[Abstract Title]. - Society for Neuroscience

Picrotoxin). The induction protocol caused a significant increase in intrinsic excitability in cells
from both hemispheres. However, MD induced a far greater increase in the LTP-IE in the
deprived hemisphere compared to the control hemisphere (control hemisphere: 142.72±2.14% of
control, n = 7; deprived hemisphere: 200.21±24.13% of control, n = 10: p < 0.001). Further,
LTP-IE caused a leftward shift of the FI curve, and reduced the current threshold in both
hemispheres, but did not alter passive neuronal properties, suggesting the involvement of voltage
dependent conductances. These data suggest that MD reduces the intrinsic excitability of L5
pyramidal neurons by reducing LTP-IE. Further, the increased magnitude of LTP-IE in deprived
cortex suggests that LTP-IE could play a role in recovery from an insult or visual deprivation
Disclosures: K. Nataraj , None; G. Turrigiano, None.
Poster
240. Intrinsic Membrane Properties: Modulation of Neuronal Firing Properties by Inputs
and Activity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 240.24/F6
Topic: B.10.b. Modulation of neuronal firing properties
Support: the EJLB–Canadian Institutes of Health Research (CIHR) Michael Smith Chair in
Neurosciences and Mental Health
Title: Plastic changes of electrophysiological properties of cingulate neurons after nerve injury
Authors: *X. CAO, H. XU, L. WU, M. ZHUO;
Physiol., Univ. of Toronto, Toronto, ON, Canada
Abstract: The anterior cingulate cortex (ACC), a large region around the rostrum of the corpus
callosum, undergoes dramatic changes under chronic pain conditions (Zhuo, 2005; Zhuo, 2006).
Here, we have tested the hypothesis that electrophysiological changes occurred in ACC cells
after neuropathic pain. Whole-cell patch-clamp recordings from ACC neurons in mice brain slice
preparation were used to record active and passive membrane properties. Three physiological
groups of pyramidal cells were defined according to their action potential firing behavior: (i)
Regular spiking (RS) cells that fired single spikes, with each spike followed by a prominent
sAHP and an obvious deflection of fAHP and ADP during the hyperpolarizing phase; (ii)
Intermediate (IM) cells that fired single spikes and the action potential was followed by a fast
AHP, ADP, and sAHP; (iii) Intrinsic bursting (IB) cells that fired an initial spike doublet,
followed by single spikes. The most frequent firing patterns observed in neuropathic and wild
type animals were the IM cells (neuropathic: 53%, wild type: 49%), IB cells (neuropathic: 31%,