scholarly journals Neuroinflammation-Induced Parvalbumin Interneuron and Oscillation Deficits Might Contribute to Neurobehavioral Abnormities in a Two-Hit Model of Depression

2021 ◽  
Author(s):  
Fei Wang ◽  
Jianhua Tong ◽  
Yuzhu Gao ◽  
Shixu Wang ◽  
Muhuo Ji
Keyword(s):  
Gamma Oscillations ◽  
Underlying Mechanism ◽  
Male Mice ◽  
Chronic Unpredictable Stress ◽  
Reduced Body ◽  
Fluoxetine Treatment ◽  
Parvalbumin Interneuron ◽  
Chronic Fluoxetine ◽  
Profound Disability ◽  
And Behavior

Abstract Background: Depression is a common neuropsychiatric disorder that causes profound disability worldwide, yet the underlying mechanism remains unclear. Thus, the present study aimed to evaluate the effects of a two-hit model of depression on glial activation, parvalbumin (PV) interneuron, oscillation activity, and behavior alternations, and whether chronic fluoxetine treatment can reverse these abnormalities. Methods: Male mice were submitted to lipopolysaccharide (LPS) injection, followed by a modified chronic unpredictable stress (CUS) protocol. Results: In our study, we showed that mice exposed to LPS and CUS exhibited reduced body weight, anhedonic-like behavior as well as cognitive and anxiety symptoms. These behavioral alternations were related to enhanced neuroinflammation, as reflected by significantly increased IL-1β and IL-6 levels and microglia activation in the prefrontal cortex (PFC). In addition, mice exposed to LPS and CUS displayed significantly decreased PV expression and disturbance of theta and gamma oscillations in the PFC. However, chronic fluoxetine treatment reversed most of these abnormalities. Conclusion: Our study of this two-hit model of depression is clinically relevant and suggests the combination of different etiological and pathophysiological components of depression may provide with a more translational value.

scholarly journals Parvabumin interneuron-mediated hippocampal network activity disruption in a two-hit model with relevance to postintensive care syndrome: prevention by fluoxetine

2020 ◽  
Author(s):  
Mu-huo Ji ◽  
JianHua Tong ◽  
Zhi-qiang Zhou ◽  
Jian-Jun Yang
Keyword(s):  
Animal Model ◽  
Underlying Mechanism ◽  
Network Activity ◽  
Gabaergic Interneuron ◽  
Neural Activities ◽  
Fluoxetine Treatment ◽  
Relevant Animal Model ◽  
Gamma Power ◽  
Chronic Fluoxetine ◽  
Hippocampal Network

Abstract Background Postintensive care syndrome (PICS) is defined as a new or worsening impairment in cognition, mental health, and physical function after critical illness, which is associated with reduced quality of life and increased mortality. We recently have developed a clinically relevant animal model of PICS, which can mimic most features of human PICS. However, the underlying mechanism remains largely to be elucidated. Accumulating evidence has suggested that hippocampal GABAergic interneuron dysfunction is implicated in various mood disorders induced by stress. Methods We explored the role of hippocampal GABAergic interneurons and relevant neural activities in an animal model of PICS based on two-hit hypothesis. In addition, we tested whether fluoxetine treatment early following combined stress can prevent subsequent anatomical and behavioral pathologies. Results Here our study further supported our previous findings that this PICS model displayed reproducible anxiety- and depression like behavior and cognitive impairments, which resembles clinical features of human PICS. This behavioral state is accompanied by hippocampal neuroinflammation, reduced parvalbumin (PV) expression, and decreased theta and gamma power. Importantly, chronic fluoxetine treatment reversed most of these abnormities. Conclusions Our study provides additional evidence that PV interneuron-mediated hippocampal network activity disruption might play a key role in the pathological of PICS, while fluoxetine offers protection via modulation of the hippocampal PV interneuron and relevant network activities.

Increase in neurogenesis and behavioural benefit after chronic fluoxetine treatment in Wistar rats

2007 ◽  
Vol 0 (0) ◽  
pp. 070905010742003-??? ◽  
Author(s):  
A. B. Marcussen ◽  
P. Flagstad ◽  
P. E. G. Kristjansen ◽  
F. F. Johansen ◽  
U. Englund
Keyword(s):  
Wistar Rats ◽  
Fluoxetine Treatment ◽  
Chronic Fluoxetine

scholarly journals Robust Rhythmogenesis in the Gamma Band via Spike Timing Dependent Plasticity

2020 ◽  
Author(s):  
Gabi Socolovsky ◽  
Maoz Shamir
Keyword(s):  
Mean Field ◽  
Rhythmic Activity ◽  
Gamma Oscillations ◽  
Underlying Mechanism ◽  
Spike Timing ◽  
Gamma Band ◽  
Fine Tuning ◽  
Spike Timing Dependent Plasticity ◽  
Dependent Plasticity ◽  
Wide Range

Rhythmic activity in the gamma band (30-100Hz) has been observed in numerous animal species ranging from insects to humans, and in relation to a wide range of cognitive tasks. Various experimental and theoretical studies have investigated this rhythmic activity. The theoretical efforts have mainly been focused on the neuronal dynamics, under the assumption that network connectivity satisfies certain fine-tuning conditions required to generate gamma oscillations. However, it remains unclear how this fine tuning is achieved.Here we investigated the hypothesis that spike timing dependent plasticity (STDP) can provide the underlying mechanism for tuning synaptic connectivity to generate rhythmic activity in the gamma band. We addressed this question in a modeling study. We examined STDP dynamics in the framework of a network of excitatory and inhibitory neuronal populations that has been suggested to underlie the generation of gamma. Mean field Fokker Planck equations for the synaptic weights dynamics are derived in the limit of slow learning. We drew on this approximation to determine which types of STDP rules drive the system to exhibit gamma oscillations, and demonstrate how the parameters that characterize the plasticity rule govern the rhythmic activity. Finally, we propose a novel mechanism that can ensure the robustness of self-developing processes, in general and for rhythmogenesis in particular.

scholarly journals Phase Coupled Firing of Prefrontal Parvalbumin Interneuron With High Frequency Oscillations

2020 ◽  
Vol 14 ◽  
Author(s):  
Yanting Yao ◽  
Mengmeng Wu ◽  
Lina Wang ◽  
Longnian Lin ◽  
Jiamin Xu
Keyword(s):  
High Frequency ◽  
Pyramidal Neurons ◽  
Temporal Dynamics ◽  
Gamma Oscillations ◽  
Cognitive Behaviors ◽  
Firing Rates ◽  
High Frequency Oscillations ◽  
Electrophysiological Recordings ◽  
Parvalbumin Interneuron

The prefrontal cortex (PFC) plays a central role in executive functions and inhibitory control over many cognitive behaviors. Dynamic changes in local field potentials (LFPs), such as gamma oscillation, have been hypothesized to be important for attentive behaviors and modulated by local interneurons such as parvalbumin (PV) cells. However, the precise relationships between the firing patterns of PV interneurons and temporal dynamics of PFC activities remains elusive. In this study, by combining in vivo electrophysiological recordings with optogenetics, we investigated the activities of prefrontal PV interneurons and categorized them into three subtypes based on their distinct firing rates under different behavioral states. Interestingly, all the three subtypes of interneurons showed strong phase-locked firing to cortical high frequency oscillations (HFOs), but not to theta or gamma oscillations, despite of behavior states. Moreover, we showed that sustained optogenetic stimulation (over a period of 10 s) of PV interneurons can consequently modulate the activities of local pyramidal neurons. Interestingly, such optogenetic manipulations only showed moderate effects on LFPs in the PFC. We conclude that prefrontal PV interneurons are consist of several subclasses of cells with distinct state-dependent modulation of firing rates, selectively coupled to HFOs.

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