The big warp: Registration of disparate retinal imaging modalities and an example overlay of ultrawide-field photos and en-face OCTA images

Subthreshold repetitive transcranial magnetic stimulation induces cortical layer-, brain region-, and protocol-dependent neural plasticity

Repetitive transcranial magnetic stimulation (rTMS) is commonly used to study the brain or as a treatment for neurological disorders, but the neural circuits and molecular mechanisms it affects remain unclear. To determine the molecular mechanisms of rTMS and the brain regions they occur in, we used spatial transcriptomics to map changes to gene expression across the mouse brain in response to two commonly used rTMS protocols. Our results revealed that rTMS alters the expression of genes related to several cellular processes and neural plasticity mechanisms across the brain, which was both brain region- and rTMS protocol-dependent. In the cortex, the effect of rTMS was dependent not only on the cortical region but also on each cortical layer. These findings uncover the diverse molecular mechanisms induced by rTMS, which will be useful in interpreting its effects on cortical and subcortical circuits.

THE PROGNOSTIC SIGNIFICANCE OF ACUTE HENLE FIBER LAYER HYPERREFLECTIVITY IN PLACOID DISEASES

PURPOSE

To investigate the pathophysiology and prognostic significance of acute Henle fiber layer (HFL) hyperreflectivity in placoid diseases by examining its relationship with impaired choroidal flow and persistent photoreceptor disruption.

METHODS

Retrospective-prospective observational study on patients with placoid diseases. Indocyanine green angiography and optical coherence tomography were performed during the acute phase and follow-up. Impaired choroidal flow, HFL hyperreflectivity, and persistent ellipsoid zone disruption, their colocalization index, and their associations with initial and final visual acuity were explored.

RESULTS

Sixteen eyes from eight patients (mean age, 25.3 ± 6.44 years) were included (median follow-up, 13.5 months). Quantitative analysis revealed significant correlations between areas of impaired choroidal flow, HFL hyperreflectivity, and persistent ellipsoid zone disruption (correlation coefficients of 0.69, 0.63, and 0.46, respectively). Impaired choroidal flow area exceeded HFL hyperreflectivity (P = 0.002) and ellipsoid zone disruption (P = 0.003). A noteworthy 94% nonrandom overlap between HFL hyperreflectivity and ellipsoid zone disruption was observed. Worse initial visual acuity correlated with foveal involvement (P = 0.0002), thicker choroid (P = 0.001), larger impaired choroidal flow areas (P = 0.02), and thinner outer retina post lesion inactivation (P = 0.04).

CONCLUSION

Henle fiber layer hyperreflectivity predicted photoreceptor recovery potential in placoid diseases. If HFL hyperreflectivity corresponds to acute HFL damage, it may suggest more severe involvement of the entire photoreceptor length.

How to apply the broad toolbox of correlative light and electron microscopy to address a specific biological question

Correlative light and electron microscopy (CLEM) is an approach that combines the strength of multiple imaging techniques to obtain complementary information about a given specimen. The "toolbox" for CLEM is broad, making it sometimes difficult to choose an appropriate approach for a given biological question. In this chapter, we provide experimental details for three CLEM approaches that can help the interested reader in designing a personalized CLEM strategy for obtaining ultrastructural data by using transmission electron microscopy (TEM). First, we describe chemical fixation of cells grown on a solid support (broadest approach). Second, we apply high-pressure freezing/freeze substitution to describe cellular ultrastructure (cryo-immobilization approach). Third, we give a protocol for a ultrastructural labeling by immuno-electron microscopy (immuno-EM approach). In addition, we also describe how to overlay fluorescence and electron microscopy images, an approach that is applicable to each of the reported different CLEM strategies. Here we provide step-by step descriptions prior to discussing possible technical problems and variations of these three general schemes to suit different models or different biological questions. This chapter is written for electron microscopists that are new to CLEM and unsure how to begin. Therefore, our protocols are meant to provide basic information with further references that should help the reader get started with applying a tailored strategy for a specific CLEM experiment.

Changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus: Assessed by optical coherence tomography angiography

OBJECTIVE

The aim was to investigate the changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus (SLE) using optical coherence tomography angiography (OCTA).

METHODS

Twenty-nine patients with SLE (29 eyes) and 25 control subjects (25 eyes) were enrolled. SLE activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Retinal thickness (RT), inner retinal thickness (IRT), outer retinal thickness (ORT), choroidal thickness (ChT), retinal superficial vascular density (SVD), retinal deep vascular density (DVD), choriocapillary vascular density (CCVD), foveal avascular zone (FAZ), superficial FAZ (sFAZ), and deep FAZ (dFAZ) were measured using OCTA. The retinal and choroidal thickness and vascular density between the control group and SLE group were compared. The relationships between SLEDAI scores and the retinal and choroidal thickness and vascular density in SLE group were analyzed.

RESULTS

The SVD was significantly increased, and the DVD and CCVD were significantly decreased in the SLE group compared to the control group (p < .05). The results of receiver operating characteristic (ROC) showed that the area under the curve (AUC) values of SVD, DVD, and CCVD were 0.873, 0.729, and 0.727, indicating a high accuracy in discriminating patients with SLE from controls. Correlation analysis showed that the SLEDAI scores were positively correlated with dFAZ (r = 0.589, p = .001) and FAZ (r = 0.451, p = .018), and negatively correlated with DVD (r = -0.491, p = .009) and CCVD (r = -0.521, p = .005).

CONCLUSIONS

DVD and CCVD were decreased in the SLE and might be related to the disease activity. SVD, DVD, and CCVD may hold promise in the discovery of biomarkers for diagnosing SLE.