Properties of thin, unmyelinated axons in mammalian brain

In order to better understand and control how neurons work we need more knowledge about thin, unmyelinated axons. This is because: - They are the most common axonal type in the mammalian cortex. - They are the part of the neuron that we have least knowled ge about, which is mostly due to their tiny dimensions, below the light microscopic resolution. - They are the most excitable part of the neuron are, therefore, important for control neuronal activity. - Both theory and experiments suggest that they have properties that are different from other axons. During the last years, we have developed methods for direct axonal recordings that have opened the possibility to investigate such axons at a much more detailed level than before. The use of these methods h as given results, from our own and other groups, that shows that these axons have unique properties. They have, for example, an H-current that is important for their ability to work at high frequencies. We have also found that they display bursting activi ty, independent of the somatic activity. Such knowledge gives the opportunity to develop treatment strategies that specifically targets neuronal hyperactivity, sparing low, normal activity, which is a strategy of great clinical significance. We suggest co ntinuing the axonal research to find out more about the spike generation and conduction process, and which channels and other processes that interfere with the conduction abilities. The results will fill a significant gap in the knowledge about how neuron s work, and can illuminate axonal properties that can be targeted with pharmacological methods in the clinic.