The diagonal band of Broca is one of the

basal forebrain Part of the human brain, the basal forebrain structures are located in the forebrain to the front of and below the striatum. They include the ventral basal ganglia (including nucleus accumbens and ventral pallidum), nucleus basalis, diagonal b ...

structures that are derived from the ventral

telencephalon The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In ...

during development. This structure forms the medial margin of the anterior perforated substance. This brain region was described by the French neuroanatomist

Paul Broca Pierre Paul Broca (, also , , ; 28 June 1824 – 9 July 1880) was a French physician, anatomist and anthropologist. He is best known for his research on Broca's area, a region of the frontal lobe that is named after him. Broca's area is involve ...

Structure

It consists of fibers that are said to arise in the

parolfactory area The subcallosal area (parolfactory area of Broca) is a small triangular field on the medial surface of the hemisphere in front of the subcallosal gyrus, from which it is separated by the posterior parolfactory sulcus; it is continuous below with t ...

, the gyrus subcallosus and the anterior perforated substance, and course backward in the longitudinal striae to the

dentate gyrus The dentate gyrus (DG) is part of the hippocampal formation in the temporal lobe of the brain, which also includes the hippocampus and the subiculum. The dentate gyrus is part of the hippocampal trisynaptic circuit and is thought to contribute t ...

and the hippocampal region. This is a

cholinergic Cholinergic agents are compounds which mimic the action of acetylcholine and/or butyrylcholine. In general, the word " choline" describes the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cati ...

bundle of nerve fibers posterior to the anterior perforated substance. It interconnects the

subcallosal gyrus The subcallosal gyrus (paraterminal gyrus, peduncle of the corpus callosum) is a narrow lamina on the medial surface of the hemisphere in front of the lamina terminalis, behind the parolfactory area, and below the rostrum of the corpus callosum. I ...

in the

septal area The septal area (medial olfactory area), consisting of the lateral septum and medial septum, is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum. The septal nuclei are loca ...

with 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, ...

and lateral olfactory area.

Nuclei

Two structures are often described in this brain regions, namely the nuclei of the vertical and horizontal limbs of the diagonal band of Broca (nvlDBB and nhlDBB, respectively). nvlDBB projects to the

hippocampal formation The hippocampal formation is a compound structure in the medial temporal lobe of the brain. It forms a c-shaped bulge on the floor of the temporal horn of the lateral ventricle. There is no consensus concerning which brain regions are encompassed ...

through the fornix and it is the second largest assembly of cholinergic neurons in the basal forebrain whereas nhlDBB projects to the

olfactory bulb The olfactory bulb (Latin: ''bulbus olfactorius'') is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex ( ...

and it does not have a significant population of cholinergic neurons.

Function

Along with the

septum pellucidum The septum pellucidum (Latin for "translucent wall") is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the f ...

and medial septal nucleus, the diagonal band of Broca is believed to be involved in the generation of

theta wave Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals. It can be recorded using various electrophysi ...

s in the

. It also inhibits

magnocellular neurosecretory cell Magnocellular neurosecretory cells are large neuroendocrine cells within the supraoptic nucleus and paraventricular nucleus of the hypothalamus. They are also found in smaller numbers in accessory cell groups between these two nuclei, the larges ...

s via GABA interneurons. Its behavior can be altered by nerve growth factor.

Pathology

A significant nvlDBB neuronal loss is seen in

Lewy body dementia Lewy body dementias are two similar and common subtypes of dementia—dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Both are characterized by changes in thinking, movement, behavior, and mood. The two conditions have si ...

References

{{Authority control Rostral basal ganglia and associated structures