University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

169

Pages:

2
Author:

Mariam A.

Language areas of the Brain          Broca: o Examined patients who had difficulty with functional speech. o Post-mortem examination revealed lesion on the surface of the left temporal lobe. o Important relationship between speech and the inferior frontal gyrus (pars opercularis and pars triangularis) of the left hemisphere. Wernicke: o Reported a post-moterm study of a patient who had impaired speech comprehension. o Important relationship between auditory comprehension of speech and the posterior superior temporal cortex. Anterior perisylvian area (Broca’s area) is for the production of speech sounds (or phonemes). Posterior portion of superior temporal lobe (Wernicke’s areas) is for memories of how words sound (“the area of word images”). Arcuate (superior) longitudinal fasciculus connects Wernicke (posterior) to Broca (anterior) language areas and include fibres of the arcuate fasciculus. o Wernicke suggested that a disconnection from the anterior regions important for motor programming of sounds would produce a fluent speech disorder: good comprehension, yet with impaired spontaneous speech, naming and repetition. o There is failure to carry information from Wernicke’s to Broca’s, leading to Leitungsaphasia (or conduction aphasia). Broca’s area is part of a larger region that plays an important role in processing meaning, sounds and syntax, as well as many nonlinguistic functions. There is rostro-caudal division of Broca’s area for semantic and phonological processing. o Rostral Broca’s area is necessary for semantic processing. o Caudal Broca’s area is necessary for phonological processing. Left posterior fusiform gyrus is important for visual comprehension. o Acts as an interface between visual form information and higher-order stimulus properties such as its associated sound and meaning. o Not specific to reading, but also processing meaningful visual stimulus. Sylvian fissure, superior temporal gyrus and sulcus and transverse temporal gyrus (Heschl’s gyrus) is important for auditory comprehension. o Primary auditory cortical regions are located within the Heschl’s gyrus. o Secondary auditory cortical regions are located within the belt and parabelt regions, along the superior temporal gyrus.  Perisylvian language areas:  o Frontal operculum contains Broca’s area. o Inferior parietal lobule contains Wernicke’s area. o Superior temporal gyrus and sulcus, and middle temporal gyrus, contains the secondary auditory association cortex. Cortical lateralisation is plastic, increasing with training. o In musicians: passive perception is associated with a predominantly left-sided activation (because everything is on the left!), especially within the perisylvian language cortices. o In non-musicians: conversely, activation is relatively greater on the right.