Growth hormone modulates hippocampal excitatory synaptic transmission and plasticity in old rats

Cataloged from PDF version of article.Alterations in the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPA-R) and N-methyl-D-aspartate receptor (NMDA-R) have been documented in aged animals and may contribute to changes in hippocampal-dependent memory. Growth hormone (GH) regulates AMPA-R and NMDA-R-dependent excitatory transmission and decreases with age. Chronic GH treatment mitigates age-related cognitive decline. An in vitro CA1 hippocampal slice preparation was used to compare hippocampal excitatory transmission and plasticity in old animals treated for 6–8 months with either saline or GH. Our findings indicate that GH treatment restores NMDA-Rdependent basal synaptic transmission in old rats to young adult levels and enhances both AMPA-R-dependent basal synaptic transmission and long-term potentiation. These alterations in synaptic function occurred in the absence of changes in presynaptic function, as measured by paired-pulse ratios, the total protein levels of AMPA-R and NMDA-R subunits or in plasma or hippocampal levels of insulin-like growth factor-I. These data suggest a direct role for GH in altering age-related changes in excitatory transmission and provide a possible cellular mechanism through which GH changes the course of cognitive decline. © 2012 Elsevier Inc. All rights reserved

Complexity of the self-schema and responses to disconfirming feedback

This study focused on complexity of the self-schema as one factor that influences people's responses to social feedback that challenges their established view of self. Complexity refers to the number of independent attributes included in the schema. A card-sorting task (Zajonc, 1960) was used to identify the high- and low-complexity groups. Subjects were given bogus feedback relevant to the targeted domain of self-knowledge, and changes in self-descriptiveness ratings and response latency times were monitored. Results suggest that high-complexity subjects were able to attend to and encode the disconfirming feedback, while low-complexity subjects responded by rejecting the feedback and reasserting positive aspects of the self. The implications of these findings for clarifying the process of self-schema updating, revision, and change are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44337/1/10608_2006_Article_BF02357222.pd

Perceiving Mixed Valence Emotions Reduces Intergroup Dehumanization

To deny others’ humanity is one of the most heinous forms of intergroup prejudice. Given evidence that perceiving various forms of complexity in outgroup members reduces intergroup prejudice, we investigated across three experiments whether the novel dimension of emotional complexity, or outgroup members’ joint experience of mixed-valence emotions, would also reduce their dehumanization. Experiment 1 found that perceiving fictitious aliens’ experience of the same primary emotions (e.g., sadness) presented in mixed vs. non-mixed valence pairs led to reduced prejudice via attenuated dehumanization, i.e. attribution of uniquely human emotions. Experiment 2 confirmed these results, using an unfamiliar real-world group as an outgroup target. Experiment 3 used a familiar outgroup and found generally similar effects, reducing social distance through reduced dehumanization. These processes suggest that an alternate route to reduced dehumanizing of outgroups might involve presenting mixed valence emotions

Development and characterization of a Yucatan miniature biomedical pig permanent middle cerebral artery occlusion stroke model

BACKGROUND: Efforts to develop stroke treatments have met with limited success despite an intense need to produce novel treatments. The failed translation of many of these therapies in clinical trials has lead to a close examination of the therapeutic development process. One of the major factors believed to be limiting effective screening of these treatments is the absence of an animal model more predictive of human responses to treatments. The pig may potentially fill this gap with a gyrencephalic brain that is larger in size with a more similar gray-white matter composition to humans than traditional stroke animal models. In this study we develop and characterize a novel pig middle cerebral artery occlusion (MCAO) ischemic stroke model. METHODS: Eleven male pigs underwent MCAO surgery with the first 4 landrace pigs utilized to optimize stroke procedure and 7 additional Yucatan stroked pigs studied over a 90 day period. MRI analysis was done at 24 hrs and 90 days and included T2w, T2w FLAIR, T1w FLAIR and DWI sequences and associated ADC maps. Pigs were sacrificed at 90 days and underwent gross and microscopic histological evaluation. Significance in quantitative changes was determined by two-way analysis of variance and post-hoc Tukey’s Pair-Wise comparisons. RESULTS: MRI analysis of animals that underwent MCAO surgery at 24 hrs had hyperintense regions in T2w and DWI images with corresponding ADC maps having hypointense regions indicating cytotoxic edema consistent with an ischemic stroke. At 90 days, region of interest analysis of T1 FLAIR and ADC maps had an average lesion size of 59.17 cc, a loss of 8% brain matter. Histological examination of pig brains showed atrophy and loss of tissue, consistent with MRI, as well as glial scar formation and macrophage infiltration. CONCLUSIONS: The MCAO procedure led to significant and consistent strokes with high survivability. These results suggest that the pig model is potentially a robust system for the study of stroke pathophysiology and potential diagnostics and therapeutics

The association between depressive symptoms and executive control impairments in response to emotional and non-emotional information

Depression has been linked with impaired executive control and specific impairments in inhibition of negative material. To date, only a few studies have examined the relationship between depressive symptoms and executive functions in response to emotional information. Using a new paradigm, the Affective Shift Task (AST), the present study examined whether depressive symptoms in general, and rumination specifically, are related to impairments in inhibition and set shifting in response to emotional and non-emotional material. The main finding was that depressive symptoms in general were not related to inhibition. Set-shifting impairments were only observed in moderate to severely depressed individuals. Interestingly, rumination was related to inhibition impairments, specifically when processing negative information, as well as impaired set shifting as reflected in a larger shift cost. These results are discussed in relation to cognitive views on vulnerability for depression

Paramagnetic to antiferromagnetic phase transformation in sputter deposited Pt–Mn thin films

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Auditory Feedback Control of Vocal Pitch during Sustained Vocalization: A Cross-Sectional Study of Adult Aging

Background: Auditory feedback has been demonstrated to play an important role in the control of voice fundamental frequency (F0), but the mechanisms underlying the processing of auditory feedback remain poorly understood. It has been well documented that young adults can use auditory feedback to stabilize their voice F0 by making compensatory responses to perturbations they hear in their vocal pitch feedback. However, little is known about the effects of aging on the processing of audio-vocal feedback during vocalization. Methodology/Principal Findings: In the present study, we recruited adults who were between 19 and 75 years of age and divided them into five age groups. Using a pitch-shift paradigm, the pitch of their vocal feedback was unexpectedly shifted 650 or 6100 cents during sustained vocalization of the vowel sound/u/. Compensatory vocal F0 response magnitudes and latencies to pitch feedback perturbations were examined. A significant effect of age was found such that response magnitudes increased with increasing age until maximal values were reached for adults 51–60 years of age and then decreased for adults 61–75 years of age. Adults 51–60 years of age were also more sensitive to the direction and magnitude of the pitch feedback perturbations compared to younger adults. Conclusion: These findings demonstrate that the pitch-shift reflex systematically changes across the adult lifespan. Understanding aging-related changes to the role of auditory feedback is critically important for our theoretica

Why do People Worry and Ruminate? Investigating Factors that Maintain Repetitive Negative Thought

The overarching aim of this research was to understand factors implicated in the maintenance of rumination and worry, conceptualised as a transdiagnostic process of repetitive negative thought (RNT), through the use of cross-sectional, prospective, and experimental research designs. Rumination and worry have been repeatedly implicated in the development and maintenance of various forms of psychopathology, in particular, depression and anxiety disorders. Given the negative outcomes for mood and psychopathology, there is a need for a better understanding of vulnerability factors that maintain this unconstructive thinking. Based on a review of the literature, an integrative theoretical model was developed and tested using structural equation modelling. Using cross-sectional data, the model was tested in a large sample of adults (n = 506). Of the broad range of proximal and distal vulnerability factors examined, only neuroticism and beliefs about the function of repetitive thought remained significantly associated with RNT once current symptoms were statistically controlled. Emotional abuse and abstract processing were indirectly associated with RNT. Following on from this, a prospective study examined which of these vulnerability factors prospectively predicted change in RNT over six to eight weeks. Only neuroticism and the specific belief that repetitive thought aids instrumental understanding predicted change in RNT, after controlling for depression and anxiety symptoms. Next, two experimental studies were conducted to explore the causal relationship between RNT and the belief that RNT aids insight and understanding, by experimentally manipulating this appraisal and measuring the impact on state RNT. Whilst methodological issues with the first experimental study precluded clear conclusions being drawn about the nature of the relationship, the second experimental study demonstrated that participants manipulated to believe that RNT is helpful for increasing insight and understanding had greater levels of state RNT after exposure to a stressor, relative to participants manipulated to believe that RNT is unhelpful. Finally, in order to see whether rumination has any consequences that may potentially reinforce its further use, an experimental study was conducted to manipulate processing mode (abstract rumination versus concrete thinking) and examine the effect on a range of outcomes relating to insightfulness and avoidance. Whilst rumination did not lead to increased insight, it did afford more justification for avoidance, relative to concrete thinking. The clinical and theoretical implications of these findings are discussed with respect to existing theories of repetitive negative thought

What’s retinoic acid got to do with it? Retinoic acid regulation of the neural crest in craniofacial and ocular development

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151310/1/dvg23308.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151310/2/dvg23308_am.pd