Diagonal band of Broca

Structure

It consists of fibers that are said to arise in the parolfactory area, the gyrus subcallosus and the anterior perforated substance, and course backward in the longitudinal striae to the dentate gyrus and the hippocampal region.

This is a cholinergic bundle of nerve fibers posterior to the anterior perforated substance. It interconnects the subcallosal gyrus in the septal area with the hippocampus 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 through the fornix and it is the second largest assembly of cholinergic neurons in the basal forebrain whereas nhlDBB projects to the olfactory bulb and it does not have a significant population of cholinergic neurons.

Development

It is one of the basal forebrain structures that are derived from the ventral telencephalon during development.

Function

Along with the septum pellucidum and medial septal nucleus, the diagonal band of Broca is believed to be involved in the generation of theta waves in the hippocampus. It also inhibits magnocellular neurosecretory cells via GABA interneurons.

Its behavior can be altered by nerve growth factor.

Pathology

A significant nvlDBB neuronal loss is seen in Lewy body dementia.

References

References

1. (2015). "High-Yield Neuroanatomy". Wolters Kluwer.
2. Fix, James D.. (2002). "Neuroanatomy". Lippincott Williams & Wilkins.
3. (December 2018). "Review: Revisiting the human cholinergic nucleus of the diagonal band of Broca". Neuropathology and Applied Neurobiology.
4. O'Keefe, John. (2007). "The hippocampus book". Oxford University Press.
5. (2016). "Magnocellular Neurons and Posterior Pituitary Function". American Cancer Society.
6. (February 2008). "Chronic exposure to nerve growth factor increases acetylcholine and glutamate release from cholinergic neurons of the rat medial septum and diagonal band of Broca via mechanisms mediated by p75NTR". J. Neurosci..