Point pattern of synaptic vesicles observed in rat brain tissue.
As part of a study on the effects of stress on brain function, Khanmohammadi et al (2014) analysed the spatial pattern of synaptic vesicles in 45-nanometre-thick sections of rat brain tissue visualised in transmission electron microscopy. To investigate the influence of stress, Khanmohammadi et al (2014) study the distribution of the synaptic vesicles in the pre-synaptic neuron in relation to the active zone of the presynaptic membrane. They hypothesize that the synaptic vesicle density is a decreasing function of distance to the active zone.
The boundaries for the active zone, mitochondria, pre- and post synaptic terminals, and the centre of the synaptic vesicles were annotated by hand on the image.
vesicles is a point pattern
(object of class
"ppp") representing the location
of the synaptic vesicles. The window of the point pattern
represents the region of presynapse where synaptic vesicles were
observed in this study.
There is a hole in the window, representing the region occupied by
mitochondria, where synaptic vesicles do not occur.
vesicles.extra is a list with entries
presynapse outer polygonal boundary of presynapse
mitochondria polygonal boundary of mitochondria
mask binary mask representation of vesicles window
activezone line segment pattern representing
the active zone.
All coordinates are in nanometres (nm).
For demonstration and training purposes,
the raw data files for this dataset are also
provided in the
vesicles.txt spatial locations of vesicles
presynapse.txt vertices of
mitochondria.txt vertices of
vesiclesimage.tif greyscale microscope image
vesiclesmask.tif binary image of
activezone.txt coordinates of
The files are in the folder
rawdata/vesicles in the
system.file, as shown
in the examples.
Nicoletta Nava, Mahdieh Khanmohammadi and Jens Randel Nyengaard. Experiment performed by Nicoletta Nava at the Stereology and Electron Microscopy Laboratory, Aarhus University, Denmark. Images were annotated by Mahdieh Khanmohammadi at the Department of Computer Science, University of Copenhagen. Jens Randel Nyengaard provided supervision and guidance, and curated the data.
Khanmohammadi, M., Waagepetersen, R., Nava, N., Nyengaard, J.R. and Sporring, J. (2014) Analysing the distribution of synaptic vesicles using a spatial point process model. 5th ACM Conference on Bioinformatics, Computational Biology and Health Informatics, Newport Beach, CA, USA, September 2014.
plot(vesicles) with(vesicles.extra, plot(activezone, add=TRUE, col="red")) ## read coordinates of vesicles from raw data, for training purposes vf <- system.file("rawdata/vesicles/vesicles.txt", package="spatstat") vdf <- read.table(vf, header=TRUE)