Brodmann area 25 (BA25) is the subgenual area, area subgenualis or subgenual cingulatea area in the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

of the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

and delineated based on its cytoarchitectonic characteristics. It is the 25th "

Brodmann area A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells. History Brodmann areas were originally defined and numbered by th ...

" defined by

Korbinian Brodmann Korbinian Brodmann (17 November 1868 – 22 August 1918) was a German neurologist who became famous for mapping the cerebral cortex and defining 52 distinct regions, known as Brodmann areas, based on their cytoarchitectonic (histological) char ...

(thus its name). BA25 is located in the cingulate region as a narrow band in the caudal portion of the subcallosal area adjacent to the paraterminal gyrus. The posterior parolfactory sulcus separates the paraterminal gyrus from BA25. Rostrally it is bound by the prefrontal area 11 of Brodmann.

History

Brodmann described this area as it is labeled now in 1909. Originally in 1905, Brodmann labeled the area as part of area 24. In 1909, he divided the area into area 24 and 25.

Function

This region is extremely rich in

serotonin transporter The serotonin transporter (SERT or 5-HTT) also known as the sodium-dependent serotonin transporter and solute carrier family 6 member 4 is a protein that in humans is encoded by the SLC6A4 gene. SERT is a type of monoamine transporter protein tha ...

s and is considered as a governor for a vast network involving areas like

hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...

and

brain stem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is co ...

, which influences changes in appetite and sleep; the

amygdala The amygdala (; plural: amygdalae or amygdalas; also '; Latin from Greek, , ', 'almond', 'tonsil') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain's cerebrum in complex verte ...

and insula, which affect the mood and anxiety; the

hippocampus The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, a ...

, which plays an important role in memory formation; and some parts of the frontal cortex responsible for self-esteem.Faulty Circuits
, ''Scientific American'', April 2010 This region is particularly implicated in the normal processing of sadness.

Involvement in depression

The subcallosal cingulate gyrus CG25 which consists of BA25 as well as parts of BA24 and BA32 has been implicated as playing an important role in

major depression Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...

and has been the target of

deep brain stimulation Deep brain stimulation (DBS) is a neurosurgical procedure involving the placement of a medical device called a neurostimulator, which sends electrical impulses, through implanted electrodes, to specific targets in the brain (the brain nucleus ...

to treat the disorder. One study found that BA25 is metabolically overactive in

treatment-resistant depression Treatment-resistant depression is a term used in psychiatry to describe people with major depressive disorder (MDD) who do not respond adequately to a course of appropriate antidepressant medication within a certain time. Definitions of treatment- ...

. A different study found that metabolic hyperactivity in this area is associated with poor therapeutic response of persons with

major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...

cognitive-behavioral therapy Cognitive behavioral therapy (CBT) is a psycho-social intervention that aims to reduce symptoms of various mental health conditions, primarily depression and anxiety disorders. CBT focuses on challenging and changing cognitive distortions (suc ...

and

venlafaxine Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin-norepinephrine reuptake inhibitor (SNRI) class. It is used to treat major depressive disorder, generalized anxiety disorder, panic ...

. In 2005 Helen S. Mayberg and collaborators described how they successfully treated a number of depressed people—individuals virtually catatonic with depression despite years of talk therapy, drugs, and electroconvulsive therapy—with pacemaker-like electrodes (

) in area 25. In 2013, Walker and Lawson conducted neurofeedback research with 183 subjects experiencing drug resistant depression. The neurofeedback specifically targeted Brodmann area 25. The treatment consisted of 6 neurofeedback sessions that were 20min long each over the course of 3 weeks. 1 year after the treatment 84% of subjects experienced over a 50% reduction in depression symptoms. 9% reported a 20-50% reduction in depression symptoms. 7% reported a 0-20% improvement. 1% initially reported positive effects, but had a depression relapse before the year follow up completed. There were no side effects or complications reported from the treatment. A recent study found that

transcranial magnetic stimulation Transcranial magnetic stimulation (TMS) is a noninvasive form of brain stimulation in which a changing magnetic field is used to induce an electric current at a specific area of the brain through electromagnetic induction. An electric pulse gener ...

is more clinically effective treating depression when targeted specifically to

Brodmann area 46 Brodmann area 46, or BA46, is part of the frontal cortex in the human brain. It is between BA10 and BA45. BA46 is known as middle frontal area 46. In the human brain it occupies approximately the middle third of the middle frontal gyrus and the ...

, because this area has intrinsic functional connectivity (negative correlation) with area 25. Another recent study has found that the responses of area 25 to viewing sad stimuli are affected by cortisol. This suggests that depression related changes in the activity in area 25 could be due to

hypothalamic–pituitary–adrenal axis The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a ...

dysregulation.

Image

File:Brodmann area 25 animation small.gif, Animation. File:Brodmann area 25 medial.jpg, Medial view.

Notes and references

{{DEFAULTSORT:Brodmann Area 25 25 Serotonin Neuroscience of depression Medial surface of cerebral hemisphere

History

Function

Involvement in depression

Image

See also

Notes and references