Gyrus in the context of "Gyrification"

Broca's area, or the Broca area (/ˈbroʊkə/, also UK: /ˈbrɒkə/, US: /ˈbroʊkɑː/), is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production.

Language processing has been linked to Broca's area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal gyrus (pars triangularis) (BA45) of the brain. Since then, the approximate region he identified has become known as Broca's area, and the deficit in language production as Broca's aphasia, also called expressive aphasia. Broca's area is now typically defined in terms of the pars opercularis and pars triangularis of the inferior frontal gyrus, represented in Brodmann's cytoarchitectonic map as Brodmann area 44 and Brodmann area 45 of the dominant hemisphere.

In neuroanatomy, a sulcus (Latin: "furrow"; pl.: sulci) is a shallow depression or groove in the cerebral cortex. One or more sulci surround a gyrus (pl. gyri), a ridge on the surface of the cortex, creating the characteristic folded appearance of the brain in humans and most other mammals. The larger sulci are also called fissures. The cortex develops in the fetal stage of corticogenesis, preceding the cortical folding stage known as gyrification. The large fissures and main sulci are the first to develop.

Mammals that have a folded cortex are known as gyrencephalic, and the small-brained mammals that have a smooth cortex, such as rats and mice are termed lissencephalic.

In neuroanatomy, the postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the sensory homunculus.

The primary somatosensory cortex was initially defined from surface stimulation studies of Wilder Penfield, and parallel surface potential studies of Bard, Woolsey, and Marshall. Although initially defined to be roughly the same as Brodmann areas 3, 1, and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it receives the bulk of the thalamocortical projections from the sensory input fields.

Electroencephalography (EEG)is a method to record an electrogram of the spontaneous electrical activity of the brain. The bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the International 10–20 system, or variations of it. Electrocorticography, involving surgical placement of electrodes, is sometimes called "intracranial EEG". Clinical interpretation of EEG recordings is most often performed by visual inspection of the tracing or quantitative EEG analysis.

Voltage fluctuations measured by the EEG bio amplifier and electrodes allow the evaluation of normal brain activity. As the electrical activity monitored by EEG originates in neurons in the underlying brain tissue, the recordings made by the electrodes on the surface of the scalp vary in accordance with their orientation and distance to the source of the activity. Furthermore, the value recorded is distorted by intermediary tissues and bones, which act in a manner akin to resistors and capacitors in an electrical circuit. This means that not all neurons will contribute equally to an EEG signal, with an EEG predominately reflecting the activity of cortical neurons near the electrodes on the scalp. Deep structures within the brain further away from the electrodes will not contribute directly to an EEG; these include the base of the cortical gyrus, medial walls of the major lobes, hippocampus, thalamus, and brain stem.

The inferior frontal gyrus (IFG; also gyrus frontalis inferior) is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex.

Its superior border is the inferior frontal sulcus (which divides it from the middle frontal gyrus), its inferior border is the lateral sulcus (which divides it from the superior temporal gyrus) and its posterior border is the inferior precentral sulcus. Above it is the middle frontal gyrus, behind it is the precentral gyrus.

The superior temporal gyrus (STG) is one of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear.