Higher Functions (Langauge and Memory)

8/3/2019 Higher Functions (Langauge and Memory)

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Higher functions

HaythamEloqayli
http://info.just.edu.jo/just.jpg


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Higher functions

sensation (somatic, vision, and hearing)

motor

primary areas (primary motor area, primarysensory areas)

the secondary areas (secondary sensory areas,

premotor and supplementary motor areas )

association areas


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The most important association areas are

(1) the parieto-occipitotemporal association

area,

(2) the prefrontal association area, and

(3) the limbic association area


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primary sensory areas detect specificsensations-visual, auditory, or somatic.

secondary sensory areas analyze the specificsensation (e.g details: shape or texture , color..etc)


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association areas

receive and analyze signals simultaneously

from multiple regions ( both the motor andsensory cortices and from subcorticalstructures)

Interpretation of the received signals


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1. Analysis of the Spatial Coordinates of the Body: therelation of the body with the surroundings

2. Area for Initial Processing of Visual Language(Reading) :feeds the Wernicke's area with the words we read.

This area called anguler gyrus.3. Area for Naming Objects:names are learned through auditory

input and visual input4. Area for Language Comprehension (Wernicke's area)

- interpreting the complicated meanings of the sensoryexperiences (somatic, auditory, visual)

-use these to form thought

- choice of word


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Prefrontal Association Area :

-plan of motor movements

-Broca's Area: word formation through the motor control of the

muscles of speech (mouth, larynx, respiratory system..etc)

-elaboration of thoughts

Limbic Association Area: anterior pole of the temporallobe, in the ventral portion of the frontal lobe.

-behavior, emotions, and motivation

-aggressiveness and social response


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Wernicke's (sensory)Aphasia:unable to interpretthe thought

-auditory receptive aphasiainability to understand the spoken word

-visual receptive aphasia: inability to understand the written word

-global aphasia: inability to understand both spoken word andwritten word due to widespread damage to Wernicke's area

Motor Aphasia:person is capable of deciding what he or shewants to say but cannot say it (cannot form words). results fromdamage to Broca's speech area


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Same patient with large menengioma (coronal T1+ and T2 which showthe MCA going around the tumor)


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Malignent Lt. MCA infarction


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prosophenosiais inability to recognize faces due toextensive damage on the medial undersides of bothoccipital lobes and along the medioventral surfaces ofthe temporal lobes

dominant hemisphere:the functions of the speech andmotor control areas, are highly developed in onecerebral hemisphere than in the other.

Lt side in nearly all right handed and in more than 95 %of the Lt handed.


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Memory and learning

Learning

acquisition of knowledge/information

Memoryretention of learned information


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memories are stored by changing the basic sensitivityof synaptic transmission (facilitated pathways calledmemory traces)

Sensitization: facilitationof the synaptic pathways ifthe information is important.

Habituation: inhibitionof the synaptic pathways if theinformation is unimportant (ignorance or no storageof the memory)


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(1) short-term memory

(2) intermediate long-term memories

(3) long-term memory


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Declarative memorybasically means memoryof details, thought, verbal.

Skill memoryis memory of motor activities


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(1) short-term memory-memories that last for seconds or at most minutes

-may result from continual neural activity

(2) intermediate long-term memories,-memories that last for days to weeks

- result from temporary chemical or physical changes at the level of thesynapse

(3) long-term memory-lasts weeks to lifetime

-result from structural changes at the synapse ( at the level of theDNA)


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Consolidation of Memory

-Means convertion of short-term memory to into long-

term memory

-Rehearsal enhance this process

-Momories are codified: stored according to similarities

and differences


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Anterograde Amnesia: inability to establishintermediate memory or long-term memory(cannotform new memories)

e.g hippocampus lesionsRetrograde Amnesia

-Inability to recall Memories from the Past

-amnesia for recent events is likely to be muchgreater than for events of the distant past

e.g damage in some thalamic areas


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Amnesia

Disorders of memory

Anterograde amnesia: deficit in learningnew information

Retrograde amnesia: deficit in recallingpreviously learned information


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H.M.


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Lt hippocampus tumor in a patient with epilepsy, difficult to see with T1or T2 and no contrast enhancement but seen with flair (low gradeastrocytoma)


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hippocampal lesions,

-Anterograde amnesia but retrograde amnesia can

occur.

- Involves declarative memoryand spare the skillmemory.


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Higher Functions (Langauge and Memory)

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