3) Mapping Mind, Nature & Nurture, Questions Flashcards
phrenology
1800s
- one of the first attempts to map mind to brain
- evaluate bumps
- super incorrect, relied on anecdotal observation
EEG : electroencephalograph
- Non invasive
- Electrodes placed on scalp
- Device that measures electrical activity generated by brain
- Can infer wakefulness, dream or not, which regions of brain are active at the time
Weakness of EEG
Average activity that reaches surface of scalp tells us WHEN rather than where activity is happening
What is neuroimaging?
brain scans / imaging techniques that allow us to peer inside brain structure or functions
Which neuroimaging techniques allow us to visualize brain structure?
CT & MRI
CT Scans
Computed Tomography
- Non invasive
- Scanning technique using multiple X rays to construct 3D images of brain structure
MRI Images
Magnetic Resonance Imaging
- Non invasive
- Technique that uses magnetic fields to indirectly visualize brain structure
- Measures release of energy from water in tissues after exposing
What is the weakness of CT and MRI scans?
show brain structure only, not activity
PET
Positron Emission Tomography
- Functional imaging technique, measures consumption of glucose-ish molecules
- Inject radioactive glucose-like molecules
- Yield picture of neural activity in diff regions of brain in response to stimuli
- Works cuz cells increase intake of glucose when active
Which neuroimaging technique is invasive?
PET
What is the weakness of PET?
invasive, was later replaced by fMRI
fMRI
Functional Magnetic Resonance Imaging
- Indirect indicator, non invasive
- Technique that uses magnetic fields to visualize brain activity using changes in blood oxygen level
- Brain cells require more oxygen when busy means increased oxygen in blood flowing to active brain areas
Which neuroimaging technique involves changes in blood oxygen level?
fMRI
-> visualize brain activity
Which neuroimaging technique measures consumption of radioactive glucose?
PET
-> shows activity in diff regions
Which neuroimaging technique is good at detecting soft tissues like brain tumours?
MRI
-> better than CT for detecting soft tissue
Which neuroimaging technique involves using X rays?
CT
-> constructs 3D images
Default mode network
regions associated with spontaneous thoughts (ex/ daydreaming)
Brain is active even when we’re doing nothing
Discovered by fMRI researchers
What network did fMRI help discover?
Default Mode Network
MEG
Magnetoencephalography
- Detect electrical activity in brain by measuring tiny magnetic fields on skull surface
- Non invasive
- ability to track brain changes over super brief time intervals
Describe the difference in time between brain changes measured in MEG vs PET and fMRI
PET and fMRI measure brain changes second by second
vs
MEG measures changes millisecond by millisecond
What are some misinterpretations of neuroimaging techniques?
- Assuming that functional brain images (like PET and fMRI) are actual photos of brain in action
- Neuro seduction
- There’s risk of chance findings cuz things get complex when comparing activity of hundreds of brain areas
What is neuro seduction?
Placing unwarranted confidence in evidence derived from brain-imaging studies
- Do not assume the imaging techniques can read minds, or be more persuaded just becuz it’s scientific
Functional brain images are not actual photos of brain in action, what are they?
ex/ PET and fMRI
- Photo is subtraction of brain activity of control task from experimental task
- Light up means active, but dunno if neurons are inhibited or excited
- Doesn’t allow definitive diagnoses of mental disorders (but can be helpful)
What are genes?
Sections of DNA that contain hereditary info
Allele
one of two or more alternative forms of a gene
Homozygous vs heterozygous
homo = when 2 alleles of a gene in the pair are the same
heter = when they diff
Dominant vs Recessive allele
Dominant allele attributes are expressed in a HETEROZYGOUS pair
Recessive allele attributes are masked and only expressed in the absence of dominant gene
Genotype vs Phenotype
Genotype is a person’s genetic makeup, or allelic combo
Phenotype is how genotype is manifested in observable characteristics
Behavioural adaptation
physical and behavioral changes that help survival, become better suited for envo
fitness - organism’s capacity to survive
Monogenic vs polygenic inheritance
a trait or characteristic is determined by
mono - one pair of genes
poly - more than one pair of genes
Heritability
proportion of phenotypic variance attributable to genetic variance
- extent to which genes contribute in observable differences AMONG individuals
- ranges from 0 to 1
Environmentability
proportion of phenotypic variance attributable to environmental variance
- whatever isn’t attributable to genes must be because of environment
Heritability + environmentability =
1.0
What are the 3 ways we can study heritability?
- family studies
- twin studies
- adoption studies
Family studies
Analysis of how characteristics run in intact families (blood relatives)
family studies pros and cons
pros
- useful for estimating risk of disorder among relatives
cons
- shared environment and similar genetic material don’t allow us to disentangle the effects of nature vs nurture
Twin studies
comparing traits of identical twins and fraternal twins
What are twin studies useful for?
can infer genetical influence
Share common environment, so if identical twins are more alike on a trait than fraternal twins, then we can infer it’s genetically influenced
Identical vs fraternal twins
identical (monozygotic) have 100% shared genes and placenta
- higher correlation between traits compared to fraternal
fraternal (dizygotic) have 50% shared genes, like normal siblings
Adoption studies
Assess the influence of heredity by examining the resemblance between adopted children and both their biological and their adoptive parents
What are adoption studies useful for?
genetical influence
- diff environment, so anything similar between kid and biological parent is attributable to genes
Potential confound for adoption studies
selective placement
- may mess up study if kid is placed in similar envo
What are the 5 common misconceptions of heritability?
- Heritability applies to a single individual rather than differences among individuals
- Heritability tells us whether a trait can be changed by environmental factors
- Heritability is a fixed number
- Effects of genes (heritability) are really the same for everybody across whole population
- Heritability implies destiny and high heritability for problems implies the only hope is to alter genes
Reaction range
the extent to which your genes set limits to how much a trait can change in a new environment
is it nature or nurture?
both!
additive and interactive
describe gene x environment interactions
- A phenotypic effect is determined by the interaction between the environment and the organism’s genetic makeup
- Genetic differences may only be apparent in specific environments
«_space;look at notes for depression and maze rats examples»_space;
Epigenetics
Heritable changes in phenotype with no changes in DNA sequence (usually in response to environment)
How environmental influences the expression of genes
- envo influences can turn certain genes on or off, impacts whether it can be read
- life stressors & maternal affection very important
- Removing methyl groups allow dna to be unwound and red
What were the major findings on Szyf & Meaney’s studies on rats?
- envo influences can turn genes on or off, impacts if it can be red
- the presence of maternal affection lead to nurtured pups, whose DNA were not methylated and can be read = more calm
- removing methyl groups allowed DNA to be unwound and read
Which technique: Electrical stimulation of brain and elicit vivid images / movement, allow researchers to see brain activity
EEG
MEG
Which imaging techniques allow us to see brain structure or function
CT
MRI
Imaging techniques that allow us to see how the brain’s activity changes in response to psychological stimuli
PET
fMRI
Why can’t many cognitive functions be neatly localized?
cuz individual brain areas participate in multiple functions, so many parts of brain contribute to any specific task
what do proteins influence?
observable physical and psychological traits
Can heritability change?
yes
can sometimes change within individuals & over time in population
If the voltage inside the cell is 60mV and outside is 80mV, what is the membrane potential?
-20 mV
When Na ions rush into the cell, the cell becomes?
depolarized
aka more positive
A neuron is hyper polarized during which stage?
undershoot or refractory period (basically same thing)
Without myelination, an action potential might
A) Be faster
B) Be Slower
C) Fade
D) 2 of the above
E) None of the above
D (slower or fade)
An action potential will occur if
a. The sum of EPSPs is larger than threshold
b. Neuron is in refractory state
c. Sum of IPSPs are larger than threshold
d. Neuron is hyperpolarized
e. Two of the above
a
If both parents are heterozygous, there are ___ possible different genotypes in their children leading to a ___ phenotypic ratio of detached to connected earlobes
3 // 3:1 ← phenotypic ratio
What kind of study would tell you about the influence of a unique environment on childhood obesity?
A) Family
B) Twin
C) Adoption
Adoption
If we reduce the range of environmental influences on a trait within a population, the heritability of that trait will ____ because ____
increase, more of the differences will be due to genetic factors
If we could magically equalize all schools and home environments to promote higher intelligence in children. What percentage of differences among them would be explained by genetics?
100%
What if we could magically change genes in the population so everyone’s genes had the same impact on IQ. If there were still differences in IQ between people, we would know that heritability has… [ increased / decreased / stayed the same ]
decreased
Darker skin produces more of the pigment called melanin that helps protect skin from sun damage. Which group is least likely to get skin cancer?
A) People with dominant genes for darker skin
B) Dominant genes for lighter skin
C) Recessive genes for darker skin
D) Recessive genes for lighter skin
E) Need more information
E
