Studies suggest that the amygdala is a key region for regulation of anxiety, fear and social function. Therefore, dysfunction of the amygdala has been proposed as a potential mechanism for negative symptoms in schizophrenia. This may be due to NMDA receptor-mediated hypofunction, which is thought to be related to the pathogenesis of schizophrenia. In this study, electroencephalographic amygdala activity was assessed in mice during the three-chamber social test. This activity was also evaluated following exposure to the NMDA receptor antagonist ketamine. Vehicle-treated mice spent significantly more time in the social than the non-social chamber. This social preference was eliminated by ketamine. However, ketamine-treated mice spent significantly less time in the social chamber and significantly more time in the nonsocial chamber than vehicle treated mice. There were no significant differences in induced powers between social and non-social chamber entries in vehicle-treated mice, except for theta frequencies, which featured greater induced theta power during non-social chamber entry. Ketamine eliminated differences in induced theta power between social and nonsocial chamber entries. Moreover, ketamine increased the induced gamma power during social chamber entry compared to that of vehicle-treated mice. All other frequency ranges were not significantly influenced by zone or drug condition. All significant findings were upon entry to chambers not during interaction. Results suggest that impaired function of NMDA receptor-mediated glutamate transmission can induce social impairments and amygdala dysfunction, similar to the pattern in schizophrenia. Future studies will utilize this method to evaluate mechanisms of social dysfunction and development of treatments of social impairments in schizophrenia.

Purpose:To characterize a recently developed model, the retinal degenerate immunodeficient S334ter line-3 rat (SD-Foxn1 Tg(S334ter)3Lav) (RD nude rat), and to test whether transplanted rat fetal retinal sheets can elicit lost responses to light.Methods:National Institutes of Health nude rats (SD-Foxn1 Tg) with normal retina were compared to RD nude rats with and without transplant for morphology and visual function. Retinal sheets from transgenic rats expressing human placental alkaline phosphatase (hPAP) were transplanted into the subretinal space of RD nude rats between postnatal day (P) 26 and P38. Transplant morphology was examined in vivo using optical coherence tomography (OCT). Visual function was assessed by optokinetic (OKN) testing, electroretinogram (ERG), and superior colliculus (SC) electrophysiology. Cryostat sections were analyzed for various retinal/synaptic markers and for the expression of donor hPAP.Results:Optical coherence tomography scans showed the placement and laminar development of retinal sheet transplants in the subretinal space. Optokinetic testing demonstrated a deficit in visual acuity in RD nude rats that was improved after retinal sheet transplantation. No ERG responses were detected in the RD nude rats with or without transplantation. Superior colliculus responses were absent in age-matched control and sham surgery RD nude rats; however, robust light-evoked responses were observed in a specific location in the SC of transplanted RD nude rats. Responsive regions corresponded to the area of transplant placement in the eye. The quality of visual responses correlated with transplant organization and placement.Conclusions:The data suggest that retinal sheet transplants integrate into the host retina of RD nude rats and recover significant visual function.

Dexras1 is a novel GTPase that acts at a confluence of signaling mechanisms associated with psychiatric and neurological disease including NMDA receptors, NOS1AP and nNOS. Recent work has shown that Dexras1 mediates iron trafficking and NMDA-dependent neurodegeneration but a role for Dexras1 in normal brain function or psychiatric disease has not been studied. To test for such a role, mice with germline knockout (KO) of Dexras1 were assayed for behavioral abnormalities as well as changes in NMDA receptor subunit protein expression. Because Dexras1 is up-regulated during stress or by dexamethasone treatment, we included measures associated with emotion including anxiety and depression. Baseline anxiety-like measures (open field and zero maze) were not altered, nor were depression-like behavior (tail suspension). Measures of memory function yielded mixed results, with no changes in episodic memory (novel object recognition) but a significant decrement on working memory (T-maze). Alternatively, there was an increase in pre-pulse inhibition (PPI), without concomitant changes in either startle amplitude or locomotor activity. PPI data are consistent with the direction of change seen following exposure to dopamine D2 antagonists. An examination of NMDA subunit expression levels revealed an increased expression of the NR2A subunit, contrary to previous studies demonstrating down-regulation of the receptor following antipsychotic exposure (Schmitt et al., 2003) and up-regulation after exposure to isolation rearing (Turnock-Jones et al., 2009). These findings suggest a potential role for Dexras1 in modulating a selective subset of psychiatric symptoms, possibly via its interaction with NMDARs and/or other disease-related binding-partners. Furthermore, data suggest that modulating Dexras1 activity has contrasting effects on emotional, sensory and cognitive domains.

Background: The vasopressin deficient Brattleboro (BRAT) rats have behavioral impairments which mimic those seen in other schizophrenia models. However, the mechanism by which vasopressin produces these behavioral abnormalities is unclear. Notably, elevations in dopamine signaling as well as reductions in glutamatergic signaling have been associated with behavioral impairments consistent with those observed in the BRAT rats. Therefore, a potential mechanism for vasopressin induces behavioral abnormalities could be through modulation of dopamine or glutamate signaling. Consequently, the aim of this study was to assess the modulatory function of vasopressin on dopamine and NMDA signaling. Methods: Single intraperitoneal injection of amphetamine (0.5 mg/kg), a dopamine agonist, and MK801 (0.25 mg/kg), a NMDA antagonist, were used to assess vasopressin (VP) modulatory activity on dopaminergic and glutamatergic pre-pulse inhibition of startle (PPI), social interaction and auditory event related potential (ERPs) impairments in BRAT and littermate control WT rats. Results: MK801-induced impairments were consistent and not significantly different between WT and BRAT rats suggesting minimal modulatory activity of vasopressin on NMDA signaling. In contrast, amphetamine-induced deficits were genotype dependent. In control animals, amphetamine caused a statistically significant deficit in PPI and social interaction whereas there was no effect in BRAT rats. Conversely, ERP components were unaltered in control rats, whereas N40 amplitude, evoked gamma power, and gamma signal to noise ratio were all elevated in BRAT rats. Conclusions: The ERP component analyses of BRAT rats treated with amphetamine suggest modulation of auditory information processing through interplay between dopaminergic and vasopressin. However, the behavioral and electrophysiological evidence presented here also suggest that vasopressin does not modulate glutamatergic signaling through NMDA receptors. Further evidence in necessary to determine the interaction between vasopressin and dopamine signaling and future studies are necessary to comprehend glutamatergic interactions with vasopressin that are not NMDA-mediated.

BACKGROUND:Neuronal activity at gamma frequency is impaired in schizophrenia (SZ) and is considered critical for cognitive performance. Such impairments are thought to be due to reduced N-methyl-D-aspartate receptor (NMDAR)-mediated inhibition from parvalbumin interneurons, rather than a direct role of impaired NMDAR signaling on pyramidal neurons. However, recent studies suggest a direct role of pyramidal neurons in regulating gamma oscillations. In particular, a computational model has been proposed in which phasic currents from pyramidal cells could drive synchronized feedback inhibition from interneurons. As such, impairments in pyramidal neuron activity could lead to abnormal gamma oscillations. However, this computational model has not been tested experimentally and the molecular mechanisms underlying pyramidal neuron dysfunction in SZ remain unclear.METHODS:In the present study, we tested the hypothesis that SZ-related phenotypes could arise from reduced NMDAR signaling in pyramidal neurons using forebrain pyramidal neuron specific NMDA receptor 1 knockout mice.RESULTS:The mice displayed increased baseline gamma power, as well as sociocognitive impairments. These phenotypes were associated with increased pyramidal cell excitability due to changes in inherent membrane properties. Interestingly, mutant mice showed decreased expression of GIRK2 channels, which has been linked to increased neuronal excitability.CONCLUSIONS:Our data demonstrate for the first time that NMDAR hypofunction in pyramidal cells is sufficient to cause electrophysiological, molecular, neuropathological, and behavioral changes related to SZ.

NMDA-receptor (NMDAR) hypofunction is strongly implicated in the pathophysiology of schizophrenia. Several convergent lines of evidence suggest that net excitation propagated by impaired NMDAR signaling on GABAergic interneurons may be of particular interest in mediating several aspects of schizophrenia. However, it is unclear which behavioral domains are governed by a net increase of excitation and whether modulating downstream GABAergic signaling can reverse neural and thus behavioral deficits. The current study determines the selective contributions of NMDAR dysfunction on PV-containing interneurons to electrophysiological, cognitive, and negative-symptom-related behavioral phenotypes of schizophrenia using mice with a PVcre-NR1flox-driven ablation of NR1 on PV-containing interneurons. In addition, we assessed the efficacy of one agent that directly modulates GABAergic signaling (baclofen) and one agent that indirectly modifies NMDAR-mediated signaling through antagonism of mGluR5 receptors (2-methyl-6-(phenylethynyl) pyridine (MPEP)). The data indicate that loss of NMDAR function on PV interneurons impairs self-care and sociability while increasing N1 latency and baseline gamma power, and reducing induction and maintenance of long-term potentiation. Baclofen normalized baseline gamma power without corresponding effects on behavior. MPEP further increased N1 latency and reduced social behavior in PVcre/NR1+/+ mice. These two indices were negatively correlated before and following MPEP such that as N1 latency increases, sociability decreases. This finding suggests a predictive role for N1 latency with respect to social function. Although previous data suggest that MPEP may be beneficial for core features of autism spectrum disorders, current data suggest that such effects require intact function of NMDAR on PV interneurons.

A number of studies have associated reduced Akt1 expression with vulnerability for schizophrenia. Although mice with deletion of a single copy of the Akt1 gene (Akt1+/−) show reduced Akt1 expression relative to wild-type (WT) animals, the extent to which these mice show schizophrenia-like phenotypic changes and/or increased susceptibility to epigenetic or non-genetic factors related to schizophrenia is unknown.

Purpose: We compared efficacy and side effects of ropinirole implants with oral ropinirole in parkinsonian monkeys. Methods: Twenty monkeys received injections of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-hydrochloride (MPTP) to render them parkinsonian. Monkeys were then placed into 3 groups based upon clinical rating scores (CRS). Group 1 received oral ropinirole and placebo implants. Group 2 receivedropinirole implants that released 1/9th of the animals’ optimal daily oral dose and oral placebo. Group 3 received placebo implants and oral placebo. Monkeys were assessed for pharmacokinetic data, CRS, Global Dyskinesia Rating Scale, and skin irritation. Results: For the ropinirole implant group, the activity pattern was similar to that seen pre-MPTP; which extended through the weekends and was greater than control treated parkinsonian monkeys. Oral ropinirole yielded a high degree of variability for activity, with values following oral dosing being higher than the pre-MPTP periodbut levels similar to placebo treated parkinsonian animals during weekends, which were excluded from oral dosing. Implants and oral treatment achieved significant improvement in CRS between 11 - 60 days and 4 - 60 days respectively. Conclusion: Low dose ropinirole implants have the potential to provide continuous clinical improvement in bradykinesia with fewer “off periods” and lower risk for medication-induced psychosis than oral medication.

Reductions in the levels of the neuropeptide vasopressin (VP) and its receptors have been associated with schizophrenia. VP is also critical for appropriate social behaviors in humans as well as rodents. One of the prominent symptoms of schizophrenia is asociality and these symptoms may develop prodromally. A reduction in event-related potential (ERP) peak amplitudes is an endophenotype of schizophrenia. In this study, we use the Brattleboro (BRAT) rat to assess the role of VP deficiency in vocal communication during early development and on auditory ERPs during adulthood. BRAT rats had similar vocal communication to wild-type littermate controls during postnatal days 2 and 5 but the time between vocalizations was increased and the power of the vocalizations was reduced beginning at postnatal day 9. During adulthood, BRAT rats had deficits in auditory ERPs including reduced N40 amplitude and reduced low and high gamma intertrial coherence. These results suggest that the role of VP on vocal communication is an age-dependent process. Additionally, the deficits in ERPs indicate an impairment of auditory information processing related to the reduction in VP. Therefore, manipulation of the VP system could provide a novel mechanism for treatment for negative symptoms of schizophrenia.

Extracellular signals in development, physiology, homeostasis and disease often act by regulating transcription. Herein we describe a general method and specific resources for determining where and when such signaling occurs in live animals and for systematically comparing the timing and extent of different signals in different cellular contexts. We used recombinase-mediated cassette exchange (RMCE) to test the effect of successively deleting conserved genomic regions of the ubiquitously active Rosa26 promoter and substituting the deleted regions for regulatory sequences that respond to diverse extracellular signals. We thereby created an allelic series of embryonic stem cells and mice, each containing a signal-responsive sentinel with different fluorescent reporters that respond with sensitivity and specificity to retinoic acids, bone morphogenic proteins, activin A, Wnts or Notch, and that can be adapted to any pathway that acts via DNA elements.

This chapter covers the clinical features, classification, differential diagnosis, and pathogenesis of Hodgkin lymphoma. Differences between the histogenesis and appearance of classical subtypes (nodular sclerosis, mixed cellularity, lymphocyte-rich, and lymphocyte-depleted) and the nodular lymphocyte predominant type are covered.

Nonadherence to antipsychotic medications is a major obstacle preventing optimal outcomes for patients with schizophrenia. Extended release systems exist in the form of depot injections, but these formulations exhibit several disadvantages. To address these concerns, we previously demonstrated proof of concept for an antipsychotic implant containing risperidone and the biodegradable polymer poly(lactic-co-glycolic) acid (PLGA).

In this paper, we propose a novel imaging system that enables the capture of photos and videos with sparse informational pixels. Our system is based on the projection and detection of 3D optical tags. We use an infrared (IR) projector to project temporally-coded (blinking) dots onto selected points in a scene. These tags are invisible to the human eye, but appear as clearly visible time-varying codes to an IR photosensor. As a proof of concept, we have built a prototype camera system (consisting of co-located visible and IR sensors) to simultaneously capture visible and IR images. When a user takes an image of a tagged scene using such a camera system, all the scene tags that are visible from the system's viewpoint are detected. In addition, tags that lie in the field of view but are occluded, and ones that lie just outside the field of view, are also automatically generated for the image. Associated with each tagged pixel is its 3D location and the identity of the object that the tag falls on. Our system can interface with conventional image recognition methods for efficient scene authoring, enabling objects in an image to be robustly identified using cheap cameras, minimal computations, and no domain knowledge. We demonstrate several applications of our system, including, photo-browsing, e-commerce, augmented reality, and objection localization.

We study the paper of Hadley to compare the order quantities for inventory models using the average annual cost and the discounted cost. The purpose of this note is threefold. First, we show that the solution for the discounted cost inventory model is exist and unique. Second, we provide a formulated approximation for the discounted cost inventory model. Third, we use our approximation to explain why two solutions by the average annual cost and the discounted cost are close each other such that the numerical analysis in Hadley's examples to demonstrate a negligible difference between them is explained. Our findings will undoubtedly improve the theoretical base for inventory models and develop new practical application for operational research.