. To explore potential risk factors for recurrence and describe outcome.

MATERIALS AND METHODS

Medical records were retrospectively reviewed for cases with spontaneous pneumothorax managed surgically between 2000 and 2017. Signalment, clinical presentation, diagnostic imaging, surgery, histopathology findings and patient outcomes were recorded. Follow-up was performed via patient records and telephone contact.

RESULTS

Records of 120 dogs with surgically treated pneumothorax were identified and reviewed, with 99 cases appropriate for exploratory statistical analysis. Median follow-up was 850 days (range: 9-5105 days). Two- and 5-year survival rates were 88.4% and 83.5%, respectively. There was recurrence in 14 of 99 dogs (14.1%) with adequate follow-up, with a median time to recurrence of 25 days (1-1719 days). Univariable Cox regression analysis suggested increased risk for recurrence in giant breeds (hazard ratio = 11.05, 95% confidence interval: 2.82-43.35) and with increasing bodyweight (HR = 1.04, 95% confidence interval: 1.00-1.09). Of 14 dogs with recurrence, six were euthanased, two died of causes related to pneumothorax and six underwent further treatment, of which five were resolved.

CLINICAL SIGNIFICANCE

Long-term survival for dogs with surgically managed spontaneous pneumothorax was good and associated with a low risk of recurrence. Giant breed dogs and increased bodyweight were the only variables identified as possible risk factors for recurrence. The outcome for dogs with recurrence undergoing a second intervention was also favourable.

Building Capacity: The Case for Values-based Operations

Since the opening of the University of Nebraska at Omaha’s (UNO) Community Engagement Center in 2014, both university and community building partners have been guided by a set of core values. Established by a community/university task force after months of focus groups, community conversations, and other data gathering activities, these values have helped provide a foundation for the selection of university and community building partners, decision-making, and ongoing operations. This study explored the ways in which building partner alignment with the Weitz CEC values influenced their subsequent perceived organizational capacity. Results indicated that embracing the values was positively associated with increased perceptions of organizational capacity. Essentially, those who indicated they embraced the values experienced heightened feelings of belongingness, participated in more networking activities, and agreed that the culture was more cooperative, which contributed to their organization’s perceived capacity.

Assessment of the FilmArray® multiplex PCR system and associated meningitis/encephalitis panel in the diagnostic service of a tertiary hospital

Rapid and accurate diagnosis of meningitis/encephalitis (M/E) is essential for successful patient outcomes. The FilmArray® meningitis/encephalitis Panel (MEP) is a multiplexed PCR test for simultaneous, rapid detection of pathogens directly from cerebrospinal fluid (CSF) samples. 94 prospectively collected CSF specimens from patients with clinical suspicion of infective M/E underwent testing for 14 pathogens simultaneously, including Escherichia coli, Haemophilus influenzae, Neisseria meningitidis, and Varicella zoster. MEP demonstrated 95% agreement with current PCR methods, resulting in 16 diagnosed cases of M/E. Typically, the FilmArray® MEP results were delivered within approximately one hour, contrasting with current practices taking up to 5.6 days. Given the significant morbidity and mortality associated with delayed diagnosis of central nervous system infections, the FilmArray® MEP is a useful addition to the diagnostic capabilities of a clinical microbiology department.

Effect of age on the relationship between metabolizable energy and digestible energy for broiler chickens

A total of 960 male Ross 308 chicks (day-old) were used to investigate the effect of age on the relationship between metabolizable energy (ME) and digestible energy (DE) for broiler chickens. Bird growth variables, nitrogen retention (NR), nitrogen digestibility (ND), as well as the relative weight of liver, pancreas, and the gastrointestinal tract were determined. Practical diets that compared 2 cereals (corn and wheat) and exogenous xylanase (0 or 16,000 BXU/kg) were evaluated at 5 ages (7, 14, 21, 28, and 35 D) in a 2 × 2 × 5 factorial arrangement of treatments with 8 replicates per treatment and started with 30 birds per replicate. A randomized block ANOVA analysis of repeated measures was performed, and a 2 × 2 × 5 factorial structure was used to investigate the 2 dietary treatment factors (cereal type and the presence of xylanase) within the 5 bird ages (7, 14, 21, 28, and 35 D), and their interactions. Apparent metabolizable energy (AME) increased linearly from 7 until 28 D of age, but (P < 0.05) decreased at 35 D of age. Digestible energy was high at 7 D of age, then dropped and remained similar (P > 0.05) from 14 to 35 D of age. The AME: DE ratio was lowest (P < 0.05) at 7 D of age but there were no (P > 0.05) differences thereafter. Cereal type and xylanase supplementation did not (P > 0.05) change the ME: DE ratio. The results indicate that determining ME before 14 D of age may give absolute values that are lower than would be obtained with older birds. ME values that are determined on older broiler chickens may overestimate the energy availability of practical feeds used in broiler starter feeds.

From opiates to methamphetamine: building new harm reduction responses in Jakarta, Indonesia

BACKGROUND

Despite the rise of stimulant use, most harm reduction programs still focus on people who inject opioids, leaving many people who use methamphetamine (PWUM) underserviced. In Asia, especially, where methamphetamine prevalence has overtaken opioids prevalence, harm reduction programs assisting PWUM are rare. The few existing innovative practices focusing on methamphetamine use lie underreported. Understanding how these programs moved their focus from opiates to methamphetamine could help inspire new harm reduction responses. Hence, this paper analyzes a newly implemented outreach program assisting methamphetamine users in Jakarta, Indonesia. It addresses the program's critical learning points when making the transition to respond to stimulant use.

METHODS

This case study is part of a more extensive research on good practices of harm reduction for stimulant use. For this case study, data was collected through Indonesian contextual documents and documents from the program, structured questionnaire, in-depth interviews with service staff and service users, a focus group discussion with service users, and in-loco observations of activities. For this paper, data was reinterpreted to focus on the key topics that needed to be addressed when the program transitioned from working with people who use opioids to PWUM.

RESULTS

Four key topics were found: (1) getting in touch with different types of PWUM and building trust relationships; (2) adapting safer smoking kits to local circumstances; (3) reframing partnerships while finding ways to address mental health issues; and (4) responding to local law enforcement practices.

CONCLUSIONS

The meaningful involvement of PWUM was essential in the development and evaluation of outreach work, the planning, and the adaptation of safer smoking kits to local circumstances. Also, it helped to gain understanding of the broader needs of PWUM, including mental health care and their difficulties related to law enforcement activities. Operating under a broad harm reduction definition and addressing a broad spectrum of individual and social needs are preferable to focusing solely on specific interventions and supplies for safer drug use. Since many PWUM smoke rather than inject, securing funding for harm reduction focused on people who do not inject drugs and/or who do not use opioids is fundamental in keeping programs sustainable.

Feeding dihydroquercetin to broiler chickens

1. A total of 80 male Ross 308 broilers were used in a study to investigate the effect of dietary dihydroquercetin (DHQ) on growth performance variables, gastrointestinal tract (GIT) and immune organ development, glutathione peroxidase (GPx) and haemoglobin in blood, hepatic vitamin E content, dietary N-corrected metabolisable energy (AMEn) and nutrient retention coefficients when fed to broiler chickens from 7 to 35 d of age.2. Two treatments were used in this study: control (C) and C + 0.5 g/kg extract of Siberian Larch (Larix sibirica) per kg feed, containing 85% DHQ. The diets were fed over 2 feeding phases, a grower phase from 7 to 28 d of age and a finisher phase from 28 to 35 d of age. The birds were reared under the breeder's recommended conditions.3. In general, there were no effects of DHQ on growth performance of broiler chickens. However, the results of this experiment showed that there can be changes in the redness colour of the breast meat when DQH is fed. No negative effects of feeding DHQ at 0.5 g/kg diet were observed in this study.4. Supplementation of poultry diets with DHQ under standard industry-rearing conditions did not improve the performance or any of the studied variables, except an increase of redness index of the breast fillets. Feeding DHQ at different doses and/or under more challenging conditions, e.g. heat stress, may, however, bring positive responses.

Surgical management of impalement injuries to the trunk of dogs: a multicentre retrospective study

OBJECTIVES

To review a large series of dogs referred for treatment of traumatic impalement injuries to the thorax and/or abdomen and to report aetiologies, injury characteristics, management and long-term outcomes.

MATERIALS AND METHODS

Previously collected data on dogs that were surgically treated for impalement injuries to the trunk at six veterinary specialist referral institutions in the UK over an 11-year period were reviewed. Data included patient signalment, physiological variables, injury-specific variables, diagnostic imaging reports, surgical procedures undertaken, duration of hospitalisation, antibiotic use, complications and outcomes. Data were reported with summary statistics.

RESULTS

Fifty-four dogs were included. Impalement occurred most frequently on wooden objects (n=34), and the thoracic cavity was most commonly penetrated (n=37). Computed tomography was sensitive and specific to identifying wooden material in 64% and 88% of cases (n=11), respectively. Thoracotomy was performed in 56%, coeliotomy in 20% and a foreign body or its fragments were retrieved during surgery in 37% of the cases. Complications occurred in 19 dogs (35%), and of these, 68% were minor and 32% major. The survival rate for thoracotomy cases was 93% (n=30). Overall long-term survival was 90%.

CLINICAL SIGNIFICANCE

Despite the often dramatic presentation of impalement injuries, the majority of patients treated in the specialist referral setting can achieve excellent outcomes. These injuries require thorough diagnostic imaging and interpretation before adequate surgical exploration and management, augmented by anaesthesia and critical care during the peri- and postoperative periods; therefore stable patients should be referred to centres able to provide this type of care.

Activated eosinophils in association with enteric nerves in inflammatory bowel disease

Enteric neural dysfunction leads to increased mucous production and dysmotility in inflammatory bowel disease (IBD). Prior studies have shown that tissue eosinophilia is related to disease activity. We hypothesized that interactions between eosinophils and nerves contribute to neural dysfunction in IBD. Tissue from patients with intractable IBD, endoscopic biopsies from patients with steroid responsive IBD, both when active and quiescent, and control tissue were studied. Immunohistochemical studies showed that eosinophils localize to nerves in the mucosal layer of patients with Crohn’s disease (CD) (p<0.001) and ulcerative colitis (UC), (p<0.01). Eosinophils localized to substance P and choline acetyltransferase (ChAT) immunostained nerves. Real time PCR of laser capture micro-dissected enteric ganglia demonstrated Intercellular Adhesion Molecule 1 (ICAM-1) mRNA was increased 7-fold in UC (n = 4), (p = 0.03), and 10-fold in CD (n = 3), (p = 0.05). Compared with controls, eotaxin-3 (CCL-26) mRNA was increased 9-fold in UC (p = 0.04) and 15-fold in CD (p = 0.06). Eosinophil numbers correlated with disease activity, while deposition of major basic protein (MBP) and eosinophil Transforming Growth Factor β -1 (TGFβ-1) expression were seen in therapeutically responsive disease. These data indicate a significant localization of eosinophils to nerves in IBD, mediated through neurally expressed ICAM-1 and eotaxin-3. This cell/neural interaction may influence the function of nerves and contribute to symptoms in IBD.

5-HT(6) receptor agonists and antagonists enhance learning and memory in a conditioned emotion response paradigm by modulation of cholinergic and glutamatergic mechanisms

BACKGROUND AND PURPOSE

5-HT(6) receptors are abundant in the hippocampus, nucleus accumbens and striatum, supporting their role in learning and memory. Selective 5-HT(6) receptor antagonists produce pro-cognitive effects in several learning and memory paradigms while 5-HT(6) receptor agonists have been found to enhance and impair memory.

EXPERIMENTAL APPROACH

The conditioned emotion response (CER) paradigm was validated in rats. Then we examined the effect of the 5-HT(6) receptor antagonist, EMD 386088 (10 mg·kg(-1) , i.p.), and agonists, E-6801 (2.5 mg·kg(-1) , i.p.) and EMD 386088 (5 mg·kg(-1) , i.p.) on CER-induced behaviour either alone or after induction of memory impairment by the muscarinic receptor antagonist, scopolamine (0.3 mg·kg(-1) , i.p) or the NMDA receptor antagonist, MK-801 (0.1 mg·kg(-1) , i.p).

KEY RESULTS

Pairing unavoidable foot shocks with a light and tone cue during CER training induced a robust freezing response, providing a quantitative index of contextual memory when the rat was returned to the shock chamber 24 h later. Pretreatment (-20 min pre-training) with scopolamine or MK-801 reduced contextual freezing 24 h after CER training, showing production of memory impairment. Immediate post-training administration of 5-HT(6) receptor antagonist, SB-270146, and agonists, EMD 386088 and E-6801, had little effect on CER freezing when given alone, but all significantly reversed scopolamine- and MK-801-induced reduction in freezing. CONCLUSION AND IMPLICATIONS Both the 5-HT(6) receptor agonists and antagonist reversed cholinergic- and glutamatergic-induced deficits in associative learning. These findings support the therapeutic potential of 5-HT(6) receptor compounds in the treatment of cognitive dysfunction, such as seen in Alzheimer's disease and schizophrenia.