A novel method for precisely timed stimulation of mouse whiskers in a freely moving preparation: Application for delivery of the conditioned stimulus in trace eyeblink conditioning

doi:10.1016/j.jneumeth.2008.11.002

Journal of Neuroscience Methods

Volume 177, Issue 2, 15 March 2009, Pages 434-439

https://doi.org/10.1016/j.jneumeth.2008.11.002 Get rights and content

Abstract

The somatosensory whisker pathway has been a useful system for increasing our understanding of experience-induced plasticity. However, precisely timed whisker activation in the awake freely moving mouse has been very difficult. This manuscript describes a method for construction of a whisker stimulator that can be attached to a freely moving mouse. The stimulator was used to activate the whiskers in a time-sensitive forebrain-dependent task, trace eyeblink conditioning. After repeatedly pairing whisker stimulation with delivery of a mild periorbital shock following a stimulus-free trace interval, trace-conditioned mice were able to learn the association. This study demonstrates the potential for using the whisker stimulator in time-sensitive behavioral tasks, such as trace eyeblink conditioning, thus enhancing our ability to examine experience-induced neuronal plasticity in the somatosensory whisker pathway in awake behaving rodents.

Section snippets

Methods

A “headbolt” connector affixed to the mouse's skull where a tether and the stimulator can be attached is required for whisker stimulation. We used a design routinely employed in our laboratory for eyeblink conditioning (Tseng et al., 2004, Weiss and Disterhoft, 2008). Briefly, the headbolt connector consists of a segment from a 221 series nylon strip connector (Cooper Interconnect) containing seven holes. The first hole was threaded to help anchor the tether. This was then followed by three

Whisker stimulator

The whisker stimulator is based upon activation of a piezo strip (Piezo Systems, Cambridge, MA, Piezo strip T220-A4-303) that then deflects the whiskers (Fig. 1, Fig. 2). To construct the whisker stimulator a 1 cm segment of a 221 series nylon strip connector (Cooper Interconnect) was attached to the base of the tether adjacent to the three spacer holes with quick drying epoxy to act as an anchor for the stimulator (Fig. 1a black). Two 6 cm long 17 gauge stainless steel tubes (0.058 OD 0.042 ID,

Conditioning

To illustrate the effectiveness of the whisker stimulator 3-month old C57Bl6 male mice kept on a standard 14:10 light/dark cycle and given food and water ad libitum were trained on a trace-250 eyeblink conditioning paradigm with whisker stimulation as the conditioned stimulus. We have previously demonstrated in rabbits that whisker stimulation can be used as an effective conditioned stimulus in delay and trace eyeblink conditioning (Das et al., 2001, Galvez et al., 2006). Nine mice were trained

Results

The following analysis demonstrates that we were able to control deflection of mouse facial whiskers with millisecond precision in an awake freely moving learning paradigm with the described whisker stimulator (Fig. 3B). Utilizing the whisker stimulator in a trace-250 eyeblink paradigm, we found that mice exhibited a significant increase in the number of conditioned responses (Fig. 5; F_(3,33) = 7.09; p < 0.001), demonstrating that they were able to learn that whisker stimulation was associated

Discussion

The somatosensory barrel pathway has proven to be a very useful sensory system for studying experience-induced changes in neuronal processing. However, it has been difficult to mechanically stimulate the facial whiskers in a time-sensitive manner in the unanesthetized animal. We have described a technique for precisely timed stimulation of facial whiskers in freely moving mice. We then utilized this method for stimulating the whiskers in a time-sensitive, forebrain-dependent task, trace

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Published by Elsevier B.V.

A novel method for precisely timed stimulation of mouse whiskers in a freely moving preparation: Application for delivery of the conditioned stimulus in trace eyeblink conditioning

Abstract

Section snippets

Methods

Whisker stimulator

Conditioning

Results

Discussion

Brain Res

Behav Brain Res

Brain Res

Brain Res

Neuroscience

Behav Brain Res

J Neurosci Methods

Brain Res

Encoding of whisker vibration by rat barrel cortex neurons: implications for texture discrimination

J Neurosci

J Neurosci

An innocuous bias in whisker use in adult rats modifies receptive fields of barrel cortex neurons

J Neurosci

Eyeblink conditioning in the rabbit (oryctolagus cuniculus) with stimulation of the mystacial vibrissae as a conditioned stimulus

Behav Neurosci

Experience-dependent plasticity in adult rat barrel cortex

Proc Natl Acad Sci USA

Laminar comparison of somatosensory cortical plasticity

Science