Claustrum

Question 1

What does claustrum mean?

Answer 1

hidden away or “to close or shut”

Question 2

Where is the claustrum?

Answer 2

between striatum/putamen and insula

Question 3

Compared to the cerebral cortex what percentage of cells does the claustrum have?

Answer 3

claustrum has <1% of the cells of the cerebral cortex

Question 4

Why is it difficult to stimulate the claustrum?

Answer 4

• it is hidden by surrounding axon white matter tracts
• trying to stimulate claustrum is DIFFICULT WITHOUT STIMULATING THE SURROUNDING AXONS

Question 5

What kind of imaging can be usd to detect claustrum connections with the cortex?

Answer 5

diffusion tensor imaging

Question 6

As a function of its volume, what brain structure is the most densely connected region?

Answer 6

claustrum

Question 7

which parts of the brain are the claustrum axons mostly connected to?

Answer 7

• most FRONTAL parts of cerebral cortex
• most POSTERIOR parts of the cerebral cortex

Question 8

Which part of the brain does the cluastrum have the strongest BIDIRECTIONAL communication with?

Answer 8

frontal cortex

Question 9

TRUE or FALSE: there is generally a strong sensory cortex input to the claustrum

Answer 9

FALSE: weak sensory input

Question 10

Which NT (cells) project to the claustrum?

Answer 10

• serotonin
• dopamine
• ACh

Question 11

Which part of the frontal cortex has the strongest bidirectional connection with the claustrum?

Answer 11

limbic and associative

Question 12

List the following inputs to the claustrum from most ventral to dorsal:

• olfactory
• visual
• sensory motor
• PFC
• auditory

Answer 12

olfactory > PFC > sensory-motor > auditory > visual

Question 13

TRUE or FALSE: claustrum outputs are predominantly glutamatergic, so they hyperpolarize neurons

Answer 13

FALSE: yes glutamatergic, but that means they depolarize cells

Question 14

TRUE or FALSE: frontal cortex receive input from ventral claustrum, and posterior cortex receive input from dorsal claustrum

Answer 14

FALSE:

• FRONTAL cortex receive input from DORSAL claustrum
• POSTERIOR cortex receive input from VENTRAL claustrum

Question 15

TRUE or FALSE: the anatomical organization of claustrum-cortex connections is the same across species

Answer 15

FALSE: these connections are different across species

Question 16

TRUE or FALSE:

• in humans and primates, the claustrum has pronounced connections with the pre-motor areas of the frontal cortex
• in rodents and cats, the claustrum has pronounced connections with the visual cortex

Answer 16

FALSE:

• in humans, primates, and CATS, claustrum –> VISUAL CORTEX
• in rodents, claustrum –> pre-motor areas

Question 17

TRUE or FALSE:

• in humans, primates, and cats, the claustrum plays a large role in vision
• in rodents, the claustrum plays a large role in motor control

Answer 17

TRUE

Question 18

What are the 2 subtypes of excitatory cells?

Answer 18

• type 1 (non spiny)
• type 2 (spiny)

Question 19

What is the difference between type 1 and 2 excitatory cells?

Answer 19

• type 1: non spiny; low dendritic spines; NO AP bursts
• type 2: spiny; extensive dendrites; AP bursts

Question 20

How do claustrum neurons respond to cortical inputs?

Answer 20

feedforward inhibition

Question 21

Are claustrum inputs to PV cells or ClaC cells stronger?

Answer 21

inputs to PV cells stronger

Question 22

What is the best way to activate the claustrum?

Answer 22

optogenetics

Question 23

how does ChR2 allow depolarization in response to blue light?

Answer 23

increase inward sodium currents

Question 24

TRUE or FALSE: because claustrum outputs are glutamatergic, activation of the claustrum excites excitatory cells in the PFC.

Answer 24

FALSE: it is glutamatergic, but it activates INTERNEURONS that INHIBIT excitatory cells in the PFC

Question 25

TRUE or FALSE: activation of the claustrum causes inhibition of INs and activation of pyramidal cells

Answer 25

FALSE: - inhibition of pyramidal cells - excitation of INs

Question 26

Which type of INs allow the claustrum to generate cortical inhibition?

Answer 26

NPY interneurons

Question 27

What happens to pyramidal cell firing when NPY neurons are suppressed?

Answer 27

increase in firing

Question 28

TRUE or FALSE: the claustrum excites both the PFC and the RSP (posterior cortex)

Answer 28

FALSE: - inhibit PFC - excite posterior regions

Question 29

What does RSP stand for and where is it in the brain? Is it excited or inhibited by the claustrum?

Answer 29

- retrosplenial cortex - located at posterior regions of the cortex - excited by the claustrum

Question 30

How does the frontal cortex modulate the posterior cortex?

Answer 30

connected by the claustrum

Question 31

TRUE or FALSE: activation of the LEFT frontal anterior cingulate cortex activate claustrum neurons projecting to the RIGHT visual cortex

Answer 31

TRUE

Question 32

what kind of waves does the claustrum-stimulate waves look like?

Answer 32

slow wave sleep

Question 33

Are claustrum cells more active during sleep or during awak?

Answer 33

during sleep

Question 34

What kind of memories are thought to be consolidated or stabilized during sleep?

Answer 34

episodic

Question 35

Since claustrum cells are active during slow wave sleep, what does this imply.

Answer 35

It may also play a role in memory consolidation, which happens during slow wave sleep

Question 36

In associative learning, when do claustrum cells start to increase their firing?

Answer 36

during the CS (e.g. during the tone presented before the puff of air)

Question 37

TRUE or FALSE: lesioning the claustrum increased learning of the CS-CR response

Answer 37

FALSE: decreased learning

Question 38

TRUE or FALSE: if the claustrum is inhibited, mother mice are much quicker to retrieve their pups EXPLAIN.

Answer 38

FALSE: if claustrum inhibited, mother mice take MUCH LONGER to retrieve their pups this is because the claustrum is involved in "ignoring" sensory stimuli that are not deemed important for the task

Question 39

What kind of opioid receptors are mainly found on claustrum cells?

Answer 39

kappa opioid receptors

Question 40

which drug activates kappa opioid receptors? What is the active compound?

Answer 40

- salvia - salvinorin A (active)

Question 41

Does salvia binding to kappa opioid receptors cause presynaptic inhibition or excitation of release of NTs?

Answer 41

inhibition

Question 42

What are the symptoms or taking salvia?

Answer 42

intense hallucinations; delirium; sleep-like state; detachment from reality

Question 43

Is salvia a kappa opioid agonist or antagonist?

Answer 43

agonist

Question 44

Does salvia enhance or inhibit release of NTs?

Answer 44

inihibit

Question 45

Which NT does salvia affect? How does it affect its release?

Answer 45

REDUCES release of GLUTAMATE

Question 46

Besides kappa opioid recrptors, which other receptor is largely found in the claustrum?

Answer 46

serotonergic 5HT2A receptors

Question 47

Which drug can activate 5HT2A receptors?

Answer 47

psilocybin

Question 48

What are the symptoms of taking psilocybin?

Answer 48

hallucination, euphoria, changes in perception

Question 49

What is the effect of psilocybin the PFC?

Answer 49

increase spine density

Question 50

TRUE or FALSE: psilocybin effects are long-lasting

Answer 50

TRUE

Question 51

Does psilocybin increase or decrease claustrum activity?

Answer 51

decrease claustrum activity (increase PFC activity b/c claustrum inhibits PFC)