[Abstract Title]. - Society for Neuroscience

whether this reduction in excitability requires an imbalance in drive from the two eyes, we
generated FI curves from rats that underwent 2 days of binocular lid suture (BD). BD did not
induce a reduction in excitability (sham n=14; BD n=16; p>0.22 for all current injections).
Overall, the data indicate that MD suppresses spontaneous activity, at least in part through a
reduction in intrinsic excitability. Further, the reduction in intrinsic excitability can be partially
explained by a decrease in input resistance (but likely also involves voltage gated channels), and
is a process which requires competitive input from both eyes. One locus of activity dependent
plasticity in visual cortex is thus the intrinsic excitability of cortical pyramidal neurons.
Disclosures: M.E. Lambo , None; A. Maffei, None; G.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#: 240.23/F5
Topic: B.10.c. Activity-dependent plasticity of intrinsic membrane properties
Support: NIH EY014439
DOD W81XWH-04-1-0158
Title: Metaplasticity of intrinsic excitability of cortical layer 5 pyramidal neurons induced by
visual deprivation
Authors: *K. NATARAJ, G. TURRIGIANO;
Dept Biol, Brandeis Univ., Waltham, MA
Abstract: Changes in visual experience dramatically alter the organization of visual cortical
circuits, but the cellular plasticity mechanisms that drive these changes are poorly understood.
Here we examined the role of long term potentiation of intrinsic excitability (LTP-IE) of layer-5
pyramidal neurons in the experience-dependent changes induced by monocular deprivation
(MD). MD was achieved with eyelid suture for 48 hours, starting at P18, and whole-cell patch
clamp recording were obtained from the monocular region of primary visual cortex (Vm1) from
the deprived and control hemispheres. Neurons from the deprived hemisphere had lower
spontaneous firing rates than control neurons, and exhibited a right-ward shift in their firing rate
vs. current (FI) curves, indicating a reduction in intrinsic excitability. LTP-IE was induced in
control and deprived neurons by making the neurons fire 15 spikes at 40 Hz every 4 seconds for
10 minutes, in the presence of synaptic blockers (50µM APV, 20 µM DNQX, and 20 µM