An Electrophysiological Study of Retinogeniculate and Corticogeniculate Synapses in Mouse Brain Slices

Place a mouse brain slice in a recording chamber perfused with an oxygenated recording solution.

The slice contains the dorsal lateral geniculate nucleus, or dLGN, which is rich in relay neurons. These neurons form retinogeniculate synapses with the projections of retinal ganglion cells and corticogeniculate synapses with neuronal projections from the visual cortex.

Position a stimulating pipette on the optic tract to investigate retinogeniculate synapses or on the nucleus reticularis thalami to investigate corticogeniculate synapses.

Position a recording pipette near the slice. Using a microscope, locate a relay neuron.

Apply positive pressure to prevent pipette clogging while approaching the neuron.

Switch to negative pressure, forming a seal with the cell membrane, then rupture it to establish continuity with the cytoplasm.

Using the stimulating pipette, deliver electric pulses that induce the projections to release excitatory neurotransmitters, which bind to relay neuron synaptic receptors, triggering ion flow measured by the recording pipette.