Basal plate (neural tube)
Encyclopedia
In the developing nervous system
, the basal plate is the region of the neural tube
ventral to the sulcus limitans
. It extends from the rostral mesencephalon
to the end of the spinal cord
and contains primarily motor neuron
s, whereas neurons found in the alar plate
are primarily associated with sensory functions. The cell types of the basal plate include lower motor neuron
s and four types of interneuron
.
Initially the left and right sides of the basal plate are continuous, but during neurulation
they become separated by the floor plate
, a derivative of the notochord
. Differentiation of neurons in the basal plate is under the influence of the protein Sonic hedgehog
released by ventralizing structures such as the notochord and floor plate.
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
, the basal plate is the region of the neural tube
Neural tube
In the developing vertebrate, the neural tube is the embryo's precursor to the central nervous system, which comprises the brain and spinal cord...
ventral to the sulcus limitans
Sulcus limitans
In the floor of the fourth ventricle, the sulcus limitans separates the cranial nerve motor nuclei from the sensory nuclei . In the superior part of the rhomboid fossa, it corresponds with the lateral limit of the fossa and presents a bluish-gray area, the locus ceruleus In the floor of the fourth...
. It extends from the rostral mesencephalon
Mesencephalon
The midbrain or mesencephalon is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal , and temperature regulation....
to the end of the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
and contains primarily motor neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s, whereas neurons found in the alar plate
Alar plate
The alar plate is a neural structure in the embryonic nervous system, part of the dorsal side of neural tube, that involves the communication of general somatic and general visceral sensory impulses. The caudal part later becomes sensory axon part of the spinal cord.-External links:* *...
are primarily associated with sensory functions. The cell types of the basal plate include lower motor neuron
Lower motor neuron
Lower motor neurons are the motor neurons connecting the brainstem and spinal cord to muscle fibers, bringing the nerve impulses from the upper motor neurons out to the muscles...
s and four types of interneuron
Interneuron
An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways...
.
Initially the left and right sides of the basal plate are continuous, but during neurulation
Neurulation
Neurulation is the stage of organogenesis in vertebrate embryos, during which the neural tube is transformed into the primitive structures that will later develop into the central nervous system....
they become separated by the floor plate
Floor plate
The floor plate is a structure integral to the developing nervous system of vertebrate organisms. Located on the ventral midline of the embryonic neural tube, the floor plate is a specialized glial structure that spans the anteroposterior axis from the midbrain to the tail regions...
, a derivative of the notochord
Notochord
The notochord is a flexible, rod-shaped body found in embryos of all chordates. It is composed of cells derived from the mesoderm and defines the primitive axis of the embryo. In some chordates, it persists throughout life as the main axial support of the body, while in most vertebrates it becomes...
. Differentiation of neurons in the basal plate is under the influence of the protein Sonic hedgehog
Sonic hedgehog
Sonic hedgehog homolog is one of three proteins in the mammalian signaling pathway family called hedgehog, the others being desert hedgehog and Indian hedgehog . SHH is the best studied ligand of the hedgehog signaling pathway. It plays a key role in regulating vertebrate organogenesis, such as...
released by ventralizing structures such as the notochord and floor plate.