The prethalamus or subthalamus

Subthalamus

The subthalamus is a part of the diencephalon. Its major part is the subthalamic nucleus. Functionally, it also encompasses the globus pallidus, which is topographically part of the telencephalon.-Anatomy:...

 is part of the diencephalon

Diencephalon

The diencephalon is the region of the vertebrate neural tube which gives rise to posterior forebrain structures. In development, the forebrain develops from the prosencephalon, the most anterior vesicle of the neural tube which later forms both the diencephalon and the...

 and therefore part of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

.

Developmental biologists prefer the term prethalamus, as it can be genetically defined (Puelles and Rubenstein, 2003), whereas (human) anatomists often use the expression subthalamus.

The prethalamus is part of the mid-diencephalic territory (MDT) containing also the zona limitans intrathalamica

Zona limitans intrathalamica

The zona limitans intrathalamica is a lineage-restriction compartment and primary developmental boundary in the vertebrate forebrain that serves as a signaling center and a restrictive border between the thalamus and the prethalamus...

 (ZLI), and the thalamus

Thalamus

The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

. Caudally, the prethalamus is separated from the thalamus by the ZLI acting as lineage restriction boundary. The pro-neural gene Dlx2

Dlx (gene)

Dlx is a family of homeodomain transcription factors which are related to the Drosophila distal-less gene .The family has been related to a number of developmental features.The family seems to be well preserved across species....

 serves a typical marker of the prethalamus. Typical nuclei

Nucleus (neuroanatomy)

In neuroanatomy, a nucleus is a brain structure consisting of a relatively compact cluster of neurons. It is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up...

 of the prethalamus are the zona incerta

Zona incerta

The zona incerta is a horizontally elongated region of gray matter cells in the subthalamus below the thalamus. Its connections project extensively over the brain from the cerebral cortex down into the spinal cord....

, thalamic reticular nucleus, and the fields of Forel

Fields of forel

Fields of Forel is an area in a deep part of the brain known as the diencephalon. It is below the thalamus and consists of three defined, white matter areas of the subthalamus. These three regions are named "H fields" ....

.

The prethalamus is patterned by 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...

 signalling from the ZLI. Anatomically, it develops efferent

Efferent nerve

In the nervous system, efferent nerves, otherwise known as motor or effector neurons, carry nerve impulses away from the central nervous system to effectors such as muscles or glands...

 (output) connections to the striatum

Striatum

The striatum, also known as the neostriatum or striate nucleus, is a subcortical part of the forebrain. It is the major input station of the basal ganglia system. The striatum, in turn, gets input from the cerebral cortex...

 (caudate nucleus

Caudate nucleus

The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...

 and putamen

Putamen

The putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...

) in the telencephalon

Telencephalon

The cerebrum or telencephalon, together with the diencephalon, constitutes the forebrain. The cerebrum is the most anterior region of the vertebrate central nervous system. Telencephalon refers to the embryonic structure, from which the mature cerebrum develops...

, to the thalamus (medial and lateral nuclear groups) in the diencephalon, and to the red nucleus

Red nucleus

The red nucleus is a structure in the rostral midbrain involved in motor coordination. It comprises a caudal magnocellular and a rostral parvocellular part.-Function:...

 and substantia nigra

Substantia nigra

The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in...

 in the 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....

. It receives afferent

Afferent nerve

In the nervous system, afferent neurons , carry nerve impulses from receptors or sense organs towards the central nervous system. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneurons...

(input) connections from the substantia nigra and striatum.