Simultaneous dual-color calcium imaging in freely-behaving mice.

Miniaturized fluorescence microscopes (miniscopes) enable imaging of calcium events from a large population of neurons in freely behaving animals. Traditionally, miniscopes have only been able to record from a single fluorescence wavelength. Here, we present a new open-source dual-channel Miniscope that simultaneously records two wavelengths in freely behaving animals. To enable simultaneous acquisition of two fluorescent wavelengths, we incorporated two CMOS sensors into a single Miniscope. To validate our dual-channel Miniscope, we imaged hippocampal CA1 region that co-expressed a dynamic calcium indicator (GCaMP) and a static nuclear signal (tdTomato) while mice ran on a linear track. Our results suggest that, even when neurons were registered across days using tdTomato signals, hippocampal spatial coding changes over time. In conclusion, our novel dual-channel Miniscope enables imaging of two fluorescence wavelengths with minimal crosstalk between the two channels, opening the doors to a multitude of new experimental possibilities. Teaser: Novel open-source dual-channel Miniscope that simultaneously records two wavelengths with minimal crosstalk in freely behaving animals.

Well-being at midlife: Correlates of mental health in ambulatory menopausal women with multiple sclerosis.

BACKGROUND: A majority of women with multiple sclerosis (MS) are diagnosed prior to menopause, yet their experiences during this transition are not well characterized. OBJECTIVES: To explore associations between mental health, sleep, and other quality of life metrics, and vasomotor symptoms (VMSs) in ambulatory, menopausal women with MS. METHODS: A secondary analysis was performed of baseline data from two trials enrolling ambulatory peri/postmenopausal women with MS: NCT02710214 (N = 24, bothersome VMS) and NCT04002934 (ongoing, N = 35, myelin repair). Measures analyzed were 36-Item Short-Form Survey (SF-36) (primary scale: general mental health), subjective sleep quality (Pittsburg Sleep Quality Index), VMS (daily diary, interference), mood (Center for Epidemiologist Studies-Depression Scale (CES-D)), walking impairment (timed 25-foot walk (T25FW)), and global disability (Expanded Disability Status Scale (EDSS)). RESULTS: Participants' characteristics (N = 59) were: mean age 51.8 years (SD = 3.4), mean disease duration 11.3 years (SD = 7.6), median EDSS 3.0 (IQR = 2.0-4.0). Mental health was associated with better sleep quality (rho = -0.41, p = 0.019) and better mood (rho = -0.75, p < 0.001), but not with EDSS or T25FW (rho < 0.20, p > 0.10). Worse sleep quality also correlated with more frequent VMS (rho = 0.41, p = 0.02) and VMS interference (rho = 0.59, p < 0.001). CONCLUSIONS: Findings suggest that optimizing sleep quality, mood, and hot flash quantity/interference could substantially improve mental health in menopausal women with MS-and highlight an important care gap in this population.

Aversive experience drives offline ensemble reactivation to link memories across days.

Memories are encoded in neural ensembles during learning and stabilized by post-learning reactivation. Integrating recent experiences into existing memories ensures that memories contain the most recently available information, but how the brain accomplishes this critical process remains unknown. Here we show that in mice, a strong aversive experience drives the offline ensemble reactivation of not only the recent aversive memory but also a neutral memory formed two days prior, linking the fear from the recent aversive memory to the previous neutral memory. We find that fear specifically links retrospectively, but not prospectively, to neutral memories across days. Consistent with prior studies, we find reactivation of the recent aversive memory ensemble during the offline period following learning. However, a strong aversive experience also increases co-reactivation of the aversive and neutral memory ensembles during the offline period. Finally, the expression of fear in the neutral context is associated with reactivation of the shared ensemble between the aversive and neutral memories. Taken together, these results demonstrate that strong aversive experience can drive retrospective memory-linking through the offline co-reactivation of recent memory ensembles with memory ensembles formed days prior, providing a neural mechanism by which memories can be integrated across days.