The Mysterious Case of Amphid Cells: Unraveling the History of a Once-Hypothetical Neural Cell Type

Amphid is a term that was used in the past to describe a type of neural cell that was thought to play a role in the development and maintenance of the nervous system. However, it is no longer a widely accepted term in neuroscience, and its exact definition and function are not well established.

The term "amphid" was introduced in the 1980s by a group of researchers who were studying the development of the nervous system in chick embryos. They observed that certain cells in the developing brain and spinal cord had a distinctive morphology and expressed specific sets of molecules, including neurotrophins and other growth factors. These cells were called "amphid" cells, from the Greek words "amphi" (meaning "both") and "dendrite" (meaning "tree-like structure"), because they had long, branching processes that resembled dendrites.

However, subsequent research has not been able to confirm the existence of a distinct population of cells with the properties originally described for amphid cells. Instead, it is now believed that the development and maintenance of the nervous system is a complex process that involves the coordinated action of many different cell types, including neurons, glial cells, and other supportive cells.

Therefore, while the term "amphid" was once used to describe a hypothetical type of neural cell, it is no longer a widely accepted term in neuroscience, and its exact definition and function are not well established.