Chapter 5: RECORDING AND STIMULATING NEURAL ACTIVITY

Question 1

What electrical events can be recorded in neural activity?

Answer 1

• action potentials

- postsynaptic potentials elicited by terminal buttons

Question 1

What electrical events can be recorded in neural activity?

Answer 1

• action potentials

- postsynaptic potentials elicited by terminal buttons

Question 2

What can changes in electrical activity of a particular region be used for?

Answer 2

determine whether that region plays role in various behaviours

Question 3

What are the two recording types for electrical activity ?

Answer 3

• chronological recordings

- acute recordings

Question 4

What do chronological recordings consist of ?

Answer 4

-made over an extended period of time after animal recovers from surgery

Question 5

What do acute recordings consist of?

Answer 5

• made for relatively short period of time during which the animal is anesthetized
• restricted to studies of sensory pathways
• doesn’t really involve behavioural observations because animal is not conscious.

Question 6

Why do they measure electrical activity in particular regions?

Answer 6

changes in electrical activity of a particular region are used to determine whether it plays a role in various behaviours

Question 7

What are microelectrodes?

Answer 7

Thin wires used to record activity of a single neuron

Question 8

What are macroelectrode?

Answer 8

electrode used to record the electrical activity of large numbers of neurons in a particular region of the brain

Question 9

How are changes in voltage detected by a macroelectrode plotted?

Answer 9

with EEGs (electroencephalograms)

Question 10

What can EEGs be used for?

Answer 10

may be used to diagnose or treat patients

Question 11

What does magnetoencephalography consist of?

Answer 11

-Detects groups of synchronously activated neurons by means of the magnetic field induced by their electrical activity

Question 12

How does magnetoencephalography detect groups of synchronously activated neurons?

Answer 12

-Uses an array of superconducting quantum interference devices (SQUIDs)

Question 13

How does the metabolic rate increase?

Answer 13

The metabolic rate increases with an increase in neural activity

Question 14

How is the metabolic rate measured?

Answer 14

• By injecting radioactive 2-deoxyglucose (2-DG)
• Autoradiography visualizes the activity in the brain caused by the 2-DG
• Immunocytochemical methods identify cells containing Fos proteins

Question 15

What is 2-DG?

Answer 15

A sugar that enters cells along with glucose but is not metabolized.

Question 16

What is a autoradiography?

Answer 16

• Procedure that locates radioactive substances in a slice of tissue;
• The radiation exposes a photographic emulsion or a piece of film that covers the tissue

Question 17

What is Fos?

Answer 17

A protein produced in the nucleus of a neuron in response to synaptic stimulation

Question 18

What does functional imaging consist of ?

Answer 18

A computerized method of detecting metabolic or chemical changes in the brain.

Question 19

What are the two types of functional imaging?

Answer 19

• Positron emission tomography

- Functional MRI (fMRI)

Question 20

What is Positron emission tomography (PET) scan?

Answer 20

-A functional imaging method that reveals the localization of a radioactive tracer in a living brain.

Question 21

What is an fMRI?

Answer 21

• functional imaging method
• modification of MRI procedure that permits the measurement of regional metabolism in the brain, usually by detecting changes in blood oxygen level.

Question 22

Do fMRI or pet scans have higher resolution?

Answer 22

fMRI have higher resolution

Question 23

How can we infer electrical activity from oxygen levels?

Answer 23

-Increased activity of a brain region stimulates blood flow to that region, which increases the local blood oxygen level.

Question 24

What is the former name of fMRI’s ?

Answer 24

BOLD

Question 25

How is electrical stimulation done?

Answer 25

Pass an electrical current through a wire inserted into the brain using stereotaxic surgery.

Question 26

How is chemical stimulation done?

Answer 26

injection of an excitatory amino acid such as kainic acid or glutamic acid.

Question 27

What is the main disadvantage of chemical stimulation?

Answer 27

-more complicated than electrical stimulation, because requires more equipment

Question 28

What is the main advantage of chemical stimulation?

Answer 28

• It activates cell bodies not axons

- The effects of chemical stimulation are more localized and precise than electrical stimulation.

Question 29

How is transcranial magnetic stimulation done?

Answer 29

Stimulation of cerebral cortex by means of magnetic fields produced by passing pulses of electricity through coil of wire placed next to skull.

Question 30

How does transcranial magnetic stimulation affect the brain?

Answer 30

• interferes with functions of brain region that is stimulated
• treats symptoms of mental and neurological disorders

Question 31

How do optogenetics methods work?

Answer 31

-use genetically modifies viruses to insert light-sensitive ion channels into the membrane of particular neurons in the brain.

Question 32

What effects do optogenetics methods have on the brain?

Answer 32

• stimulate or inhibit selected populations of neurons in a specific brain region
• can depolarize or hyperpolarize neurons with mights of appropriate wavelength.

Question 33

What are optogenetics used for?

Answer 33

-used to study functions of particular neural circuits in the brain

Question 34

What happens when blue light strikes ChR2-ion channel?

Answer 34

• channels opens

- rush of positively charged sodium and calcium ions depolarizes the membrane, causing excitation.

Question 35

What happens when yellow light strikes NpHR?

Answer 35

• proteins controls a transporter that moves chloride into the cell when activated by yellow light.
• influx of negative charges, hyperpolarizes membrane, causes inhibition.