Remember: fire like this

Understanding how the brain stores and retrieves memories is one of the most complex problems to remain unsolved in neuroscience. Oscillatory firing patterns in the hippocampus are thought to be central to both processes. In the 20 February Nature, Thomas Klausberger and colleagues at the University of Oxford, UK, demonstrate that different classes of hippocampal interneurons display characteristic firing patterns which may contribute to the activities of neural networks (Nature, 421:844-848, February 20, 2003).

Klausberger et al. measured firing rates in anesthetized rats of three types of inhibitory interneurons — axo-axonic cells, basket cells, and O-LM (oriens–lacunosum-moleculare) cells — distinguished by their morphology, immunohistochemistry, and connectivity to pyramidal cells of the hippocampus. They recorded firing patterns during two types of hippocampal neural activity: theta oscillations, which are regular and rhythmic that characterize movement, exploration, and REM sleep; and ripple oscillations, which are short bursts of activity...