What is 'opercularization' during embryonic development of brain?

An operculum, which means "little lid" in Latin (plural opercula), can refer to either the occipital operculum, which is a part of the occipital lobe, or the frontal, temporal, or parietal operculum, which collectively cover the insula as the opercula of insula[1].

The insular opercula covers and obscures the insular lobe, which is a portion of the cerebral cortex that has invaginated to lie deep within the lateral sulcus. The insular lobe sits like an island, almost completely encircled by the circular sulcus groove.

The frontoparietal operculum, a portion of the parietal lobe, extends from the front to the rear of the insular lobe. [2] The opercula are located on the precentral and postcentral gyri, which are on either side of the central sulcus.

The secondary somatosensory cortex is located in the region of the parietal operculum that forms the ceiling of the lateral sulcus.

The insular opercula typically start to form between weeks 20 and 22 of pregnancy. During weeks 14 and 16 of fetal development, the insula starts to invade the surface of the developing brain's cerebrum, and by the time the fetus reaches full term, the opercula has fully covered the insula. This process is known as opercularization.

The process by which the opercula, the bony plates covering fish embryos' gills, become modified and integrated into the developing brain's structures—most notably in the telencephalon region—during embryonic brain development is known as opercularization. This process is important for the evolution of vertebrate brains because it helps form specific brain regions involved in sensory processing and motor control.