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A New Concise Course on Linguistics for Students of English

2022-06-13 来源:客趣旅游网


Chapter 12 Language and Brain

1. What distinguishes the human brain from a non-human brain?

The cerebral cortex is the decision-making organ of the body and storehouse of

“memory”. It receives messages from all the sensory organs and initiates all voluntary actions. It’s the cerebral cortex that accounts for the human distinctness in the animal world

and it is within the human cortex that the secrets of language representation and processing are to be found. Animals, reptiles and amphibians, for example, have no cortex at all.

12.2.1 What is neurolinguistics?

Neuroliguistics is the study of the relationship between brain and language. It includes

research into how the structure of the brain influences language learning, how and in which parts of the brain language is stored, and how damage to the brain affects the ability to use language.

12.2.2 The structure and function of the human brain

Nerve cells are called neurons. The neurons are the basic information processing units of

the nervous system.

The Brain consists of brain stem (lower section) and cerebrum (higher section).

The Brain Stem, connecting to the spinal cord and shared by all animals, keeps the body

alive by maintaining the essential functions such as respiration, heart rate, and muscle co-ordination. The cortex is separated by the longitudinal fissure into two parts: the left and the right

cerebral hemispheres (the left and the right cerebral hemispheres or the left and the right brain.)

The main connection between them is a bundle of nerve fibres known as the corpus callosum.

Each hemisphere controls the opposite half of the body in terms of muscle movement and sensation.

The left hemisphere seems to excel in analytic tasks such as arithmetic, whereas the right hemisphere excels in tasks which require an overall appreciation of complex patterns such as the recognition of familiar faces and melodies.

12.2.3 Methods in the study of the brain and evidences for lateralization

Autopsy studies

‘Sodium Amytal’ Test (SAT)

Computerized Axial Tomography (CT scanning) 计算机化X射线轴向分层造影;计算机化轴向层面X射线摄影法

Positron Emission Tomography (PET) 正电子成象术;正电子放射断层造影术

Dichotic Listening Studies

Split brain studies

12.2.3.1 Autopsy studies

In 1860, a French neurologist Paul Broca found severe damage (called a lesion) in the

lower rear area of the left frontal lobe (大脑额叶)which caused the patient’s disability of

speaking.

This lower rear portion of the left frontal lobe is now called Broca’s area.

12.2.4 Methods to study the brain

In SAT the patient is asked to count out aloud while sodium amytal is injected into an

artery carrying blood to one side of the brain. CT scanning uses a narrow beam of X-ray to create brain images that take the form of a

series of brain slices. PET, however, makes it possible to study the brain in action. It has been found that when subjects speak, much blood flows to the left hemisphere of the cortex and to Broca’s area in particular.

12.2.3.3 Methods to examine the behaviour associated with the brain

Dichotic listening is a technique in which stimuli either linguistic or non-linguistic are

presented through headphones to the left and right ears to determine the lateralization of various cognitive functions.

The phenomenon that the right ear shows an advantage for the perception of linguistic signals is known as the right ear advantage (REA). Split brain studies As we mentioned earlier, the cerebral hemispheres are connected by the corpus callosum (胼胝体,脑胼胝体). If the corpus callosum is severed, the hemisphere cannot communicate with each other. The experiments that investigate the effects of surgically severing the corpus callosum on cognition are referred to as split brain studies. Left hemisphere is responsible for

language.

12.2.4 Aphasia Aphasia refers to a number of acquired language disorders due to the cerebral lesions caused by vascular problems, a tumour, an accident and so on.

12.2.5 12.2.4.1 Broca’s aphasia (失语症) Broca’s area is responsible for the articulation of speech. Thus, damage to parts of the brain in front of the central sulcus(中央沟) will cause non-fluent aphasia(流畅失语症;空洞型失语症). Patients who suffer from non-fluent aphasia show slow effortful speech production.

Global aphasia (completely mute)is the most severe form.

Phonologically, the speech of Broca’s aphasics is very halting and lack of normal

sentence intonation.

Broca’s aphasics produce telegraphic speech(电报式语言) (omit the functional words功能词,虚词, inflectional affixes屈折词缀 and show difficulty judging the grammaticality of

sentences).

Acquired dyslexia 难语症,诵读困难,阅读障碍 deal with disturbances of reading and writing

development in children.

Acquired dysgraphia 书写障碍 2. Describe the major symptoms of Broca’s aphasia, Wernicke’s aphasia, and acquired dyslexia?

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