climbing fiber

noun

anatomy

: any of the afferent nerve fibers arising from neurons in the inferior olive that ascend to the cerebellar cortex to synapse with Purkinje cells

The olive sends so-called climbing fibers up to the cerebellum where they wrap around Purkinje cells like vines around a tree, exerting a powerful influence on them …

—Ingrid Wickelgren, Science, 11 Sept. 1998

Individual Purkinje neurons receive synaptic input from only a single climbing fiber, whereas each climbing fiber contacts 1-10 Purkinje neurons.

—Eric R. Kandel et al., Principles of Neural Science, 4th Edition, 2000

Word History

First Known Use

1950, in the meaning defined above

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!