The neural correlates of apathy in the context of aging and brain disorders: a meta-analysis of neuroimaging studies

IntroductionApathy is a prevalent mood disturbance that occurs in a wide range of populations, including those with normal cognitive aging, mental disorders, neurodegenerative disorders and traumatic brain injuries. Recently, neuroimaging technologies have been employed to elucidate the neural substrates underlying brain disorders accompanying apathy. However, the consistent neural correlates of apathy across normal aging and brain disorders are still unclear.MethodsThis paper first provides a brief review of the neural mechanism of apathy in healthy elderly individuals, those with mental disorders, neurodegenerative disorders, and traumatic brain injuries. Further, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, the structural and functional neuroimaging meta-analysis using activation likelihood estimation method is performed on the apathy group with brain disorders and the healthy elderly, aiming at exploring the neural correlates of apathy.ResultsThe structural neuroimaging meta-analysis showed that gray matter atrophy is associated with apathy in the bilateral precentral gyrus (BA 13/6), bilateral insula (BA 47), bilateral medial frontal gyrus (BA 11), bilateral inferior frontal gyrus, left caudate (putamen) and right anterior cingulate, while the functional neuroimaging meta-analysis suggested that the functional connectivity in putamen and lateral globus pallidus is correlated with apathy.DiscussionThrough the neuroimaging meta-analysis, this study has identified the potential neural locations of apathy in terms of brain structure and function, which may offer valuable pathophysiological insights for developing more effective therapeutic interventions for affected patients

Hydrophobic surface modification of polymethyl methacrylate by two-dimensional plasma jet array at atmospheric pressure

Recently developed atmospheric pressure plasma jet (APPJ) is considered as a novel and efficient technique for uneven surfaces processing and APPJ array effectively expands the treatment area of a single APPJ. In this paper, a two-dimensional (2D) APPJ array in Ar/tetramethylsilane (TMS) is used to improve the surface hydrophobicity of polymethyl methacrylate (PMMA) by depositing polymerized silicalike clusters on the jet-PMMA interface. The electrical and optical characteristics of the 2D Ar/TMS APPJ array are measured to optimize experimental conditions. The wettability of jet-PMMA interface is assessed by measuring water contact angle, which increases from 65° to a maximum value of 115° after 240 s plasma treatment at 0.04% TMS content. Scanning electron microscopy is used to investigate the micro- and nanoscale surface morphology of PMMA after plasma treatment, and it is found that there are clusters of particles with diameters of hundreds of nanometers attached on the PMMA surface. The changes of the chemical composition and chemical bonding on the PMMA surface are further analyzed using Fourier transform infrared and x-ray photoelectron spectroscopies. It is found that the silicon-containing groups, such as Si-CH3, Si-H, and Si-O-Si, replace oxygen-containing hydrophilic polar groups (C—O and C=O), reduce the surface polarity, decrease the surface tension, and increase the surface hydrophobicity. For the intensive peak of Si-O-Si in FTIR spectra, the improvement of hydrophobicity of the PMMA surface is caused by the hydrophobic polymerized Si-O-Si thin film. The results demonstrate that the APPJ array as a novel atmospheric pressure plasma device provides an efficient way to modify large uneven material surfaces