Evoking blinks with natural stimulation and detecting them with a noninvasive optical device: A simple, inexpensive method for use with freely moving animals

Abstract

Many laboratories studying eyeblinks in unanesthetized rodents use a periorbital shock to evoke the blink. The stimulus is typically delivered via a tether and usually obliterates detection of a full unconditioned response with electromyographic (EMG) recording. Here we describe the adapter we have used successfully for several years to deliver puffs of air to the cornea of freely moving rats during our studies of eyeblink conditioning. The stimulus evokes an unconditioned response that can be recorded without affecting the EMG signal. This allows a complete analysis of the unconditioned response which is important for studies examining reflex modification or the effect of drugs, genetic manipulations, or aging on the unconditioned blink reflex. We also describe an infrared reflective sensor that can be added to the tether to minimize the number of wires that need to be implanted around the eye, and which is relatively immune to electrical artifacts associated with a periorbital shock stimulus or other devices powered by alternating current. The responses recorded simultaneously by EMG wires and the optical sensor appear highly correlated and demonstrate that the optical sensor can measure responses that might otherwise be lost due to electrical interference from a shock stimulus.

Effects of subthalamic deep brain stimulation on blink abnormalities of 6-OHDA lesioned rats

“…The first 5 min of data were not analyzed to allow the rats to habituate to the experimental setup. In addition to using the OOemg to monitor spontaneous blinks, we also recorded lid movements with an infrared detector (Weiss and Disterhoft 2008).…”

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

“…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.…”

Whisker-signaled Eyeblink Classical Conditioning in Head-fixed Mice

“…Note: The connector is a 3-D printed 7-hole strip modeled from the Amphenol 221 series nylon strip used for the tether by Weiss and Disterhoft and Galvez et al 10,17 1. Tap the first hole in the strip for a 0-80 x-1" machine screw.…”

“…A commonly used apparatus for the investigation of eyeblink conditioning in rodents is a chamber in which the rodents are allowed to move about freely during the training process [8][9][10] . With this type of apparatus, a tether is normally attached to a headpiece that is affixed to the rodent's skull.…”

“…With this type of apparatus, a tether is normally attached to a headpiece that is affixed to the rodent's skull. The tether allows for the delivery of the US (and sometimes the CS) and for transmitting the animal's response to those stimuli (i.e., the eyeblink response) 10 . The tether itself may be modified based on the type of stimuli delivered and how the eyeblink response is recorded.…”