The Development of Language: A Critical Period in Humans
A critical period for learning language is shown by the decline in language ability (fluency) of non-native speakers of English as a function of their age upon arrival in the United States
Brain as hollow organ : Nemesius (circa 320), Nature of Man
The cerebral ventricles were supposed to be responsible for mental operations
Language was not represented
Language area in Phrenology 19th century, Franz Joseph Gall and J. G. Spurzheim The Anatomy and Physiology of the Nervous System in General, and of the Brain in Particular
Aggregate field view of the brain (Flourens 1820) Experimental psychologist ‘ a large section of the cerebral lobes can be removed without loss of function. As more is removed, all functions weaken and gradually disappear. Thus the cerebral lobes operate in unison for the full exercise of their functions ... The cerebral cortex functioned as an indivisible whole ... [housing] an ‘‘essentially single faculty’’ of perception, judgement and will ... the last refuge of the soul’ (Flourens, cited by Changeux, p. 17,  ).
Cortical mapping of the language areas in the left cerebral cortex during neurosurgery (A) Location of the classical language areas. (B) Evidence for the variability of language representation among individuals. This diagram summarizes data from 117 patients whose language areas were electrically mapped at the time of surgery. The number in each circle indicates the percentage of the patients who showed interference with language in response to stimulation at that site. Note also that many of the sites that elicited interference fall outside the classic language areas. (B after Ojemann et al., 1989.)
Area 44 (the posterior part of the inferior frontal gyrus) : phonological processing and in language production as such; this role would be facilitated by its position close to the motor centres for the mouth and the tongue.
Area 45 (the anterior part of the inferior frontal gyrus) seems more involved in the semantic aspects of language. Though not directly involved in accessing meaning, Broca’s area therefore plays a role in verbal memory (selecting and manipulating semantic elements).
WA lies superior temporal gyrus, in the superior portion of Brodmann area 22 has 3 subdivision
The first responds to spoken words (including the individual’s own) and other sounds.
The second responds only to words spoken by someone else but is also activated when the individual recalls a list of words.
The third sub-area seems more closely associated with producing speech than with perceiving it
Language-related areas in the human brain: Damasio
The implementation system is made up of several regions located around the left sylvian fissure. It includes the classical language areas (B = Broca's area; W = Wernicke's area) and the adjoining supramarginal gyrus (Sm), angular gyrus (AG), auditory cortex (A), motor cortex (M), and somatosensory cortex (Ss). The posterior and anterior components of the implementation system, respectively Wernicke's area and Broca's area, are interconnected by the arcuate fasciculus
The mediational system surrounds the implementation system like a belt (blue areas). The regions identified so far are located in the left temporal pole (TP), left inferotemporal cortex (It), and left prefrontal cortex (Pf). The left basal ganglia complex (not pictured) is an integral part of the language implementation system
The supramarginal gyrus seems to be involved in phonological and articulatory processing of words,
whereas the angular gyrus (together with the posterior cingulate gyrus) seems more involved in semantic processing.
The right angular gyrus appears to be active as well as the left, thus revealing that the right hemisphere also contributes to semantic processing of language.
Insula is important for planning or coordinating the articulatory movements
A. Lesions of 25 patients with deficits in planning articulatory movements were computer-reconstructed and overlapped. All patients had lesions that included a small section of the insula, an area of cortex underneath the frontal, temporal, and parietal lobes. The area of infarction shared by all patients is depicted here in dark purple.
B. The lesions of 19 patients without a deficit in planning articulatory movements were also reconstructed and overlapped. Their lesions completely spare the precise area that was infarcted in the patients with the articulatory deficit.