Biology Reference
In-Depth Information
Forelimb placing (FP) is a test of the forelimb motor ability in
response to the vibrissae-elicited sensation of a table-top. Unilateral
damage to the striatum and/or sensorimotor cortex leads to an
impairment of the contralateral-independent limb placing response
to the respective vibrissae contact with the table-top (
7
). The limb
ipsilateral to the side of injury will exhibit a normal placing response,
even when only the contralateral vibrissae are used for the sensory
response, and this is called “crossed-midline placing” (
8
). Therefore,
the forelimb defi cit is primarily of motor etiology, and does not
absolutely require the sensory loss in order to display the neuro-
logical injury.
This test is highly correlated to the degree of brain injury, and
was originally described for functional assessments after unilateral
focal cerebral ischemia in rats (
9
), soon afterward effectively
adapted to the (autologous) blood ICH model in rats (
10
), mice
(
11
), and then later extended to collagenase ICH in rats (
12
).
Major strengths of this test include not requiring purchasing or
maintaining an expensive apparatus, and not needing animal pre-
training (unskilled) (
7, 9, 10
). Additionally, this test does not
improve due to animal learning or memory, and does not necessi-
tate any aversive manipulations such as food or water deprivations,
factors which could each signifi cantly confound the neurological
outcomes themselves (
7, 9, 10, 13
). The major drawback of this
test is the requirement of a highly skilled examiner, needing much
practice and instruction, the latter of which will be outlined in the
following sections of this chapter, describing the pertinent proce-
dures and techniques for successfully performing FP testing.
2. Materials
Table-top.
2.1. Apparatus
3. Methods
3.1. Performing
the Test
1. Hold the animal by the torso so that the forelimb is allowed to
hang free.
2. Move the animal gently up and down before testing for facili-
tation of muscle relaxation and for reduction of unwanted
movements.
3. Brushing the vibrissae along the table-top should stimulate the
unilateral forelimb to be placed upon the table.
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