Electrophysiological Evaluation of Synaptic Plasticity in Injured CNS - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 121

5. The brain is submerged into ice-cold ACSF together with the
cutting stage. Coronal cortical slices (400- μ m thick) are cut

using a Vibratome (Fig. 2c ).
6. Use a large-mouth Pasteur pipette to transfer slices into an
incubation chamber, which is fi lled with ACSF preheated to
32°C and constantly bubbled with 95% O 2 and 5% CO 2
(Fig. 2d ). The incubation chamber is maintained at 32°C for
1 h in an incubator, and then moved to room temperature.
Now the slices are ready for use.

The general procedures are similar to neocortical brain slice prepa-
ration, expect that sagittal brain slices are cut, and then whether
the nonhippocampal regions are trimmed or not depends on the
purpose of experiment. It is also a common practice that hippocampus
is fi rst dissected out, and then transverse hippocampal slices are cut
with a tissue chopper.

3.1.2. Hippocampal Slice
Preparation

1. Remove the brain with a spatula, place it on a small piece of
fi lter paper with ventral side on bottom, and then make two
parallel coronal cuts similar to what is shown in Fig. 2a .
2. Cut the brain in half through midline, and then glue hemispheres
onto cutting stage, with the medial side on bottom and poste-
rior side facing Vibratome blade.
3. Sagittal slices are cut at 400- m thick using a Vibratome. The

remaining procedures are similar to those in the neocortical
slice's preparation.

μ

3.2. FPR in Neocortical
Slices: Evaluation of
Short-Term Synaptic
Plasticity

1. A cortical slice is transferred onto an interface chamber, per-
fused with oxygenated ACSF at a rate of 2-3 ml/min. The
ACSF in interface chamber is maintained at ~32°C with a tem-
perature control system.
2. Under stereomicroscope, use a micromanipulator to place a
stimulating electrode onto the white matter beneath an inter-
ested cortical region (Fig. 3b ).
3. Use the second micromanipulator to lower a glass electrode
onto layer V or other target layer of cortex, directly above the
stimulating electrode (Figs. 3b and 4a ).
4. Stimulus current is set to a range of 50-300 μ A with duration

s. To evaluate PPF of fi eld responses, a pair of stimuli
with 20-100 ms intervals or a train of ten pulses at 5-50 Hz
can be delivered with intervals of 10-30 s between trains.
5. Run the data acquisition software to start recording. Responses
are amplifi ed, digitized, and saved in a computer for off-line
analysis.

of 100 μ