Alcohol-Induced Alterations in the Vascular Basement Membrane in the Substantia Nigra of the Adult Human Brain

Diminished reward circuit response underlies pain avoidance learning deficits in problem drinkers

Individuals engaging in problem drinking show impaired proactive pain avoidance. As successful pain avoidance is intrinsically rewarding, this impairment suggests reward deficiency, as hypothesized for those with alcohol and substance misuse. Nevertheless, how reward circuit dysfunctions impact avoidance learning and contribute to drinking behavior remains poorly understood. Here, we combined functional imaging and a probabilistic learning go/nogo task to examine the neural processes underlying proactive pain avoidance learning in 103 adult drinkers. We hypothesized that greater drinking severity would be associated with poorer avoidance learning and that the deficits would be accompanied by weakened activity and connectivity of the reward circuit. Our behavioral findings indeed showed a negative relationship between drinking severity and learning from successful pain avoidance. We identified hypoactivation of the posterior cingulate cortex (PCC), a brain region important in avoidance, as the neural correlate of lower learning rate in association with problem drinking. The reward circuit, including the medial orbitofrontal cortex, ventral tegmental area, and substantia nigra, also exhibited diminished activation and connectivity with the PCC with greater drinking severity and learning deficits. Finally, path modeling suggested a pathway in which problem drinking disengaged the reward circuit. The weakened circuit subsequently induced PCC hypoactivation, resulting in poorer pain avoidance learning. As the learning dysfunction worsened alcohol use, the pathway represents a self-perpetuating cycle of drinking and distress. Together, these findings substantiate a role of reward deficiency in problem drinkers' compromised proactive avoidance, thus identifying a potential target for intervention aimed at mitigating harmful alcohol use.

Brain Injury and Neurodegeneration: Molecular, Functional, and Translational Approach 2.0

The brain is composed of different cells, such as neurons, glia, endothelial cells, etc [...].

Crosstalk Among Glial Cells in the Blood-Brain Barrier Injury After Ischemic Stroke

Blood-brain barrier (BBB) is comprised of brain microvascular endothelial cells (ECs), astrocytes, perivascular microglia, pericytes, neuronal processes, and the basal lamina. As a complex and dynamic interface between the blood and the central nervous system (CNS), BBB is responsible for transporting nutrients essential for the normal metabolism of brain cells and hinders many toxic compounds entering into the CNS. The loss of BBB integrity following stroke induces tissue damage, inflammation, edema, and neural dysfunction. Thus, BBB disruption is an important pathophysiological process of acute ischemic stroke. Understanding the mechanism underlying BBB disruption can uncover more promising biological targets for developing treatments for ischemic stroke. Ischemic stroke-induced activation of microglia and astrocytes leads to increased production of inflammatory mediators, containing chemokines, cytokines, matrix metalloproteinases (MMPs), etc., which are important factors in the pathological process of BBB breakdown. In this review, we discussed the current knowledges about the vital and dual roles of astrocytes and microglia on the BBB breakdown during ischemic stroke. Specifically, we provided an updated overview of phenotypic transformation of microglia and astrocytes, as well as uncovered the crosstalk among astrocyte, microglia, and oligodendrocyte in the BBB disruption following ischemic stroke.