Psyc201 Test 1, Week 2

Question 1

Research Methods: Imaging

Answer 1

EEG, fMRI, PET, Microscopy.

Question 2

Research Methods: Manipulation

Answer 2

Brain damage, drugs, genetic manipulations, direct brain stimulation.

Question 3

Brain Damage (Manipulation)- pros and cons

Answer 3

(“spontaneous” or induced). Pros: Reveals role of specific brain areas. Cons: Lesions in humans are often large and variable. Animal studies allow for more controlled lesions.

Question 4

Chemical Lesions

Answer 4

Solution to brain damage (manipulation).

Question 5

Direct Brain Stimulation (manipulation)

Answer 5

Electrical or magnetic stimulation to activate brain regions.

Question 6

Deep Brain Stimulation

Answer 6

Used therapeutically, especially for Parkinson’s disease, by implanting electrodes in the basal ganglia.

Question 7

Transcranial Magnetic Stimulation (TMS) (stimulation of brain)

Answer 7

• low level: neuronal excitation
• high level: neuronal inhibition
• Mostly used for cortical studies (2-3 cm depth)- don’t go much further, subcortical structures aren’t accessible by this technique

Question 8

Direct stimulation of the brain (electrical or magnetically) Pros and Cons

Answer 8

Pros: Reversible, non-invasive. Cons: Stimulates/inhibits all cells, limited to cortical areas.

Question 9

Microscopic Imaging

Answer 9

High spatial resolution, but only post-mortem.

Question 10

Electroencephalogram (EEG) (electric imaging)

Answer 10

Measures electrical activity on the scalp. Pros: High temporal resolution. Cons: Low spatial resolution, mainly cortical.

Question 11

Structural MRI (magnetic imaging)

Answer 11

Measures hydrogen, good spatial resolution, shows brain structure.

Question 12

Functional MRI (fMRI) (magnetic imaging)

Answer 12

Measures BOLD (blood oxygen level dependent), reflects brain activity (function). Pros: Good spatial resolution. Cons: Low temporal resolution, measures correlations, not causality.

Question 13

Types of Imaging

Answer 13

• Microscopic imaging.
• Electrical imaging.
• Magnetic imaging.
• Chemical Imaging.

Question 14

Positron Emission Tomography (PET) (chemical imaging)

Answer 14

PET scans use small amounts of radioactive substances, called radiotracers or radiopharmaceuticals, that are injected, inhaled, or swallowed
* Works with relatively weak radioactive compounds.
* The compounds are selected because they bind to proteins of interest.
Advantage: we can measure changes in brain chemistry, spatial resolution is reasonable.
Limitations: expensive, requires synthesis of radioactive ligands, low temporal resolution

Question 15

Early Brain Development

Answer 15

Starts around 3 weeks into gestation, involves neurogenesis, gliogenesis, synaptogenesis, myelination, and synaptic pruning.

Question 16

Brain Size at Birth

Answer 16

Approximately 300 grams.

Question 17

Brain Size at 1 Year

Answer 17

Approximately 1000 grams, near adult size.

Question 18

Neurogenesis

Answer 18

Development of new neurons.

Question 19

Development Sequence

Answer 19

Sensory systems develop before integrative systems.

Question 20

Synaptic Pruning

Answer 20

Strengthening useful synapses and eliminating unnecessary ones.

Question 21

Axon Pathfinding

Answer 21

Axons follow chemical trails to their targets, guided by factors like NGF.

Question 22

Nerve Growth Factor (NGF)

Answer 22

Protein released by target cells that strengthens axon connections.

Question 23

Apoptosis

Answer 23

Natural cell death process when axons don’t receive NGF.

Question 24

Prefrontal Cortex Development

Answer 24

Last brain structure to fully develop, myelination completes around age 20.

Question 25

Brain Plasticity After Damage

Answer 25

* Neurons are postmitotic so they can’t divide and so cells can replicate when they die. * However, new cells are being formed in some brain structures, such as the hippocampus and striatum. * These new cells are more related to learning and memory, not to recovery Brain compensates through increased activity in surrounding areas, collateral sprouting, and denervation supersensitivity.

Question 26

Stroke

Answer 26

Temporary dysregulation of blood flow, either ischemia (lack of blood) or hemorrhage (excess blood). Both forms of stroke impair the Na+/K+ pump, leading to excess Na+ inside the cell. This increased Na+ leads to enhanced glutamate release, which can ultimately kill cells

Question 27

tPA (tissue plasminogen activator)

Answer 27

Used to break up blood clots in stroke treatment, must be administered quickly (within 4.5 hours).

Question 28

Collateral Sprouting

Answer 28

the growth of intact axons into neighboring denervated territory

Question 29

Denervation Supersensitivity

Answer 29

Increased sensitivity of receptors after loss of input.

Question 30

Phantom Limbs

Answer 30

Caused by reorganization of the somatosensory cortex after amputation.

Question 31

Axonal sprouting

Answer 31

The growth of new nerve endings which connect with other undamaged nerve cells to produce new neural pathways

Question 32

Blending Theory of Heredity

Answer 32

Incorrect theory that offspring are an average of their parents' traits.

Question 33

Gregor Mendel

Answer 33

Discovered basic principles of heredity through pea plant experiments.

Question 34

Elements of Hereditary

Answer 34

There are two elements of heredity, one from each parent. Often one element dominates, and the other is recessive.

Question 35

Allele

Answer 35

A variant form of a gene. (in flower scenario, w and P)

Question 36

Homozygous

Answer 36

Having two identical alleles for a trait (e.g., ww or PP).

Question 37

Heterozygous

Answer 37

Having two different alleles for a trait (e.g., wP, Pw).

Question 38

Chromosomes

Answer 38

Structures containing genes, 23 pairs in humans.

Question 39

DNA Bases

Answer 39

Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

Question 40

DNA Structure

Answer 40

Double helix composed of sugar-phosphate backbones and base pairs (A-T, C-G).

Question 41

DNA Replication

Answer 41

Process of producing two identical DNA copies (molecules) during cell division.

Question 42

Transcription

Answer 42

Process of DNA being copied into RNA.

Question 43

Translation

Answer 43

Process of RNA being used to create proteins. Proteins are made up of amino acids. 3 bases form the code for one amino acid.

Question 44

RNA Bases

Answer 44

Adenine (A), Uracil (U), Cytosine (C), Guanine (G).

Question 45

Mutation

Answer 45

A change in the DNA sequence.

Question 46

COMTVal158Met Mutation

Answer 46

A single DNA base change affecting dopamine breakdown and executive function. (COMT is a protein that breaks down dopamine)

Question 47

Epigenetics

Answer 47

Changes in gene expression without altering the DNA sequence, often due to environmental factors.

Question 48

DNA in the nucleus

Answer 48

DNA is very long (about 2 meters) so to get it into a cell nucleus (about 0.006 cm3), it has to be very tightly bound. Therefore chromosomes have special proteins (histones) that are positively charged to bind the negatively charged DNA.

Question 49

Epigenetic Changes vs. Mutations

Answer 49

Epigenetic changes alter protein production (quantitative), mutations alter protein structure (qualitative).