Susumu Takahashi is a Professor at Graduate School of Brain Science, Doshisha University. He is working on the mnemonic function of the hippocampus, mostly in the retrieval and encoding of episodic memory. He has a long-standing interest in the development of physiological and computational methods for neuroscience. Takahashi received a B. Eng. in Electrical Engineering and a Ph. D. in Computer Science from Keio University. For his thesis work, with Yuichiro Anzai and Yoshio Sakurai, he developed an automatic spike sorting software using independent component analysis. His postdoctoral work, with Yoshio Sakurai at Kyoto University, focused on mnemonic functions in the hippocampus. During the postdoctoral training, he acquired a skill of multi-unit recording and operant conditioning for rats and improved them with the state-of-the-art information processing and statistical methods. From 2007 until 2012 he was an Assistant Professor at Kyoto Sangyo University and a JST PRESTO Research Fellow. From 2012 until 2017 he was then an Associate Professor at Doshisha University. The hippocampus is the largest part of the mammalian brain and plays a critical role in spatial navigation and episodic memory. My goal is to decipher how the hippocampus processes information and to realize encoding and retrieval of episodic memory. The research program in our laboratory is mainly organized around the hippocampus, basal ganglia, and cortex that subserve cognition and behavior in the mouse and rat. We use a variety of computational and electrophysiological methods to record and control the circuit dynamics underlying cognitive and behavioral functions. Quantitative behavioral paradigms in freely behaving mice and rats allow us to monitor the large-scale activity patterns of neurons in awake animals. For instance, monitoring neuronal ensemble activity in the circuit can inspire hypotheses underlying cognition and behavior. Such hypotheses can be tested using large-scale multi-unit recordings during task performances of rats and mice in conjunction with operant conditioning and optogenetic manipulations. Furthermore, bringing together domain experts in neuroscience and ecology and by using a state-of-the-art logging technology called NeuroLogger that can record the activity of multiple single neurons in the brain of freely behaving wild animals, we investigate the neural underpinnings of animal migrations of migratory seabirds and salmonid fish.