Analysing the distribution of synaptic vesicles using a spatial point process model

Abstract

Stress can a↵ect the brain functionality in many ways. As the synaptic vesicles have a major role in nervous signal transportation in synapses, their distribution in relationship to the active zone is very important in studying the neuron responses. We study the e↵ect of stress on brain functionality by statistically modelling the distribution of the synaptic vesicles in two groups of rats: a control group subjected to sham stress and a stressed group subjected to a single acute foot-shock (FS)-stress episode.We hypothesize that the synaptic vesicles have di↵erent spatial distributions in the two groups. The spatial distributions are modelled using spatial point process models with an inhomogeneous conditional intensity and repulsive pairwise interactions. Our results verify the hypothesis that the two groups have di↵erent spatial distributions.

3D analysis of synaptic vesicle density and distribution after acute foot‐shock stress by using serial section transmission electron microscopy

“…Our findings show that (1) the density clearly increases near the active zone for both groups and for all combinations of analyses and estimators confirming findings in (Khanmohammadi et al . ()); that (2) the density around the active zone is higher in the group of rats subjected to acute FS‐stress as compared to the control group for all combinations of analyses confirming findings in (Nava et al . (), Treccani et al .…”

“…Thus, we compare the distribution of vesicles for small and large active zones directly by calculating the average number of vesicles in parallel distance-bands divided by the area in 2D and volume in 3D near the active zone. The usefulness of these size-and shape-normalizations is best validated through the separation of groups, where previous studies have shown clear differences and our results confirm such findings (Nava et al (2015), Treccani et al (2014), Khanmohammadi et al (2014)). Thus, we conclude that distance and active zone area are important parameters for modelling vesicle locations around the active zone.…”

“…(),Khanmohammadi et al . ()). Thus, we conclude that distance and active zone area are important parameters for modelling vesicle locations around the active zone.…”

“…Previous studies have shown that the exponential distribution is a good fit to the synaptic vesicles distribution Khanmohammadi et al . (), thus we chose , in which case, Interestingly enough, this equation is independent of ϕ, but of course ϕ influences the observed distances. For this distribution, is a non‐linear equation, so to solve for λ we formulated a minimization problem as, with respect to the parameter of the distribution.…”

“…Previous studies have shown that the exponential distribution is a good fit to the synaptic vesicles distribution Khanmohammadi et al (2014), thus we chose p(x) = λe −λx , in which case,…”