L06: Sensory Association Cortices, Language and Speech, Praxis

function of unimodal association cortex

-somatosensory

-visual

-auditory

What type of processing is done by unimodal association cortex?

multistage parallel hierarchical processing

Another name for dorsal stream?

occipitoparietal

2 visual association pathways?

dorsal stream

ventral stream

Another name for ventral stream?

occipitotemporal

What does dorsal stream do?

detects movement of an object to identify location of it ("where")

What does ventral stream do?

detects form/color of the object, identifies what it is

("what")

If you cannot point to objects named or name objects, what do you have?

apperceptive visual agnosia

Lesion causes inability to discriminate shape/color of object would be a lesion to what?

ventral (occipitotemporal) stream

Losing all ability to see color of objects, preventing proper recognition and identification would be a lesion where?

ventral (occipitotemporal) stream

With the 2 visual association cortices, which is usually spared?

The dorsal (occipitoparietal) stream

-we can recognize there is an object moving in a certain direction/location

-we cannot recognize what exactly that object is/does

Where is language function localized?

multimodal cortex

perisylvian region

LEFT hemisphere!

Fundamental symbolic unit of speech?

phoneme

Motor speech is found where?

Broca's area

Sensory speech is found where?

Wernicke's area

What links Broca's area and Wernicke's area?

Arcuate Fasciculus

Being unable to produce much language and having nonfluent aphasia is a sign of what?

Broca's aphasia

What key symptom defines Broca's aphasia?

dysarthric speech

Is comprehension intact during Broca's aphasia?

yes

Conduction aphasia results from a lesion where?

arcuate fasciculus

Key symptom of conduction aphasia?

phonemic paraphasias

What is phonemic paraphasia?

substituting one word for another word that sounds similar but is probably made up (word substitution)

Is comprehension intact in conduction aphasia?

yes

Key symptoms of transcortical sensory aphasia?

circumlocution

word-finding difficulty

What is circumlocution?

explaining a single word with many other words because you can't remember that word

Is comprehension intact in transcortical aphasia?

no

Is repetition impaired in transcortical aphasia?

no (only aphasia where it is not impaired)

What is lesioned in transcortical sensory aphasia?

perisylvian cortex

Wernicke's aphasia

fluent

non-dysarthric

What 2 aphasias can characterize Wernicke's?

conduction + transcortical

word-finding errors

phonemic paraphasia (word substitution)

Is comprehension intact in wernicke's aphasia?

no

What is apraxia?

inability to perform certain motor activities

Components of apraxia testing (tools)

ventral stream (what tool it is)

dorsal stream (where tool is and how it moves)

left perisylvian cortex (naming the tool)

premotor cortex (moving the tool)

Ideomotor apraxia

Cannot actually perform task (does not know how to actually use a tool)

What error is commonly seen in ideomotor apraxia?

body part-as-tool error

What is lesioned in apraxia?

premotor cortex

sometimes dorsal stream

ventral stream intact (know what object is supposed to do)