Rodent visual behavior

Our goal is to study the neural basis of visual perception using rodents. To this end we have developed an efficient, automated visual behavior paradigm for rodents.

General Paradigm
The animal is placed in a training box that has visual stimuli and response/reward ports on one wall. The animal requests a trial by putting its nose in the central nose poke, at which time the stimulus appears on the screen. The animal is trained to make a two-alternative forced choice based on some feature of the stimulus, and to indicate its response by going either to the right or left port. Correct responses are rewarded with water. Incorrect responses are penalized by an enforced delay, and indicated by distinct visual and auditory stimuli.

Rat Psychophysics Click on the image to see a rat performing a 2-AFC task. Two stimuli appear in each trial; the task is to go to the side with the horizontal grating. The stimulus remains on only while the animal's nose is in the center port. Naive rats learn this task to criterion in 2 weeks.

Squirrel Psychophysics Click on the image to see a squirrel doing visual psychophysics. The task is the same as shown for the rat, but now the spatial frequency of the grating varies. We have used this task to obtain psychometric curves for spatial acuity. (We also have a quicktime version of this movie).

Chronic Recording We use standard (home-built or commercial) chronically implanted multi-electrode multidrives to record from single LGN neurons in freely behaving rats.

Head-fixed behavior We have also developed a novel 3-response nose-poke that allows the same tasks to be performed in a head-fixed configuration, which is necessary for some types of physiological experiments.

Eye Tracking We use high-speed non-invasive infrared eye tracking to determine the location of visual stimuli relative to the retina. We find that rats spontaneously hold fixation for several seconds at a time (eye position traces, below left; scale bar = 3 sec). We can record eye positions in head-fixed rats with an accuracy of 0.2 degrees visual angle at kHz sampling rates (eye position estimates for three stimulus-evoked fixations, below right).

Credits Graduate students Philip Meier and Erik Flister developed this novel rodent visual behavior paradigm, with lots of help and advice from members of the Zador Lab and Mainen Lab (check out the cool rat auditory and olfactory behavior movies on their websites!). The videos shown above were from experiments done with help from undergraduate Liz Reed (rat) and collaborator Bevil Conway (squirrel). Development of the rodent vision preparation was made possible by the generous support of the Sloan Foundation, the Hellman Foundation, and the Kavli Institute of Brain and Mind.