Extra-Synaptic GABAA Receptor Potentiation and Neurosteroid-Induced Learning Deficits Are Inhibited by GR3027, a GABAA Modulating Steroid Antagonist.

Objectives In Vitro: To study the effects of GR3027 (golexanolone) on neurosteroid-induced GABA-mediated current responses under physiological GABAergic conditions with recombinant human α5ß3γ2L and α1ß2γ2L GABAA receptors expressed in human embryonic kidney cells, using the response patch clamp technique combined with the Dynaflow™ application system. With α5ß3γ2L receptors, 0.01-3 µM GR3027, in a concentration-dependent manner, reduced the current response induced by 200 nM THDOC + 0.3 µM GABA, as well as the THDOC-induced direct gated effect. GR3027 (1 µM) alone had no effect on the GABA-mediated current response or current in the absence of GABA. With α1ß2γ2L receptors, GR3027 alone had no effect on the GABA-mediated current response or did not affect the receptor by itself. Meanwhile, 1-3 µM GR3027 reduced the current response induced by 200 nM THDOC + 30 µM GABA and 3 µM GR3027 that induced by 200 nM THDOC when GABA was not present. Objectives In Vivo: GR3027 reduces allopregnanolone (AP)-induced decreased learning and anesthesia in male Wistar rats. Rats treated i.v. with AP (2.2 mg/kg) or vehicle were given GR3027 in ratios of 1:0.5 to 1:5 dissolved in 10% 2-hydroxypropyl-beta-cyclodextrin. A dose ratio of AP:GR3027 of at least 1:2.5 antagonized the AP-induced decreased learning in the Morris Water Mase (MWM) and 1:7.5 antagonized the loss of righting reflex (LoR). GR3027 treatment did not change other functions in the rat compared to the vehicle group. Conclusions: GR3027 functions in vitro as an inhibitor of GABAA receptors holding α5ß3γ2L and α1ß2γ2L, in vivo, in the rat, as a dose-dependent inhibitor toward AP's negative effects on LoR and learning in the MWM.

A double-blinded randomised controlled trial of vitamin A drops to treat post-viral olfactory loss: study protocol for a proof-of-concept study for vitamin A nasal drops in post-viral olfactory loss (APOLLO).

BACKGROUND: Smell loss is a common problem with an estimated 5% of the population having no functioning sense of smell. Viral causes of smell loss are the second most common cause and the coronavirus (COVID-19) pandemic is estimated to have caused 20,000 more people this year to have a lasting loss of smell. Isolation, depression, anxiety, and risk of danger from hazards such as toxic gas and spoiled food are all negative impacts. It also affects appetite with weight loss/gain in two-thirds of those affected. Phantosmia or smell distortion can also occur making most foods seem unpalatable. Smell training has been tried with good results in the immediate post-viral phase. Evidence behind treatment with steroids has not shown to have proven effectiveness. With this, a key problem for patients and their clinicians is the lack of proven effective therapeutic treatment options. Based on previous studies, there is some evidence supporting the regenerative potential of retinoic acid, the metabolically active form of vitamin A in the regeneration of olfactory receptor neurons. It is based on this concept that we have chosen vitamin A as our study comparator. AIM: To undertake a two-arm randomised trial of intranasally delivered vitamin A vs no intervention to determine proof of concept. METHODS/DESIGN: The study will compare 10,000 IU once daily Vitamin A self-administered intranasal drops versus peanut oil drops (placebo) delivered over 12 weeks in patients with post-viral olfactory loss. Potentially eligible patients will be recruited from the Smell & Taste Clinic and via the charity Fifth Sense. They will be invited to attend the Brain Imaging Centre at the University of East Anglia on two occasions, 3 months apart. If they meet the eligibility criteria, they will be consented to enter the study and randomised to receive vitamin A drops or no treatment in a 2:1 ratio. MRI scanning will enable volumetric measurement of the OB and ROS; fMRI will then be conducted using an olfactometer to deliver pulsed odours-phenethylalcohol (rose-like) and hydrogen sulphide (rotten eggs). Participants will also perform a standard smell test at both visits as well as complete a quality-of-life questionnaire. Change in OB volume will be the primary outcome measure. DISCUSSION: We expect the outputs of this study to enable a subsequent randomised controlled trial of Vitamin A versus placebo. With PPI input we will make the outputs publicly available using journals, conferences, and social media via Fifth Sense. We have already prepared a draft RCT proposal in partnership with the Norwich Clinical Trials Unit and plan to develop this further in light of the findings. TRIAL REGISTRATION: ISRCTN registry 39523. Date of registration in the primary registry: 23rd February 2021.

Isoallopregnanolone Inhibits Estrus Cycle-Dependent Aggressive Behavior.

Among female rats, some individuals show estrus cycle-dependent irritability/aggressive behaviors, and these individual rats may be used as a model for premenstrual dysphoric disorder (PMDD). We wanted to investigate if these behaviors are related to the estrus cycle phase containing moderately increased levels of positive GABA-A receptor-modulating steroids (steroid-PAM), especially allopregnanolone (ALLO), and if the adverse behavior can be antagonized. The electrophysiology studies in this paper show that isoallopregnanolone (ISO) is a GABA-A-modulating steroid antagonist (GAMSA), meaning that ISO can antagonize the agonistic effects of positive GABA-A receptor-modulating steroids in both α1ß2γ2L and α4ß3δ GABA-A receptor subtypes. In this study, we also investigated whether ISO could antagonize the estrus cycle-dependent aggressive behaviors in female Wistar rats using a resident-intruder test. Our results confirmed previous reports of estrus cycle-dependent behaviors in that 42% of the tested rats showed higher levels of irritability/aggression at diestrus compared to those at estrus. Furthermore, we found that, during the treatment with ISO, the aggressive behavior at diestrus was alleviated to a level comparable to that of estrus. We noticed an 89% reduction in the increase in aggressive behavior at diestrus compared to that at estrus. Vehicle treatment in the same animals showed a minimal effect on the diestrus-related aggressive behavior. In conclusion, we showed that ISO can antagonize Steroid-PAM both in α1ß2γ2L and α4ß3δ GABA-A receptor subtypes and inhibit estrus cycle-dependent aggressive behavior.

A large multi-country outbreak of monkeypox across 41 countries in the WHO European Region, 7 March to 23 August 2022.

Following the report of a non-travel-associated cluster of monkeypox cases by the United Kingdom in May 2022, 41 countries across the WHO European Region have reported 21,098 cases and two deaths by 23 August 2022. Nowcasting suggests a plateauing in case notifications. Most cases (97%) are MSM, with atypical rash-illness presentation. Spread is mainly through close contact during sexual activities. Few cases are reported among women and children. Targeted interventions of at-risk groups are needed to stop further transmission.

A Participatory Intervention to Improve the Psychosocial Work Environment and Mental Health in Human Service Organisations. A Mixed Methods Evaluation Study.

Work-related stress is a global problem causing suffering and economic costs. In Sweden, employees in human service occupations are overrepresented among persons on sick leave due to mental health problems such as stress-related disorders. The psychosocial work environment is one contributing factor for this problem, making it urgent to identify effective methods to decrease stress at the workplace. The aim of the study is to evaluate a participatory intervention to improve the psychosocial work environment and mental health using an embedded mixed methods design. The study is a controlled trial with a parallel process evaluation exploring fidelity and participants' reactions to the intervention activities, experiences of learning and changes in behaviours and work routines. We collected data through documentation, interviews and three waves of questionnaires. Our results show small changes in behaviours and work routines and no positive effects of the intervention on the psychosocial work environment nor health outcomes. One explanation is end-users' perceived lack of involvement over the process causing the intervention to be seen as a burden. Another explanation is that the intervention activities were perceived targeting the wrong organisational level. A representative participation over both content and process can be an effective strategy to change psychosocial working conditions and mental health.

The Sustained Influence of an Error on Future Decision-Making.

Post-error slowing (PES) is consistently observed in decision-making tasks after negative feedback. Yet, findings are inconclusive as to whether PES supports performance accuracy. We addressed the role of PES by employing drift diffusion modeling which enabled us to investigate latent processes of reaction times and accuracy on a large-scale dataset (>5,800 participants) of a visual search experiment with emotional face stimuli. In our experiment, post-error trials were characterized by both adaptive and non-adaptive decision processes. An adaptive increase in participants' response threshold was sustained over several trials post-error. Contrarily, an initial decrease in evidence accumulation rate, followed by an increase on the subsequent trials, indicates a momentary distraction of task-relevant attention and resulted in an initial accuracy drop. Higher values of decision threshold and evidence accumulation on the post-error trial were associated with higher accuracy on subsequent trials which further gives credence to these parameters' role in post-error adaptation. Finally, the evidence accumulation rate post-error decreased when the error trial presented angry faces, a finding suggesting that the post-error decision can be influenced by the error context. In conclusion, we demonstrate that error-related response adaptations are multi-component processes that change dynamically over several trials post-error.

Memory-reliant Post-error Slowing Is Associated with Successful Learning and Fronto-occipital Activity.

Negative feedback after an action in a cognitive task can lead to devaluing that action on future trials as well as to more cautious responding when encountering that same choice again. These phenomena have been explored in the past by reinforcement learning theories and cognitive control accounts, respectively. Yet, how cognitive control interacts with value updating to give rise to adequate adaptations under uncertainty is less clear. In this fMRI study, we investigated cognitive control-based behavioral adjustments during a probabilistic reinforcement learning task and studied their influence on performance in a later test phase in which the learned value of items is tested. We provide support for the idea that functionally relevant and memory-reliant behavioral adjustments in the form of post-error slowing during reinforcement learning are associated with test performance. Adjusting response speed after negative feedback was correlated with BOLD activity in right inferior frontal gyrus and bilateral middle occipital cortex during the event of receiving the feedback. Bilateral middle occipital cortex activity overlapped partly with activity reflecting feedback deviance from expectations as measured by unsigned prediction error. These results suggest that cognitive control and feature processing cortical regions interact to implement feedback-congruent adaptations beneficial to learning.

An Anti-ß-Amyloid Vaccine for Treating Cognitive Deficits in a Mouse Model of Down Syndrome.

In Down syndrome (DS) or trisomy of chromosome 21, the ß-amyloid (Aß) peptide product of the amyloid precursor protein (APP) is present in excess. Evidence points to increased APP gene dose and Aß as playing a critical role in cognitive difficulties experienced by people with DS. Particularly, Aß is linked to the late-life emergence of dementia as associated with neuropathological markers of Alzheimer's disease (AD). At present, no treatment targets Aß-related pathogenesis in people with DS. Herein we used a vaccine containing the Aß 1-15 peptide embedded into liposomes together with the adjuvant monophosphoryl lipid A (MPLA). Ts65Dn mice, a model of DS, were immunized with the anti-Aß vaccine at 5 months of age and were examined for cognitive measures at 8 months of age. The status of basal forebrain cholinergic neurons and brain levels of APP and its proteolytic products were measured. Immunization of Ts65Dn mice resulted in robust anti-Aß IgG titers, demonstrating the ability of the vaccine to break self-tolerance. The vaccine-induced antibodies reacted with Aß without detectable binding to either APP or its C-terminal fragments. Vaccination of Ts65Dn mice resulted in a modest, but non-significant reduction in brain Aß levels relative to vehicle-treated Ts65Dn mice, resulting in similar levels of Aß as diploid (2N) mice. Importantly, vaccinated Ts65Dn mice showed resolution of memory deficits in the novel object recognition and contextual fear conditioning tests, as well as reduction of cholinergic neuron atrophy. No treatment adverse effects were observed; vaccine did not result in inflammation, cellular infiltration, or hemorrhage. These data are the first to show that an anti-Aß immunotherapeutic approach may act to target Aß-related pathology in a mouse model of DS.

Long-term continuous allopregnanolone elevation causes memory decline and hippocampus shrinkage, in female wild-type B6 mice.

Chronic stress in various forms increases the risk for cognitive dysfunction, dementia and Alzheimer's disease. While the pathogenesis behind these findings is unknown, growing evidence suggests that chronic increase in neurosteroid levels, such as allopregnanolone, is part of the mechanism. We treated wild-type C57BL/6J mice with allopregnanolone for 5months, using osmotic pumps. This treatment led to moderately increased levels of allopregnanolone, equivalent to that of mild chronic stress. After an interval of no treatment for 1month, female mice showed impaired learning and memory function in the Morris water maze (MWM) in combination with diminished hippocampus weight and increased cerebellum weight, both correlating to MWM performance. Male mice showed a minor reduction in memory function and no differences in brain structure. We conclude that chronic allopregnanolone elevation can lead to cognitive dysfunction and negative brain alterations. We suggest that allopregnanolone could play a key role in the pathogenesis of stress-induced cognitive disturbances and perhaps dementia.

Feedback on Trait or Action Impacts on Caudate and Paracingulum Activity.

There is a general conception that positive associations to one's trait, e.g. 'I'm clever', are beneficial for cognitive performance. Scientific evidence shows that this is a simplification. In this functional magnetic resonance imaging (fMRI) study we used written trial-based trait feedback 'you are clever', or task feedback 'your choice was correct', on each correct response of a rule-switching task, to investigate how the character of positive self-associations influences performance outcome. Twenty participants took part in this crossover design study. We found that trait feedback was less beneficial for motivation and performance improvement, and resulting in enhanced neural activation on more difficult bivalent rule trials. This indicates that the task was treated as more complex in this condition. For example, 'you are clever' feedback led to enhanced activation in anterior caudate nucleus, an area known to process uncertainty. We further observed that activation in anterior paracingulate cortex was sensitive to whether self-reflection was imposed by external feedback or generated from internal processes, where the latter activation correlated positively with performance when following after task feedback. Our results illustrate how feedback can evoke self-reflections that either help or hinder motivation and performance, most likely by impacting on processes of uncertainty. The results support social psychological models stipulating that trait focus take resources away from task focus.

Isoallopregnanolone antagonize allopregnanolone-induced effects on saccadic eye velocity and self-reported sedation in humans.

Allopregnanolone (AP) is an endogenous neurosteroid. It modulates the effect of γ-amino-butyric acid (GABA) on the GABA type A (GABAA) receptor, which leads to increased receptor activity. Since the GABA-system is mainly inhibitory, increased AP activity leads to modulation of neuronal activity. In vitro studies of GABAA receptor activity and in vivo animal studies of sedation have shown that AP-induced effects can be inhibited by another endogenous steroid, namely isoallopregnanolone (ISO). In this study we investigated if ISO can antagonize AP-induced effects in healthy female volunteers, via measurements of saccadic eye velocity (SEV) and self-rated sedation. With a single-blind cross-over design, 12 women were studied on three separate occasions; given AP alone or AP in combination with one of two ISO doses. Congruent with previous reports, AP administration decreased SEV and induced sedation and these effects were diminished by simultaneous ISO administration. Also, the ISO effect modulation was seemingly stronger for SEV than for sedation. These effects were observed already at an ISO dose exposure that was approximately half of that of AP. In conclusion, ISO antagonized AP-induced decrease in SEV and self-reported sedation, probably in a non-competitive manner.

Impact of feedback on three phases of performance monitoring.

We investigated if certain phases of performance monitoring show differential sensitivity to external feedback and thus rely on distinct mechanisms. The phases of interest were: the error phase (FE), the phase of the correct response after errors (FEC), and the phase of correct responses following corrects (FCC). We tested accuracy and reaction time (RT) on 12 conditions of a continuous-choice-response task; the 2-back task. External feedback was either presented or not in FE and FEC, and delivered on 0%, 20%, or 100% of FCC trials. The FCC20 was matched to FE and FEC in the number of sounds received so that we could investigate when external feedback was most valuable to the participants. We found that external feedback led to a reduction in accuracy when presented on all the correct responses. Moreover, RT was significantly reduced for FCC100, which in turn correlated with the accuracy reduction. Interestingly, the correct response after an error was particularly sensitive to external feedback since accuracy was reduced when external feedback was presented during this phase but not for FCC20. Notably, error-monitoring was not influenced by feedback-type. The results are in line with models suggesting that the internal error-monitoring system is sufficient in cognitively demanding tasks where performance is ∼ 80%, as well as theories stipulating that external feedback directs attention away from the task. Our data highlight the first correct response after an error as particularly sensitive to external feedback, suggesting that important consolidation of response strategy takes place here.

Self-Associations Influence Task-Performance through Bayesian Inference.

The way we think about ourselves impacts greatly on our behavior. This paper describes a behavioral study and a computational model that shed new light on this important area. Participants were primed "clever" and "stupid" using a scrambled sentence task, and we measured the effect on response time and error-rate on a rule-association task. First, we observed a confirmation bias effect in that associations to being "stupid" led to a gradual decrease in performance, whereas associations to being "clever" did not. Second, we observed that the activated self-concepts selectively modified attention toward one's performance. There was an early to late double dissociation in RTs in that primed "clever" resulted in RT increase following error responses, whereas primed "stupid" resulted in RT increase following correct responses. We propose a computational model of subjects' behavior based on the logic of the experimental task that involves two processes; memory for rules and the integration of rules with subsequent visual cues. The model incorporates an adaptive decision threshold based on Bayes rule, whereby decision thresholds are increased if integration was inferred to be faulty. Fitting the computational model to experimental data confirmed our hypothesis that priming affects the memory process. This model explains both the confirmation bias and double dissociation effects and demonstrates that Bayesian inferential principles can be used to study the effect of self-concepts on behavior.

Allopregnanolone promotes success in food competition in subordinate male rats.

BACKGROUND/AIMS: Allopregnanolone or 3α-hydroxy-5α-pregnan-20-one (AlloP) is normally sedative and anxiolytic, but can under provoking circumstances paradoxically induce aggressive behavior. Therefore, it is of particular interest to determine if there is a relationship between an anxiolytic effect and aggressive behavior following AlloP administration. METHOD: Male Wistar rats were housed in triads comprising of 1 young rat (35 days) and 2 older rats (55 days), with the intent of producing a social hierarchy. The triads were sampled for total serum testosterone and submitted to a social challenge in the form of a food competition test (FCT), where the rats competed for access to drinking sweetened milk. At baseline, the younger rats were identified as subordinates. To test for the behavioral effect of AlloP, the subordinate rats were given intravenous AlloP injections of 0.5 and 1 mg/kg. To assess the optimal AlloP effect, 6 intervals (5, 10, 15, 20, 30 and 40 min) between injection and the FCT were used. In separate studies, AlloP was also given by subcutaneous and intraperitoneal administration at 10 and 17 mg/kg. RESULTS: AlloP (1 mg/kg, i.v.) increased drinking time and aggressive behavior in subordinate rats, with a positive correlation between these behaviors. The subcutaneous injection (17 mg/kg) also increased drinking time in subordinate animals. Serum testosterone concentration was higher in dominant compared to subordinate rats, and correlated with drinking time and weight. CONCLUSIONS: AlloP increased drinking time and aggressive behavior, and the correlation indicates a relationship between an anxiolytic effect and aggressive behavior.

Brief but chronic increase in allopregnanolone cause accelerated AD pathology differently in two mouse models.

Previously, we have shown that chronic treatment with allopregnanolone (ALLO) for three months impaired learning function in the Swe/PS1 mouse model. ALLO is a neurosteroid, produced in the CNS and a GABAA receptor agonist. ALLO modulates the general inhibitory system in the CNS by enhancing the effect of GABA. Chronic treatment with other GABAA receptor active compounds, such as benzodiazepines, ethanol and medroxy-progesterone acetate has been associated to cognitive decline and/or increased risk for dementia. In this study, we sufficed with a treatment period of one month for the Swe/PS1 mouse, and included another Alzheimer's disease mouse model; the Swe/Arc model. We found that one month of chronic treatment with elevated ALLO levels within physiological range impaired learning and memory function in the Swe/Arc female and male mice. Male Swe/PS1 mice also showed marginally impaired function, while the female mice did not. Furthermore, the chronic ALLO treatment caused increased levels of soluble Aß in the Swe/PS1 mouse model while the levels were unchanged in the Swe/Arc model. Therefore, both Swe/Arc and Swe/PS1 mice showed signs of accelerated disease progression. Still, further studies are required to determine the mechanisms behind the cognitive impairment and the increased Aß-levels caused by mildly elevated ALLO-levels.

Chronic allopregnanolone treatment accelerates Alzheimer's disease development in AßPP(Swe)PSEN1(ΔE9) mice.

The endogenous neurosteroid allopregnanolone alters neuronal excitability via modulation of the GABAA receptor and causes decreased neurotransmission. In Alzheimer's disease (AD), neurotransmission seems to alter the levels of toxic intracellular amyloid-ß (Aß) oligomers, which are implicated in AD pathogenesis and cause cognitive decline. Inhibition of synaptic activity has been shown to increase levels of intracellular Aß. Allopregnanolone at endogenous stress levels inhibits synaptic activity and could have similar effects. By using a transgenic AßPP(Swe)PSEN1(ΔE9) mouse model for AD, we observed that chronic allopregnanolone treatment for three months with stress levels of allopregnanolone impaired learning in the Morris water maze. The learning impairment was seen one month after the end of treatment. Chronic allopregnanolone treatment also led to increased levels of soluble Aß in the brain, which could be a sign of advanced pathogenesis. Since the learning and memory of wild-type mice was not affected by the treatment, we propose that chronic allopregnanolone treatment accelerates the pathogenesis of AD. However, further studies are required in order to determine the underlying mechanism.

Priming for self-esteem influences the monitoring of one's own performance.

Social cues have subtle effects on a person, often without them being aware. One explanation for this influence involves implicit priming of trait associations. To study this effect, we activated implicit associations in participants of 'being Clever' or 'being Stupid' that were task relevant, and studied its behavioural impact on an independent cognitive task (the n-back task). Activating a representation of 'Clever' caused participants to slow their reaction times after errors on the working memory task, while the reverse pattern was seen for associations to 'Stupid'. Critically, these behavioural effects were absent in control conditions. Using functional magnetic resonance imaging, we show that the neural basis of this effect involves the anterior paracingulate cortex (area 32) where activity tracked the observed behavioural pattern, increasing its activity during error monitoring in the 'Clever' condition and decreasing in the 'Stupid' condition. The data provide a quantitative demonstration of how implicit cues, which specifically target a person's self-concept, influences the way we react to our own behaviour and point to the anterior paracingulate cortex as a critical cortical locus for mediating these self-concept related behavioural regulations.

Medial frontal cortex: from self-generated action to reflection on one's own performance.

It was suggested over 20 years ago that the supplementary motor cortex is involved in self-generated behaviour. Since then, there have been many studies using electrophysiology and brain imaging of the role of the supplementary motor cortex and anterior cingulate cortex. In light of the findings, the proposal that these regions are crucial for self-generated action has recently been challenged. Here, we review the recent literature and argue that the proposal survives the findings. We further argue that it can be generalised to cover reflection on mental states. Finally, we suggest that the pattern of anatomical connections is consistent with the proposal that the medial frontal cortex is crucially involved in self-generated action and self-reflection.

Motivation to do well enhances responses to errors and self-monitoring.

Humans are unique in being able to reflect on their own performance. For example, we are more motivated to do well on a task when we are told that our abilities are being evaluated. We set out to study the effect of self-motivation on a working memory task. By telling one group of participants that we were assessing their cognitive abilities, and another group that we were simply optimizing task parameters, we managed to enhance the motivation to do well in the first group. We matched the performance between the groups. During functional magnetic resonance imaging, the motivated group showed enhanced activity when making errors. This activity was extensive, including the anterior paracingulate cortex, lateral prefrontal and orbitofrontal cortex. These areas showed enhanced interaction with each other. The anterior paracingulate activity correlated with self-image ratings, and overlapped with activity when participants explicitly reflected upon their performance. We suggest that the motivation to do well leads to treating errors as being in conflict with one's ideals for oneself.

The representation of abstract task rules in the human prefrontal cortex.

We have previously reported sustained activation in the ventral prefrontal cortex while participants prepared to perform 1 of 2 tasks as instructed. But there are studies that have reported activation reflecting task rules elsewhere in prefrontal cortex, and this is true in particular when it was left to the participants to decide which rule to obey. The aim of the present experiment was to use functional magnetic resonance imaging (fMRI) to find whether there was activation in common, irrespective of the way that the task rules were established. On each trial, we presented a word after a variable delay, and participants had to decide either whether the word was abstract or concrete or whether it had 2 syllables. The participants either decided before the delay which task they would perform or were instructed by written cues. Comparing the self-generated with the instructed trials, there was early task set activation during the delay in the middle frontal gyrus. On the other hand, a conjunction analysis revealed sustained activation in the ventral prefrontal and polar cortex for both conditions. We argue that the ventral prefrontal cortex is specialized for handling conditional rules regardless of how the task rules were established.