In our lab we use rodents (mice, rats, and squirrels) as model systems to study mammalian vision. Squirrels have excellent, human-like visual systems including high acuity, color vision, extensive binocular fields, and extensive cortical representation of visual information. However, rats are also a robust visual preparation sufficient for many studies that do not require these special characteristics. Mice are under development as a third preparation in order to exploit their advantages for genetic experiments. In addition to visual behavior and electrophysiology, we are also looking at anatomy of the visual pathways in these species. These experiments pave the way for the use of retrogradely transported viral vectors to selectively label, ablate, or modulate cell populations of interest in the visual circuit.

Visual anatomy in squirrels (in collaboration with Harvey Karten)

In this experiment we injected anterograde tracer in one eye of the squirrel and then stained the brain for the tracer (black), over a background of nissl (blue). The vertical stripes on the left are the the 3 layers of the LGN: two contralateral layers stained black, separated by an ipsilateral layer which appears blue. The large circle of black staining at right is the tectum.

In this experiment we injected retrograde tracer in the LGN of the squirrel and then stained with antibody to the tracer (red). This section of striate cortex (V1) shows diffuse staining of the LGN axon terminals in layer 4 (fuzzy layer above), and retrogradely labelled cell bodies of the feedback neurons in layer 6 (below).

These experiments were made possible by the support of the Hellman Foundation.