Long-term potentiation in guinea pig hippocampal slices monitored by optical recording of neuronal activity.

Pre- and postsynaptic potential changes evoked by stimulation of the Schaffer collateral-commissural input to CA1 pyramidal neurons were optically recorded in guinea pig hippocampal slices after staining the preparation with a suitable voltage-sensitive fluorescent dye. Brief tetanic stimulation induced long-term potentiation of synaptic transmission as monitored both optically and electrically. The results demonstrate that non-invasive optical techniques can be used to study long-term changes in spatial neuronal interactions, possibly involved in learning and other higher functions of the nervous system.