week 9 - language organisation in the brain

Question 1

language is not unitary, outline what is included in receptive and productive language

Answer 1

receptive -> listening, reading

productive -> speaking, writing

Question 2

outline what the antaomo-clinical method is

Answer 2

• studies patients with acquired language impairment from brain injury or stroke
• found that depending on where the damage is and lesion size, that different patterns of language deficit can occur.

Question 3

what are the limitations with the anatomo-clinical method?

Answer 3

• it is impossible to observe relationships between skills and tasks and brain areas in real time
• deficits change over time, usually decrease

Question 4

what are aphasias

Answer 4

• language disorders due to damage in the language areas of the brain
• causes of these are CVA, strokes, head injury, brain tumours, infections and dementia.

Question 5

where do aphasias occur

Answer 5

aphasia can be general or affect an isolated aspect of language.
this depends on where the damage is

Question 6

what are the difficulties found in aphasias

Answer 6

• langauge production - fluency, naming, agrammatism
• repetition
• auditory comprehension

Question 7

in some aphasias naming is an issue, outline the problems that can occur with this

Answer 7

• word avoidance
• circumlocations
• paraphasia (incorrect word substitute)

Question 8

outline the 3 types of paraphasias

Answer 8

neologistic -> invention of new words

semantic -> substitution with related word meaning

phonemic -> substitution or rearrangment of sounds

Question 9

outline agrammatism

Answer 9

• difficulty in producing syntactically well-formed sentences
• tend not to use function words, there is great difficulty in using passive voice

Question 10

Outline auditory comprehension

Answer 10

• the ability to understand spoken language
• complex process that involves, segmenting sounds into phonemes, combing those to make words.

Question 11

what are 4 main types of aphasias

Answer 11

brocas -> non-fluent aphasia
wernicke’s -> fluent aphasia
conduction -> difficulty repeating words and sentences
global aphasia -> difficulties in both speaking and comprehending due to extensive brain damage

Question 12

discuss Broca’s aphasia

Answer 12

• post mortem done of 2 patients, showed damage to the posterior part of the left inferior frontal gyrus (brocas area)
• this area is fundamental for language expression
• they found speech production difficulties such as non-fluent speech
• naming and word-finding difficulties

Question 13

discuss wernicke’s aphasia

Answer 13

• studied deficits in 2 patients with severe auditory comprehension difficulties - fluent meaningless speech
• damage was seen in the left superior temporal gyrus region known as wernicke’s area.

Question 14

discuss conduction aphasia

Answer 14

• repetition is a major deficit
• originally associated with damage to fibres in the arcuate fasciculus , more recently areas surrounding the sylvian fissure.
• speech is fluent in production, naming is impacted by paraphasic errors.

Question 15

what are the levels of language processing

Answer 15

• semantics
• syntax
• lexical access
• phonology

Question 16

discuss event-related potentials

Answer 16

• electrical potentials recorded from the start of a stimulus
• waveforms are distinguished based on their position, onset of peak, scalp distribution

Question 17

what is mismatch negativity

Answer 17

• a standard sound and an oddball are presented
• negativity 100-200ms after presentation of the oddball, with a frontal scalp distribution
• it is elicited with any sounds

Question 18

what are the advantages of event-related potentials

Answer 18

• usually can match the fast rate of language comprehension
• high temporal resolution
• components are multidimensional, so allow for qualitative inferences about underlying nature

Question 19

discuss the disadvantages of event-related potentials

Answer 19

• many trials are necessary for appropriate averaging
• some trials are lost due to artefacts such as blinking and eye movement
• poor spatial resolution

Question 20

discuss fMRI’s

Answer 20

• in fMRI stimuli are presented during the scan, to see the inner functions
• images reflect changes in oxygenated blood levels
• high spatial resolution, poor temporal resolution
• intensively used in reading research

Question 21

outline lexical access in reading and damage to the area

Answer 21

• an area in the posterior of the left inferior temporal gyrus is proposed to be the area of orthographic representations or lexicon
• known as visual word form area (VWFA)
• injury or damage to this area is called pure alexia (inability to read, but functions such as spelling and writing are intact)