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The Frontal Lobe

The frontal lobe is located at the front of the brain and extends back to the central sulcus, which separates it from the parietal lobe. It is also limited below by part of the lateral fissure and, on the inner surface, by the cingulate sulcus. 

The surface of the frontal lobe is divided by several grooves, called sulci, into four main ridges, called gyri. These include the precentral gyrus and the superior, middle, and inferior frontal gyri. 

The anterior central gyrus lies just in front of the central sulcus and plays an important role in controlling voluntary movements. The superior, middle, and inferior frontal gyri run forward and are involved in more complex brain functions. The inferior frontal gyrus is further divided into parts, one of which (especially on the left side) is known as Broca’s area, which is important for speech production. 

On the lower surface, the frontal lobe rests above the eye sockets and contains the orbital gyri, which are separated by an H-shaped groove. There is also a groove for the olfactory tract, related to the sense of smell. 

On the inner surface, part of the frontal lobe forms the paracentral lobule, which connects with nearby motor and sensory areas. 

Overall, the frontal lobe is mainly responsible for motor control, planning movements, eye movement control, speech production, and higher cognitive functions such as personality, decision-making, and short-term memory.

The Parietal Lobe

The parietal lobe lies behind the frontal lobe and is separated from it by the central sulcus, although its boundaries with other lobes are less clearly defined. 

It extends back toward the parieto-occipital fissure and is separated from the temporal lobe below by part of the lateral fissure. 

Its surface is divided by the intraparietal sulcus into two main regions: the superior and inferior parietal lobules. 

In front of this area is the postcentral gyrus, which lies just behind the central sulcus and is closely connected to the precentral gyrus. 

The superior parietal lobule is located above the intraparietal sulcus and connects with the occipital lobe at the back. The inferior parietal lobule lies below and is divided into two parts: the supramarginal gyrus, which curves over the end of the lateral fissure, and the angular gyrus, which curves over the end of another groove and connects with the temporal lobe. 

On the inner surface, the parietal lobe includes a small region called the precuneus. 

Functionally, the parietal lobe is responsible for processing somatosensory information, including touch, pressure, pain, temperature, and awareness of body position and movement.

The Occipital Lobe

The occipital lobe is located at the back of the brain and is relatively small and pyramid-shaped. It has three surfaces: lateral, medial, and inferior (tentorial). 

The lateral surface is divided by grooves into upper and lower regions and connects with both the parietal and temporal lobes. 

The medial surface is especially important, as it contains the calcarine fissure, which divides the area into the cuneus above and the lingual gyrus below. 

The cuneus is a wedge-shaped region, while the lingual gyrus extends toward the front and connects with structures in the temporal lobe. 

The Temporal Lobe

The temporal lobe is located on the side of the brain, below the frontal and parietal lobes. It has superior, lateral, and inferior surfaces.

The superior surface forms part of the lateral fissure and contains the transverse temporal gyri, which are involved in processing sound.

The lateral surface is divided into three main gyri (superior, middle, and inferior temporal gyri) by two grooves called the superior and middle temporal sulci.

The superior temporal gyrus lies just below the lateral fissure and connects with parts of the parietal lobe. The middle temporal gyrus lies below it, and the inferior temporal gyrus extends further down and continues onto the lower surface of the lobe.