Corticotropin-Releasing Factor Concentrations Exhibit an Apparent Diurnal Rhythm in Hypothalamic and Extrahypothalamic Brain Regions: Differential Sensitivity to Corticosterone

1990 ◽  
Vol 52 (6) ◽  
pp. 626-631 ◽  
Author(s):  
Micheal J. Owens ◽  
Jorge Bartolome ◽  
Saul M. Schanberg ◽  
Charles B. Nemeroff
2021 ◽  
Author(s):  
Douglas Miller ◽  
Dylan T. Guenther ◽  
Andrew P. Maurer ◽  
Carissa A. Hansen ◽  
Andrew Zalesky ◽  
...  

AbstractDopaminergic neurons of the substantia nigra (SNC) and ventral tegmental area (VTA) exhibit spontaneous firing activity. The dopaminergic neurons in these regions have been shown to exhibit differential sensitivity to neuronal loss and psychostimulants targeting dopamine transporter. However, it remains unclear whether these regional differences scale beyond individual neuronal activity to regional neuronal networks. Here we utilized live-cell calcium imaging to show that network connectivity greatly differs between SNC and VTA regions with higher incidence of hub-like neurons in the VTA. Specifically, the frequency of hub-like neurons was significantly lower in SNC dopamine neurons than in the adjacent VTA, consistent with the interpretation of a lower network resilience to SNC neuronal loss. We tested this hypothesis when activity of an individual dopaminergic neuron is suppressed, through whole-cell patch clamp electrophysiology, in either SNC, or VTA networks. Neuronal loss in the SNC decreased network clustering, whereas the larger number of hub-neurons in the VTA overcompensated by increasing network clustering in the VTA. We further show that network properties are regulatable via a dopamine transporter but not a D2 receptor dependent mechanism. Our results demonstrate novel regulatory mechanisms of functional network topology in dopaminergic brain regions.


2020 ◽  
Vol 21 (24) ◽  
pp. 9441
Author(s):  
Daniele Lana ◽  
Filippo Ugolini ◽  
Maria Grazia Giovannini

This review is focused on the description and discussion of the alterations of astrocytes and microglia interplay in models of Alzheimer’s disease (AD). AD is an age-related neurodegenerative pathology with a slowly progressive and irreversible decline of cognitive functions. One of AD’s histopathological hallmarks is the deposition of amyloid beta (Aβ) plaques in the brain. Long regarded as a non-specific, mere consequence of AD pathology, activation of microglia and astrocytes is now considered a key factor in both initiation and progression of the disease, and suppression of astrogliosis exacerbates neuropathology. Reactive astrocytes and microglia overexpress many cytokines, chemokines, and signaling molecules that activate or damage neighboring cells and their mutual interplay can result in virtuous/vicious cycles which differ in different brain regions. Heterogeneity of glia, either between or within a particular brain region, is likely to be relevant in healthy conditions and disease processes. Differential crosstalk between astrocytes and microglia in CA1 and CA3 areas of the hippocampus can be responsible for the differential sensitivity of the two areas to insults. Understanding the spatial differences and roles of glia will allow us to assess how these interactions can influence the state and progression of the disease, and will be critical for identifying therapeutic strategies.


CNS Spectrums ◽  
2008 ◽  
Vol 13 (7) ◽  
pp. 585-591 ◽  
Author(s):  
Jyotsna Nair ◽  
Sarbjot Singh Ajit

ABSTRACTAntiglutamatergic agents, such as lamotrigine, have been used successfully for the treatment of posttraumatic stress disorder (PTSD). They could be potentially acting through the stabilization of the corticotropin-releasing factor (CRF) systems. Glutamate mediates CRF release in various brain regions involved in the pathophysiology of PTSD, antiglutamatergic agents could stabilize the CRF system and, thereby, improve the symptom complex of PTSD (reexperiencing, hyperarousal, and avoidance). The role of glutamate and CRF in PTSD and other anxiety disorders are still being elucidated. However, it is clear that the glutamatergic systems play a role in the pathophysiology of PTSD.


1993 ◽  
Vol 616 (1-2) ◽  
pp. 315-319 ◽  
Author(s):  
Zoltán Sarnyai ◽  
Éva Bíró ◽  
János Gardi ◽  
Miklós Vecsernyés ◽  
János Julesz ◽  
...  

1973 ◽  
Vol 51 (10) ◽  
pp. 743-747 ◽  
Author(s):  
Takenori Sato ◽  
John C. George

An attempt was made to detect diurnal periodicity in the hypothalamic content of corticotropin-releasing factor (CRF) activity in the normal pigeon (Columba livia) employing the intrapituitary microinjection method. It was found that CRF activity in the pigeon hypothalamus exhibits a typical diurnal rhythm, with its peak value at 6 a.m. and its trough at 8 p.m. under a lighting regimen of 12-h light and 12-h dark daily cycle. Moreover, this rhythm of CRF activity was shown to be well correlated with a diurnal rhythm of plasma corticosterone level with a definite phase shift. These findings support the concept that the diurnal periodicity of plasma corticosteroid level in the pigeon, originates in the cyclic phases of the releasing factor within the hypothalamus. The physiological significance of these findings is discussed with special reference to the hypothalamic regulation of adrenocorticotropin secretion in the pigeon.


2020 ◽  
pp. 1-12 ◽  
Author(s):  
Kshitij Dwivedi ◽  
Radoslaw Martin Cichy ◽  
Gemma Roig

Visual scene perception is mediated by a set of cortical regions that respond preferentially to images of scenes, including the occipital place area (OPA) and parahippocampal place area (PPA). However, the differential contribution of OPA and PPA to scene perception remains an open research question. In this study, we take a deep neural network (DNN)-based computational approach to investigate the differences in OPA and PPA function. In a first step, we search for a computational model that predicts fMRI responses to scenes in OPA and PPA well. We find that DNNs trained to predict scene components (e.g., wall, ceiling, floor) explain higher variance uniquely in OPA and PPA than a DNN trained to predict scene category (e.g., bathroom, kitchen, office). This result is robust across several DNN architectures. On this basis, we then determine whether particular scene components predicted by DNNs differentially account for unique variance in OPA and PPA. We find that variance in OPA responses uniquely explained by the navigation-related floor component is higher compared to the variance explained by the wall and ceiling components. In contrast, PPA responses are better explained by the combination of wall and floor, that is, scene components that together contain the structure and texture of the scene. This differential sensitivity to scene components suggests differential functions of OPA and PPA in scene processing. Moreover, our results further highlight the potential of the proposed computational approach as a general tool in the investigation of the neural basis of human scene perception.


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