Smell bark

At the base of the frontal lobe there are also phylogenetic components (olfactory cortex, paleocortex and archicortex), which are dedicated to the sense of smell (olfactory sense). Presumably, the olfactory sensations come into consciousness in the so-called “primary olfactory cortex” (prepiriform cortex, which is also located to a lesser extent in the temporal lobe next to the frontal lobe), the further classifications, a comparison with known sensations, etc. are made in the adjacent “secondary olfactory cortex”. Secondary olfactory cortex areas overlap at the orbital prefrontal cortex with the secondary centers of the sense of taste (see island cortex below). In general, these two senses are close to each other (“lower senses”) and are charged with emotions and great willingness to act by the limbic system (see below) and the motivational circuit.

Basal forebrain structures

Also at the base of the frontal lobe, but in the form of core areas and not in the cortex, are the basal forebrain structures. One of them, the nucleus basalis (Nucleus Meynert), is to be understood as the link of the limbic system (see below) with several parts of the cerebral cortex. In this way, complex behaviors are influenced, and it is also said to be important for learning (see below Alzheimer’s disease).

In addition, the gyrus precentralis (motocortex, primary somatomotor cortex) is particularly important at the frontal lobe, because it serves as the uppermost center of any consciously planned movement (voluntary motor activity).The forehead is surrounded by “premotor” and “supplementary motor” cortical fields, which have a regulatory function in interaction with pons (brain bridge) and cerebellum and prepare movements in an organizing way. Back to the forehead, the frontal eye field (frontal visual center) follows. Here, randomly targeted eye movements (saccades) are generated.

The precentral gyrus is separated from the postcentral gyrus (primary somatosensory cortex) by the prominent central sulcus. The latter is the important temporary terminus of most sensitive human sensations such as pain (protopathic sensitivity), tactile sensation (exteroception), positional sensation of the locomotor system (proprioception) and some others. Only at this point do the above-mentioned sensory qualities enter our consciousness, albeit initially without interpretation.

By the way, the transverse sulcus centralis separates the motocortex from the primary somatosensory cortex, also separating the frontal lobe from the parietal lobe! Another prominent furrow, the lateral sulcus, separates the lower parts of the frontal and parietal lobes from the temporal lobe. If a finger were to be advanced into the temporal sulcus, the lower surface of the finger (palmar surface) would rub over certain turns that belong to the temporal lobe. They are in different spatial orientation to the other turns of the temporal lobe and were therefore called “Gyri temporales transversi” (Heschl transverse turns). Red = Gyrus precentralis, center for motor function (movement) Blue = Gyrus postcentralis, center for sensory function (feeling-sense perception) Green = Wernicke – language center, center for speech understanding Yellow = Broca – language center, center for speech articulation