Transcript ImageSurfer: Visualization of Dendritic Spines

ImageSurfer: Visualization of Dendritic Spines
CISMM: Computer Integrated Systems for Microscopy and Manipulation
The Problem: Finding Relationships
Scientific Domain
Neurons transmit information using electrochemical reactions.
When a neuron fires, it sends an electrical impulse down a
long arm-like structure called an axon. At the end of the axon
the impulse sets off a chemical transfer. The chemicals diffuse
across a gap to dendrites, on neighboring receiver neurons.
These neurons then fire their own electrical impulses thus
propagating the signal.
Dendritic spines are tiny structures (0.5-2 m length, 0.1 m
diameter) that protrude along the length the dendrites. These
small bodies are shaped like miniature light bulbs with distinct
head and neck regions. In addition, these spines may play a
role in insulating specific regions of the dendrite to signal
molecules from neighboring neurons at the cellular level and
might even be the basis of memory.
Scientific Questions
1. How is the concentration of PMCA
distributed within dendritic spines?
2. In a given spine, where is the greatest
concentration of PMCA? Where is the
least concentration?
Data Collection
Images of the sample are taken using a confocal microscope.
A single slice of the sample is illuminated with a wavelength
that causes the a phosphorescing tag named DiO
(dioctadecyloxacarbocyanine perchlorate) to glow and an
image is captured. The phosphorescing DiO reveals the lipid
layor of the dendrites. The sample is then illuminated with
another wavelength that causes the PMCA (plasma membrane
calcium ATPase) antibody to phosphoresce and another image
is captured. This process yields two images for every slice.
The resulting image pairs show the locations and
concentration of PMCA proteins as well as the general
structure of the nerve cells.
Figure 1: Former Method, images of a single slice of
DiO (left image) and PMCA (right image). The
collaborators would flip between these two datasets to
find relationships between the data. In addition to being
time consuming, only the spines that fell into the image
plane could be analyzed in this technique.
The Solution: Visualizing Both Datasets
Colored Isosurface
The isosurface is a 3D
reconstruction of the DiO
dataset. The surface
structure exhibits the
shape of the dendritic
spine and color exhibits
the concentration of the
protein, PMCA, at the
surface.
Magic Cut Plane
Spline Tool
This tool can be
thought of as a
cross between a
magic lens and a
cut plane. The
magic cut plane
enables capturing spines at arbitrary
angles. This increases the number of
spines that can be analyzed beyond
those that lie in the image plane.
The spline tool
enables users
to capture
concentrations
of PMCA and
DiO along a
user-defined curve.
Height Field
The magic cut plane
captures a slice
from the DiO and
PMCA datasets and
maps the PMCA
concentration to a
height field. The color indicates DiO,
thus providing an outline of the dendrite.
Graph
After the DiO
and PMCA are
captured, the
graph window
displays the
concentrations
as a function of distance from the
start of the spline. The red line
indicates the DiO and the green
line indicates PMCA.
http://www.cs.unc.edu/Research/nano/cismm/
Collaborators: Alain Burette and Richard Weinberg, UNC Cell Development and Biology.
Project Lead: Russell Taylor . Investigator: Dennis Jen.
December 2003