ラット事象関連電位P3-like成分の神経生理学的基盤の検討 <学位論文要旨>

P3 potentials have been widely used to study normal human cognitive functions and assess cognitive impairment in patients. However, several studies suggest that the usefulness of P3 potentials as practical assessment tools is limited, because their neural mechanisms remain unclear thus far. The aim of the present study was to investigate the neural mechanism of P3 potentials by using the socalled P3-like potentials in rats.

Chapter 1 presents a review of the relevant literature on the neural mechanisms of P3 potentials and P3-like potentials in animals.

In Chapter 2, we describe appropriate animal models to explain the neural basis of P3 potentials. The results of Experiments 1–5 demonstrate that rat P3-like potentials refl ect "attention processes," similar to human P3 potentials. Experiment 6 shows that rat P3-like potentials showed high reliability. Therefore, the rat model is useful for investigating the neural mechanisms underlying human P3 potentials.

Chapter 3 describes the investigations of the regions that generate P3 potentials, such as the ACC and hippocampus, conducted using the rat model. Experiment 7 showed that the latency of P3-like potentials from the ACC was shorter than that of potentials from the hippocampal CA1 region. Moreover, only highly deviant stimuli elicited P3-like amplitudes in the ACC, while the target stimulus elicited P3-like amplitudes in the hippocampal CA1 region, irrespective of stimulus deviation (Experiment 8).

In Chapter 4, on the basis of the results presented in chapters 2 and 3, a model describing the process of P3 generation is presented. Further, future studies are proposed.