The supraesophageal ganglion (also "supraoesophageal ganglion", "arthropod brain" or "microbrain") is the first part of the

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...

, especially

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

. It receives and processes information from the first, second, and third metameres. The supraesophageal

ganglion A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympathe ...

lies

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

to the

esophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to t ...

and consists of three parts, each a pair of ganglia that may be more or less pronounced, reduced, or fused depending on the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

* The ''

protocerebrum The protocerebrum is the first segment of the panarthropod brain. Recent studies suggest that it comprises two regions. Region associated with the expression of ''six3'' ''six3'' is a transcription factor that marks the anteriormost part of ...

'', associated with the eyes (

compound eyes A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distin ...

and

ocelli A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...

). Directly associated with the eyes is the optic lobe, as the visual center of the brain. * The ''deutocerebrum'' processes sensory information from the antennae. It consists of two parts, the

antennal lobe The antennal lobe is the primary (first order) olfactory brain area in insects. The antennal lobe is a sphere-shaped deutocerebral neuropil in the brain that receives input from the olfactory sensory neurons in the antennae and mouthparts. Functi ...

and the

dorsal lobe The dorsal lobe of arthropods is also known as the ''Antenna (biology), antennal mechanosensory center'' in contrast to the Optic lobe (arthropods), Optic lobe (visual center) and the antennal lobe (olfactory center). Together with the antennal lob ...

. The dorsal lobe also contains

motor neurons A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly ...

which control the antennal muscles. * The ''tritocerebrum'' integrates sensory inputs from the previous two pairs of ganglia. The lobes of the tritocerebrum split to circumvent the esophagus and begin the

subesophageal ganglion The suboesophageal ganglion (acronym: SOG; synonym: ''subesophageal ganglion'') of arthropods and in particular insects is part of the arthropod central nervous system (CNS). As indicated by its name, it is located ''below the'' ''oesophagus'', ins ...

The subesophageal ganglion continues the nervous system and lies

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

to the

. Finally, the

segmental ganglia The segmental ganglia (singular: s. ganglion) are ganglia of the annelid and arthropod central nervous system that lie in the segmented ventral nerve cord The ventral nerve cord is a major structure of the invertebrate central nervous system. It ...

of the

ventral nerve cord The ventral nerve cord is a major structure of the invertebrate central nervous system. It is the functional equivalent of the vertebrate spinal cord. The ventral nerve cord coordinates neural signaling from the brain to the body and vice versa, i ...

are found in each

body segment Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, an ...

as a fused ganglion; they provide the segments with some autonomous control. A locust brain dissection to expose the central brain and carry out electro-physiology recordings can be seen here.

References

External links

* Insect anatomy Fish anatomy Invertebrate nervous system {{Insect-anatomy-stub

See also

References

Further reading

External links