Spontaneous Ultrasonic Vocalization Transmission in Adult, Male Long-Evans Rats Is Age-Dependent and Sensitive to EtOH Modulation.

Ultrasonic vocalizations (USVs) are well-established markers of motivational and emotional status. Recent work from our lab has provided novel evidence for a role of USVs in models of ethanol (EtOH) use. For instance, USV acoustic characteristics can be used to accurately discriminate between rats selectively bred for high EtOH intake (e.g., alcohol-preferring (P) and high-alcohol-drinking (HAD)) versus EtOH-avoiding (e.g., alcohol-non-preferring (NP) and low-alcohol-drinking (LAD)) strains, as well as differentiate between male and female rats. In the present study we sought to explore the effect of age and alcohol availability on spontaneously emitted 50-55 kHz frequency modulated (FM) and 22-28 kHz USVs in adult, male Long-Evans rats. With the hypothesis that age and alcohol experience influence spontaneous USV emissions, we examined USV data collected across a 24-week intermittent EtOH access experiment in male Long-Evans rats. USV counts and acoustic characteristic (i.e., mean frequency, duration, bandwidth and power) data revealed distinct age-dependent phenotypes in both 50-55 kHz FM and 22-28 kHz USV transmission patterns that were modulated by EtOH exposure. These results highlight the influence of age and EtOH experience on the unique emotional phenotypes of male Long-Evans rats.

Alcohol-naïve USVs distinguish male HAD-1 from LAD-1 rat strains.

Ultrasonic vocalizations (USVs) are mediated through specific dopaminergic and cholinergic neural pathways and serve as real-time measures of positive and negative emotional status in rodents. Although most USV studies focus primarily on USV counts, each USV possesses a number of characteristics shown to reflect activity in the associated neurotransmitter system. In the present study, we recorded spontaneously emitted USVs from alcohol-naïve high alcohol drinking (HAD-1) and low alcohol drinking (LAD-1) rats. Using our recently developed WAAVES algorithm, we quantified four acoustic characteristics (mean frequency, duration, power, and bandwidth) from each 22-28 kHz and 50-55 kHz frequency-modulated (FM) USV. This rich USV representation allowed us to apply advanced statistical techniques to identify the USV acoustic characteristics that distinguished HAD-1 from LAD-1 rats. Linear mixed models (LMM) examined the predictability of each USV characteristic in isolation and linear discriminant analysis (LDA), and binomial logistic regression examined the predictability of linear combinations of the USV characteristics as a group. Results revealed significant differences in acoustic characteristics between HAD-1 and LAD-1 rats in both 22-28 kHz and 50-55 kHz FM USVs. In other words, these rats selectively bred for high- and low-alcohol consumption can be identified as HAD-1 or LAD-1 rats with high classification accuracy (approximately 92-100%) exclusively based on their emitted 22-28 kHz and 50-55 kHz FM USV acoustic characteristics. In addition, acoustic characteristics of 22-28 kHz and 50-55 kHz FM USVs emitted by alcohol-naïve HAD-1 and LAD-1 rats significantly correlate with their future alcohol consumption. Our current findings provide novel evidence that USV acoustic characteristics can be used to discriminate between alcohol-naïve HAD-1 and LAD-1 rats, and may serve as biomarkers in rodents with a predisposition for, or against, excessive alcohol intake.

Rodent ultrasonic vocalizations as biomarkers of future alcohol use: A predictive analytic approach.

Excessive alcohol consumption has a vast, negative impact on society. Rodent models have been successful in furthering our understanding of the biological underpinnings that drive alcohol consumption. Rodents emit ultrasonic vocalizations (USVs) that are each composed of several acoustic characteristics (e.g., frequency, duration, bandwidth, power). USVs reflect neurotransmitter activity in the ascending limb of the mesolimbic dopaminergic and cholinergic neurotransmitter systems and serve as noninvasive, real-time biomarkers of dopaminergic and cholinergic neurotransmission in the limbic system. In the present study, we recorded spontaneously emitted USVs from alcohol-naïve Long-Evans (LE) rats and then measured their alcohol intake. We compared the USV acoustic characteristics and alcohol consumption data from these LE rats with previously published data from selectively bred high-alcohol (P and HAD-1) and low-alcohol (NP and LAD-1) drinking lines from studies with the same experimental method. Predictive analytic techniques were applied simultaneously to this combined data set and revealed that (a) USVs emitted by alcohol-naïve rats accurately discriminated among high-alcohol consuming, LE, and low-alcohol consuming rat lines, and (b) future alcohol consumption in these same rat lines was reliably predicted from the USV data collected in an alcohol-naïve state. To our knowledge, this is the first study to show that alcohol consumption is predicted directly from USV profiles of alcohol-naïve rats. Because USV acoustic characteristics are sensitive to underlying neural activity, these findings suggest that baseline differences in mesolimbic cholinergic and dopaminergic tone could determine the propensity for future alcohol consumption in rodents.

Beta-arrestin 1 regulation of reward-motivated behaviors and glutamatergic function.

The two highly homologous non-visual arrestins, beta-arrestin 1 and 2, are ubiquitously expressed in the central nervous system, yet knowledge of their disparate roles is limited. While beta-arrestin 2 (ßarr2) has been implicated in several aspects of reward-related learning and behavior, very little is known about the behavioral function of beta-arrestin 1 (ßarr1). Using mice lacking ßarr1, we focused on the role of this scaffolding and signal transduction protein in reward-motivated behaviors and in striatal glutamatergic function. We found that ßarr1 KO mice were both slower in acquiring cocaine self-administration and in extinguishing this behavior. They also showed deficits in learning tasks supported by a natural food reward, suggesting a general alteration in reward processing. We then examined glutamatergic synaptic strength in WT and KO medium spiny neurons (MSNs) of the Nucleus Accumbens (NAc) shell in naïve animals, and from those that underwent cocaine self-administration. An increase in the AMPA/NMDA (A/N) ratio and a relative lack of GluN2B-enriched NMDARs was found in naïve KO vs WT MSNs. Applying Lim Domain Kinase (LIMK1), the kinase that phosphorylates and inactivates cofilin, to these cells, showed that both ßarr1 and LIMK regulate the A/N ratio and GluN2B-NMDARs. Cocaine self-administration increased the A/N ratio and GluN2B-NMDARs in WT MSNs and, although the A/N ratio also increased in KO MSNs, this was accompanied by fewer GluN2B-NMDARs and an appearance of calcium-permeable AMPARs. Finally, to examine the consequences of reduced basal GluN2B-NMDARs in reward-processing seen in KO mice, we chronically infused ifenprodil, a GluN2B antagonist, into the NAc shell of WT mice. This intervention substantially reduced food-motivated behavior. Together these findings identify a previously unknown role of ßarr1 in regulating specific reward-motivated behaviors and glutamatergic function.

Negative Affect-Associated USV Acoustic Characteristics Predict Future Excessive Alcohol Drinking and Alcohol Avoidance in Male P and NP Rats.

BACKGROUND: Negative emotional status and adverse emotional events increase vulnerability to alcohol abuse. Ultrasonic vocalizations (USVs) emitted by rats are a well-established model of emotional status that can reflect positive or negative affective responses in real time. Most USV studies assess counts, yet each USV is a multidimensional data point characterized by several acoustic characteristics that may provide insight into the neurocircuitry underlying emotional response. METHODS: USVs emitted from selectively bred alcohol-naïve and alcohol-experienced alcohol-preferring and nonpreferring rats (P and NP rats) were recorded during 4-hour sessions on alternating days over 4 weeks. Linear mixed modeling (LMM) and linear discriminant analysis (LDA) were applied to USV acoustic characteristics (e.g., frequency, duration, power, and bandwidth) of negative affect (22 to 28 kilohertz [kHz])- and positive (50 to 55 kHz) affect-related USVs. RESULTS: Hundred percent separation between alcohol-naïve P and NP rats was achieved through a linear combination (produced by LDA) of USV acoustic characteristics of 22- to 28-kHz USVs, whereas poor separation (36.5%) was observed for 50- to 55-kHz USVs. 22- to 28-kHz LDA separation was high (87%) between alcohol-experienced P and NP rats, but was poor for 50- to 55-kHz USVs (57.3%). USV mean frequency and duration were the highest weighted characteristics in both the naïve and experienced 22- to 28-kHz LDA representations suggesting that alcohol experience does not alter the representations. LMM analyses of 22- to 28-kHz USV acoustic characteristics matched the LDA results. Poor LDA separation was observed between alcohol-naïve and alcohol-experienced P rats for both 22- to 28-kHz and 50- to 55-kHz USVs. CONCLUSIONS: Advanced statistical analysis of negative affect-associated USV data predicts future behaviors of excessive alcohol drinking and alcohol avoidance in selectively bred rats. USV characteristics across rat lines reveal affect-related motivation to consume alcohol and may predict neural pathways mediating emotional response. Further characterization of these differences could delineate particular neurocircuitry and methods to ameliorate dysregulated emotional states often observed in human alcohol abusers.

Recovery of sensorimotor function following sciatic nerve injury across multiple rat strains.

BACKGROUND: Peripheral nerve injury (PNI) can result in neurodegenerative changes leading to motor, sensory and autonomic dysfunction. Injury to the rat sciatic nerve is used to model pathophysiologic processes following PNI and assess the efficacy of therapeutic interventions. Frequently, temporal changes in the sciatic functional index (SFI), a measure of sensorimotor integration are measured in rats to assess functional recovery following sciatic nerve injury. However, multiple rat strains and behavioral endpoints have been employed to investigate pathophysiology of PNI and impact of therapeutic intervention on recovery, raising the possibility that rat strain may influence the outcome of such studies. NEW METHOD: The temporal course of recovery from sham, sciatic nerve crush or transection injury was assessed using SFI determined by two methods (footprint and DigiGait), and proprioceptive hind limb placement (a measure of proprioceptive integrity) of the sciatic nerve innervation, in male Sprague Dawley, Lewis, Fischer, Wistar and Long Evans rats. RESULTS: The SFI profile, as assessed by both inked footprint analysis and DigiGait, following sciatic nerve injury was remarkably conserved across strains. Dramatic strain-related differences were observed in the latency to place the crush- or transection-injured hind limb following proprioceptive hind limb stimulation. COMPARISON WITH EXISTING METHOD: The novelty of this study is the parallel comparison of multiple strains using existing and novel tests. CONCLUSION: These results suggest that some sensorimotor function tests may be sensitive to the choice of strain, as evidenced by the differences between SFI and proprioceptive function outcomes.

The impact of l-dopa on attentional impairments in a rat model of Parkinson's disease.

Attentional deficits including difficulty in switching attention between tasks or rules, sustaining attention, and selectively attending to specific stimuli are commonly seen in patients with Parkinson's disease (PD). While these deficits are frequently reported, it is unclear how traditional dopamine replacement therapy such as l-dopa affects these deficits. In a rat model of PD in which dopamine is unilaterally depleted with a 6-hydroxydopamine infusion to the medial forebrain bundle, we first examined the impact of acute and chronic l-dopa treatment on attention switching as modeled by disengagement behavior (i.e. the ability to disengage from an on-going behavior such as eating or drinking to attend to perioral stimulation). Then, in a separate experiment, we evaluated the effects of l-dopa treatment on selective and sustained attention deficits using a five choice task. Our data suggest that the l-dopa dose necessary to recover motor function can successfully restore attention switching behavior (i.e. disengagement behavior), but further worsens performance in the selective and sustained attention task. Furthermore, this same dose was responsible for inducing dyskinesias in rats given chronic daily injections. Taken together, these findings demonstrate that dopamine replacement therapy may not be sufficient for treating all types of attentional dysfunction occurring in PD.

Therapeutic targeting of oxygen-sensing prolyl hydroxylases abrogates ATF4-dependent neuronal death and improves outcomes after brain hemorrhage in several rodent models.

Disability or death due to intracerebral hemorrhage (ICH) is attributed to blood lysis, liberation of iron, and consequent oxidative stress. Iron chelators bind to free iron and prevent neuronal death induced by oxidative stress and disability due to ICH, but the mechanisms for this effect remain unclear. We show that the hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) family of iron-dependent, oxygen-sensing enzymes are effectors of iron chelation. Molecular reduction of the three HIF-PHD enzyme isoforms in the mouse striatum improved functional recovery after ICH. A low-molecular-weight hydroxyquinoline inhibitor of the HIF-PHD enzymes, adaptaquin, reduced neuronal death and behavioral deficits after ICH in several rodent models without affecting total iron or zinc distribution in the brain. Unexpectedly, protection from oxidative death in vitro or from ICH in vivo by adaptaquin was associated with suppression of activity of the prodeath factor ATF4 rather than activation of an HIF-dependent prosurvival pathway. Together, these findings demonstrate that brain-specific inactivation of the HIF-PHD metalloenzymes with the blood-brain barrier-permeable inhibitor adaptaquin can improve functional outcomes after ICH in several rodent models.

Ultrasonic vocalization in murine experimental stroke: A mechanistic model of aphasia.

PURPOSE: Approximately one-fourth of stroke survivors are aphasic. Speech therapy is the main treatment approach but leaves most patients with chronic disability. Attempts to improve this situation are hampered by a lack of mechanistic understanding of the disability and treatments, reflecting the neglect of this impairment modality in pre-clinical research. Accordingly, we devised a novel murine model of speech-related impairment after stroke to investigate the role of language- and plasticity-associated molecules. Rodents communicate socially with ultrasonic vocalizations (USVs), conveying semantic and semiotic information with complex frequency modulated "songs" and alarm calls. METHODS: Transient focal cerebral ischemia was induced in male C57BL6 mice via either 30 or 45 minutes of reversible right MCAO using the intraluminal filament technique. Nine days post-operatively brains are stained with TTC and analyzed for infarct volume. For behavioral measures health scores are taken (days 1-4), cylinder tests and USV recordings performed at days 3 and 7 post operatively. Real time PCR was performed at 24 and 48 hour and 7 day time points to quantify mRNA expression of communication-related genes (Foxp2, Foxp1, Srpx2, Cntnap2 and Gapdh). Immunohistochemistry was performed to localize FOXP2 protein. RESULTS: After middle cerebral artery occlusion of either 30 or 45 minutes duration, mice demonstrate profoundly impaired socially evoked USVs. In addition, there is suppression of the language-associated transcription factor, Forkhead box protein 2 (Foxp2), and its downstream binding partner, contactin-associated protein 2 (Cntnap2). CONCLUSION: These findings set a foundation for further studies of mechanisms and novel treatment strategies for post-stroke vocalization impairments.

Alcohol enhances unprovoked 22-28 kHz USVs and suppresses USV mean frequency in High Alcohol Drinking (HAD-1) male rats.

Heightened emotional states increase impulsive behaviors such as excessive ethanol consumption in humans. Though positive and negative affective states in rodents can be monitored in real-time through ultrasonic vocalization (USV) emissions, few animal studies have focused on the role of emotional status as a stimulus for initial ethanol drinking. Our laboratory has recently developed reliable, high-speed analysis techniques to compile USV data during multiple-hour drinking sessions. Since High Alcohol Drinking (HAD-1) rats are selectively bred to voluntarily consume intoxicating levels of alcohol, we hypothesized that USVs emitted by HAD-1 rats would reveal unique emotional phenotypes predictive of alcohol intake and sensitive to alcohol experience. In this study, male HAD-1 rats had access to water, 15% and 30% EtOH or water only (i.e., Controls) during 8 weeks of daily 7-h drinking-in-the-dark (DID) sessions. USVs, associated with both positive (i.e., 50-55 kHz frequency-modulated or FM) and negative (i.e., 22-28 kHz) emotional states, emitted during these daily DID sessions were examined. Findings showed basal 22-28 kHz USVs were emitted by both EtOH-Naïve (Control) and EtOH-experienced rats, alcohol experience enhanced 22-28 kHz USV emissions, and USV acoustic parameters (i.e., mean frequency in kHz) of both positive and negative USVs were significantly suppressed by chronic alcohol experience. These data suggest that negative affective status initiates and maintains excessive alcohol intake in selectively bred HAD-1 rats and support the notion that unprovoked emissions of negative affect-associated USVs (i.e., 22-28 kHz) predict vulnerability to excessive alcohol intake in distinct rodent models.

Analysis of Small Ischemic Lesions in the Examinees of a Brain Dock and Neurological Examination of Animals Subjected to Cortical or Basal Ganglia Photothrombotic Infarction.

We analyzed cases of small brain ischemic lesions found in examinees of a brain dock (neurological health screening center). Small cerebral infarction was found in 17 % of the examinees (733 cases). White matter lesions were found in 24 %. Infarctions were located in the cortex or subcortical white matter in 31 % and in the basal ganglia in 44 % of cases. Infratentorial infarction was found in 1.6 %. We have developed an animal model of small infarction in the cortex or basal ganglia induced by photothrombosis in rodents. Sprague-Dawley rats or Mongolian gerbils were anesthetized and photothrombotic infarction was induced in the left caudate nucleus or parietal cortex by light exposure via an optic fiber and intravenous Rose Bengal dye injection. Histological examination revealed development of a small spherical infarction surrounding the tip of the optic fiber. The lesion turned to a cyst by 6 weeks after lesioning. Neurological deficits were found in animals both with cortical and caudate infarction. Behavioral changes in an open field test differed with the lesion site. Neurological deficits were sustained longer in animals with larger infarctions. Thus, photothrombotic infarction is useful for analyzing location-dependent and size-dependent neurological and neuropathological changes after cerebral infarction.

Changes in Rat 50-kHz Ultrasonic Vocalizations During Dopamine Denervation and Aging: Relevance to Neurodegeneration.

Vocal communication is negatively affected by neurodegenerative diseases, such as Parkinson disease, and by aging. The neurological and sensorimotor mechanisms underlying voice deficits in Parkinson disease and aging are not well-understood. Rat ultrasonic vocalizations provide a unique behavioral model for studying communication deficits and the mechanisms underlying these deficits in these conditions. The purpose of this review was to examine the existing literature for methods using rat ultrasonic vocalization with regard to the primary disease pathology of Parkinson disease, dopamine denervation, and aging. Although only a small amount of papers were found for each of these topics, results suggest that both shared and unique acoustic deficits in ultrasonic vocalizations exist across conditions and that these acoustic deficits are due to changes in either dopamine signaling or denervation and in aging models changes to the nucleus ambiguus, at the level of the neuromuscular junction, and the composition of the vocal folds in the larynx. We conclude that ultrasonic vocalizations are a useful tool for studying biologic mechanisms underlying vocal communication deficits in neurodegenerative diseases and aging.

So you think you can jump? A novel long jump assessment to detect deficits in stroked mice.

BACKGROUND: Stroke survivors suffer from persistent disability, as well as severe sensorimotor and cognitive deficits. The preclinical assessment of such deficits is important for the development of novel interventions and therapeutics. NEW METHOD: The aim of this study was to develop a quantitative behavioral measure of hindlimb functionality in rodents, which could be used to assess deficits after a neural injury, such as stroke. Here we introduce a test to measure long jump behavior in mice. RESULTS: Using this test we first showed that while male and female mice exhibited no differences in jump success rate, the female mice showed lower baseline jumping latencies. Next we demonstrated that the induction of a cerebral stroke via middle cerebral artery occlusion (MCAO) for 45min did not affect the jump success rate in either group; however, it did significantly increase jump latencies in both male and female mice. Finally, we used therapeutic interventions to explore mechanisms that may be involved in producing this increase in jump latency by administering the anti-depressant fluoxetine prior to the long jump assay, and also tested for potential changes in anxiety levels after stroke. COMPARISON WITH EXISTING METHODS: Other methods to assess hindlimb functionality are not specific, because they measure behaviors that rely not only on hindlimbs, but also on forelimbs and tail. CONCLUSIONS: This study introduces a novel assay that can be used to measure a stroke induced behavioral deficit with great sensitivity, and raises interesting questions about potential mechanisms regulating this effect.

Alcohol-preferring P rats emit spontaneous 22-28 kHz ultrasonic vocalizations that are altered by acute and chronic alcohol experience.

BACKGROUND: Emotional states are often thought to drive excessive alcohol intake and influence the development of alcohol use disorders. To gain insight into affective properties associated with excessive alcohol intake, we utilized ultrasonic vocalization (USV) detection and analyses to characterize the emotional phenotype of selectively bred alcohol-preferring (P) rats; an established animal model of excessive alcohol intake. USVs emitted by rodents have been convincingly associated with positive (50-55 kHz frequency-modulated [FM]) and negative (22-28 kHz) affective states. Therefore, we hypothesized that 50-55 and 22-28 kHz USV emission patterns in P rats would reveal a unique emotional phenotype sensitive to alcohol experience. METHODS: 50-55 kHz FM and 22-28 kHz USVs elicited from male P rats were assessed during access to water, 15 and 30% EtOH (v/v). Ethanol (EtOH; n = 12) or water only (Control; n = 4) across 8 weeks of daily drinking-in-the-dark (DID) sessions. RESULTS: Spontaneous 22-28 kHz USVs are emitted by alcohol-naïve P rats and are enhanced by alcohol experience. During DID sessions when alcohol was not available (e.g., "EtOH OFF" intervals), significantly more 22-28 kHz than 50-55 kHz USVs were elicited, while significantly more 50-55 kHz FM than 22-28 kHz USVs were emitted when alcohol was available (e.g., "EtOH ON" intervals). In addition, USV acoustic property analyses revealed chronic effects of alcohol experience on 22-28 kHz USV mean frequency, indicative of lasting alcohol-mediated alterations to neural substrates underlying emotional response. CONCLUSIONS: Our findings demonstrate that acute and chronic effects of alcohol exposure are reflected in changes in 22-28 and 50-55 kHz FM USV counts and acoustic patterns. These data support the notion that initiation and maintenance of alcohol intake in P rats may be due to a unique, alcohol-responsive emotional phenotype and further suggest that spontaneous 22-28 kHz USVs serve as behavioral markers for excessive drinking vulnerability.

Cerebrolysin improves cognitive performance in rats after mild traumatic brain injury.

OBJECT: Long-term memory deficits occur after mild traumatic brain injuries (mTBIs), and effective treatment modalities are currently unavailable. Cerebrolysin, a peptide preparation mimicking the action of neurotrophic factors, has beneficial effects on neurodegenerative diseases and brain injuries. The present study investigated the long-term effects of Cerebrolysin treatment on cognitive function in rats after mTBI. METHODS: Rats subjected to closed-head mTBI were treated with saline (n = 11) or Cerebrolysin (2.5 ml/kg, n = 11) starting 24 hours after injury and then daily for 28 days. Sham animals underwent surgery without injury (n = 8). To evaluate cognitive function, the modified Morris water maze (MWM) test and a social odor-based novelty recognition task were performed after mTBI. All rats were killed on Day 90 after mTBI, and brain sections were immunostained for histological analyses of amyloid precursor protein (APP), astrogliosis, neuroblasts, and neurogenesis. RESULTS: Mild TBI caused long-lasting cognitive memory deficits in the MWM and social odor recognition tests up to 90 days after injury. Compared with saline treatment, Cerebrolysin treatment significantly improved both long-term spatial learning and memory in the MWM test and nonspatial recognition memory in the social odor recognition task up to 90 days after mTBI (p < 0.05). Cerebrolysin significantly increased the number of neuroblasts and promoted neurogenesis in the dentate gyrus, and it reduced APP levels and astrogliosis in the corpus callosum, cortex, dentate gyrus, CA1, and CA3 regions (p < 0.05). CONCLUSIONS: These results indicate that Cerebrolysin treatment of mTBI improves long-term cognitive function, and this improvement may be partially related to decreased brain APP accumulation and astrogliosis as well as increased neuroblasts and neurogenesis.

Novel humanized recombinant T cell receptor ligands protect the female brain after experimental stroke.

Transmigration of peripheral leukocytes to the brain is a major contributor to cerebral ischemic cell death mechanisms. Humanized partial major histocompatibility complex class II constructs (pMHC), covalently linked to myelin peptides, are effective for treating experimental stroke in males, but new evidence suggests that some inflammatory cell death mechanisms after brain injury are sex-specific. We here demonstrate that treatment with pMHC constructs also improves outcomes in female mice with middle cerebral artery occlusion (MCAO). HLA-DR2 transgenic female mice with MCAO were treated with RTL1000 (HLA-DR2 moiety linked to human MOG-35-55 peptide), HLA-DRa1-MOG-35-55, or vehicle (VEH) at 3, 24, 48, and 72 h after reperfusion and were recovered for 96 h or 2 weeks post-injury for measurement of histology (TTC staining) or behavioral testing. RTL1000- and DRa1-MOG-treated mice had profoundly reduced infarct volumes as compared to the VEH group, although higher doses of DRa1-MOG were needed for females vs. males evaluated previously. RTL1000-treated females also exhibited strongly improved functional recovery in a standard cylinder test. In novel studies of post-ischemic ultrasonic vocalization (USV), as measured by animal calls to their cage mates, we modeled in mice the post-stroke speech deficits common in human stroke survivors. The number of calls was reduced in injured animals relative to pre-MCAO baseline regardless of RTL1000 treatment status. However, call duration was significantly improved by RTL1000 treatment, suggesting benefit to the animal's recovery of vocalization capability. We conclude that both the parent RTL1000 molecule and the novel non-polymorphic DRα1-MOG-35-55 construct were highly effective immunotherapies for treatment of transient cerebral ischemia in females.

Impaired limb reaction to displacement of center of gravity in rats with unilateral striatal ischemic injury.

Clinical stroke often results in impaired balance and increased vulnerability to severe injuries due to falling. To evaluate potential preclinical treatments that might target these deficits, it will be important to include tests capable of assessing these impairments chronically in animal models. Previously, we developed a postural instability test (PIT) that revealed chronic, unilateral impairments in postural stability in rat models of hemi-Parkinson's disease (PD) and of unilateral cervical spinal cord injury. Here, we investigated whether this test was also capable of revealing long-term stroke-induced impairments in postural support in rats. Additionally, we examined the ability of more common tests of sensorimotor function to detect chronic impairments. We found that the PIT detected chronic deficits in postural stability/balance enduring for up to 6 weeks post-stroke, outlasting impairments detected in other tests of forelimb sensorimotor function, including asymmetries in upright postural support (cylinder test) and vibrissae-evoked forelimb placing.

Simvastatin and environmental enrichment effect on recognition and temporal order memory after mild-to-moderate traumatic brain injury.

PRIMARY OBJECTIVE: The purpose of this study was to investigate the effect of mild-to- moderate (m-mod) traumatic brain injury (TBI) on spontaneous object (SO) recognition and temporal order (TO) memory in male Wistar rats and to compare the effects of environmental enrichment (EE) and simvastatin (Sim) on SO and TO memory post-injury. RESEARCH DESIGN: A randomized repeated measure experimental design was used. METHODS AND PROCEDURE: Seven days after arrival, animals received the injury or sham surgery. Using a Y-shaped maze, SO and TO memory was assessed in the two groups of animals at 6, 24, 48, 72 hours and 7, 14, 21 and 35 days post-surgery. Total time exploring each object and discrimination ratio were calculated and analysed. Then SO and TO memory were compared between two groups that received either Sim or EE for 2 hours daily starting 24 hours post-injury and a sham group that received saline for 14 days post-injury. RESULTS: The results showed that the injury impaired SO and TO memory compared to the sham up to 35 days post-trauma. Injured animals exhibited familiarity preference, novelty aversion and impaired TO performance. EE improved the animals' SO recognition deficits 7 days post-injury after a shorter delay (1 minute) only and Sim reversed TO memory deficits 14 days post-injury after a longer delay (60 minutes). CONCLUSION: Persistent SO and TO memory deficits follow TBI in animals; Simv and EE seem to be promising therapies of TBI memory deficits.

Assessing forelimb function after unilateral cervical SCI using novel tasks: limb step-alternation, postural instability and pasta handling.

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority of the spinal cord injuries in humans occur at the cervical levels. Therefore, developing cervical injury models and developing relevant and sensitive behavioral tests is of great importance. Here we describe the use of a newly developed forelimb step-alternation test after cervical spinal cord injury in rats. In addition, we describe two behavioral tests that have not been used after spinal cord injury: a postural instability test (PIT), and a pasta-handling test. All three behavioral tests are highly sensitive to injury and are easy to use. Therefore, we feel that these behavioral tests can be instrumental in investigating therapeutic strategies after cSCI.