Lecture 18 - Higher function 2: Regulation of behaviour by the prefrontal cortex

Question 1

Prefontal cortex

Answer 1

Major difference between higher primates which includes humans and other animals
Largest in humans

Question 2

Prefrontal cortex has subtle roles in

Answer 2

Subtle roles in
Working memory
Region we are actively behaving in due to the information in it being current

Planning, judgement
Including interpersonal relationships

Behavioural regulation

Emotional regulation

Question 3

Phineas Gage

Answer 3

Phineas Gage: Accidental prefrontal lobotomy, Vermont,1848.

Subtle changes in personality: “Gage was no longer Gage” - his whole nature as a human had been changed
Before: competent, responsible, prudent, popular
After: fitful, irreverent, profane, vagrant

Question 4

Who gave rise to the main functions of the prefrontal cortex?

Answer 4

Phineas Gage

Question 5

Functions of the prefrontal cortex

Answer 5

Personality

Executive functions:
Planning
Moral judgement
Emotional control

Question 6

Prefrontal lobotomy

Answer 6

“Therapeutic” prefrontal lobotomy
Rapid “outpatient” procedure
Cut fibres connecting PFC with rest of brain (disrupt the prefrontal cortex)
Became a treatment craze in the 1940’s
Used to reduce violent, antisocial, agitated, and just “troublesome” behaviour, as well as depression
Little evidence for any benefit overall Many bad side effects on personality and emotional life

Question 7

Declarative memory

Answer 7

Memory for things that can be described in words
Episodic (snapshots of life events, experiences). Allows imagining the future.
Semantic (words and their meanings, people, faces, things, concepts – in categories)

Question 8

Declarative memory STM to LTM

Answer 8

STM - Hippocampus and other temporal lobe structures
to
LTM - many areas of the association cortex

Question 9

Procedural memory

Answer 9

Memory for how to do things
Widely stored in regions of the brain that are involved in doing what we just had to do)
In the long term it is stored in parts of the brain involved in motor control

Question 10

Procedural memory STM to LTM

Answer 10

STM - widely distributed
to
LTM - basal nuclei, cerebellum, premotor cortex

Question 11

Consolidation

Answer 11

transition from STM to LTM

Question 12

Short term memory also called

Answer 12

working memory

Question 13

Short term memory

Answer 13

Continued activity in brain circuits. If activity is interrupted, memory is lost.
Does not involve long term changes in synapse etc.

Question 14

Long term memory

Answer 14

More permanent changes in brain function &/or structure

Probably involves long term changes in strength of specific synapses (“long term potentiation”, LTP)
(LTP) Requires the post synaptic cell to be generating action potential for there to be Ca2+ entry in the presynaptic terminal for there to be some coincidence/close matching in time which involved Ca2+ post synaptic entry through NMDA receptors s it is the strengthening of the synapse that is the consequence of the calcium that enters during repeated activity

Question 15

LTM and long term potentiation

Answer 15

Probably involves long term changes in strength of specific synapses (“long term potentiation”, LTP)
(LTP) Requires the post synaptic cell to be generating action potential for there to be Ca2+ entry in the presynaptic terminal for there to be some coincidence/close matching in time which involved Ca2+ post synaptic entry through NMDA receptors s it is the strengthening of the synapse that is the consequence of the calcium that enters during repeated activity

Question 16

Where are the memories stored in the brain?

Answer 16

no single memory storage area

Memories are distributed among brain areas involved in processing the information

Question 17

Transfer of working to LTM is enhanced by

Answer 17

High emotional impact
High can enhance it

Importance for survival (one-trial learning can occur)

Repetition (recency important)
Primacy effect

Processing, forming new combinations, linkage to existing knowledge
If you can make network of ideas and associate them together then paint a bigger picture for yourself then by making these lints in the memory then all of these memories collectively become much more effective and more likely to be retained long term

Involves hippocampus
Damage reduces ability to form new memories
Consolidation involves the hippocampus

Question 18

Clive Wearing

Answer 18

Had to be in care

Life was stalled as he could not remember anything due to hippocampus damage

Question 19

Hippocampus plays a role in

Answer 19

memory

Question 20

H.M.

Answer 20

Unable to form any new declarative memories from now on
Anterograde amnesia: Unable to form new declarative memory.
Memory of prior events intact (No/more limited retrograde amnesia)
HM’s procedural memory also intact.

Question 21

Language

Answer 21

Involves both word knowledge (vocabulary) and structure knowledge (grammar)
Language functions concentrated in left hemisphere in 90% of people, including left- handers
Main areas identified by problems commonly suffered by stroke patients

Question 22

Language areas of the brain

Answer 22

Broca’s area = Involved in “constructing” language Most obvious in output (fluency)
Assembling sentences that mean something

Unilateral in most people… does only one side of the brain speak?

Wernicke’s area= Involved in processing language “meaning”… Both input & output (comprehension)
Undestanding what we hear and speaking in a comprehensive way

Question 23

Language areas of the brain - ______ in most people

Answer 23

unilateral

Question 24

Broca’s area

Answer 24

frontal lobe

Broca’s area = Involved in “constructing” language Most obvious in output (fluency)
Assembling sentences that mean something

Question 25

Wernicke’s area

Answer 25

Temporal lobe
Wernicke’s area= Involved in processing language “meaning”… Both input & output (comprehension)
Undestanding what we hear and speaking in a comprehensive way

Question 26

Corpus callosum

Answer 26

joints the two halves of the brain

Interconnecting fibres between the two hemispheres, dense white matter fibre band
In some cases of very extreme and untreatable epilepsy particularly in childhood then the seizure may originate in one side of the brain which is damaged/poorly developed in some way and then spread to the other side and in extreme cases the side of the brain that is generating the seizure is generally irretrievable and so its functionality is not there so the solution in some patients is to just cut the corpus callosum which prevents the seizures from brain propagated through the brain
If shown in the RVF (left hemisphere) can say what it is, if show in the LVF of split brain patient then they can identify images of the same object but not say what the object is

Question 27

Left brain

Answer 27

Analytical

Verbal

Question 28

Right brain

Answer 28

Intuitive
Involved in how things feel, to do with the nature of things

Space perception (maps)

Music

Primitive language ability, but gives context
More in a poetic way than a grammatical way as in it is about the deeper meaning of language

Question 29

Split brain - two minds?

Answer 29

Patients appear entirely normal, report no odd experience

If you ask a person if they feel any differently after surgery then they say they do not feel any differently but this is because only one hand of the brain can speak and it is not aware that it is missing all this subconscious input that would normally be getting and feeding into the broader network that would be driving their behaviour

Conflict plays out in patients brain and this disconnection results in 2 independently but fully functioning personalities
There are uncrossed and crossed pathways deeper in the brainstem that are still intact so can still coordinate bipedal movement because the corpus callosum is not necessarily depriving one side of the brain from any access of spinal motor circuits on the other side