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

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

, especially

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

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

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

ganglion A ganglion (: ganglia) 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 ...

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 The fus ...

to the

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

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 (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

* The ''

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

'', associated with the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

s (

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 or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

). 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 '' antennal mechanosensory center'' in contrast to the Optic lobe (visual center) and the antennal lobe The antennal lobe is the primary (first order) olfactory brain area in insects. The antenna ...

. The dorsal lobe also contains

motor neurons A motor neuron (or motoneuron), also known as 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 ...

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 describe unambiguously the anatomy of humans and other animals. 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 syste ...

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 ve ...

are found in each

body segment Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other. This article focuses on the segmentation of animal body plans, specifica ...

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