Brodmann area 45
Overview
Brodmann area 45 (BA45), also known as the pars triangularis, is a region of the brain located in the frontal lobe. It is part of the Brodmann area classification system, which divides the cerebral cortex into 52 distinct regions based on cytoarchitectural characteristics. BA45 is one of the key areas involved in language production and comprehension, and is particularly associated with semantic processing and working memory.
Anatomy
BA45 is located in the inferior frontal gyrus, which is part of the prefrontal cortex. It is bordered by Brodmann area 44 anteriorly, Brodmann area 46 dorsally, and Brodmann area 47 ventrally. The area is named after its discoverer, Korbinian Brodmann, who first described it in 1909. The region is larger in the left hemisphere in most right-handed individuals and in about 70% of left-handed individuals, a phenomenon known as asymmetry.
Function
The primary function of BA45 is related to language comprehension and production. It is a part of the Broca's area, which is traditionally associated with speech production. However, more recent research has shown that BA45 is also involved in semantic processing, working memory, and decision making. It plays a critical role in the selection of appropriate words during speech and comprehension of complex sentences.
Clinical Significance
Damage to BA45 can result in various language disorders, most notably Broca's aphasia, which is characterized by difficulty with speech production but relatively preserved comprehension. Other potential effects of damage to this area include deficits in semantic processing and working memory. BA45 is also a region of interest in the study of neurodevelopmental disorders such as autism and dyslexia.
Research
Research into BA45 has been extensive, with many studies focusing on its role in language and cognition. Functional imaging studies have shown that BA45 is activated during tasks that require semantic processing, such as word generation or sentence comprehension. Other research has explored the role of BA45 in working memory and decision making, suggesting a broader role for this area beyond language.