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Full-Text Articles in Medicine and Health Sciences

High Frequency Oscillations Are Phase-Amplitude Coupled In Stress Induced Seizures Following Traumatic Brain Injury, Paul Jung Oct 2019

High Frequency Oscillations Are Phase-Amplitude Coupled In Stress Induced Seizures Following Traumatic Brain Injury, Paul Jung

Electronic Thesis and Dissertation Repository

Traumatic Brain Injury (TBI) often leads to the development of epilepsy, especially with the occurrence of stressful events. Stressors increase the levels of corticotropin-releasing factor (CRF) in the amygdala, which can be damaged by the secondary effects of TBI. It is hypothesized that the activity of CRF receptor type 1 (CRFR1) in the amygdala is altered post-TBI and supports the generation of epileptiform waves, namely high-frequency oscillations (HFOs). Sprague-Dawley rats were given a moderate TBI and in vivo recordings of the amygdala were taken during the administration of an acute tail pinch stressor. The stressor increased broadband activity …


Crf Mediates Stress-Induced Pathophysiological High-Frequency Oscillations In Traumatic Brain Injury, Chakravarthi Narla, Paul S. Jung, Francisco Bautista Cruz, Michelle Everest, Julio Martinez-Trujillo, Michael O. Poulter Mar 2019

Crf Mediates Stress-Induced Pathophysiological High-Frequency Oscillations In Traumatic Brain Injury, Chakravarthi Narla, Paul S. Jung, Francisco Bautista Cruz, Michelle Everest, Julio Martinez-Trujillo, Michael O. Poulter

Physiology and Pharmacology Publications

Copyright © 2019 Narla et al. It is not known why there is increased risk to have seizures with increased anxiety and stress after traumatic brain injury (TBI). Stressors cause the release of corticotropin-releasing factor (CRF) both from the hypothalamic pituitary adrenal (HPA) axis and from CNS neurons located in the central amygdala and GABAergic interneurons. We have previously shown that CRF signaling is plastic, becoming excitatory instead of inhibitory after the kindling model of epilepsy. Here, using Sprague Dawley rats we have found that CRF signaling increased excitability after TBI. Following TBI, CRF type 1 receptor (CRFR1)-mediated activity caused …


Neuronal Correlates For Neuroendocrine Habituation To Repeated Stress, Sara Matovic Dec 2017

Neuronal Correlates For Neuroendocrine Habituation To Repeated Stress, Sara Matovic

Electronic Thesis and Dissertation Repository

One way that the body actively responds to an impending stressor is by increasing systemic glucocorticoids through the activation of the hypothalamic-pituitary-adrenal (HPA) axis. While it is essential for short-term adaptation to stress, the sustained activation of the HPA axis during chronic stress can be detrimental and is linked to stress-related psychiatric conditions such as anxiety and depression. Therefore, it is important that the HPA axis adapts, or habituates, during chronic stress to minimize the negative consequences. Corticotropin releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) function to assimilate incoming information from the stress circuitry and …


Characterizing The Role Of The Neuropeptide Y-Y5r System In Breast Cancer, Jenna Kara Aug 2016

Characterizing The Role Of The Neuropeptide Y-Y5r System In Breast Cancer, Jenna Kara

Electronic Thesis and Dissertation Repository

Studies have demonstrated a correlation between stress and an increased risk of breast cancer. Neuropeptide Y (NPY) is up- regulated in chronic stress and induces proliferation and chemotaxis of 4T1 breast cancer cells via Y5 receptor (Y5R) activation. In the studies performed in this thesis, we characterize NPY-Y5R as a regulatory system that promotes breast cancer metastasis. We compared three cancer cell sublines derived from the same murine mammary fat pad tumour, that greatly differ in metastatic potential (67NR, 168FARN, and 4T1) in addition to a 4T1-Y5R knockdown established in our labs. In this thesis we demonstrate significance of up-regulation …


Developmental Stress, Condition, And Birdsong: A Case Study In Song Sparrows., Kim L Schmidt, Elizabeth A Macdougall-Shackleton, Shawn P Kubli, Scott A Macdougall-Shackleton Oct 2014

Developmental Stress, Condition, And Birdsong: A Case Study In Song Sparrows., Kim L Schmidt, Elizabeth A Macdougall-Shackleton, Shawn P Kubli, Scott A Macdougall-Shackleton

Brain and Mind Institute Researchers' Publications

Sexual-selection theory posits that ornaments and displays can reflect a signaler's condition, which in turn is affected both by recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits exhibit developmental phenotypic plasticity in response to stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. Here, we review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of birds from a long-term study of a population of song sparrows (Melospiza melodia). Field studies of free-living birds indicate that the …


Links Between White Matter Microstructure And Cortisol Reactivity To Stress In Early Childhood: Evidence For Moderation By Parenting., Haroon I Sheikh, Marc F Joanisse, Sarah M Mackrell, Katie R Kryski, Heather J Smith, Shiva M Singh, Elizabeth P Hayden Jan 2014

Links Between White Matter Microstructure And Cortisol Reactivity To Stress In Early Childhood: Evidence For Moderation By Parenting., Haroon I Sheikh, Marc F Joanisse, Sarah M Mackrell, Katie R Kryski, Heather J Smith, Shiva M Singh, Elizabeth P Hayden

Brain and Mind Institute Researchers' Publications

Activity of the hypothalamic-pituitary-adrenal axis (measured via cortisol reactivity) may be a biological marker of risk for depression and anxiety, possibly even early in development. However, the structural neural correlates of early cortisol reactivity are not well known, although these would potentially inform broader models of mechanisms of risk, especially if the early environment further shapes these relationships. Therefore, we examined links between white matter architecture and young girls' cortisol reactivity and whether early caregiving moderated these links. We recruited 45 6-year-old girls based on whether they had previously shown high or low cortisol reactivity to a stress task at …


Paradoxical Reversal Learning Enhancement By Stress Or Prefrontal Cortical Damage: Rescue With Bdnf., Carolyn Graybeal, Michael Feyder, Emily Schulman, Lisa M Saksida, Timothy J Bussey, Jonathan L Brigman, Andrew Holmes Nov 2011

Paradoxical Reversal Learning Enhancement By Stress Or Prefrontal Cortical Damage: Rescue With Bdnf., Carolyn Graybeal, Michael Feyder, Emily Schulman, Lisa M Saksida, Timothy J Bussey, Jonathan L Brigman, Andrew Holmes

Brain and Mind Institute Researchers' Publications

Stress affects various forms of cognition. We found that moderate stress enhanced late reversal learning in a mouse touchscreen-based choice task. Ventromedial prefrontal cortex (vmPFC) lesions mimicked the effect of stress, whereas orbitofrontal and dorsolateral striatal lesions impaired reversal. Stress facilitation of reversal was prevented by BDNF infusion into the vmPFC. These findings suggest a mechanism by which stress-induced vmPFC dysfunction disinhibits learning by alternate (for example, striatal) systems.