Microscopy is a widely used method in biological research to observe the morphology and structure of cells. Amongst the plethora of microscopy techniques, fluorescent labeling with dyes or antibodies is the most popular method for revealing specific cellular organelles. However, fluorescent labeling also introduces new challenges to cellular observation, as it increases the workload, and the process may result in nonspecific labeling. Recent advances in deep visual learning have shown that there are systematic relationships between fluorescent and bright-field images, thus facilitating image translation between the two. In this article, we propose the cross-attention conditional generative adversarial network (XAcGAN) model. It employs state-of-the-art GANs (GANs) to solve the image translation task. The model uses supervised learning and combines attention-based networks to explore spatial information during translation. In addition, we demonstrate the successful application of XAcGAN to infer the health state of translated nuclei from bright-field microscopy images. The results show that our approach achieves excellent performance both in terms of image translation and nuclei state inference.

Objectives: Individuals with chronic traumatic brain injury (TBI) often show detrimental deficits in higher order cognitive functions requiring coordination of multiple brain networks. Although assessing TBI-related deficits in higher order cognition in the context of network dysfunction is promising, few studies have systematically investigated altered interactions among multiple networks in chronic TBI. Method: We characterized disrupted resting-state functional connectivity of the default mode network (DMN), dorsal attention network (DAN), and frontoparietal control network (FPCN) whose interactions are required for internally and externally focused goal-directed cognition in chronic TBI. Specifically, we compared the network interactions of 40 chronic TBI individuals (8 years post-injury on average) with those of 17 healthy individuals matched for gender, age, and years of education. Results: The network-based statistic (NBS) on DMN-DAN-FPCN connectivity of these groups revealed statistically significant (pNBS<.05; |Z|>2.58) reductions in within-DMN, within-FPCN, DMN-DAN, and DMN-FPCN connectivity of the TBI group over healthy controls. Importantly, such disruptions occurred prominently in between-network connectivity. Subsequent analyses further exhibited the disrupted connectivity patterns of the chronic TBI group occurring preferentially in long-range and inter-hemispheric connectivity of DMN-DAN-FPCN. Most importantly, graph-theoretic analysis demonstrated relative reductions in global, local and cost efficiency (p<.05) as a consequence of the network disruption patterns in the TBI group. Conclusion: Our findings suggest that assessing multiple networks-of-interest simultaneously will allow us to better understand deficits in goal-directed cognition and other higher order cognitive phenomena in chronic TBI. Future research will be needed to better understand the behavioral consequences related to these network disruptions. (JINS, 2016, 22, 263–279)

Functional magnetic resonance imaging (fMRI) studies have identified consistent age-related changes during various cognitive tasks, such that older individuals display more positive and less negative task-related activity than young adults. Recently, evidence shows that chronic physical exercise may alter aging-related changes in brain activity; however, the effect of exercise has not been studied for the neural substrates of language function. Additionally, the potential mechanisms by which aging alters neural recruitment remain understudied. To address these points, the present study enrolled elderly adults who were either sedentary or physically active to characterize the neural correlates of language function during semantic fluency between these groups in comparison to a young adult sample. Participants underwent fMRI during semantic fluency and transcranial magnetic stimulation to collect the ipsilateral silent period, a measure of interhemispheric inhibition. Results indicated that sedentary older adults displayed reductions in negative task-related activity compared to the active old group in areas of the attention network. Longer interhemispheric inhibition was associated with more negative task-related activity in the right and left posterior perisylvian cortex, suggesting that sedentary aging may result in losses in task facilitatory cortical inhibition. However, these losses may be mitigated by regular engagement in physical exercise. (JINS, 2013, 19, 1–10)