Chapter Two

Question 1

Myelin:

Answer 1

fatty substance deposits that surround an axon of some cells (mostly motor)

blocks the Na/K exchange allowing the signal to jump to the Nodes of Ranvier

Question 2

Destruction of myelin is found in a number of pathologies, most notably…

Answer 2

multiple sclerosis

Question 3

Briefly summarize how inhibitory (GABA) neurons function:

Answer 3

makes the inside more negative than normal and harder to depolarize

etc: chloride channels

Question 4

What are the differences between these two groups:

1. serotonin, dopamine, acetylcholine
2. GABA and glutamate

Answer 4

modulatory which can have bodily effects; their cell bodies are localized but their axonal projections spread diffusely

GABA and glutamate have their cell bodies distributed throughout the brain

Question 5

Explain the process of AP:

Answer 5

1. Passive currents collectively carry the strength to reach a threshold and Na+ channels begin to open
2. Na+ enters the cell and the negative potential inside is reduced (depolarization)
3. Cell membrane is completely permeable and momentarily reverses.
4. Negative potential of the cell is restored via the outward flow of K+. Na+ closes.
5. Hyperpolarization occurs, preventing AP from traveling backward.

Question 6

How does myelin allow an AP to propagate faster?

Answer 6

This blocks the Na/K transfer and the AP jumps via passive conduction

Question 7

What are some biological functions that can have a high spiking rate? Low?

Answer 7

High: speech
Low: vision

Question 8

The function of a brain region is determined by its…

Neurons responding to similar types of information tend to…

Answer 8

neuronal inputs and outputs

be grouped together

Question 9

Gray matter consists of […].
White matter consists of […].

Answer 9

neuronal cell bodies; axons and support/glia cells

Question 10

Association tracts: []
Commissures: []
Projection tracts: []

Answer 10

WM tracts project between different cortical regions of the same hemisphere

WM tracts project between different cortical regions in different hemispheres

WM tracts project between cortical and subcortical structures

Question 11

Ventricles:

Answer 11

hollow chambers filled with CSF carries waste, transfers messenger signals, protective cushion

Question 12

Raised folds of the cortex [].

Buried grooves of the cortex [].

Answer 12

Gyri

Sulci

Question 13

What are the three types of densities?

Answer 13

1. neocortex
2. mesocortex
3. allocortex

Question 14

What structural component divides the frontal and temporal lobes?

Answer 14

Sylvian fissure

Question 15

What is the island cortex of the brain? Where is it located?

Answer 15

insula; located buried underneath the temporal lobe

Question 16

Action Potential

Answer 16

A sudden change in the electrical properties of the neuron membrane in an axon, which forms the basis for how neurons code information (in the form of the rate and synchrony of AP; temporal and summation)

Question 17

Electrical currents are actively transmitted though …

Electrical currents flow passively through …

Passive currents will initiate AP if …

Answer 17

axons by an action potential

dendrites and soma of neurons

their summed potential is strong
enough at the start of the
axon (called the hillock)

Question 18

What is the most important commissure?

Answer 18

corpus callosum

Question 19

What structures does the hindbrain consist of?

Answer 19

cerebellum
pons
medulla oblongata

Question 20

What does the midbrain consist of?

Answer 20

substantia nigra
superior and inferior colliculi

Question 21

What does the diencephalon consist of?

Answer 21

thalamus
hypothalamus
mamillary bodies

Question 22

What does the forebrain consist of?

Answer 22

cerebrum (telencephalon)
dencephalon

Question 23

What does the telencephalon consist of?

Answer 23

basal ganglia
limbic system
cerebral cortex

Question 24

What do the basal ganglia consist of?

What are the basal ganglia?

Answer 24

caudate nucleus
putamen
globius pallidus

subcortical gray matter involved in aspects of motor control, skill learning and reward learning

Question 25

What does the limbic system consist of? What is the limbic system?

Answer 25

cingulate cortex hippocampus amygdala subcortex involved in relating the organism to its present and past environment

Question 26

What does the cerebral cortex consist of?

Answer 26

frontal cortex temporal cortex parietal cortex occipital cortex

Question 27

What are the four different ways in which regions of the cerebral cortex may be divided hence labeled:

Answer 27

1. Pattern of gyri and sulci: same pattern found on everyone (different shapes and sizes) 2. Cytoarchitecture: Brodmann's areas 3. Function: only for primary visual and motor cortex; higher cortical regions are harder to ascribe unique functions to 4. Connectivity: different regions have different connectivity profile; connect to some regions strongly and others weakly; MRI techniques can be used to segment individual brains with this information

Question 28

Brodmann's areas:

Answer 28

regions of cortex defined by the relative distribution of cell types across cortical layers (cytoarchitecture)

Question 29

The amygdala has been implicated in the detection of [...]. Parts of the cingulate gyrus have been implicated in the detection of [...]. Hippocampus is particularly important for [...].

Answer 29

fearful or threatening stimuli emotional and cognitive conflicts learning and memory

Question 30

Thalamus:

Answer 30

major subcortical relay center processing station between all sensory organs (except small) and the cortex

Question 31

Hypothalamus:

Answer 31

consists of a variety of nuclei that are specialized for different functions that are primarily concerned with the body and its regulation EX: body temperature, hunger/thirst, sexual activity, endocrine functions

Question 32

Tumors of the hypothalamus result in...

Answer 32

eating and drinking disorders, precocious puberty, dwarfism, and gigantism

Question 33

Superior colliculi: Inferior colliculi:

Answer 33

midbrain nucleus that forms part of a subcortical sensory pathway (integrates information from several senses) midbrain nucleus that forms a part of a subcortical auditory pathway

Question 34

Cerebellum:

Answer 34

structure attached to the hindbrain important for refined motor movements

Question 35

Unilateral lesions to the cerebellum result in... Bilateral lesions result in ...

Answer 35

poor coordination on the same side of the body as the lesion (ipsilesional side) abnormal gait, dysarthria, nystagmus

Question 36

Pons:

Answer 36

part of the hindbrain key link between the cerebellum and the cerebrum retrieves visual system information to control eye and body movements

Question 37

Medulla oblongata:

Answer 37

part of the hindbrain regulates vital functions EX: breathing, swallowing, heart rate, wake-sleep cycle