Consomic mouse strain selection based on effect size measurement, statistical significance testing and integrated behavioral z-scoring: focus on anxiety-related behavior and locomotion.

BACKGROUND: Selecting chromosome substitution strains (CSSs, also called consomic strains/lines) used in the search for quantitative trait loci (QTLs) consistently requires the identification of the respective phenotypic trait of interest and is simply based on a significant difference between a consomic and host strain. However, statistical significance as represented by P values does not necessarily predicate practical importance. We therefore propose a method that pays attention to both the statistical significance and the actual size of the observed effect. The present paper extends on this approach and describes in more detail the use of effect size measures (Cohen's d, partial eta squared - η p (2) ) together with the P value as statistical selection parameters for the chromosomal assignment of QTLs influencing anxiety-related behavior and locomotion in laboratory mice. RESULTS: The effect size measures were based on integrated behavioral z-scoring and were calculated in three experiments: (A) a complete consomic male mouse panel with A/J as the donor strain and C57BL/6J as the host strain. This panel, including host and donor strains, was analyzed in the modified Hole Board (mHB). The consomic line with chromosome 19 from A/J (CSS-19A) was selected since it showed increased anxiety-related behavior, but similar locomotion compared to its host. (B) Following experiment A, female CSS-19A mice were compared with their C57BL/6J counterparts; however no significant differences and effect sizes close to zero were found. (C) A different consomic mouse strain (CSS-19PWD), with chromosome 19 from PWD/PhJ transferred on the genetic background of C57BL/6J, was compared with its host strain. Here, in contrast with CSS-19A, there was a decreased overall anxiety in CSS-19PWD compared to C57BL/6J males, but not locomotion. CONCLUSIONS: This new method shows an improved way to identify CSSs for QTL analysis for anxiety-related behavior using a combination of statistical significance testing and effect sizes. In addition, an intercross between CSS-19A and CSS-19PWD may be of interest for future studies on the genetic background of anxiety-related behavior.

Substrain and light regime effects on integrated anxiety-related behavioral z-scores in male C57BL/6 mice-Hypomagnesaemia has only a small effect on avoidance behavior.

Magnesium (Mg) has been described to possess an anxiolytic function, but a number of studies present inconsistent results on this matter. In this study the effect of Mg deficiency on anxiety-related behavior, brain and blood plasma Mg in young adult male C57BL/6JOlaHsd and C57BL/6NCrl mice was studied. The animals were put on a control or Mg deficient diet from day 0 and significant hypomagnesaemia was evident from day 12 onwards in the test animals. Housing and test conditions were under either conventional light regime (white light behavioral test conditions) or reverse light regime (red light behavioral test conditions). The animals were tested in three tests for unconditioned anxiety: the modified Hole Board (day 14), the light-dark test (day 21) and the elevated plus maze (day 28). Overall integrated behavioral z-scores were calculated over these three behavioral tests. Mg showed a structure dependent distribution at the level of the brain, that differed between C57BL/6 substrain and light regime (conventional versus reverse), respectively. Likewise, total brain Mg did differ between substrain and light regime, but was not affected by the diet. Animals on the Mg deficient diet housed under conventional light regime had a higher final (day 28) blood plasma corticosterone level as compared to controls. Animals housed under reverse light regime exhibited no diet effect of plasma corticosterone levels. The significant hypomagnesaemia at blood plasma level resulted in an effect of Mg deficiency on avoidance, but not overall anxiety-related behavior. Significant differences regarding avoidance behavior were found between the two substrains and light regimes, respectively.

Disrupted cross-laminar cortical processing in ß amyloid pathology precedes cell death.

Disruption of neuronal networks in the Alzheimer-afflicted brain is increasingly recognized as a key correlate of cognitive and memory decline in Alzheimer patients. We hypothesized that functional synaptic disconnections within cortical columnar microcircuits by pathological ß-amyloid accumulation, rather than cell death, initially causes the cognitive impairments. During development of cortical ß-amyloidosis with still few plaques in the transgenic 5xFAD mouse model single cell resolution mapping of neuronal thallium uptake revealed that electrical activity of pyramidal cells breaks down throughout infragranular cortical layer V long before cell death occurs. Treatment of 5xFAD mice with the glutaminyl cyclase inhibitor, PQ 529, partially prevented the decline of pyramidal cell activity, indicating pyroglutamate-modified forms, potentially mixed oligomers of Aß are contributing to neuronal impairment. Laminar investigation of cortical circuit dysfunction with current source density analysis identified an early loss of excitatory synaptic input in infragranular layers, linked to pathological recurrent activations in supragranular layers. This specific disruption of normal cross-laminar cortical processing coincided with a decline of contextual fear learning.

Animal welfare at the group level: more than the sum of individual welfare?

Currently assessment and management of animal welfare are based on the supposition that welfare status is something experienced identically by each individual animal when exposed to the same conditions. However, many authors argue that individual welfare cannot be seen as an 'objective' state, but is based on the animal's own self-perception; such perception might vary significantly between individuals which appear to be exposed to exactly the same challenges. We argue that this has two implications: (1) actual perceived welfare status of individuals in a population may vary over a wide range even under identical environmental conditions; (2) animals that appear to an external observer to be in better or poorer welfare condition may all in fact perceive their own individual status as the same. This would imply that optimum welfare of a social group might be achieved in situations where individual group members differ markedly in apparent welfare status and perceive their own welfare as being optimal under differing circumstances. Welfare phenotypes may also vary along a continuum between self-regarding and other-regarding behaviour; a variety of situations exist where (social) individuals appear to invest in the welfare of other individuals instead of maximising their own welfare; in such a case it is necessary to re-evaluate individual welfare within the context of a social group and recognise that there may be consequences for the welfare of individuals, of decisions made at the group level or by other group members.

Phase de-synchronization effects auditory gating in the ventral striatum but not auditory cortex.

The underlying mechanisms and involved brain areas in sensory gating of repetitive auditory stimuli remain unclear. Especially, the influence of the auditory cortex and the role of temporal precision are under debate. Our first objective was to analyze gating dynamics of local field potentials in the primary auditory cortex and the ventral striatum in an animal experiment, particularly, assessing the influence of the cortex. The second aim was to follow the hypothesis that auditory gating results from phase de-synchronization of evoked potentials in response to the second auditory stimulus. Local field potentials were recorded simultaneously in the auditory cortex and ventral striatum of awake Mongolian gerbils (n=15) during stimulation with trains of frequency-modulated tones. Gating was analyzed by amplitude ratios of the auditory potentials evoked by the first two stimuli in a train, as well as by time-frequency analyses and between-area phase coupling. The strength of auditory gating in the striatum was found to exceed that in the primary auditory cortex by more than 50%. While total-signal-power was comparable between areas, energy in the striatum was primarily expressed in the non-phase-locked fraction. At the same time, energy in the auditory cortex remained phase-locked to the stimuli. Furthermore, we also observed a between-area phase unlocking during sound presentations. Phase de-synchronization appears to be the candidate mechanism behind attenuation of responses to identical repetitive stimuli in the ventral striatum. We conclude that a direct inhibitory response suppression by the auditory cortex plays a minor role in this process.

Animal welfare: at the interface between science and society.

The general concept of animal welfare embraces a continuum between negative/bad welfare and positive/good welfare. Early approaches to defining animal welfare were mainly based on the exclusion of negative states, neglecting the fact that during evolution animals optimised their ability to interact with and adapt to their environment(s). An animal's welfare status might best be represented by the adaptive value of the individual's interaction with a given environmental setting but this dynamic welfare concept has significant implications for practical welfare assessments. Animal welfare issues cannot simply be addressed by means of objective biological measurements of an animal's welfare status under certain circumstances. In practice, interpretation of welfare status and its translation into the active management of perceived welfare issues are both strongly influenced by context and, especially, by cultural and societal values. In assessing whether or not a given welfare status is morally acceptable, animal welfare scientists must be aware that scientifically based, operational definitions of animal welfare will necessarily be influenced strongly by a given society's moral understanding.

Can we measure accurately the prevalence of doping?

Questionnaires are used in the majority of the studies on doping prevalence in sport. Nevertheless, prevalence is not easy to evaluate and previous epidemiologic studies demonstrated a wide variance. This variance has mostly been explained by sample differences. The way to evaluate doping prevalence in the survey is questioned in this paper. A questionnaire was administered to 1810 amateur athletes (993 males, 817 females). Doping use was ascertained in various ways, using different definitions of doping and types of question in the survey. Depending on the definition of doping and the type of question used, the prevalence of doping obtained can differ enormously, between 1.3 and 39.2% of athletes. Marijuana and drugs for asthma were the two banned substances most used. The majority of athletes often ignored the banned list and did not use prohibited substances to dope. Using various ways to question athletes, observing the usage of substances, cross checking the data, taking into account the aim of substances uses and the various definitions of doping are necessary to give more reliable prevalence of doping. Moreover, doping at an amateur level seems to be less of a sport problem than a social problem.

[SILS, LESS, NOS, and Co. for minimally invasive kidney treatment: is less more?]. / SILS, LESS, NOS & Co. bei minimalinvasiven Niereneingriffen : Ist weniger mehr?

BACKGROUND: Single-port surgery (LESS) is a new method of minimally invasive laparoscopic urology. These modern methods reduce the tissue trauma of the patient; however, high demands are placed on the surgeon. We report our initial clinical experience. MATERIAL AND METHODS: Eight patients with different pathologies in the abdomen and retroperitoneum (nephrectomy, renal cyst resection) were treated with an abdominal LESS access and two patients with vaginal NOS (natural orifice surgery) access. Previously, we obtained extensive experience with the setup and implementation in animal studies. The port placements were realized by various single-port systems in the paraumbilical region. RESULTS: All procedures were performed without conversion to an open surgical procedure. Two additional trocars were needed in the first single-port operation. The intra- and postoperative follow-up was uneventful in all patients. The average age of the patients was 58.9 years, the average operating time 131 min, the mean blood loss 70 ml, and the median body mass index 27. The postoperative evaluation of patient satisfaction revealed that all patients were perfectly satisfied. CONCLUSIONS: With appropriate experience and training of the whole team, single-port surgery is a safe and appropriate method for selected renal surgery.

Resonance phenomena in the human auditory cortex: individual resonance frequencies of the cerebral cortex determine electrophysiological responses.

The brain can be considered a dynamical system which is able to oscillate at multiple frequencies. To study the brain's preferred oscillation frequencies, the resonance frequencies in the frequency response of the system can be assessed by stimulating the brain at various stimulation frequencies. Furthermore, the event-related potential (ERP) can be considered as the brain's impulse response. For linear dynamical systems, the frequency response should be equivalent to the frequency transform of the impulse response. The present study test whether this fundamental relation is also true for the frequency transform of the ERP and the frequency response of the brain. Results show that the spectral characteristics of both impulse and frequency response in the gamma frequency range are significantly correlated. Thus, we speculate that the resonance frequencies determine the frequency spectrum of the impulse response. This, in turn, implies that both measures are determined by the same, individually specific, neuronal generator mechanisms.

Trait anxiety affects decision-making differently in healthy men and women: towards gender-specific endophenotypes of anxiety.

Excessive levels of trait anxiety are a risk factor for psychiatric conditions, including anxiety disorders and substance abuse. High trait anxiety has been associated with altered cognitive functioning, in particular with an attentional bias towards aversive stimuli. Decision-making is a crucial aspect of cognitive functioning that relies on the correct processing and control of emotional stimuli. Interestingly, anxiety and decision-making share underlying neural substrates, involving cortico-limbic pathways, including the amygdala, striatum and medial and dorsolateral prefrontal cortices. In the present study, we investigated the relationship between trait anxiety, measured by the State-Trait Anxiety Inventory, and complex decision-making, measured by the Iowa Gambling Task, in healthy male and female volunteers. The main focus of this study was the inclusion of gender as a discriminative factor. Indeed, we found distinct gender-specific effects of trait anxiety: in men, both low and high anxiety groups showed impaired decision-making compared to medium anxiety individuals, whereas in women only high anxiety individuals performed poorly. Furthermore, anxiety affected decision-making in men early in the task, i.e. the exploration phase, as opposed to an effect on performance in women during the second part of the test, i.e. the exploitation phase. These findings were related to different profiles of trait anxiety in men and women, and were independent of performance in the Wisconsin Card Sorting Test and cortisol levels. Our data show gender-specific effects of trait anxiety on emotional decision-making. We suggest gender-specific endophenotypes of anxiety to exist, that differentially affect cognitive functioning.

The combination of appetitive and aversive reinforcers and the nature of their interaction during auditory learning.

Learned changes in behavior can be elicited by either appetitive or aversive reinforcers. It is, however, not clear whether the two types of motivation, (approaching appetitive stimuli and avoiding aversive stimuli) drive learning in the same or different ways, nor is their interaction understood in situations where the two types are combined in a single experiment. To investigate this question we have developed a novel learning paradigm for Mongolian gerbils, which not only allows rewards and punishments to be presented in isolation or in combination with each other, but also can use these opposite reinforcers to drive the same learned behavior. Specifically, we studied learning of tone-conditioned hurdle crossing in a shuttle box driven by either an appetitive reinforcer (brain stimulation reward) or an aversive reinforcer (electrical footshock), or by a combination of both. Combination of the two reinforcers potentiated speed of acquisition, led to maximum possible performance, and delayed extinction as compared to either reinforcer alone. Additional experiments, using partial reinforcement protocols and experiments in which one of the reinforcers was omitted after the animals had been previously trained with the combination of both reinforcers, indicated that appetitive and aversive reinforcers operated together but acted in different ways: in this particular experimental context, punishment appeared to be more effective for initial acquisition and reward more effective to maintain a high level of conditioned responses (CRs). The results imply that learning mechanisms in problem solving were maximally effective when the initial punishment of mistakes was combined with the subsequent rewarding of correct performance.

Identifying emotional adaptation: behavioural habituation to novelty and immediate early gene expression in two inbred mouse strains.

Normal anxiety is an adaptive emotional response. However, when anxiety appears to lack adaptive value, it might be defined as pathological. Adaptation in animals can be assessed for example by changes in behavioural responses over time, i.e. habituation. We hypothesize that non-adaptive anxiety might be reflected by impaired habituation. To test our hypothesis, we repeatedly exposed male mice from two inbred strains to a novel environment, the modified hole board. BALB/cJ mice were found to be initially highly anxious, but subsequently habituated to the test environment. In contrast, 129P3/J mice initially showed less anxiety-related behaviour compared with the BALB/cJ mice but no habituation in anxiety-related behaviour was observed. Notably, anxiety-related behaviour even increased during the experimental period. Complementary, 129P3/J mice did not show habituation in other parameters such as locomotor and exploratory activity, whereas significant changes appeared in these behaviours in BALB/c mice. Finally, the expression of the immediate early gene c-fos differed between the two strains in distinct brain areas, known to regulate the integration of emotional and cognitive processes. These results suggest that 129P3/J mice might be a promising (neuro)-behavioural animal model for non-adaptive, i.e. pathological anxiety.

Long-term anxiolytic and antidepressant-like behavioural effects of tiagabine, a selective GABA transporter-1 (GAT-1) inhibitor, coincide with a decrease in HPA system activity in C57BL/6 mice.

Gamma-aminobutyric acid (GABA) system plays a pivotal role in the pathophysiology of anxiety and mood disorders. This study was aimed to assess the anxiolytic and antidepressant-like properties of tiagabine, an inhibitor of the GABA transporter-1 (GAT-1), after acute and chronic administration in C57BL/6JOlaHsD mice with paroxetine as a positive control. In first experiments, the acute administration of tiagabine (7.5 mg/kg, orally [PO]) and paroxetine (10 mg/kg PO) induced anxiolytic effects in the elevated plus maze test and the modified hole board test and an antidepressant-like effect in the forced swim test. Chronic application of tiagabine (7.5 mg/kg PO) and paroxetine (10 mg/kg PO) for 22 days revealed an anxiolytic and antidepressant-like efficacy of tiagabine only. In a further experiment, we analysed the impact of chronic tiagabine versus paroxetine treatment on the hypothalamic-pituitary-adrenocortical (HPA) system regulation. GAT-1 blockade induced a setpoint-shift of the stress hormone system toward lower levels as indicated by decreased plasma corticosterone concentrations and attenuated gene expression levels of corticotropin-releasing factor in the paraventricular nucleus of the hypothalamus and of hippocampal steroid receptors. This data indicate that both acute and long-term anxiolytic and antidepressant-like properties of brain GAT-1 inhibition coincide with a reduction in HPA system activity in mice.

Identification methods in newborn C57BL/6 mice: a developmental and behavioural evaluation.

The use of group-housed rodents in many fields of biomedical research imposes a need to identify individuals in a cage. Few studies have been designed to assess possible negative effects of identification methods of newborn mice on their development and wellbeing. In the present study, three different identification methods were applied to newborn C57BL/6J mice on postnatal day (pnd) 5 (toe clipping, toe tattoo ink puncture and subcutaneous implantation of a small transponder). All identification methods used proved to be effective for long-term marking of individual animals. Newborn mice showed the least reaction to toe clipping followed by toe tattoo ink puncture and transponder implantation was the most distressful individual identification procedure in newborn mice. Importantly, clipped toe tissue proved to be enough for genotyping purposes. No overall consistent differences in somatic and neurological reflex development during the postnatal period were shown as a result of the newborn individual identification procedures used. Further, none of the methods interfered significantly with the adult animals' general normal behaviour (e.g. ability to move, grasp, climb) and sensory-motor functions as assessed with a simplified SHIRPA battery of tests, as well as Rotarod and Elevated Plus Maze tests. Postmortem thymus and adrenal gland weights gave no indication of chronic stress as a consequence of the identification method. We conclude that toe clipping might even be advisable in newborn mice at a very young age, when genotyping is needed. Toe tattoo ink puncture is also a good identification method for newborn mice and transponder implantation should only be used in older newborns or applied at weaning.

Consequences of chronic social stress on behaviour and vasopressin gene expression in the PVN of DBA/2OlaHsd mice--influence of treatment with the CRHR1-antagonist R121919/NBI 30775.

Accumulating evidence suggests that corticotropin-releasing hormone (CRH) neurocircuitry modulate the neuroendocrine and behavioural phenotypes in depression and anxiety. Thus, the administration of the selective CRH-receptor 1 (CRHR1)-antagonist R121919/NBI 30775 has proven its ability to act as an anxiolytic in rats. It is still unclear whether vasopressinergic neuronal circuits, which are known to be involved in the regulation of emotionality, are affected by R121919/NBI 30775. Using DBA/2OlaHsd mice, we investigated the effects of chronic social defeat and concomitant treatment with R121919/NBI 30775 on 1) the behavioural profile in the modified hole board test and 2) in-situ hybridization analysis-based expression of arginine vasopressin (AVP) and CRH mRNA in both the hypothalamic paraventricular nucleus and supraoptic nucleus. The results suggest that chronic social defeat leads to increased avoidance behaviour and reduction in directed exploration, general exploration, and locomotion. Chronic treatment with the CRHR1-antagonist was effective in reversing the directed exploration to control level. The dissection of the antagonist-treated group into responders and non-responders using the parameter time spent on board revealed further positive effects of R121919/NBI 30775 on avoidance behaviour and locomotion. Behavioural changes were accompanied by alterations in AVP gene expression in the paraventricular nucleus. Taken together, the anxiolytic action of the CRHR1 antagonist was found in a subgroup of animals only, and further studies have to be done to clarify the inter-individual biological differences in response patterns to this compound to optimise its application under clinical conditions.

Differential disinhibition of the neonatal hypothalamic- pituitary-adrenal axis in brain-specific CRH receptor 1-knockout mice.

In the adult, corticotropin-releasing hormone (CRH) is the key mediator for the behavioural and neuroendocrine response to stress. It has also been hypothesized that, during postnatal development of the stress system, CRH controls the activity of the HPA axis and mediates the effects of early disturbances, e.g. 24 h of maternal deprivation. In the current study we investigated the function of specific brain corticotropin-releasing hormone receptor type 1 (CRHR1) subpopulations in the control of the HPA axis during postnatal development under basal conditions as well as after 24 h of maternal deprivation. We used two conditional CRHR1-deficient mouse lines which lack this receptor, either specifically in forebrain and limbic structures (Cam-CRHR1) or in all neurons (Nes-CRHR1). Basal circulating corticosterone was increased in Nes-CRHR1 mice compared to controls. Corticosterone response to maternal deprivation was significantly increased in both CRHR1-deficient lines. In the paraventricular nucleus, Cam-CRHR1 animals displayed enhanced CRH and decreased vasopressin expression levels. In contrast, gene expression in Nes-CRHR1 pups was strikingly similar to that in maternally deprived control pups. Furthermore, maternal deprivation resulted in an enhanced response of Cam-CRHR1 pups in the brain, while expression levels in Nes-CRHR1 mouse pups were mostly unchanged. Our results demonstrate that brainstem and/or hypothalamic CRHR1 contribute to the suppression of basal corticosterone secretion in the neonate, while limbic and/or forebrain CRHR1 dampen the activation of the neonatal HPA axis induced by maternal deprivation.

Animal models of anxiety.

Animal models for anxiety-related behavior are based on the assumption that anxiety in animals is comparable to anxiety in humans. Being anxious is an adaptive response to an unfamiliar environment, especially when confronted with danger or threat. However, pathological variants of anxiety can strongly impede the daily life of those affected. To unravel neurobiological mechanisms underlying normal anxiety as well as its pathologi- cal variations, animal models are indispensable tools. What are the characteristics of an ideal animal model? First, it should display reduced anxiety when treated with anxiolytics (predictive validity). Second, the behavioral response of an animal model to a threatening stimulus should be comparable to the response known for humans (face validity). And third, the mechanisms underlying anxiety as well as the psychological causes should be identical (construct validity). Meeting these three requirements is difficult for any animal model. Since both the physiological and the behavioral response to aversive (threatening) stimuli are similar in humans and animals, it can be assumed that animal models can serve at least two distinct purposes: as (1) behavioral tests to screen for potential anxiolytic and antidepressant effects of new drugs and (2) tools to investigate specific pathogenetic aspects of cardinal symptoms of anxiety disorders. The examples presented in this chapter have been selected to illustrate the potential as well as the caveats of current models and the emerging possibilities offered by gene technology. The main concepts in generating animal models for anxiety-that is, selective breeding of rat lines, experience-related models, genetically engineered mice, and phenotype-driven approaches-are concisely introduced and discussed. Independent of the animal model used, one major challenge remains, which is to reliably identify animal behavioral characteristics. Therefore, a description of behavioral expressions of anxiety in rodents as well as tests assays to measure anxiety-related behavior in these animals is also included in this chapter.

Early and late patterns of stimulus-related activity in auditory cortex of trained animals.

Epidural electrocorticograms over the right auditory cortex (field AI) were measured using implanted 18-channel (3 x 6) electrode arrays in four animals (Mongolian gerbil) trained to discriminate between a rising and a falling frequency modulated tone (frequency range 2-4 kHz). Using a previously introduced classification procedure, transient patterns of cortical activity suitable to discriminate between the rising and the falling modulation were identified. Early (locked to stimulus onset) and late (emerging at variable times poststimulus) patterns could be differentiated. Deletion of increasing numbers of randomly selected electrodes was used to determine a critical density of recording channels required to capture the discriminative power of the early and late patterns. Statistical analysis of the classification revealed a sigmoid dependence of the discriminative power from the number of remaining electrodes with an inflection point at 12 electrodes. The analysis of the minima of the classification statistic revealed that in the early patterns discriminative information was focal on regions corresponding to the tonotopic representation of the stimuli, whereas in late patterns this information seemed to be distributed nonfocally across larger cortical regions. This analysis supports the previous notion of the coexistence of topographically organized activity states related to the physical stimulus features and nontopographically organized states determined largely by intrinsic factors (Ohl et al. 2001).

Regulation of the developing hypothalamic-pituitary-adrenal axis in corticotropin releasing hormone receptor 1-deficient mice.

During postnatal development, mice undergo a so-called stress hyporesponsive period, which is characterized by low basal corticosterone levels and the inability of mild stressors to induce a corticosterone response. The stress hyporesponsiveness is in part regulated by maternal factors. Twenty-four hours of deprivation results in an activation of basal and stress-induced corticosterone and a down-regulation of corticotropin releasing hormone (CRH), mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) expression in the brain. It has been hypothesized that the CRH receptor 1 (CRHr1) may play an important regulatory role during development by mediating the effects of maternal deprivation. Using CRHr1-deficient mice we examined the role of this receptor on the maternal deprivation effects and in regulating the expression of hypothalamic-pituitary-adrenal axis-related genes. We could demonstrate that the CRHr1 is essential for the activation of the corticosterone response following maternal deprivation, most likely due to the lack of the receptor in the pituitary. Furthermore, we could show that the CRHr1 is regulating the expression of CRH and MRs. In contrast, effects of maternal deprivation during postnatal development on GRs are not mediated by this receptor.