The Calyx of Held (1895–1896)

Illustration of Calyx of Held drawing by Dawn Hunter, 11" x 14," marker and pen on paper.

The Calyx of Held (1895–1896) which Hans Held discovered in 1893 represents one of the biggest synaptic structures which exist within the mammalian nervous system. The structure serves as an essential component for auditory signal processing because it develops when the globular bushy cell axon from the anteroventral cochlear nucleus surrounds a principal neuron in the medial nucleus of the trapezoid body. The synapse functions as a specialized connection which enables fast and exact transmission of auditory data needed for identifying and pinpointing high-frequency sounds. Santiago Ramón y Cajal used his drawings of the mammalian auditory pathway to show how neurons connect through synapses during a period when this concept was not yet recognized by scientists. The artist uses color to show the Calyx of Held and neuronal soma as individual cellular structures which he understands need to transmit signals between them.