Alden and I studied it quite thoroughly over a three-year period. I thought it was only going to be a two-year period. I was supposed to start my residency at Harvard in 1959, but I called up Dr Ewalt who was the chairman of the department and said, ‘I’m in the midst of wonderful set of experiments, I’ll never do anything comparable like this in science again, I wonder whether you can give me a year’s extension?’ He said take as long as you want. So instead of leaving in ’59 I left in ’60. So ’57 to ’60 I worked there, almost all that time Alden was there. And we recorded intracellularly from these cells. We described their properties, the action potentials, the resting potentials. Synaptic inputs into it, very powerful recurrent collaterals. They tended to fire in bursts, and we described the bursting activity. We also pioneered… we were not the first ones to do it, but very early ones. We had a bridge circuit so we could not only record, we could stimulate the individual cells. And then we found amazingly little spikelets that we could indirectly ascribe to coming from dendrites. So while everyone was thinking the dendrites gave rise to graded properties, we showed that the dendrites gave rise to little spikes that propagated to the initial segment where the big spike was initiated, and boom. So we had a lot of little insights in this thing, and we were very thrilled, and we published four papers back-to-back in the Journal of Neurophysiology. It was a big deal.

But we turned to each other, and we said, what the hell did we learn about memory? Not a goddamned thing. Memory is not a property of individual cells. These cells had some differences from motor neurons which is a prototype cell that had been studied well, the spinal cord motor neuron. It had some distinctive properties, this recurrent inhibition, the spikes in the dendrites, but that didn’t tell us anything about memory storage. Memory, we realized, it’s obvious, is a property of a neural circuit that is modified as a result of sensory input coming in. So we tried to see whether we could get sensory input in the hippocampus, we tried light, we tried touch, we tried pain, nothing worked. We didn’t realize that [the hippocampus represents space and that] space represents multiple modalities, and so we decided we needed to take another approach, and we discussed repeatedly, over days, what approaches we would take.