![Drosophila melanogaster brain expression patterns](https://upload.wikimedia.org/wikipedia/commons/d/dd/Drosophila_melanogaster_brain_expression_patterns.jpg)
The mushroom bodies or ''corpora pedunculata'' are a pair of structures in the
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...
of
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 ...
s, other
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 ...
s, and some
annelids
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecolog ...
(notably the
ragworm
Nereididae (formerly spelled Nereidae) are a family of polychaete worms. It contains about 500 – mostly marine – species grouped into 42 genera. They may be commonly called ragworms or clam worms.
Characteristics
The prostomium of ...
''
Platynereis dumerilii
''Platynereis dumerilii'' is a species of annelid polychaete worm. It was originally placed into the genus ''Nereis'' and later reassigned to the genus '' Platynereis''. ''Platynereis dumerilii'' lives in coastal marine waters from temperate t ...
''). They are known to play a role in
olfactory learning and memory. In most insects, the mushroom bodies and the
lateral horn are the two higher brain regions that receive olfactory information from 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. Function ...
via projection neurons.
They were first identified and described by French biologist
Félix Dujardin
Félix Dujardin (5 April 1801 – 8 April 1860) was a French biologist born in Tours. He is remembered for his research on protozoans and other invertebrates.
Biography
In 1840 he was appointed professor of geology and mineralogy at the U ...
in 1850.
Structure
Mushroom bodies are usually described as
neuropil
Neuropil (or "neuropile") is any area in the nervous system composed of mostly unmyelinated axons, dendrites and glial cell processes that forms a synaptically dense region containing a relatively low number of cell bodies. The most prevalent an ...
s, i.e. as dense networks of
neuron
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. ...
al processes (
dendrite
Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the ...
and
axon terminals
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...
) and
glia
Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myel ...
. They get their name from their roughly hemispherical ''calyx'', a protuberance that is joined to the rest of the brain by a central nerve tract or ''peduncle''.
Most of our current knowledge of mushroom bodies comes from studies of a few species of insect, especially the
cockroach
Cockroaches (or roaches) are a Paraphyly, paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are we ...
''
Periplaneta americana
The american cockroach (''Periplaneta americana'') is the largest species of common cockroach, and often considered a pest. In certain regions of the U.S. it is colloquially known as the waterbug, though it is not a true waterbug since it is not ...
'', the
honey bee
A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
''
Apis mellifera'',
the
locust
Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...
and the fruit fly ''
Drosophila melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...
''. Studies of fruit fly mushroom bodies have been particularly important for understanding the genetic basis of mushroom body functioning, since their
genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...
has been sequenced and a vast number of tools to manipulate their gene expression exist.
In the
insect brain
The supraesophageal ganglion (also "supraoesophageal ganglion", "arthropod brain" or "microbrain") is the first part of the arthropod, especially insect, central nervous system. It receives and processes information from the first, second, and th ...
, the peduncles of the mushroom bodies extend through the
midbrain
The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', " ...
. They are mainly composed of the long, densely packed nerve fibres of the
Kenyon cell Kenyon cells are the intrinsic neurons of the mushroom body, a neuropil found in the brains of most arthropods and some annelids. They were first described by F. C. Kenyon in 1896. The number of Kenyon cells in an organism varies greatly between s ...
s, the intrinsic neurons of the mushroom bodies. These cells have been found in the mushroom bodies of all species that have been investigated, though their number varies. Fruit flies, for example, have around 2,500, whereas cockroaches have about 200,000.
A locust brain dissection to expose the central brain and carry out electro-physiology recordings can be seen here.
Function
Mushroom bodies are best known for their role in
olfactory associative learning. These olfactory signals are received from
dopaminergic,
octopaminergic
Octopamine (molecular formula C8H11NO2; also known as OA, and also norsynephrine, ''para''-octopamine and others) is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway. Octopamine is ofte ...
,
cholinergic
Cholinergic agents are compounds which mimic the action of acetylcholine and/or butyrylcholine. In general, the word " choline" describes the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cati ...
,
serotonergic
Serotonergic () or serotoninergic () means "pertaining to or affecting serotonin". Serotonin is a neurotransmitter. A synapse is serotonergic if it uses serotonin as its neurotransmitter. A serotonergic neuron ''produces'' serotonin. A substance is ...
, and
GABAergic neurons outside the MB.
They are largest in the
Hymenoptera, which are known to have particularly elaborate control over olfactory behaviours. However, since mushroom bodies are also found in
anosmic primitive insects, their role is likely to extend beyond olfactory processing. Anatomical studies suggest a role in the processing of
visual
The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (th ...
and
mechanosensory input in some species. In
Hymenoptera in particular, subregions of the mushroom body neuropil are specialized to receive olfactory, visual, or both types of sensory input. In Hymenoptera, olfactory input is layered in the calyx. In ants, several layers can be discriminated, corresponding to different clusters of glomeruli in 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. Function ...
s, perhaps for processing different classes of odors.
There are two main groups of
projection neurons dividing the antennal lobe into two main regions, anterior and posterior. Projection neuron groups are segregated, innervating glomerular groups separately and sending axons by separate routes, either through the medial-antenno protocerebral tract (m-APT) or through the lateral-antenno protocerebral tract (l-APT), and connecting with two layers in the calyx of the mushroom bodies. In these layers the organization of the two efferent regions of the antennal lobe is represented topographically, establishing a coarse
odotopic map of the antennal lobe in the region of the
lip
The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...
of the mushroom bodies.
Mushroom bodies are known to be involved in
learning and
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...
, particularly for
smell, and thus are the subject of current intense research. In larger insects, studies suggest that mushroom bodies have other learning and memory functions, like
associative memory, sensory filtering,
motor control, and place memory. Research implies that mushroom bodies generally act as a sort of
coincidence detector, integrating multi-
modal inputs
and creating novel associations, thus suggesting their role in learning and memory. Recent work also shows evidence for the involvement of the mushroom body in innate olfactory behaviors through interactions with the lateral horn, possibly making use of the partially stereotyped sensory responses of the mushroom body output neurons (MBONs) across individuals.
Although the connections between the projection neurons and the Kenyon cells are random (i.e., not stereotyped across individuals), the stereotypy in MBON responses is made possible by the dense convergence of many Kenyon cells onto a few MBONs along with other network properties.
Information about odors may be encoded in the mushroom body by the identities of the responsive neurons as well as the timing of their spikes. Experiments in locusts have shown that
Kenyon cells Kenyon cells are the intrinsic neurons of the mushroom body, a neuropil found in the brains of most arthropods and some annelids. They were first described by F. C. Kenyon in 1896. The number of Kenyon cells in an organism varies greatly between s ...
have their activity synchronized to 20-Hz
neural oscillations
Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by ...
and are particularly responsive to projection neuron spikes at specific phases of the oscillatory cycle.
Sleep
The neurons which receive signals from
serotonergic
Serotonergic () or serotoninergic () means "pertaining to or affecting serotonin". Serotonin is a neurotransmitter. A synapse is serotonergic if it uses serotonin as its neurotransmitter. A serotonergic neuron ''produces'' serotonin. A substance is ...
and
GABAergic neurons outside the MB produce wakefulness, and experimentally stimulating these serotonergic upstream neurons forces sleep. The target neurons in the MB are inhibited by
serotonin,
GABA, and the combination of both. On the other hand
octopamine
Octopamine (molecular formula C8H11NO2; also known as OA, and also norsynephrine, ''para''-octopamine and others) is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway. Octopamine is ofte ...
does not seem to affect the MB's sleep function.
''Drosophila melanogaster''
![D](https://upload.wikimedia.org/wikipedia/commons/2/21/D._melanogaster_mushroom_body.png)
We know that mushroom body structures are important for
olfactory learning and
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...
in
''Drosophila'' because their
ablation
Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for a ...
destroys this function. The mushroom body is also able to combine information from the internal state of the body and the olfactory input to determine innate behavior. The exact roles of the specific neurons making up the mushroom bodies are still unclear. However, these structures are studied extensively because much is known about their
genetic make-up
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...
. There are three specific classes of neurons that make up the mushroom body lobes: α/β, α’/β’, and γ neurons, which all have distinct gene expression. A topic of current research is which of these substructures in the mushroom body are involved in each phase and process of learning and memory. ''Drosophila'' mushroom bodies are also often used to study learning and memory and are manipulated due to their relatively discrete nature. Typically, olfactory learning assays consist of exposing flies to two odors separately; one is paired with electric shock pulses (the
conditioned stimulus, or CS+), and the second is not (
unconditioned stimulus
Classical conditioning (also known as Pavlovian or respondent conditioning) is a behavioral procedure in which a biologically potent stimulus (e.g. food) is paired with a previously neutral stimulus (e.g. a triangle). It also refers to the learni ...
, or US). After this training period, flies are placed in a
T-maze
In behavioral science, a T-maze (or the variant Y-maze) is a simple forked passage used in animal cognition experiments.Olton, D.S. (1979). Mazes, maps, and memory. ''American Psychologist'', 34, 583–596). It is shaped like the letter T (or ...
with the two odors placed individually on either end of the horizontal ‘T’ arms. The percent of flies that avoid the CS+ is calculated, with high avoidance considered evidence of learning and memory.
Cellular memory traces
Recent studies combining odor conditioning and cellular imaging have identified six memory traces that coincide with
molecular changes in the
''Drosophila'' olfactory system
The olfactory system, or sense of smell, is the sensory system used for smelling ( olfaction). Olfaction is one of the special senses, that have directly associated specific organs. Most mammals and reptiles have a main olfactory system and an ...
. Three of these traces are associated with early forming behavioral memory. One such trace was visualized in 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. Function ...
(AL) by
synapto-pHluorin Synapto-pHluorin is a genetically encoded optical indicator of vesicle release and recycling. It is used in neuroscience to study transmitter release. It consists of a pH-sensitive form of green fluorescent protein (GFP) fused to the luminal side of ...
reporter molecules. Immediately after conditioning, an additional set of
projection neurons in a set of eight
glomeruli
''Glomerulus'' () is a common term used in anatomy to describe globular structures of entwined vessels, fibers, or neurons. ''Glomerulus'' is the diminutive of the Latin ''glomus'', meaning "ball of yarn".
''Glomerulus'' may refer to:
* the filter ...
in the AL becomes synaptically activated by the conditioned odor, and lasts for only 7 minutes. A second trace is detectable by
GCaMP expression, and thus an increase in Ca
2+ influx, in the α’/β’ axons of the mushroom body neurons. This is a longer-lasting trace, present for up to one hour following conditioning. The third memory trace is the reduction of activity of the anterior-paired lateral neuron, which acts as a memory formation suppressor through one of its inhibitory
GABAergic receptors. Decrease in
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
response of APL neurons and subsequent decrease in
GABA release onto the mushroom bodies persisted up to 5 minutes after odor conditioning.
The intermediate term memory trace is dependent on expression of the ''amn'' gene located in dorsal paired medial neurons. An increase in
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
influx and synaptic release that innervates the mushroom bodies becomes detectable approximately 30 minutes after pairing of electric shock with an odor, and persists for at least an hour. Both long-term memory traces that have been mapped depend on activity and protein synthesis of
CREB
CREB-TF (CREB, cAMP response element-binding protein) is a cellular transcription factor. It binds to certain DNA sequences called cAMP response elements (CRE), thereby increasing or decreasing the transcription of the genes. CREB was first de ...
and
CaMKII
/calmodulin-dependent protein kinase II (CaM kinase II or CaMKII) is a serine/threonine-specific protein kinase that is regulated by the /calmodulin complex. CaMKII is involved in many signaling cascades and is thought to be an important mediator ...
, and only exist after spaced conditioning. The first trace is detected in α/β neurons between 9 and 24 hours after conditioning, and is characterized by an increase in
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
influx in response to the conditioned odor. The second long-term memory trace forms in the γ mushroom bodies and is detected by increase
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
influx between 18 and 24 hours after conditioning
cAMP dynamics
Cyclic adenosine monophosphate
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transd ...
(cAMP or cyclic AMP) is a second messenger that has been implicated in facilitating mushroom body
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
influx in
Drosophila melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...
mushroom body neurons. cAMP elevation induces presynaptic plasticity in Drosophila. cAMP levels are affected by both
neurotransmitters, such as
dopamine and
octopamine
Octopamine (molecular formula C8H11NO2; also known as OA, and also norsynephrine, ''para''-octopamine and others) is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway. Octopamine is ofte ...
, and odors themselves. Dopamine and octopamine are released by mushroom body
interneurons, while odors directly activate neurons in the olfactory pathway, causing calcium influx through
voltage-gated calcium channels
Voltage-gated calcium channels (VGCCs), also known as voltage-dependent calcium channels (VDCCs), are a group of voltage-gated ion channels found in the membrane of excitable cells (''e.g.'', muscle, glial cells, neurons, etc.) with a permeabi ...
.
In a
classical conditioning
Classical conditioning (also known as Pavlovian or respondent conditioning) is a behavioral procedure in which a biologically potent stimulus (e.g. food) is paired with a previously neutral stimulus (e.g. a triangle). It also refers to the learni ...
paradigm, pairing neuronal
depolarization
In biology, depolarization or hypopolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolarization is ess ...
(via
acetylcholine application to represent the
odor or
CS) with subsequent dopamine application (to represent the shock or
US), results in a synergistic increase in
cAMP
Camp may refer to:
Outdoor accommodation and recreation
* Campsite or campground, a recreational outdoor sleeping and eating site
* a temporary settlement for nomads
* Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
in the mushroom body lobes.
These results suggest that the mushroom body lobes are a critical site of CS/US integration via the action of cAMP. This synergistic effect was originally observed in
Aplysia
''Aplysia'' () is a genus of medium-sized to extremely large sea slugs, specifically sea hares, which are one clade of large sea slugs, marine gastropod mollusks.
These benthic herbivorous creatures can become rather large compared with most ...
, where pairing calcium influx with activation of
G protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their a ...
signaling by
serotonin generates a similar synergistic increase in cAMP.
Additionally, this synergistic increase in cAMP is mediated by and dependent on
rutabaga
Rutabaga (; North American English) or swede (British English and some Commonwealth English) is a root vegetable, a form of ''Brassica napus'' (which also includes rapeseed). Other names include Swedish turnip, neep (Scots), and turnip (Scott ...
adenylyl cyclase (rut AC), which is sensitive to both calcium (which results from voltage-gated calcium channel opening by odors) and
G protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their a ...
stimulation (caused by dopamine).
While a forward pairing of neuronal
depolarization
In biology, depolarization or hypopolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolarization is ess ...
and dopamine, (acetylcholine followed by dopamine) results in a synergistic increase in cAMP, a forward pairing of neuronal
depolarization
In biology, depolarization or hypopolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolarization is ess ...
and octopamine produces a sub-additive effect on cAMP.
More specifically, this means that this pairing produces significantly less cAMP than the sum of each stimulus individually in the lobes. Therefore, rut AC in mushroom body neurons works as a
coincidence detector with dopamine and octopamine functioning bidirectionally to affect cAMP levels.
PKA dynamics
Protein kinase A
In cell biology, protein kinase A (PKA) is a family of enzymes whose activity is dependent on cellular levels of cyclic AMP (cAMP). PKA is also known as cAMP-dependent protein kinase (). PKA has several functions in the cell, including regulatio ...
(PKA) has been found to play an important role in learning and memory in ''Drosophila''.
When
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
enters a cell and binds with
calmodulin, it stimulates
adenylate cyclase
Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction:
:A ...
(AC), which is encoded by the
rutabaga gene (''rut'').
This AC activation increases the concentration of
cAMP
Camp may refer to:
Outdoor accommodation and recreation
* Campsite or campground, a recreational outdoor sleeping and eating site
* a temporary settlement for nomads
* Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
, which activates PKA.
When
dopamine, an aversive olfactory stimulant, is applied it activates PKA specifically in the vertical mushroom body lobes.
This spatial specificity is regulated by the dunce (''dnc'') PDE, a cAMP-specific
phosphodiesterase
A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, ''phosphodiesterase'' refers to cyclic nucleotide phosphodiesterases, which have great clinical significance and are described below. However, there are many ot ...
. If the dunce gene is abolished, as found in the ''dnc'' mutant, the spatial specificity is not maintained. In contrast, an appetitive stimulation created by an
octopamine
Octopamine (molecular formula C8H11NO2; also known as OA, and also norsynephrine, ''para''-octopamine and others) is an organic chemical closely related to norepinephrine, and synthesized biologically by a homologous pathway. Octopamine is ofte ...
application increases PKA in all lobes.
In the ''rut'' mutant, a genotype in which the rutabaga is abolished, the responses to both dopamine and octopamine were greatly reduced and close to experimental noise.
Acetylcholine, which represents the
conditioned stimulus, leads to a strong increase in PKA activation compared to stimulation with dopamine or octopamine alone.
This reaction is abolished in ''rut'' mutants, which demonstrates that PKA is essential for sensory integration.
The specificity of activation of the alpha lobe in the presence of dopamine is maintained when dopamine is in combination with acetylcholine.
Essentially, during a conditioning paradigm when a conditioned stimulus is paired with an unconditioned stimulus, PKA exhibits heightened activation. This shows that PKA is required for conditioned learning in ''
Drosophila melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...
''.
''Apis mellifera''
Stimulus output responses are the product of pairs of
excitation and
inhibition
Inhibitor or inhibition may refer to:
In biology
* Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity
* Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...
. This is the same pattern of organisation as with
mammals' brains. These patterns may, as with mammals, precede action. this is an area only recently elucidated by Zwaka et al 2018, Duer et al 2015, and Paffhausen et al 2020.
See also
*
Cerebral cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consistin ...
References
Further reading
*
*
*
{{refend
External links
Standard BeeBrain
Insect anatomy
Arthropod anatomy
Invertebrate nervous system