Lecture 6- Cortex

Question 1

Purkinje cell sends output where

Answer 1

Cerebellar nuclei (including dentate nucleus)

Question 2

Purkinje cell gets 2 inputs from where

Answer 2

Parallel fibers
– provide ongoing info about what the motor plan is (copy from cortex)
Mossy fibers
– Mossy fibers from spinal cord say that motor plan/sensory info is not what’s expected

Question 3

What happens when climbing and parallel fibers fire at the same time

Answer 3

Parallel fiber gets kicked off –> purkinje cell fires –> deep nuclei are inhibited –> motor behavior is stopped

Question 4

Where are climbing fires from

Answer 4

Inferior olive

Question 5

Parallel fibers are what to the mossy fibers

Answer 5

Parallel fibers are axons of granule cells

Question 6

Indirect vs direct circuits

Answer 6

Direct path GO – inhibit internal globus palladus (inhibitor) so thalamus can talk to cortex (inhibit the inhibitor to go)

Indirect path STOP – external globus palladus inhibits the internal globus palladus which then inhibits the thalamus so it will NOT talk to cortex

Question 7

Motor cortex controls the muscles via what

Answer 7

Corticalspinal tract

Question 8

Parkinson’s Disease pathway

Answer 8

No substantia nigra –> no dopamine input –> more STOP less go –> even more inhibition on thalamus and thalamus cannot talk to cortex –> less motor output (cannot initiate motor movements easily and motor activity that the person would not like to have…not enough control over indirect pathway and not enough activation of direct pathway)

Question 9

How can Parkinson’s Disease be treated

Answer 9

By increasing dopamine with drugs or by electrically stimulating the basal ganglia

Question 10

Symptoms of Parkinson’s Disease

Answer 10

Akinesia = lack of movement and difficulty initiating movement Resting tremor
Muscle rigidity

Question 11

Huntington’s Disease Pathway

Answer 11

Protein causes cell death starting in striatum –> not enough input into indirect pathway (STOP) –> too much direct pathway activation –> not enough thalamus regulation –> too much motor output

Question 11

Early signs of Huntington’s

Answer 11

Loss of cognitive and emotional control

Question 12

Late signs of Huntington’s

Answer 12

Chorea (jerky, involuntary, brief movements)

Question 13

White and gray matter in cortex

Answer 13

White inside
Gray outside

Question 14

Neocortex has how many layers

Answer 14

6

Question 15

Outputs from layer 2

Answer 15

Go to ipsilateral cortex

Question 16

Outputs from layer 3

Answer 16

Go to contralateral cortex

Question 17

Ipsilateral

Answer 17

Same side

Question 18

Contralateral

Answer 18

Opposite side

Question 19

Outputs from layer 5

Answer 19

Go to brainstem/spinal cord

Question 20

Outputs from later 6

Answer 20

Go to thalamus

Question 21

Inputs to layer 2-5

Answer 21

From cortex

Question 22

Inputs to layer 4

Answer 22

From thalamus

Question 23

Inputs to layer 2-6

Answer 23

From brainstem

Question 24

Primary sensory cortex should have a big amount of what layer

Answer 24

Layer 4 (big input part of the brain so you need a big input layer)

Question 25

Primary motor cortex should have a big amount of what layer

Answer 25

Layer 5 (big output where corticospinal tract starts)

Question 26

Association cortex should have big amounts of what layers

Answer 26

2 and 3 (they just associate with other parts of cortex)

Question 27

4 lobes of brain

Answer 27

Frontal Parietal Occipital Temporal (Free pizza on tuesdays)

Question 28

Gyri

Answer 28

Hill

Question 29

Sulci

Answer 29

Valley

Question 30

Anterior to central sulcus (precentral gyrus)

Answer 30

Primary motor cortex

Question 31

Posterior to central sulcus (postcentral gyrus)

Answer 31

Primary sensory cortex

Question 32

3 divisions of frontal lobe

Answer 32

Superior frontal gyrus Middle frontal gyrus Inferior frontal gyrus

Question 33

3 divisions of temporal lobe

Answer 33

Superior temporal gyrus Middle temporal gyrus Inferior temporal gyrus

Question 34

2 divisions of parietal lobe

Answer 34

Superior parietal lobe Inferior parietal lobe

Question 35

Sylvian fissure

Answer 35

Break between frontal and temporal lobe

Question 36

Output of corticospinal tract starts where

Answer 36

Primary motor cortex

Question 37

Primary sensory cortex is where what occurs

Answer 37

Sensory info stops first (destination of dorsal columns)

Question 38

Connectivity based parcellation

Answer 38

Cell structure is difficult to assess in humans Cortex can be divided based on connectivity with other areas Same color = active in the same task

Question 39

Occipital lobe areas process what (purple)

Answer 39

Visual information

Question 40

Inferior temporal lobe areas do what (purple)

Answer 40

Determine what an object is

Question 41

Somatomotor network (blue)

Answer 41

Primary motor and primary sensory cortex work together

Question 42

Dorsal attention network (green)

Answer 42

Areas determine whether an object is moving, where it is in space, and guide eye movements to the object

Question 43

Ventral attention/salience network (light purple)

Answer 43

Areas important for monitoring the enviornment broadly and detecting unexpected stimuli, and for shifting attention

Question 44

Limbic network (yellow)

Answer 44

Orbitofrontal cortex regulates emotion Entorhinal cortex regulates memory

Question 45

Control network (orange)

Answer 45

Areas important for complex cognition: making decisions, solving problems, holding information in mind, representing numbers

Question 46

Default mode network (pink)

Answer 46

Areas are task negative (they are suppressed while doing anything) How we are most of the time Responsible for internally directed thought: thinking about things not in the current environment, the past, the future, the minds of other people

Question 47

Where do association fibers communicate

Answer 47

Within a hemisphere

Question 48

Short range association fibers

Answer 48

U-fibers

Question 49

Long range association fibers (3) -- superior longitudinal fasciculus

Answer 49

Connects all lobes

Question 50

Long range association fibers (3) -- arcuate fasciculus

Answer 50

Connects language areas

Question 51

Long range association fibers (3) -- uncinate

Answer 51

Connects limbic areas in temporal lobe to limbic areas in frontal lobe

Question 52

Where do commissural fibers communicate

Answer 52

Between hemispheres

Question 53

Example of commissural fiber

Answer 53

Corpus callosum

Question 54

Anterior commissure

Answer 54

Olfaction

Question 55

Posterior commissure

Answer 55

Pupillary light reflex

Question 56

Where do projection fibers communicate

Answer 56

With brainstem and body (includes ascending, sensory fibers)

Question 57

Why a decrease in gray matter volume over lifetime

Answer 57

Rapid growth in first 5 years of life then decrease as connections we don't use are pruned away

Question 58

Why a decrease in white matter volume over lifetime

Answer 58

Rapid growth throughout life until you start aging effects and brain loss

Question 59

Connection between brain loss and growth in ventricles

Answer 59

As you see more brain loss you see more growth in ventricles

Question 60

Where is gray matter loss faster

Answer 60

In the back of the brain

Question 61

Idea behind development of cognitive vs sensory areas

Answer 61

Sensory areas (back of brain) develop first and cognitive areas develop last

Question 62

Cortical thinning is a marker of what

Answer 62

Maturation

Question 63

What drives white matter expansion and increased coherence

Answer 63

Myelination

Question 64

Sensory areas thin ____ and association areas thin _____

Answer 64

Sensory first, association last

Question 65

White matter consists of what fibers

Answer 65

Association fibers, commisural fibers, and projection fibers