Limbic brain responses in mothers with post-traumatic stress disorder and comorbid dissociation to video clips of their children.

Maternal dissociative symptoms which can be comorbid with interpersonal violence-related post-traumatic stress disorder (IPV-PTSD) have been linked to decreased sensitivity and responsiveness to children's emotional communication. This study examined the influence of dissociation on neural activation independently of IPV-PTSD symptom severity when mothers watch video-stimuli of their children during stressful and non-stressful mother-child interactions. Based on previous observations in related fields, we hypothesized that more severe comorbid dissociation in IPV-PTSD would be associated with lower limbic system activation and greater neural activity in regions of the emotion regulation circuit such as the medial prefrontal cortex and dorsolateral prefrontal cortex (dlPFC). Twenty mothers (of children aged 12-42 months), with and without IPV-PTSD watched epochs showing their child during separation and play while undergoing functional magnetic resonance imaging (fMRI). Multiple regression indicated that when mothers diagnosed with IPV-PTSD watched their children during separation compared to play, dissociative symptom severity was indeed linked to lowered activation within the limbic system, while greater IPV-PTSD symptom severity was associated with heightened limbic activity. Concerning emotion regulation areas, there was activation associated to dissociation in the right dlPFC. Our results are likely a neural correlate of affected mothers' reduced capacity for sensitive responsiveness to their young child following exposure to interpersonal stress, situations that are common in day-to-day parenting.

VOR gain by head impulse video-oculography differentiates acute vestibular neuritis from stroke

OBJECTIVE Vestibular neuritis is often mimicked by stroke (pseudoneuritis). Vestibular eye movements help discriminate the two conditions. We report vestibulo-ocular reflex (VOR) gain measures in neuritis and stroke presenting acute vestibular syndrome (AVS). METHODS Prospective cross-sectional study of AVS (acute continuous vertigo/dizziness lasting >24 h) at two academic centers. We measured horizontal head impulse test (HIT) VOR gains in 26 AVS patients using a video HIT device (ICS Impulse). All patients were assessed within 1 week of symptom onset. Diagnoses were confirmed by clinical examinations, brain magnetic resonance imaging with diffusion-weighted images, and follow-up. Brainstem and cerebellar strokes were classified by vascular territory-posterior inferior cerebellar artery (PICA) or anterior inferior cerebellar artery (AICA). RESULTS Diagnoses were vestibular neuritis (n = 16) and posterior fossa stroke (PICA, n = 7; AICA, n = 3). Mean HIT VOR gains (ipsilesional [standard error of the mean], contralesional [standard error of the mean]) were as follows: vestibular neuritis (0.52 [0.04], 0.87 [0.04]); PICA stroke (0.94 [0.04], 0.93 [0.04]); AICA stroke (0.84 [0.10], 0.74 [0.10]). VOR gains were asymmetric in neuritis (unilateral vestibulopathy) and symmetric in PICA stroke (bilaterally normal VOR), whereas gains in AICA stroke were heterogeneous (asymmetric, bilaterally low, or normal). In vestibular neuritis, borderline gains ranged from 0.62 to 0.73. Twenty patients (12 neuritis, six PICA strokes, two AICA strokes) had at least five interpretable HIT trials (for both ears), allowing an appropriate classification based on mean VOR gains per ear. Classifying AVS patients with bilateral VOR mean gains of 0.70 or more as suspected strokes yielded a total diagnostic accuracy of 90%, with stroke sensitivity of 88% and specificity of 92%. CONCLUSION Video HIT VOR gains differ between peripheral and central causes of AVS. PICA strokes were readily separated from neuritis using gain measures, but AICA strokes were at risk of being misclassified based on VOR gain alone.

Retinal slit lamp video mosaicking

Purpose To this day, the slit lamp remains the first tool used by an ophthalmologist to examine patient eyes. Imaging of the retina poses, however, a variety of problems, namely a shallow depth of focus, reflections from the optical system, a small field of view and non-uniform illumination. For ophthalmologists, the use of slit lamp images for documentation and analysis purposes, however, remains extremely challenging due to large image artifacts. For this reason, we propose an automatic retinal slit lamp video mosaicking, which enlarges the field of view and reduces amount of noise and reflections, thus enhancing image quality. Methods Our method is composed of three parts: (i) viable content segmentation, (ii) global registration and (iii) image blending. Frame content is segmented using gradient boosting with custom pixel-wise features. Speeded-up robust features are used for finding pair-wise translations between frames with robust random sample consensus estimation and graph-based simultaneous localization and mapping for global bundle adjustment. Foreground-aware blending based on feathering merges video frames into comprehensive mosaics. Results Foreground is segmented successfully with an area under the curve of the receiver operating characteristic curve of 0.9557. Mosaicking results and state-of-the-art methods were compared and rated by ophthalmologists showing a strong preference for a large field of view provided by our method. Conclusions The proposed method for global registration of retinal slit lamp images of the retina into comprehensive mosaics improves over state-of-the-art methods and is preferred qualitatively.

Imaging liver-stage malaria parasites

Plasmodium parasites, the causative agents of malaria, first invade and develop within hepatocytes before infecting red blood cells and causing symptomatic disease. Because of the low infection rates in vitro and in vivo, the liver stage of Plasmodium infection is not very amenable to biochemical assays, but the large size of the parasite at this stage in comparison with Plasmodium blood stages makes it accessible to microscopic analysis. A variety of imaging techniques has been used to this aim, ranging from electron microscopy to widefield epifluorescence and laser scanning confocal microscopy. High-speed live video microscopy of fluorescent parasites in particular has radically changed our view on key events in Plasmodium liver-stage development. This includes the fate of motile sporozoites inoculated by Anopheles mosquitoes as well as the transport of merozoites within merosomes from the liver tissue into the blood vessel. It is safe to predict that in the near future the application of the latest microscopy techniques in Plasmodium research will bring important insights and allow us spectacular views of parasites during their development in the liver.