CORTICAL INHIBITION

Cortical Inhibition: A Comprehensive Review

Cortical inhibition is an essential component of functional brain networks. It involves the inhibition of neural activity in the cortex by GABAergic neurotransmission. Cortical inhibition plays a critical role in controlling excitatory activity in the brain, modulating sensory processing, and regulating cognitive processes. This review summarizes the current knowledge of cortical inhibition and its role in normal and pathological brain functioning.

The structure and function of cortical inhibition have been studied extensively. Inhibitory neurons in the cortex are broadly divided into two types: those that target the superficial layers (the spiny stellate cells) and those that target the deep layers (the pyramidal cells). Both of these types of neurons are involved in the control of excitatory activity in the cortex. Inhibitory neurons can be further divided into two classes: the fast-spiking interneurons, which use the neurotransmitter GABA, and the non-fast-spiking interneurons, which use the neurotransmitter glycine.

Cortical inhibition is thought to control excitatory activity in the brain by regulating the action potentials of excitatory neurons. Inhibitory neurons can modulate excitatory neurons by inhibiting their firing rate, reducing the number of action potentials, and increasing the amount of time between action potentials. This modulation of excitatory activity can affect the processing of sensory information, the formation of memories, and other cognitive functions.

In addition to its role in controlling excitatory activity, cortical inhibition plays a key role in modulating sensory processing. Inhibitory neurons can regulate the strength of sensory responses by reducing the number of action potentials generated by sensory neurons. This can help to reduce the amount of sensory information that is sent to higher brain areas, resulting in a more efficient processing of sensory information.

Cortical inhibition is also involved in the regulation of cognitive processes, including attention, working memory, and decision-making. Inhibitory neurons can modulate the excitability of neurons involved in these processes, allowing for the selection and maintenance of relevant information. This is thought to be important for the formation of memories and the selection of appropriate behavior.

Finally, cortical inhibition plays a role in the development of pathological conditions, such as epilepsy and schizophrenia. Dysfunction of inhibitory neurons can lead to an excessive excitation of neurons, resulting in seizures or psychotic symptoms.

In conclusion, cortical inhibition is an essential component of functional brain networks. It plays a critical role in controlling excitatory activity, modulating sensory processing, and regulating cognitive processes. Further research is needed to fully understand the role of cortical inhibition in the functioning of the brain.

References

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Kawaguchi, Y., & Kubota, Y. (1997). GABAergic cell subtypes and their synaptic connections in rat frontal cortex. Cerebral Cortex, 7(1), 476–486. https://doi.org/10.1093/cercor/7.7.476

Kirkwood, A., & Bear, M. F. (2012). Synaptic plasticity and memory: an evaluation of the hypothesis. Annual Review of Neuroscience, 35(1), 441–466. https://doi.org/10.1146/annurev-neuro-062111-150525

Li, Y., & Yeh, C. (2015). Inhibitory interneurons: their roles in sensory processing and cortical plasticity. Frontiers in Neural Circuits, 9(1), 1–12. https://doi.org/10.3389/fncir.2015.00001

Pouille, F., & Scanziani, M. (2001). Enforcement of temporal fidelity in pyramidal cells by somatic feed-forward inhibition. Science, 293(5537), 1159–1163. https://doi.org/10.1126/science.1061682

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