Biomedical Engineering Reference
In-Depth Information
Speed time course
a
b
Center of mass
Isolate an animal
time (sec)
c
Curvature map
angle
Curvature
head
30
head
Microscopic Observation
20
10
Objective
lens
0
-10
-20
tail
tail
-30
time (sec)
And / Or
d
Omega turn
(pirouette)
Durat
ion time between omega tu
rns
80
Trail on an agar plate
70
60
50
40
30
20
10
0
50 100 150 200 250 300 350
(sec)
Fig. 1.2
Examples of single worm analysis. (
a
) Typical protocol of single animal assay: fi rst isolate a
cultivated animal to an agar plate, then observe with a microscope and/or picture a trail of the animal
on agar plate after certain time. (
b
) Migrating speed is usually measured with center of body mass. (
c
)
Curvature map along body axis clearly shows kinematic property of
C. elegans
behavior. White square
region in the map denotes curled or turning bend of the animal detected by another recognition algo-
rithm. (
d
) Distribution of characteristic behavior such as turning is often used for depicting behavior
1.3.1
Conventional Methods of Single Animal Observation
Depicting with a stereomicroscope is the most sensitive and conventional way for
behavioral observation of
C. elegans.
A researcher can recognize different styles of
animal response to given stimulus and can compare quantity of particular action
among mutants, for instance, tapping the plate provokes backward motion of
C. elegans
; comparison of frequency and distance of the backward motion in
response to tapping stimulus was classically performed by human observation to
measure habituation. The critical step of such a human judge-based analysis is defi -
nition of each behavior for scoring. For example, in the case of reversal behavior,
there are several types of reversals including short quick reversals or long reversal
with directional change. Therefore, precise defi nition of identifying behavior should
be used consistently among experimenters and publications.
Another way of observation for individual
C. elegans
behavior is the use of a
trail on an agar plate. With a certain condition of agar plate, a trail of freely moving
