Lecture 10 - The Claustrum

Question 1

what does the word “claustrum” mean?

Answer 1

‘hidden away’, or ‘to close/shut’

Question 2

the claustrum is hidden away as a thin sheet of cells between:

Answer 2

the striatum/putamen and the insula

Question 3

what percent of cells in the cerebral cortex are part of the claustrum?

Answer 3

<1%

Question 4

why is it difficult to stimulate the claustrum directly?

Answer 4

it is surrounded by axon white matter fibre tracts which signal between many different regions (so stimulating the claustrum is difficult without stimulating these bundles of axons)

Question 5

can detect claustrum connections with the cortex

Answer 5

diffusion tensor imaging

Question 6

the claustrum was found to be the most:

Answer 6

densely connected region (as a function of its volume)

Question 7

axons from the claustrum were found to connect to:

Answer 7

the most frontal and most posterior parts of the cerebral cortex

Question 8

the claustrum has the strongest _____ with the frontal cortex

Answer 8

bidirectional communication

Question 9

region of the brain involved in integrating

Answer 9

association cortex

Question 10

there is generally weak ______ input to the claustrum

Answer 10

sensory cortex

Question 11

_____, _____, and _____ cells also project to the claustrum

Answer 11

serotonin, dopamine, acetylcholine

Question 12

the cortex is responsible for:

Answer 12

sensing the world and is topographically organized into different sensory and motor regions

Question 13

each sensory/motor cortical region provides input to:

Answer 13

different zones of the claustrum

Question 14

is it possible for different cortical regions to receive inputs from the claustrum?

Answer 14

yes

Question 15

claustrum outputs are predominantly:

Answer 15

glutamatergic (they release glutamate and depolarize neurons)

Question 16

frontal cortical regions receive inputs from the _____, and more posterior regions receive inputs from the ______

Answer 16

dorsal claustrum, ventral claustrum

Question 17

true or false: species differences exist with respect to the anatomical organization of claustrum-cortex connections

Answer 17

true

Question 18

in humans, cats, and primates, there is a pronounced connection with areas of the:

Answer 18

visual cortex

Question 19

in rodents, claustrum connections with pre-motor areas of the frontal cortex are dominant, suggesting:

Answer 19

a role in motor control

Question 20

claustrum connectivity depends on:

Answer 20

species specific sensory/motor specialization (prefers connectivity to parts of the cortex being used most)

Question 21

excitatory cells in the claustrum can be classified into how many major subgroups?

Answer 21

two

Question 22

have low dendritic spines, small dentritic branches, and do not typically fire action potential bursts

Answer 22

type one (non spiny) excitatory cells

Question 23

have extensive dendrites and fire action potential bursts in response to inputs

Answer 23

type two (spiny) excitatory cells

Question 24

inhibitory claustrum cells appear to be similar to the cortex and express GABA, with different subtypes such as:

Answer 24

parvalbumin, somatostatin, and vasoactive intestinal polypeptide

Question 25

overall, the composition of neuron types in the claustrum is:

Answer 25

comparable to the cortex

Question 26

how do neurons in the claustrum respond to cortical inputs?

Answer 26

- the inputs to the parvalbumin (PV) cells was stronger - detection of an inhibitory response was found in excitatory cells, with a longer latency after the stimulation (this implies a feedforward inhibitory circuit)

Question 27

excitation happens _____, whereas inhibiton happens due to _____

Answer 27

directly, the activation of an interneuron

Question 28

the cortex activates the ______ and inhibits the ______

Answer 28

contralateral claustrum, ipsolateral claustrum

Question 29

using the claustrum, areas of the frontal cortex can:

Answer 29

modulate the posterior cortex efficiantly

Question 30

due to the claustrum's high connectivity, it can serve as a way for:

Answer 30

disconnected cortical regions to communicate

Question 31

activation of the left frontal anterior cingulate cortex activates the claustrum neurons projecting to:

Answer 31

the right visual cortex

Question 32

signals from one hemisphere activates the other hemisphere in order to:

Answer 32

let it know what's happening

Question 33

can be used to specifically activate claustrum neurons with blue light

Answer 33

optogenetics

Question 34

an opsin that can be used to increase inward sodium currents in neurons

Answer 34

channelrhodopsin (ChR2)

Question 35

how can ChR2 be expressed in specific cells?

Answer 35

using an adeno associated virus (AAV) that is coupled to a fluorescent tag (GFP) that shows us where the virus is located

Question 36

go review slide 190

Answer 36

weeeeeeee

Question 37

claustrum cells can reduce cortical inhibition by:

Answer 37

inhibiting specific interneurons (decreases the inhibitory response)

Question 38

the effects of claustrum stimulation is similar to:

Answer 38

spontaneous slow waves (sleepy waves)

Question 39

slow wave sleep is essential for many functions such as:

Answer 39

learning and memory

Question 40

claustrum cells are more active during:

Answer 40

sleep than during awake

Question 41

thought to be consolidated or stabilized during sleep

Answer 41

episodic memories

Question 42

replay or reactivation of neurons during REM or slow wave sleep have been show to:

Answer 42

participate in memory consolidation

Question 43

if claustrum cells are active during slow wave sleep, this it is possible that:

Answer 43

this region functions in memory consolidation

Question 44

how do we test the memory of mice?

Answer 44

by measuring how much time they spend exploring objects/spaces (if they explore something a lot, they likely believe it is new)

Question 45

activation of the claustrum in mice during slow wave sleep increases:

Answer 45

their exploration of the new, displaced object

Question 46

claustrum stimulation induces a _____, which help consolidate memories

Answer 46

delta wave

Question 47

is the claustrum associated with associative learning?

Answer 47

some claustrum neurons start to increase their firing during the conditioned stimulus (see slide 196), indicating that they could be participating in this learned response

Question 48

lesioning the claustrum slowed down the learning of the:

Answer 48

coditioned stimulus (CS) - conditioned response (CR) relationship

Question 49

claustrum lesions slowed down associative learning in rabbits by:

Answer 49

4-5 days (instead of showing peak performance on day 3, they were delayed until day 7-8)

Question 50

the active component in 'magic mushrooms' that activates serotonergic 5-HT2a receptors to cause hallucinations, euphoria, and changes in perception

Answer 50

psilocybin

Question 51

claustrum neurons have a dense expression of:

Answer 51

5-HT2a

Question 52

what effect does psilocybin have on the prefrontal cortex?

Answer 52

increases spine density (particularly in female mice)

Question 53

spine density reflects:

Answer 53

excitatory synaptic input

Question 54

the prefrontal cortex receives dense input from:

Answer 54

the claustrum

Question 55

what effect does psilocybin have on the claustrum?

Answer 55

decreases claustrum activity

Question 56

how do the actions of psilocybin on the claustrum explain the increase of cortical activity?

Answer 56

the claustrum facilitates feedforward inhibition on the cortex, thus reduced claustrum activity would reduce the amount of inhibition on the cortex

Question 57

which major diseases is the claustrum involved in?

Answer 57

1) decreased claustrum/cortical connectivity in Parkinson's 2) increased/decrease claustrum activity in epilepsy 3) smaller claustrum size in schizophrenia and major depression

Question 58

a rare condition where a healthy individual presents with epilepsy without a known cause

Answer 58

new onset refractory status epilepticus (NORSE)

Question 59

new onset refractory status epilepticus (NORSE) is often associated with:

Answer 59

claustrum lesion or hyperintensity

Question 60

a toxin injected into animal paws in order to induce pain

Answer 60

CFA

Question 61

pain caused by CFA is associated with a pathological increase in neural firing in the:

Answer 61

anterior cingulate cortex (ACC)

Question 62

what effect does the claustrum have on the anterior cingulate cortex (ACC)?

Answer 62

supresses ACC activity

Question 63

activating claustrum-cingulate connections reduces:

Answer 63

pain