What is the neural tube and how does it relate to the development of functional columns?

The neural tube is the embryonic structure that gives rise to the brain and spinal cord. During development, nerve cells in its wall organize into functional groups, which later form the columns and nuclei.

What is the sulcus limitans and what role does it play in spinal cord development?

The sulcus limitans is a groove formed by the central canal indenting the lateral wall of the spinal cord. It divides the wall into the alar lamina (dorsal, sensory) and basal lamina (ventral, motor), establishing the basis for functional columns.

What are the four functional columns in the spinal cord?

In the spinal cord, each side has four functional columns: General somatic afferent (GSA), General visceral afferent (GVA), General visceral efferent (GVE), and General somatic efferent (GSE). These arise from the alar and basal laminae.

How do functional columns differ between the spinal cord and brainstem?

The brainstem has a similar layout to the spinal cord but includes two additional columns due to specialized functions: Special visceral efferent (SVE) for pharyngeal arch derivatives and Special somatic afferent (SSA) for vestibular and cochlear organs, resulting in seven total columns.

What are the seven functional columns in the brainstem?

The brainstem has seven functional columns, organized into sensory (alar lamina): SSA, GSA, SVA, GVA, and motor (basal lamina): GVE, SVE, GSE. These columns differentiate into specific cranial nerve nuclei.

How do functional columns develop into cranial nerve nuclei?

As development progresses, each functional column in the brainstem further differentiates into specific cranial nerve nuclei. This specialization allows for the distinct sensory and motor functions associated with cranial nerves.

Brainstem Functional Columns – Development & Nuclei Layout