PSY 246: Midterm

frontal lobe

front of brain

parietal lobe

above occipital lobe

occipital lobe

back of brain, vision

temporal lobe

under the frontal lobe

What are the cerebral hemispheres?

the two halves of the brain

what are the cerebral hemispheres separated by?

longitudinal fissure

What do the cerebral hemispheres do?

Control voluntary movement, interpret sensory information and are responsible for learning and memory

central sulcus

separates frontal and parietal lobes

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

what is the benefit of the corpus callosum?

the communication between the hemispheres allows for faster processing and thinking

Thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

brain lateralization

The organization of the brain into right and left hemispheres, with each hemisphere performing unique and specialized functions

why is brain lateralization important?

it allows for parallel processing and the redundant systems allow for processing to occur if one hemisphere is damaged

motor system (efferent)

Carries messages from the central nervous system to muscles and glands

cerebral dominance

refers to hemisphere that is dominant for language (usually left hemisphere)

Anterior

front

Posterior

back

superior/dorsal

top

inferior/ventral

bottom

anterior dominant cortex controls...

expressive language (including writing)

posterior dominant cortex controls...

expressive language (including reading)

left hemisphere of brain

controls right side of the body and is logical, contains mathamatics, lauguage, & speech

right hemisphere of brain

plays significant role in prosodic aspects of language

expressive prosody is controlled by...

the non dominant anterior cortex

receptive prosody is controlled by...

the non dominant posterior cortex

language deficits

most commonly produced by focal lesions, but more diffuse lesions can product subtle language deficits in high level language skills such as organization

Broca's area

Anterior structure responsible for ability to speak or write (motor patterns)

Wernicke's area

Posterior structure responsible for auditory images/ Information

Arcuate Fasciculus

fibre track connecting Wernicke's and Broca's areas

Broca's aphasia

o Halting speech and writing
o Stroke damage in Broca's area
o Non-fluid Agrammatic speech
o Communication of language not great

Wernicke's aphasia

o Fluent Aphasia
o Echolalia - repetition of words over and over again (severe cases repeat same word)
o No complete answers or understanding
o Understanding of language is not great

progressive non-fluent aphasia (primary progressive aphasia)

- degenerative disease that looks like Broca's (expressive deficits)
- early to mid 50's onset
- caused by frontotemporal lobar degeneration or frontotemporal dementia

expressive deficits

-Reduced vocabulary
-Omission/addition of words
-Stereotypic speech
-Delayed or reduced output of speech
-Hyperfluent speech
-Word substitutions

Expressive aphasia (Broca's)

- left posterior frontal (Broca's area)
- impaired speech
- impaired writing
- impaired repetition
- grossly intact comprehension
- grossly intact reading

receptive aphasia (Wernicke's aphasia)

- left posterior temporal/parietal (wernicke's area)
- fluent, nonsensical speech
- Impaired comprehension
- impaired reading
- grossly intact writing
- mildly impaired repetition

Semantic Dementia (SD)

Fluent speech, anomia, impaired comprehension, empty speech, semantic memory network broken, looks like Wernicke's aphasia

Global aphasia

- left anterior and posterior
- impaired speech
- impaired comprehension
- impaired reading
- impaired writing
- impaired repetition

Mixed Transcortical Aphasia

- left anterior and posterior, sparing broca's and wernicke's areas
- impaired speech
- impaired comprehension
- impaired reading
- impaired writing
- intact repetition

Transcortical Motor Aphasia

- left anterior frontal, mildly affected Broca's area
- impaired speech
- typically intact comprehension
- typically intact reading
- impaired writing
- typically intact repetition

Transcortical Sensory Aphasia

- posterior parietal/temporal cortical lesion with sparring of wernicke's area
- impaired speech
- impaired comprehension
- impaired reading
- typically intact writing
- typically intact repetition

Conduction aphasia

- lesion of the acute fasciculus which connects broca's and wernicke's area
- grossly intact speech
- intact comprehension
- intact reading comprehension, oral reading poor due to paraphasias
- grossly intact writing
- severely impaired repetition

Wernicke-Lichtheim Model: Conduction Aphasia

- arcuate fasciculus impacted, nothing else
- unable to repeat

Wernicke-Lichtheim Model: Wernicke's Aphasia

- Auditory images region impacted

Wernicke-Lichtheim Model: Transcortical Sensory Aphasia

- damage between Wernicke's and Concept area
- able to repeat because arcuate fasciculus is intact

Wernicke-Lichtheim Model: Transcortical Motor Aphasia

- damage between concept area and Broca's
- able to repeat, can't produce speech

Wernicke-Lichtheim Model: Broca's Aphasia

- damage to speech region

What anatomical areas are close to Wernicke's area?

Wernicke's area located in temporal lobe, close to supramarginal gyrus, angular gyrus, primary auditory area

What anatomical areas are close to Broca's area?

Broca's area located in frontal lobe, close to primary motor strip

What is the purpose of redundant, communicating arteries in brain?

To try and avoid catastrophic damage to the tissues

medulla and pons functions

associated with basic life functions

Cerebellum functions

associated with balance, postuire, motor coordination, implicit learning

The frontal lobes are associated with

motor functions, expressive language, "executive" functions (e.g., behavioral planning, monitoring/regulation, inhibition, motivation, judge,ent), and mood/affect (emotional regulation) Also includes olfactory cortex.

parietal lobe function

is associated with somatsensory functions, spatial awareness/attention and complex visuoperceptual processing (reading and shape orientation/direction)

The temporal lobe is associated with:

receptive language, primary auditory cortex, declarative memory, visuoperceptual processing (form/shape integration), mood/affect, and olfactory cortex.

Occipital lobe associated with

o primary and secondary visual processing.

Sylvian fissure (Lateral fissure)

Separates the temporal from the frontal lobe, and the temporal from the parietal lobe

Sulcus

indentations in brain

fissure

large sulcus (indentation)

gyrus (gyri)

rounded elevation on the surface of the cerebral hemispheres

superior temporal gyrus

the large gyrus of the temporal lobe adjacent to the lateral fissure; the location of auditory cortex

anterior cerebral artery

The arteries that supply oxygen to most medial portions of frontal lobes and superior medial parietal lobes; strokes here can affect leg use

anterior communicating artery

connects right and left anterior cerebral arteries

posterior cerebral artery

supplies occipital lobe

middle cerebral artery stem

- largest branch of internal carotid artery,
- supplies blood to entire lateral cortex.
- involved in language because it provides blood to subcortical structures of temporal and frontal lobes

lenticulostriate arteries

small, deep penetrating arteries that branch from the middle cerebral artery, very thin and vulnerable to strokes

language assessment

includes expressive skills, Receptive skills, repetition, prosody

language assessment: expressive skills

- fluency
-articulation
-organization
-writing

language assessment: receptive skills

- naming
- aural comprehension
- reading

language assessment: prosody

- expressive prosody
- receptive prosody

What is the relay center of the brain?

the thalamus

paraphasia

-phonemic
-semantic

right hemisphere contributions to language

- Good auditory comprehension of language
-If left hemisphere removed early, the right hemisphere can acquire language
- If left hemisphere removed in adults, severe deficits in speech but still good auditory comprehension
-Removal of the right hemisphere produces subtle changes in language comprehension

Hemispherectomy

removal of a hemisphere

Heschel's gyrus

- primary auditory cortex, anterior to Wernicke's area in right hemisphere
- important for words

right hemisphere damage

- unable to process non-verbal sounds
- auditory agnosia and amusia

pure word deafness

the ability to hear, to speak, and (usually) to read and write without being able to comprehend the meaning of speech; caused by damage to Wernicke's area or disruption of auditory input to this region

what is the right hemisphere's main contribution in langauge?

prosody

receptive aprosody

- associated with lesion in right hemisphere temporoparietal area
- patient unable to appreciate tone, inflection and expression of another even in repetition
- patient can express inflection, tone, emotion

expressive aprosody

- associated with lesion in right hemisphere frontal region, next to left hemisphere's Broca's area
- patient can't express inflection and tonal quality of emotion
- patient can appreciate another's inflection and tone

memory

- encode, retain, retrieve
- verbal (lateralized function), non verbal
- hierarchical function - requires the basics such as attention and other cognitive components to be intact

sensory registration

- auditory, visual, gustatory, tactile, or olfactory information enters
-consciously registered, brain deems importance of information very quickly
- lasts ms to s
- attention required for next step

short-term memory

- working memory, but more of an attention system
- normal person able to remember 7±2 items in STM
- brief system
- chunking of information can help
- organizing or rehearsal required for next step

long-term memory

- includes everything that can be recalled within few minutes
- relatively permanent
- can be accessed
- consolidation process used in LTM

LTM (long term memory) factors

- rehearsal
- emotional salience: things are easier to remember when there is emotion attached
- Levels of encoding:
o Elaboration: building new information on top of what is known
o State dependent learning: able to recall better when in same internal state as when information was learned
o Environmental dependent learning: internal and external cues help with recollection of information

Papez circuit

- a circuit of structures interconnecting hippocampus, mamillary bodies, thalamus and cingulate gyrus.
- involved in forming new autobiographical memories and declarative memories

stages of memory

1. sensory storage
- no attention = forgetting
- attention = STM
2. STM
- processing = LTM
- no processing = forgetting
3. LTM
- encoding from STM

explicit memory (declarative memory)

- can declare it
- contains episodic memory and semantic memory
- Verbal-visual
- Intentional- incidental
- Recent - remote
- Frequently disrupted due to many etiologies of disease

episodic memory (part of explicit memory)

- truly autobiographical or autobiographically bound
o - where you learned it, when you learned it
o - retrieval of the learning event

semantic memory (part of explicit memory)

- facts
- language concept area
- not time dependant
- Retrieval of a fact
- No idea where or when you learned it - it is a fact

implicit memory

- Skills and procedures
- Origins of learning often lost
- Often preserved in disease due to more distributed nature of this neuroanatomically

Why are there more clinical problems associated with declarative memory than non-declarative memory?

Declarative memory involves the medial temporal lobes which are neuroanatomically vulnerable. Non-declarative memory is diffused across many subcortical structures meaning it is harder to damage

anterograde amnesia (AA)

- damaged episodic memory due to damage in hippocampus or other regions of papez circuit
- inability to form new memories
- Cannot learn new information
- Most common memory impairment
- patient HM: had bilateral resection of hippocampus

retrograde amnesia (RA)

- loss of memory for events prior to injury
- temporally graded: tend to remember less closer to injury, and more further from memory
- rarely spans years
- very rare to have RA without AA
- can have AA without RA

encoding

the process of getting information into the memory system,

Consolidation

taking encoded information and storing it more permanently, associated with neuroanatomical change in brain making new circuit

retrieval

accessing stored memory, do better with cues than free recall

primacy effect

tendency to remember words at the beginning of a list especially well

recency effect

tendency to remember words at the end of a list especially well

memory assessment focuses on...

- immediate: asking for information right away
- learning: repeat and test information to see progress
- delayed: distract to prevent rehearsal and see consolidation
- cued: help to assess retrieval
- recognition: help to asses retrieval

memory impairments caused by....

- Orbitofrontal and medial frontal structures
- Diencephalic lesions
- Severe mesial temporal lobe damage