Anatomical components of the<unk>  The<unk>  was originally defined by Paul D. MacLean as a series of cortical structures surrounding the boundary between the cerebral hemispheres and the brainstem. The name<unk> " comes from the Latin word for the border, limbus, and these structures were known together as the<unk>  lobe. Further studies began to associate these areas with emotional and motivational processes and linked them to subcortical components that were then grouped into the<unk> . Currently, it is not considered an isolated entity responsible for the neurological regulation of emotion, but rather one of the many parts of the brain that regulate visceral autonomic processes. Therefore, the set of anatomical structures considered part of the<unk>  is controversial. The following structures are, or have been considered, part of the<unk> : *Cortical areas:<unk>  lobe *Orbitofrontal cortex: a region in the frontal lobe involved in the process of decision-making *Piriform cortex: part of the olfactory system *Entorhinal cortex: related to memory and associative components *Fornix: a white matter structure connecting the hippocampus with other brain structures, particularly the mammillary bodies and septal nuclei *Subcortical areas: *Septal nuclei: a set of structures that lie in front of the lamina terminalis, considered a pleasure zone *Hippocampus and associated structures: play a central role in the consolidation of new memories *Amygdala: located deep within the temporal lobes and related with a number of emotional processes *Nucleus accumbens: involved in reward, pleasure, and addiction *Diencephalic structures: *Hypothalamus: a center for the<unk> , connected with the frontal lobes, septal nuclei, and the brain stem reticular formation via the medial forebrain bundle, with the hippocampus via the fornix, and with the thalamus via the mammillothalamic fasciculus; regulates many autonomic processes *Mammillary bodies: part of the hypothalamus that receives signals from the hippocampus via the fornix and projects them to the thalamus *Anterior nuclei of thalamus: receive input from the mammillary bodies and involved in memory processing
Limbic system
Extrapyramidal system
Sensory cortex
Somatosensory system
Ciliospinal center
Motor system
Primary sensory areas
Mesolimbic pathway