90. The role of the basal forebrain in episodic memory retrieval: A positron emission tomography study in humans

We used positron emission tomography to examine the neural basis of recall processes for contextual information in young normal volunteers. Comparison of the two temporal-context-specific recall tasks with the control task showed significant increases in rCBF in the left basal forebrain, the right superior temporal gyrus, and the right posterior cingulate gyrus. Activated regions associated with two source-context-specific recall tasks were the left posterior insula and the right posterior cingulate gyrus. We conclude that there are different neural networks in the human brain subserving memory recall for different contextual information, i.e., temporal context and source context in the present study. Among these findings, we would like to emphasize that the human basal forebrain region plays an important role in episodic recall especially from temporal contextual information