Leica Biosystems ANGLE TWO - Manual (Page 30)

Software Overview
Leica Angle Two ™ User Manual Rev A02 © Leica Biosystems Richmond Inc. 2010 30
Enter Offsets
Offsets are used when performing surgery on animals that do not fall within the weight range of the
atlas being used. Offsets are a distance in millimeters that is added or subtracted from the probe’s
path to the target site. The offsets are determined in pre-experiments by locating the target site
using the atlas coordinates. The amount that the atlas coordinates miss the actual target site is
determined and used as the offset values.
Once the offsets are entered, and the bregma and lambda points have been located, the offset
values are automatically factored into the To Target coordinates, and the display is updated to
show the probe approaching the correct target site.
To enter offsets, click Use Zero Offsets in the Set Up dialog and enter the values. Click Close
when finished.
Bregma and Lambda
Typically, the bregma and lambda points of the skull are used as zero reference points to determine
the location of the target site. Once entered into the software, they are used in the skull flat feature
which automatically incorporates any tilt in the animal’s skull into the calculation of the “to target”
values.
To set the bregma point, carefully place the probe tip on the bregma point of the animal’s skull and
click at Bregma. To set the lambda point, gently lower the probe tip on the lambda point of the
animal’s skull and click at Lambda.
Always locate the bregma point first.