A Comparative Analysis of Centrosome and Soma Migration in Neurons

Rachel BoernerCalvin College

Richard WardComputational Sciences and Engineering

Ryan KerekesMeasurement Science and Systems Engineering

August 2009

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Overview

• Background

• Previous work

• Methods

• Results

• Future work

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Neuron structure

• Basic structures

• Somas

• Axons

• Dendrites

• Centrosomeshttp://serendip.brynmawr.edu/bb/kinser/definitions/def-neuron.html

AxonSoma

Dendrites

Actual images of cerebral neurons

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Neuron function and migration

• Function determines structure

• Migrate

http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php

Migrating neuron along radial glial cell

http://glia-uab.infomedia.com/content.asp?id=104968

Examples of different neuron structures based on their function

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St. Jude Children’s Research Hospital

• Neurons migrate during the utero stage or early years of development

• Abnormal neuron migration has been linked to certain diseases

• St. Jude’s interested in tracking the neurons for diagnostic purposes

• Images taken with a Marianas spinning disk confocal microscope

Hundreds of images waiting to be manually analyzed Weeks to go through one data set

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Oak Ridge National Laboratory• Centrosome detection

and tracking• Filter• Threshold• Search for small,

round, bright objects• Use joint

probabilistic data association filter

(above) A three dimensional plot of centrosome movement in the x-, y-, and z-directions.

(above) The right image shows the detections made by Ryan's code. The left image is those detections locations superimposed on the original image.

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Current Work

Different color schemes show more details

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Method

• Attempted method• Gradient and fill

• Centroid

(left) An image after a rotationally symmetric Gaussian lowpass filter is applied. (center) The image after thresholding for intensity and distance from the center of an object. (right) The segmentation of the somas based on regions being larger than a certain radius.

• Actual method

• Euclidean transform equation

• Thresholding

Sequence of attempted code for soma segmentation

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Results• Analyzed visually• See random motion

• Centrosomes move at an average speed of 0.1 μm

• Somas move at an average speed of 0.03 μm

• Not much correlation between soma and centrosome migration

Chemicals inhibited cell motion

Centrosome and soma pairs are difficult to match

(below) This graph is the plot of the motion of the soma throughout the various timeframes. Each pixel corresponds to 0.15 μm.

(above) The graphs are 3D images of the detections and tracks of somas and centrosomes. The red marks the soma tracks and the blue corresponds to the centrosome tracks. The images were taken ever 16 seconds.

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Conclusion• Developed code for soma segmentation

• Detected no correlation between soma and centrosome motion

• Analyze neuron migration in three dimensions• Study and track actin movement• Recognize patterns of behavior between neuron

migration and specific diseases• Build techniques for the alteration or prevention of

abnormal neuron migration

Future Work

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Bibliography

R. A. Kerekes, S. S. Gleason, N. Trivedi, and D. J. Solecki, “Automated 3-D tracking of centrosomes in sequences of confocal image stacks,” submitted to EMBC `09, Minneapolis, 2009.

"Neuron." Serendip. 2003. 20 July 2009 <http://images.google.com/imgres?imgurl=http://serendip.brynmawr.edu/bb/kinser/definitions/neuron1.gif&imgrefurl=http://serendip.brynmawr.edu/bb/kinser/definitions/def-neuron.html&usg=__sDy8e5q728xNzj7>.

McCoy, Eric. "Glia as Guides for Neuronal Migration,." UAB Center for Glial Biology in Medicine. UAB. 22 July 2009 <http://glia-uab.infomedia.com/content.asp?id=113339>.

"ORNL, St. Jude track neurons to predict and prevent disease." The Oak Ridger, 30 March 2009, sec. A3.

Stufflebeam, Robert. "Neurons, Synapses, Action Potentials, and Neurotransmission." Consortium on Cognitive Science Instruction. 2008. The Mind Project. 22 July 2009 <http://www.mind.ilstu.edu/curriculum/neurons_intro/neurons_intro.php>.

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Acknowledgements

• I would like to thank Richard Ward and Ryan Kerekes for the opportunity to work on this project.

• Also, thanks to Debbie McCoy, who made provisions for this research experience.

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Questions?