Inducing Long-Term Plasticity of Intrinsic Neuronal Excitability in Neurons of the Dorsal Lateral Geniculate Nucleus

Summary

Here, we describe a protocol for inducing long-term plasticity of neuronal intrinsic excitability in relay neurons from the dorsal lateral geniculate nucleus maintained in ex vivo brain slices.

Abstract

The dorsal lateral geniculate nucleus (dLGN) has long been held to act as a basic relay for visual information traveling from the retina to cortical areas, but recent findings suggest largely underestimated functional plasticity of dLGN principal cells. However, the cellular mechanisms supporting these changes have not been fully explored. Here, we report a protocol to induce long-term potentiation of intrinsic neuronal excitability (LTP-IE) in dorsal dLGN relay cells from acute brain slices of young rats. Intrinsic plasticity is generally induced in parallel with synaptic plasticity. However, in dLGN neurons, LTP-IE is reliably induced by spiking activity at a frequency of 40 Hz for 10 min. LTP-IE in dLGN relay neurons is long-lasting as it can be followed up to 40 min after the induction protocol. In conclusion, the results of this study provide the first evidence for the induction of intrinsic plasticity in dLGN relay cells, thus further pointing to the role of thalamic neurons in activity-dependent visual plasticity.

Introduction

The overall goal of this method paper is to provide a simple way to induce long-lasting plasticity of neuronal excitability in visual thalamic neurons of the rat in vitro, using the standard current-clamp mode of the patch clamp technique^1,2. The rationale behind the development of this technique is its simplicity and reproducibility. The advantage over alternative techniques, such as stimulation of synaptic inputs paired or not with postsynaptic action potentials delivered with a given timing, is its reliability.

Plasticity in the visual system is traditionally thought to ....

Protocol

All experiments were conducted according to the European and Institutional guidelines (Council Directive 86/609/EEC and French National Research Council and approved by the local health authority (Veterinary Services, Préfecture des Bouches-du-Rhône, Marseille)).

1. Animals

1. Conduct experiments using 19-25-day-old Long Evans rats of both sexes (weighing between 50-90 g).
2. House the animals in conventional plastic cages, together with their mother .......

Discussion

We report here the induction of LTP-IE in dLGN neurons maintained alive in acute brain slices by stimulation of the recorded neuron to evoke action potentials at a frequency of 40 Hz for 10 min. This protocol is simple to implement in any neurophysiology lab as it requires a minimal number of equipment (slicer, microscope, 1 amplifier, 1 acquisition board and computer). However, a few critical steps must be respected in order to collect valuable data. The first critical step within the protocol is the quality of the.......

Materials

Name	Company	Catalog Number	Comments
Automated vibrating blade microtome	Leica	VT-1200S	vibratome/slicer
Borosilicate glass tube	Phymep	B-15086-10
Controller Typ V	Luigs&Neumann	Typ V	temperature controller
Igor software	wavemetrics		analysis software
Infrared videomicroscopy	Olympus	XM-10 Camera
Kynurenate	Merk/Sigma	K3375	AMPA/NMDA receptors blocker
Low-noise Data Acquisition System	Axon - Molecular devices	Digidata 1440A	analog/digital interface
Micromanipulators	Luigs&Neumann	LN Mini25
Multiclamp 200B	Axon - Molecular devices	N/A	Patch-clamp amplifier
Multiclamp 700B	Axon - Molecular devices	N/A	patch-clamp amplifier
PC-100 puller	Narishige	PC-100	micropipette puller
PClamp10	Axon - Molecular devices	N/A	patch-clamp recording software
Picrotoxin	AbCam	ab120315	GABAA receptors blocker
Slice mini chamber	Luigs&Neumann	LN Chambre Slice mini I-II	Submerged Chamber
Upright microscope	Olympus	BX51 WI