What are the two most numerous subtypes of cortical interneurons?

The two most studied groups of interneurons (PV and SST expressing) are derived exclusively from the MGE (Xu et al., 2004; Fogarty et al., 2007; Miyoshi et al., 2007).

What is a cortical interneuron?

Cortical interneurons (INs) are a diverse group of neurons that project locally and shape the function of neural networks throughout the brain. Multiple lines of evidence suggest that a proper balance of glutamate and GABA signaling is essential for both the proper function and development of the brain.

What are the types of interneurons?

Interneuron can be broken down into two groups: local interneuron and relay interneuron. Local interneuron has short axons and form circuits with nearby neurons to analyze small pieces of information.

What is cortical interneuron migration?

During embryogenesis, cortical interneurons are generated by ventral progenitors located in the ganglionic eminences of the telencephalon. At the cellular level, migrating interneurons are highly polarized cells that extend and retract processes using dynamic remodeling of microtubule and actin cytoskeleton.

What is the origin of cortical inhibitory neurons?

Cerebral cortical functions are conducted by two general classes of neurons: glutamatergic projection neurons and GABAergic interneurons. Recent evidence suggests that many cortical interneurons originate within the subcortical telencephalon and then migrate tangentially into the overlying cortex.

What are GABAergic interneurons?

GABAergic interneurons are inhibitory neurons of the nervous system that play a vital role in neural circuitry and activity. They are so named due to their release of the neurotransmitter gamma-aminobutyric acid (GABA), and occupy different areas of the brain.

What are VIP interneurons?

Vasoactive intestinal peptide-expressing (VIP) interneurons in the cortex regulate feedback inhibition of pyramidal neurons through suppression of somatostatin-expressing (SST) interneurons and, reciprocally, SST neurons inhibit VIP neurons. VIP and SST neurons have complementary contrast tuning.

Are cortical neurons interneurons?

Cortical interneurons are cells that connect only with nearby neurons, to distinguish them from “projection” neurons, whose axons span to more distant regions of the brain. Interneurons typically express the inhibitory neurotransmitter gamma-amino butyric (GABA) and have aspiny dendrites (Markram et al., 2004).

What is the main function of interneurons?

As the name suggests, interneurons are the ones in between – they connect spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity. They are multipolar, just like motor neurons.

How do interneurons transfer messages?

Interneurons. Interneurons, which are found only in the CNS, connect one neuron to another. They receive information from other neurons (either sensory neurons or interneurons) and transmit information to other neurons (either motor neurons or interneurons).

How do interneurons migrate?

Interneurons migrate from the MGE (M) and traverse the LGE (L) whilst avoiding the striatum (Str). Upon entry into the cortical wall, cells migrate in 3 major streams, through the marginal zone at early stages, followed by a second route in the intermediate zone and at later stages through the subplate.

What is neural migration?

Definition. Neuronal migration disorders (NMDs) are a group of birth defects caused by the abnormal migration of neurons in the developing brain and nervous system. In the developing brain, neurons must migrate from the areas where they are born to the areas where they will settle into their proper neural circuits.

Where do GABAergic cortical interneurons originate in mice?

The medial ganglionic eminence has long been regarded as a primary source of GABAergic cortical interneurons; it is thought to be the site of origin of approximately~ 50-60% of the cortical interneuron population in mice [63, 79, 80].

Which is the second largest interneuron group in the neocortex?

The SST-expressing interneuron group is the second-largest interneuron group in the mouse neocortex, representing roughly 30% of the total cortical interneuron population [ 8 ]. SST-positive interneurons are known as Martinotti cells]

Where are interneurons generated during embryonic development?

Throughout embryogenesis, interneurons are primarily generated in a structure broadly termed the ganglionic eminence (GE) (Figure 1) [70]. The GE is a transitory brain structure located in the ventral area of the telencephalon, and is anatomically present during embryonic development.

How is an interneuron different from a projection neuron?

Generally speaking, an interneuron is a specialized type of neuron whose primary role is to form a connection between other types of neurons. They are neither motor neurons nor sensory neurons, and also differ from projection neurons in that projection neurons send their signals to more distant locations such as the brain or the spinal cord.