Takashi OKADA

In various neuroscientific studies the hippocampus is reported to play crucial roles in declarative memory. The hippocampus is composed of several synaptic field subdivisions, such as the dentate gyrus, CA3 and CA1. Synaptic plasticity in these areas is thought to be a candidate for the biological basis of memory function. In the last decade there have been efforts to elucidate the memory functions of each synaptic subfield by using gene-manipulated animals and recombinant viral vector-infected animals. The underlying circuit mechanisms have been studied by electrophysiological recordings from the hippocampus of the animals. High spatial resolution functional MRI must be used to clearly define the activated areas within the hippocampus of the living human brain, and studies using a high resolution imaging system for that purpose have recently begun to appear. The prospects and challenges for future integration of animal and human studies are discussed.