Anatomical Basis of EEG

Question 1

What are the electrical fields recorded during an EEG?

These are a (higher/lower) voltage than an AP, but they have a longer …. and cover a ….. area of neuronal membrane. Unlike an AP, these are … and not propagative.

Answer 1

Post-synaptic potentials

lower

duration

larger

static

Question 2

The presence of an AP will create what two things?

Answer 2

• sink (area ions flow toward) - greater negative charge
• source (area ions flow from) - greater positive charge

Question 3

An excitatoty synapse increased the relative (positive/negative) charge outside of the neuron. In this way, the synapse becomes a … while neuronal membrane becomes a …

Answer 3

negative

sink

source

Question 4

An inhibitory synapse creates a relative (positive/negative) charge outside of the neuron. In this way the synapse becomes a … while the surrounding area is a ….

Answer 4

positive

source

sink

Question 5

How is a dipole formed?

Answer 5

source to sink flow on the surface is mirrored in the reverse direction on the internal side, creating a ‘circular’ voltage flow

Question 6

In order for dipoles to appear on the EEG, they must be…

Answer 6

simultaneous (additive)

occur in same polarity and close proximity to one another

Question 7

dipole fields with mixed polarities are…

Answer 7

closed fields

Question 8

large numbers of neurons densely packed together with nearly identical orientation will create …

Answer 8

open fields

Question 9

What kind of field is required to create an EEG wave?

Answer 9

Open Field

Question 10

What are the dendrites around the perikaryon called?

Answer 10

basal dendrites

Question 11

Apical dendrites extend which way from the perikaryon?

Answer 11

superficially

Question 12

a fiber projecting from the cerebral cortex to a neuron located “below” the cortex is called..

Answer 12

corticofugal fibers

Question 13

Pyramidal neurons form the …. of the cerebral cortex and the majority of …

Answer 13

“output” - descending

interconnections within the cerebral cortex

Question 14

Axons of pyramidal neurons form a major component of the …

Answer 14

Internal capsule

Question 15

Pyramidal neurons forming Upper Motor Neurons are aka…

Answer 15

Giant Cells of Betz

Question 16

What part of the pyramidal neurons is conducive for forming a strong dipole? Because of this, the pyramidal neurons form a …

Answer 16

distance between apical and basal dendrites

natural open dipole field

Question 17

The cerebral cortex is organized into functional units called…

All the neurons in this seem to be activated at roughly the same time, leading to …

Answer 17

cortical columns

inhibition of surrounding cortical columns

Question 18

What links the cortical columns together?

Answer 18

pyramidal axons

Question 19

Lamina 1 of the cerebral cortex

Answer 19

• low density of cells
• synaptic center
• most input from matrix (M) cells of the thalamus

Question 20

Lamina 2 and 3 of the cerebral cortex have…

Answer 20

pyramidal neurons projecting as association and commissural fibers

Question 21

Lamina 4 of the cerebral cortex is the primary…

Answer 21

input center, some commissural fibers, but most arise from the core (C) cells of the thalamus

Question 22

Lamina 5 of the cerebral cortex has the… pyramidal neurons and is the major…

Answer 22

largest

output layer for corticofugal fibers

Question 23

What lamina layer forms most of the UMNs in the CNS?

Answer 23

Lamina 5

Question 24

Lamina 6 of the cerebral cortex has pyramidal neurons projecting to…

Answer 24

thalamus and internal capsule

Question 25

Lines of Gennari/Bands of Baillarger are in what lamina layers? What are they?

Answer 25

in Lamina IV and V bands so prominent you can see with the naked eye

Question 26

All individual voltage spikes recorded during a PSP from all the pyramidal neurons within a single cortical column create...

Answer 26

Local Field Potentials

Question 27

When all local field potentials are recorded from the entire cerebral cortex, the trace is dubbed...

Answer 27

an EEG - electroencephalogram

Question 28

What kind of EEG waves will appear when large scale neuronal interaction for motor or cognitive tasks is taking place?

Answer 28

gamma waves

Question 29

from the anterior half of the brain, we will see what kind of wave form with motor function and concentrated thinking?

Answer 29

beta waves

Question 30

What kind of waves are recorded from the posterior half of the brain while 'at rest'?

Answer 30

alpha waves

Question 31

What kind of waves are found in transition to and from sleep, and is characteristic of young children?

Answer 31

theta waves

Question 32

What waves are often seen in infants and are characteristic of adult sleep?

Answer 32

delta waves

Question 33

Rhythmicity indicates that most of the neurons in the sampling pool are responding in a ... This can be generated locally or can be driven by deeper cerebral structures. The primary source for rhythmicity is...

Answer 33

coordinated fashion thalamus

Question 34

Association fibers are axons linking a cortical column to another cortical column within the same hemisphere. They make up a portion of the...

Answer 34

corona radiata

Question 35

What association fiber tract links the frontal and occipital lobes? It is the largest and longest group of association fibers.

Answer 35

Superior Longitudinal Fasciculus

Question 36

Most association fibers are located in what two laminar layers?

Answer 36

Lamina I and III

Question 37

What group of association fibers link the occipital and temporal lobes?

Answer 37

Inferior Longitudinal Fasciculus

Question 38

What fibers are axons that link a cortical column in one cerebral hemisphere with a cortical column in another cerebral hemisphere?

Answer 38

commissural fibers

Question 39

Commissural fibers form the ..., a thick band of axons located deep to the...

Answer 39

corpus callosum medial longitudinal fissure

Question 40

The rostral portion of the corpus callosum is referred to as the ... and is located superior to the ... near the posterior end of the....

Answer 40

genu optic chiasma olfactory tract

Question 41

The caudal portion of the corpus callosum is the ... and is located superior to the ...

Answer 41

splenium tectum of the MB

Question 42

The commissural fibers in certain areas of the corpus callosum are spatially organized as what?

Answer 42

genu - prefrontal rostral body - premotor, supplementary motor middle body - primary motor, somatic sensory caudal body - posterior parietal splenium - temporal and occipital

Question 43

The inferior surface of the corpus callosum supports a vertical drape of tissue, the ...

Answer 43

septum pellucidum

Question 44

In addition to association and commissural fibers, the corona radiata is formed by axons from the ...

Answer 44

internal capsule

Question 45

What are the three main groups of axons within the internal capsule?

Answer 45

* thalamo-cortical tract * cortico-thalamic tract * corticofugal fibers (which synapse on non-thalamic centers)

Question 46

What is the anterior limb of the internal capsule bordered by?

Answer 46

medial by caudate, lateral by putamen and globus pallidus

Question 47

What tracts are within the anterior crus of the internal capsule?

Answer 47

corticopontine tract (from frontal lobe) corticofugal fibers anterior thalamic radiation (reciprocal connection b/t thalamic nuclei and neurons in the frontal lobe of the cortex)

Question 48

What are the borders of the genu of the internal capsule? What tract is in the genu?

Answer 48

medially by 3v, and lateraly by putamen corticonuclear (corticobulbar) tract and thalamic radiation (thalamic nuclei to precentral gyrus)

Question 49

What is the main path through the internal capsule for motor information?

Answer 49

through genu

Question 50

What borders the posterior crus of the internal capsule?

Answer 50

medially is thalamus, laterally is putamen and globus pallidus

Question 51

What tracts are within the posterior crus of the internal capsule?

Answer 51

corticopontine (from non-frontal) , corticospinal tract, corticorubral tract, superior thalamic radiation

Question 52

What is the reciprocal connection between thalamic nuclei and neurons in the parietal lobe of teh cerebral cortex?

Answer 52

Superior Thalamic radiation

Question 53

Conduit for most somatosensory information throught the internal capsule is from...

Answer 53

Superior Thalamic radiation

Question 54

What tract courses inferior to the posterior crus of the internal capsule as part of the thalamic radiation? When it reaches the lateral surface of the globus pallidus, its name changes to what and goes where? Where did this originate?

Answer 54

Sublenticular tract Auditory radiation going to auditory cortex Medial geniculate nucleus

Question 55

The lateral geniculate nucleus gives rise to.... which courses posterior to the posterior crus, then projects caudally to the occipital lobe as the...

Answer 55

Retrolenticular tract optic radiation

Question 56

The lateral surface of the thalamus is covered by the...

Answer 56

external medullary layer

Question 57

What is the vertical, Y shaped sheet of white matter, dividing the thalamus into anterior, medial and lateral groups called?

Answer 57

Internal medullary lamina

Question 58

Where does the anterior thalamic nucleus project to and what does it transmit?

Answer 58

to cingulate and hypothalamus transmits emotion and memory

Question 59

Where does the dorsomedial nuc of thalamus project to and what does it transmit?

Answer 59

projects to prefrontal and hypothalamus transmits sensory info for mood and motor planning

Question 60

Where does the dorsolateral nuc of thalamus project to and what does it tranmit?

Answer 60

to association areas transmitting multisensory info

Question 61

Where does the ventral anterior nuc of thalamus project to and what does it transmit?

Answer 61

to premotor transmits motor activity

Question 62

Where does the ventral lateral nuc of thalamus project to and what does it transmit?

Answer 62

to primary motor and pre motor transmits motor activity, motor planning

Question 63

What does the VPL nuc project to and transmit?

Answer 63

to primary sensory transmits pain, touch, body temp

Question 64

What does the VPM nuc project to and transmit?

Answer 64

to primary sensory transmits pain, touch, temp, taste (head and face)

Question 65

Where does the medial geniculate project to and what does it transmit?

Answer 65

to primary auditory transmits audition

Question 66

Where does the lateral geniculate project to and what does it transmit?

Answer 66

primary visual transmits vision

Question 67

What does the intralaminar nuc of thalamus project to and what does it transmit?

Answer 67

thalamic nuclei transmits arousal, pain

Question 68

Thalamus is a relay center to the cortex, but it also has numerous... that form feedback and feed forward controls

Answer 68

inhibitory interneurons

Question 69

What of the thalamus serves as a master regulatory center for the activity level of the thalamus as a whole?

Answer 69

Laminar nuclei

Question 70

Laminar nuclei are a major synaptic target of a diffuse body of neurons collectively termed...

Answer 70

Reticular formation