Tracking post-error adaptation in the motor system by transcranial magnetic stimulation

The commission of an error triggers cognitive control processes dedicated to error correction and prevention. Post-error adjustments leading to response slowing following an error ("post-error slowing"; PES) might be driven by changes in excitability of the motor regions and the corticospinal tract (CST). The time-course of such excitability modulations of the CST leading to PES is largely unknown. To track these presumed excitability changes after an error, single pulse transcranial magnetic stimulation (TMS) was applied to the motor cortex ipsilateral to the responding hand, while participants were performing an Eriksen flanker task. A robotic arm with a movement compensation system was used to maintain the TMS coil in the correct position during the experiment. Magnetic pulses were delivered over the primary motor cortex ipsilateral to the active hand at different intervals (150, 300, 450 ms) after correct and erroneous responses, and the motor-evoked potentials (MEP) of the first dorsal interosseous muscle (FDI) contralateral to the stimulated hemisphere were recorded. MEP amplitude was increased 450 ms after the error. Two additional experiments showed that this increase was neither associated to the correction of the erroneous responses nor to the characteristics of the motor command. To the extent to which the excitability of the motor cortex ipsi- and contralateral to the response hand are inversely related, these results suggest a decrease in the excitability of the active motor cortex after an erroneous response. This modulation of the activity of the CST serves to prevent further premature and erroneous responses. At a more general level, the study shows the power of the TMS technique for the exploration of the temporal evolution of post-error adjustments within the motor system.

Optimal coil orientation for transcranial magnetic stimulation

We study the impact of coil orientation on the motor threshold (MT) and present an optimal coil orientation for stimulation of the foot. The result can be compared to results of models that predict this orientation from electrodynamic properties of the media in the skull and from orientations of cells, respectively. We used a robotized TMS system for precise coil placement and recorded motor-evoked potentials with surface electrodes on the abductor hallucis muscle of the right foot in 8 healthy control subjects. First, we performed a hot-spot search in standard (lateral) orientation and then rotated the coil in steps of 10° or 20°. At each step we estimated the MT. For navigated stimulation and for correlation with the underlying anatomy a structural MRI scan was obtained. Optimal coil orientation was 33.1±18.3° anteriorly in relation to the standard lateral orientation. In this orientation the threshold was 54±18% in units of maximum stimulator output. There was a significant difference of 8.0±5.9% between the MTs at optimal and at standard orientation. The optimal coil orientations were significantly correlated with the direction perpendicular to the postcentral gyrus (). Robotized TMS facilitates sufficiently precise coil positioning and orientation to study even small variations of the MT with coil orientation. The deviations from standard orientation are more closely matched by models based on field propagation in media than by models based on orientations of pyramidal cells.

A long-term study of a patient with anti-p200 pemphigoid: correlation of autoantibody levels with disease activity and an example of epitope spreading

Anti-p200 pemphigoid is a rare subepidermal blistering disease associated with autoantibodies against a 200-kDa protein, reportedly corresponding to laminin γ1. However, direct evidence of the pathogenic potential of these antibodies has not been proven. For 5 years we have followed up a patient with anti-p200 pemphigoid. During this period she experienced a total of three generalized relapses. Quantifying our patient's autoantibody concentrations against laminin γ1 by enzyme-linked immunosorbent assay throughout the course of her disease we demonstrated a clear correlation with disease activity, thus providing the first evidence of the possible pathogenic role of antibodies against laminin γ1 in anti-p200 pemphigoid. Further analysis by Western blotting revealed the occurrence of additional autoantibodies against the α3 chain of laminin 332, 1·5 years after diagnosis, suggestive of intermolecular epitope spreading. Yet, the clinical appearance was unchanged and mucous membranes remained unaffected at any stage of the disease.

Force Measuring Methods for Determination of Surface Tension of Liquids: A Comparison

Three methods for the determination of the surface tension of liquids based on force measurements namely, the vertical plate method of Wilhelmy, the frame method of Lenard and the ring method of du Noüy are compared and studied in respect of a common principle of correction. It is shown that these three most important force-based methods allow the determination of the surface tension under static conditions. The force components of the corresponding liquid column below the measuring wire obtained for the straight part of the withdrawal curve up to the transition in its curved part provides exact surface tension values. The experimentally accessible value of the force component describes the physical background of the measured value correction contrary to the approximate equations obtained by mathematical way. Usually the determination of surface tension of liquids is based merely at the vertical plate method on exact equations thermodynamically derived whereas in the case of the frame and ring methods correction factors in approximate equations are used. At usual application of the force-based methods under the non-static condition of the withdrawal of a liquid column, the force maximum measured at withdrawal of the measuring object (plate, frame, or ring) is the basis for the determination of surface tension. In these cases, the measured surface tension values are compensated by correction equations for the frame and ring methods which are based on an correction factor and correction tables empirically obtained. The surface tension values obtained in this usual way agree with those obtained by using the force component of the corresponding liquid column below the measuring wire for the straight part of the withdrawal curve up to the transition in its curved part. Problems arising at the force measurements with increasing thickness of the measuring wires inside and outside the rings are discussed.

Design, implementation and evaluation of an independent real-time safety layer for medical robotic systems using a force-torque-acceleration (FTA) sensor

PURPOSE

Most medical robotic systems require direct interaction or contact with the robot. Force-Torque (FT) sensors can easily be mounted to the robot to control the contact pressure. However, evaluation is often done in software, which leads to latencies.

METHODS

To overcome that, we developed an independent safety system, named FTA sensor, which is based on an FT sensor and an accelerometer. An embedded system (ES) runs a real-time monitoring system for continuously checking of the readings. In case of a collision or error, it instantaneously stops the robot via the robot's external emergency stop.

RESULTS

We found that the ES implementing the FTA sensor has a maximum latency of [Formula: see text] ms to trigger the robot's emergency stop. For the standard settings in the application of robotized transcranial magnetic stimulation, the robot will stop after at most 4 mm.

CONCLUSION

Therefore, it works as an independent safety layer preventing patient and/or operator from serious harm.

The effect of repetitive transcranial magnetic stimulation on monoamine outflow in the nucleus accumbens shell in freely moving rats

Evidence exists that modulation of neuronal activity in nucleus accumbens shell region may re-establish normal function in various neuropsychiatric conditions such as drug-withdrawal, obsessive-compulsive disorder, depression and chronic pain. Here, we study the effects of acute repetitive transcranial magnetic stimulation on monoamine outflow in the nucleus accumbens shell in awake and freely moving rats using in vivo microdialysis. To scale the biochemical results to the induced electric field in the rat brain, we obtained a realistic simulation of the stimulation scenario using a finite element model. Applying 20 Hz repetitive transcranial magnetic stimulation in 6 trains of 50 stimuli with 280 μs pulse width at a magnetic field strength of 130% of the individual motor threshold, dopamine as well as serotonin outflow in the nucleus accumbens shell significantly increased compared to sham stimulation. Since the electric field decays rapidly with depth in the rat brain, we can conclude that the modulation in neurotransmitter outflow from the nucleus accumbens shell is presumably a remote effect of cortical stimulation.

Diazepam-bound GABAA receptor models identify new benzodiazepine binding-site ligands

Benzodiazepines exert their anxiolytic, anticonvulsant, muscle-relaxant and sedative-hypnotic properties by allosterically enhancing the action of GABA at GABA(A) receptors via their benzodiazepine-binding site. Although these drugs have been used clinically since 1960, the molecular basis of this interaction is still not known. By using multiple homology models and an unbiased docking protocol, we identified a binding hypothesis for the diazepam-bound structure of the benzodiazepine site, which was confirmed by experimental evidence. Moreover, two independent virtual screening approaches based on this structure identified known benzodiazepine-site ligands from different structural classes and predicted potential new ligands for this site. Receptor-binding assays and electrophysiological studies on recombinant receptors confirmed these predictions and thus identified new chemotypes for the benzodiazepine-binding site. Our results support the validity of the diazepam-bound structure of the benzodiazepine-binding pocket, demonstrate its suitability for drug discovery and pave the way for structure-based drug design.

[IgA pemphigus of the subcorneal pustular dermatosis type. Successful therapy with a combination of dapsone and acitretin]

IgA pemphigus of the subcorneal pustular dermatosis type is a rare autoimmune blistering disease in the pemphigus spectrum. Patients are clinically characterized by extensive erythemas that primarily affect intertriginous areas. The erythematous macules are covered with numerous vesicles and pustules with occasional hypopyon formation. Histopathology shows subcorneal acantholysis with clefting and numerous neutrophils within the blister as well as in the edematous papillary dermis. IgA autoantibodies bind in vivo to keratinocytes within the upper half of the epidermis. Desmocollin 1, the autoantigen of this disease, is a member of desmosomal cadherins and is only expressed on more differentiated keratinocytes. The demonstration of circulating autoantibodies against desmocollin 1 in routine diagnosis is challenging and requires indirect immunofluorescence staining of desmocollin 1 transfected COS7 cells. We report a patient with a severe course of the disease who only responded to combined therapy with dapsone and acitretin.

Robust real-time robot-world calibration for robotized transcranial magnetic stimulation

BACKGROUND

For robotized transcranial magnetic stimulation (TMS), the magnetic coil is placed on the patient's head by a robot. As the robotized TMS system requires tracking of head movements, robot and tracking camera need to be calibrated. However, for robotized TMS in a clinical setting, such calibration is required frequently. Mounting/unmounting a marker to the end effector and moving the robot into different poses is impractical. Moreover, if either system is moved during treatment, recalibration is required.

METHODS

To overcome this limitation, we propose to directly track a marker at link three of the articulated arm. Using forward kinematics and a constant marker transform to link three, the calibration can be performed instantly.

RESULTS

Our experimental results indicate an accuracy similar to standard hand-eye calibration approaches. It also outperforms classical hand-held navigated TMS systems.

CONCLUSION

This robust online calibration greatly enhances the system's user-friendliness and safety.

[Quality of life, stress management and health promotion in medical and dental students. A comparative study]

OBJECTIVE

Which are the differences in health-related quality of life and stress management in medical and dental students?

METHODS

101 dental and 237 medical students from different years of Justus-Liebig University Giessen were examined during winter term 2008/09 and summer term 2009 using the specific Questionnaire on Health Promotion, Life Satisfaction, and Stress Management in Dental or Medical Students (addressing work satisfaction and choice of subject, private life, relaxation behavior and stress management, and health behavior), Beck Depression Inventory (BDI) and SF-36 Health Survey. For statistical analysis, Mann-Whitney-U-Test, analysis of variance (ANOVA), Pearson correlation and Chi2-Tests were primarily used.

RESULTS

Dental and medical students showed considerable mental impairment in SF-36. Every fifth dental student suffered from slight to moderate depression. Though averaging more hours per week, medical students were more satisfied with their studies. More than half of the dental and medical students did not have appropriate strategies of coping with stress.

CONCLUSIONS

Concerning the mental impairment in both groups and regarding a higher health-related quality of life, specific prevention courses or mentoring programs should already be offered at the beginning of medical training in order to cope with strains of medical school and future job strains in the medical or dental profession.

Simulation of a conductive shield plate for the focalization of transcranial magnetic stimulation in the rat

Transcranial Magnetic Stimulation (TMS) in the rat is a powerful tool for investigating brain function. However, the state-of-the-art experiments are considerably limited because the stimulation usually affects undesired anatomical structures. A simulation of a conductive shield plate placed between the coil stimulator and the rat brain during TMS is presented. The Finite Element (FE) method is used to obtain the 3D electric field distribution on a four-layer rat head model. The simulations show that the shield plate with a circular window can improve the focalization of stimulation, as quantitatively seen by computing the three-dimensional half power region (HPR). Focalization with the shield plate showed a clear compromise with the attenuation of the induced field. The results suggest that the shield plate can work as a helpful tool for conducting TMS rat experiments on specific targets.

Towards direct head navigation for robot-guided transcranial magnetic stimulation using 3D laserscans: Idea, setup and feasibility

Direct tracking is more robust than tracking that is based on additional markers. 3D laser scans can be used for direct tracking because they result in a 3D data set of surface points of the scanned object. For head-navigated robotized systems, it is crucial to know where the patient's head is positioned relatively to the robot. We present a novel method to use a 3D laserscanner for direct head navigation in the robotized TMS system that places a coil on the patient's head using an industrial robot. First experimental results showed a translational error < 2mm in the robot hand-eye-calibration with the laserscanner. The rotational error was 0.75° and the scaling error < 0.001. Furthermore, we found that the error of a scanned head to a reference head image was < 0.2mm using ICP. These results have shown that a direct head navigation is feasible for the robotized TMS system. Additional effort has to be made in future systems to speed up the compution time for real time capability.

Invited article: Electric solar wind sail: toward test missions

The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the solar wind is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the solar system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.

Integrating background knowledge from internet databases into predictive toxicology models

While data integration for data analysis has been investigated extensively in biological applications, it has not yet been so much the focus in computational chemistry and quantitative structure-activity relationship (QSAR) research. With the availability and growing number of chemical databases on the web, such data integration efforts become an intriguing possibility (and, in fact, a necessity). In this paper, we take a first step towards the following vision and scenario for predictive toxicology applications. Given a new structure to be predicted, the first step would be to gather (integrate) all relevant information from internet databases for the structure itself, and all structures with available information for the endpoint of interest. In a second step, the collected information is combined statistically into a prediction of the new structure. We simulate this scenario with three endpoints (data sets) from the DSSTox database and collect information from three public chemical databases: PubChem, ChemBank and Sigma-Aldrich. In the experiments, we investigate whether the addition of background knowledge from the three databases can improve predictive performance (over using chemical structure alone) in a statistically significant way. For this purpose, we define groups of features (belonging together from an application point of view) from the three databases, and perform a variant of forward selection to include these feature groups in a prediction model. Our experiments show that the integration of background knowledge from internet databases can significantly improve prediction performance, especially for regression tasks.

Strengthening families through early intervention in high HIV prevalence countries

Families have been at the forefront of the response to the HIV/AIDS epidemic in high-prevalence countries. They have also borne the greatest costs associated with the epidemic, including impoverishment, which has strained their capacity to care for vulnerable members. Within this context, there is consensus that strengthening the capacity of families to care for children is one of the most important strategies for mitigating the impacts of the HIV/AIDS epidemic on children's lives in high-prevalence countries. It is argued that evidence-based early intervention programmes that enhance caregiving and link caregivers with supports and services can play a pivotal role in strengthening families. Based on a systematic review, we recommend that two intervention strategies that should be given consideration within the context of high-prevalence countries, because of their demonstrated benefits in other settings, are nurse home visiting for first time, low-income pregnant mothers and their young children as well as early childhood development programmes for low-income children and families.

An updated unified pharmacophore model of the benzodiazepine binding site on gamma-aminobutyric acid(a) receptors: correlation with comparative models

A successful unified pharmacophore/receptor model which has guided the synthesis of subtype selective compounds is reviewed in light of recent developments both in ligand synthesis and structural studies of the binding site itself. The evaluation of experimental data in combination with a comparative model of the alpha1beta2gamma2 GABA(A) receptor leads to an orientation of the pharmacophore model within the Bz BS. Results not only are important for the rational design of selective ligands, but also for the identification and evaluation of possible roles which specific residues may have within the benzodiazepine binding pocket.

Cell hydration and mTOR-dependent signalling

Insulin- and amino acid-induced signalling by the mammalian target of rapamycin (mTOR) involves hyperphosphorylation of the p70 ribosomal S6 protein kinase (p70S6-kinase) and the eukaryotic initiation factor 4E (eIF4E) binding protein 4E-BP1 and contributes to regulation of protein metabolism. This review considers the impact of cell hydration on mTOR-dependent signalling. Although hypoosmotic hepatocyte swelling in some instances activates p70S6-kinase, the hypoosmolarity-induced proteolysis inhibition in perfused rat liver is insensitive to mTOR inhibition by rapamycin. Likewise, swelling-dependent proteolysis inhibition by insulin and swelling-independent proteolysis inhibition by leucine, a potent activator of p70S6-kinase and 4E-BP1 hyperphosphorylation, in perfused rat liver is insensitive to rapamycin, indicating that at least rapamycin-sensitive mTOR signalling is not involved. Hyperosmotic dehydration in different cell types produces inactivation of signalling components around mTOR, thereby attenuating insulin-induced glucose uptake, glycogen synthesis, and lipogenesis in adipocytes, and MAP-kinase phosphatase MKP-1 expression in hepatoma cells. Direct inactivation of mTOR, stimulation of the AMP-activated protein kinase, and the destabilization of individual proteins may impair mTOR signalling under dehydrating conditions. Further investigation of the crosstalk between the mTOR pathway(s) and hyperosmotic signalling will improve our understanding about the contribution of cell hydration changes in health and disease and will provide further rationale for fluid therapy of insulin-resistant states.

Infektionen mit Herpes-simplex- und Varicella-zoster-Viren in der Schwangerschaft

Primary infections with herpes simplex virus (HSV) and varicella-zoster virus (VZV) may lead to severe illness in pregnancy. Both diseases may be associated with transplacental virus transmission and fetal infection. Such infections can lead to intrauterine death, severe malformations and premature birth; the fetal/congenital varicella syndrome is well-defined. Herpes genitalis and varicella at the time of labor may lead to life threatening neonatal-herpes or varicella of the newborn. Currently neither active immunization nor neutralizing immunoglobulin is available for HSV infections. VZV-seronegative women in child-bearing age can be vaccinated and pregnant women exposed to VZV can be given specific immunoglobulins. While an infection is rarely blocked, the severity is generally reduced. For severe disease antiviral treatment is necessary, with valacyclovir and acyclovir represents the drugs of choice. Primary or recurrent overt disease of the genital tract at the time of delivery an indication for caesarean section. Suppression of recurrent genital herpes during the last weeks of pregnancy with valacyclovir and acyclovir reduces the need for surgical intervention. Neonates exposed to VZV should receive specific immunoglobulin. If neonates show signs of either infection, immediate treatment with acyclovir must be initiated.

The Opportunity Rover's Athena science investigation at Meridiani Planum, Mars

The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nearby plains within Meridiani Planum. The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Wind ripples are common. Underlying the thin soil layer, and exposed within small impact craters and troughs, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts. Small-scale cross-lamination in some locations provides evidence for deposition in flowing liquid water. We interpret the rocks to be a mixture of chemical and siliciclastic sediments formed by episodic inundation by shallow surface water, followed by evaporation, exposure, and desiccation. Hematite-rich spherules are embedded in the rock and eroding from them. We interpret these spherules to be concretions formed by postdepositional diagenesis, again involving liquid water.

Localization and physical property experiments conducted by Opportunity at Meridiani Planum

The location of the Opportunity landing site was determined to better than 10-m absolute accuracy from analyses of radio tracking data. We determined Rover locations during traverses with an error as small as several centimeters using engineering telemetry and overlapping images. Topographic profiles generated from rover data show that the plains are very smooth from meter- to centimeter-length scales, consistent with analyses of orbital observations. Solar cell output decreased because of the deposition of airborne dust on the panels. The lack of dust-covered surfaces on Meridiani Planum indicates that high velocity winds must remove this material on a continuing basis. The low mechanical strength of the evaporitic rocks as determined from grinding experiments, and the abundance of coarse-grained surface particles argue for differential erosion of Meridiani Planum.

Evidence from Opportunity's Microscopic Imager for water on Meridiani Planum

The Microscopic Imager on the Opportunity rover analyzed textures of soils and rocks at Meridiani Planum at a scale of 31 micrometers per pixel. The uppermost millimeter of some soils is weakly cemented, whereas other soils show little evidence of cohesion. Rock outcrops are laminated on a millimeter scale; image mosaics of cross-stratification suggest that some sediments were deposited by flowing water. Vugs in some outcrop faces are probably molds formed by dissolution of relatively soluble minerals during diagenesis. Microscopic images support the hypothesis that hematite-rich spherules observed in outcrops and soils also formed diagenetically as concretions.

Soils of Eagle Crater and Meridiani Planum at the Opportunity Rover Landing Site

The soils at the Opportunity site are fine-grained basaltic sands mixed with dust and sulfate-rich outcrop debris. Hematite is concentrated in spherules eroded from the strata. Ongoing saltation exhumes the spherules and their fragments, concentrating them at the surface. Spherules emerge from soils coated, perhaps from subsurface cementation, by salts. Two types of vesicular clasts may represent basaltic sand sources. Eolian ripples, armored by well-sorted hematite-rich grains, pervade Meridiani Planum. The thickness of the soil on the plain is estimated to be about a meter. The flatness and thin cover suggest that the plain may represent the original sedimentary surface.

The Spirit Rover's Athena science investigation at Gusev Crater, Mars

The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former lake, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.

Localization and physical properties experiments conducted by Spirit at Gusev Crater

The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, cohesive soil-like deposits in plains and hollows, bright and dark rock coatings, and relatively weak volcanic rocks of basaltic composition. Volcanic, impact, aeolian, and water-related processes produced the encountered landforms and materials.

Wind-related processes detected by the Spirit Rover at Gusev Crater, Mars

Wind-abraded rocks, ripples, drifts, and other deposits of windblown sediments are seen at the Columbia Memorial Station where the Spirit rover landed. Orientations of these features suggest formative winds from the north-northwest, consistent with predictions from atmospheric models of afternoon winds in Gusev Crater. Cuttings from the rover Rock Abrasion Tool are asymmetrically distributed toward the south-southeast, suggesting active winds from the north-northwest at the time (midday) of the abrasion operations. Characteristics of some rocks, such as a two-toned appearance, suggest that they were possibly buried and exhumed on the order of 5 to 60 centimeters by wind deflation, depending on location.

Surficial Deposits at Gusev Crater Along Spirit Rover Traverses

The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes. Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth. Some rocks have been textured and/or partially buried by windblown sediments less than 2 millimeters in diameter that concentrate within shallow, partially filled, circular impact depressions referred to as hollows. The terrain traversed during the 90-sol (martian solar day) nominal mission shows no evidence for an ancient lake in Gusev crater.

The effects of repeated intra-amygdala CRF injections on rat behavior and HPA axis function after stress

Patients diagnosed with certain anxiety disorders or depression show symptoms of a dysregulated HPA-axis secondary to increased release of corticotropin releasing factor (CRF). Male Wistar rats were injected with CRF (100 ng/microL) in the basolateral amygdala (BLA) for 5 days. Measurement of behavior was performed on the elevated plus maze and open field test. Behavioral and neuroendocrine response to restraint stress was also evaluated. Chronic treatment of CRF resulted in a significant increase in grooming after restraint stress in the Open Field test. Basal plasma corticosterone concentrations were significantly lower in the CRF-injected rats. These animals also showed greater and longer increase in corticosterone levels following the restraint stress than controls, but had comparable ACTH responses to restraint stress. Our results indicate that chronic administration of CRF into the basolateral amygdala may promote stress-induced grooming behavior in rats. In addition the data suggests that increased CRF in the amygdala may contribute to the dysregulation of corticosterone secretion. These findings may have important implications for patients suffering from psychiatric illnesses such as posttraumatic stress disorder and depression that are characterized by abnormalities in cortisol release.