 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Lobes of the brain" – news ·newspapers ·books ·scholar ·JSTOR(February 2013) (Learn how and when to remove this message) |
| Lobes of the cerebral cortex (right hemisphere view) | |
|---|---|
 Lateral surface. Four lobes visible. | |
 Medial surface. Five lobes visible. | |
| Identifiers | |
| NeuroNames | 1210 |
| NeuroLex ID | birnlex_922 |
| TA98 | A14.1.09.005 |
| TA2 | 5431 |
| FMA | 77800 |
| Anatomical terms of neuroanatomy | |
Thelobes of the brain are the four major identifiable regions of the humancerebral cortex, and they comprise the surface of eachhemisphere of thecerebrum.[1] The two hemispheres are roughly symmetrical in structure, and are connected by thecorpus callosum. Some sources include theinsula andlimbic lobe but the limbic lobe incorporates parts of the other lobes. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct. Each lobe of the brain has numerous ridges, orgyri, and furrows,sulci that constitute further subzones of the cortex.[2] The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of thecerebellum.
The frontal lobe is located at the front of eachcerebral hemisphere and positioned in front of theparietal lobe and above and in front of thetemporal lobe. It is separated from the parietal lobe by a space between tissues called thecentral sulcus, and from the temporal lobe by a deep fold called thelateral sulcus, also called the Sylvian fissure. Theprecentral gyrus, which forms the posterior border of the frontal lobe, contains theprimary motor cortex (area 4 under theBrodmann area architecture) which controls voluntary movements of specific body parts. The precentral region also contains thepremotor cortex (Brodmann area 6).
The frontal lobe contains most of thedopamine-delicateneurons in thecerebral cortex. The dopamine system is associated withreward,attention,short-term memory tasks,planning, andmotivation. Dopamine tends to limit and selectsensory information arriving from thethalamus to theforebrain.[citation needed] A report from theNational Institute of Mental Health says agene variant that reduces dopamine activity in theprefrontal cortex is related to poorer performance and inefficient functioning of that brain region during working memory tasks, and to a slightly increased risk forschizophrenia.[3]
The frontal lobe consists of theprefrontal cortex which is located in the most anterior (farthest away) section of the frontal lobe. It is critical for one's working memory and executive control which helps keep goals and complex tasks organized.
The divisions of the prefrontal cortex includeorbital, medial, andlateral prefrontal cortex. Within the lateral prefrontal cortex there are two different divisions: thedorsolateral andventrolateral prefrontal cortex. The dorsolateral prefrontal cortex is located on top of the ventrolateral prefrontal cortex and is mainly responsible for the executive control and manipulation of memories that are retrieved through episodic memory. The ventrolateral prefrontal cortex is important for the regulation of meaningful stimuli that a person experiences throughout their lifetime, such as images, letters, and names.
Damage to the prefrontal cortex can result in issues with one's long term and short-term memories, as well as create changes in people's behaviors and their abilities to plan and organize.[4]
Damage can result from lesions or tumors that have been surgically removed, andtraumatic brain injuries(TBI) experienced from a severe hit to the head causing damage to the brain from swelling. Most often a TBI is experienced within a person's childhood from playing competitive sports or an accident from normal play. Having a traumatic brain injury can increase your chances of developing neurological psychiatric problems and abusing substances, such as cannabis, is known to be a risk factor in developing symptoms associated with schizophrenia. A study found that schizophrenia symptoms (hearing voices, talking to people who were not there, etc.) worsened after the usage of cannabis, suggesting that a TBI from childhood can enhance a development of psychosis due to the changes seen in the white matter within the frontal-temporal areas.[5]
The parietal lobe is positioned above theoccipital lobe and behind thefrontal lobe andcentral sulcus.
The parietal lobe integratessensory information among variousmodalities, including spatial sense and navigation (proprioception), the main sensory receptive area for the sense of touch (mechanoreception) in thesomatosensory cortex which is just posterior to the central sulcus in thepostcentral gyrus,[6] and thedorsal stream of thevisual system. The major sensory inputs from theskin (touch,temperature, andpain receptors), relay through thethalamus to the parietal lobe.
Several areas of the parietal lobe are important inlanguage processing. The somatosensory cortex can be illustrated as a distorted figure — thehomunculus (Latin: "little man"), in which the body parts are rendered according to how much of the somatosensory cortex is devoted to them.[7] Thesuperior parietal lobule andinferior parietal lobule are the primary areas of body or spatial awareness. A lesion commonly in the right superior or inferior parietal lobule leads tohemineglect.
The occipital lobe is thevisual processing center of themammalianbrain containing most of the anatomical region of thevisual cortex.[8] Theprimary visual cortex isBrodmann area 17, commonly called V1 (visual one). Human V1 is located on themedial side of the occipital lobe within thecalcarine sulcus; the full extent of V1 often continues onto theposterior pole of the occipital lobe. V1 is often also called striate cortex because it can be identified by a large stripe of myelin, theStria of Gennari. Visually driven regions outside V1 are calledextrastriate cortex. There are many extrastriate regions, and these are specialized for different visual tasks, such as visuospatial processing, color differentiation, and motion perception.
The temporal lobe is located beneath thelateral fissure on bothcerebral hemispheres of the mammalianbrain.[9]
The temporal lobe is involved in processing sensory input into derived meanings for the appropriate retention ofvisual memories,language comprehension, and emotion association.[10]: 21
Within the temporal lobe is an area of the brain called thehippocampus which is associated with forming new memories and learning new things. The hippocampus has been studied many times in the past for its correlation with epilepsy showing there to be damage of this area. Although it has been difficult to determine the exact link between the temporal lobe and epilepsy, Chauvière (2020) suggests that there is a positive connection between the circuitry reorganization within the neurons and temporal lobe structure impacting rhythmic activities that are important for cognition.
The limbic lobe is an arc-shaped region ofcortex on the medial surface of eachcerebral hemisphere of the mammalian brain, consisting of parts of the frontal, parietal and temporal lobes. The term is ambiguous, with some authors[who?] including theparaterminal gyrus, thesubcallosal area, thecingulate gyrus, theparahippocampal gyrus, thedentate gyrus, thehippocampus and thesubiculum;[11] while theTerminologia Anatomica includes thecingulate sulcus, the cingulate gyrus, theisthmus of cingulate gyrus, thefasciolar gyrus, the parahippocampal gyrus, the parahippocampal sulcus, thedentate gyrus, the fimbrodentate sulcus, thefimbria of hippocampus, thecollateral sulcus, and therhinal sulcus, and omits the hippocampus.
The insular cortex is a portion of thecerebral cortex folded deep within thelateral sulcus (the fissure separating thetemporal lobe from theparietal andfrontal lobes). The insular cortex has an important function for sending axons to the amygdala and responding to tones and somatosensory stimulation.[12]
Berret, et al. (2019) used mice to study the fear response that is associated with perceived threats from their memory of previously being shocked on their foot, finding adverse reflex responses in shocking stimulation whenever the insular cortex was silenced. This finding supports that the insular cortex takes information to specificamygdala subdivisions creating different components for fear behaviors.[13]
The insulae are believed to be involved inconsciousness and play a role in diverse functions usually linked toemotion or the regulation of the body'shomeostasis. These functions includeperception,motor control,self-awareness,cognitive functioning, andinterpersonal experience. In relation to these, it is involved inpsychopathology.
The insular cortex is divided into two parts: the larger anterior insula and the smaller posterior insula in which more than a dozen field areas have been identified. The cortical area overlying the insula toward the lateral surface of the brain is theoperculum (meaninglid). The opercula are formed from parts of the enclosing frontal, temporal, and parietal lobes.
