Topic 1: Genes and Evolution
behaviour is a result of interaction between genes and environment
Every human cell has a nucleus -> each cell 23 pairs of chromosomes. 46 chromosomes. Each
chromosome contains a single molecule of DNA. DNA-moleculen zijn dubbelstrengs en
bestaan uit een dubbele helix. Fosfaatgroep, suikermolecuul en een nucleïnebase. Er zijn
vaste basenparen waardoor beide strengen complementair (aanvullend) zijn: adenine (A)
met thymine (T), guanine (G) met cytosine (C).
o In each cell, some genes are expressed at any point in time and others are not. This is
controlled by the biochemical environment inside the cell. The biochemical
environment inside the cell is influenced by e.g., the environment outside the cell,
timing in development, the overall environment, experience, behavior. E.g.: the
transplantation of cells results in different gene expressions when implanted in
different areas. bijv sporten (environment) kan invloed hebben op gene expression
van muscle cells -> meer spieropbouw.
o Monozygotic (identical) twins have the same genotype but
different environments. So different fenotypes.
Each cell 23 chromosomepairs: female egg and sperm-cell 23
chromosomes. So: each gene is paired with another gene. The pairs are
located at corresponding positions on pairs of chromosomes.
Allele is one specific variant of a gene: dominant or recessive
A specific trait or behavior is determined by the interaction between
the environment (past and present) and 1) one gene pair or 2)
multiple gene pairs: polygenetic inheritance.
Where do our parent’s sets of genes come from? from their parents
and theirs from their parents etc: the genome is shaped by evolution
over the years ‐> Darwin’s evolution theory
Evolution by natural selection Charles Darwin hypothesized that all modern organisms 1.
are descended from a small set of shared ancestors. 2. have merged over time through the
process of evolution.
The key mechanism of evolution is natural selection. Three conditions
1. There is variation among individuals of a populations
2. Individuals with a certain trait survive and reproduce at higher rates than others
3. The trait associated with this advantage is passed from parents to offspring
• if three conditions met -> specific traits will be better represented in the next generation.
NB: Darwin did not know how variations between individuals arose.
• Organisms differ in genotype and variations in genotype are passed from generation to
generation.
• What matters is the survival of genes, not the survival of individuals. Dus beschermen
van je kinderen voor je eigen dood = slecht voor individu maar goed voor genen.
The evidence for modern evolutionary theory comes from many sources :
o The fossil record: fossils show gradual changes in inheritage lines.
o The resemblance between genomes of various organisms: not only in physical sense,
but also in genetical sense. Vb anthropoid apes (links) en humans (Rechts).
Centromere = middelste stuk. Telomere = uiteinde. Fusion of two ancestor
chromosomes.
, o Pseudogenes = inactive gene that does not produce a protein. Non-functioning gene.
Probably functioned in our ancestors, but not in ours because of mutation. Vb we
hebben genen om vitamine c te kunnen maken van glucose. One part of its code is
missing.
o Distribution of species across the world: continental islands (were once connected to
the large continent) versus oceanic islands (were never connected). First has a very
large variety of species, latter lacked a lot of species (behalve vogels, en planten,
want die konden makkelijk daar komen, andere soorten niet).
Despite overwhelming evidence, many people remain sceptical about the theory of
evolution.
It does NOT follow that evolution:
- somehow improves organisms. Bijv zoet lekker vinden.
- can only lead to rigid behavioural patterns.
Nature (genes) versus Nurture (environment): The nature
nurture debate has become increasingly irrelevant. Instead,
there is a continuous interaction between genes and
environment! Who we are is determined by how our genes are
expressed in distinct environments. So: is it correct to claim
that “a violent person has violent genes”?
Topic 2 : the brain and the nervous system
Alle zichtbare en meetbare eigenschappen van de mens= fenotype. Dus ook nervous
system.Nervous system is made up of two basic kinds of cells: glia (supporting) en neurons
(receive and transmit information). Neurons allow us to do all the things we do.
Different types of neurons:
o Sensory receptors: translating physical stimulus into electrical signal
o Sensory (afferent) neurons: carries info into the central nervous system
o Motor (efferent) neurons: outwards from nervous system to muscle cells.
o Interneurons: make connections within the central nervous system
When neuron fires -> action potential is generated. + 40 mV tijdelijk. inside is positively
Neuron: charged relative to the outside.
Ionen bepalen potentiaal. Ionchannels can be selectively opened and
closed. Na+ = sodium are pumped out and K+ potassium ions pumped in at
rest. After stimulus sodium channels open. Immediately afterwards,
sodium channels close. Potassium channels open, pumped out of cell.
, Dus eerst Na+ naar binnen tot aan piek. Dan K+ eruit
tot laagste punt dan wisselen Na+ en K+ weer uit. !!
Tot -70. Refractory period neuron not able to fire.
Agonists: kan een van deze dingen doen • Increase of
precursor • counteracting the cleanup enzymes •
blocking the re‐uptake • mimicking the transmitter’s action
Antagonists • decrease precursor (or neurotransmitter) • increase effectiveness cleanup
enzymes • enhance the re‐uptake • blocking of receptors
SNS heeft afferent en efferent nervous system vgm. CNS directs endocrine system.
Methods for studying the brain: •Clinical observation of patients with brain damage
• Experimental techniques:
o Invasive: animal studies (e.g., lesions, single‐cell recordings). Entering body.
o TMS (Transcranial Magnetic Stimulation)
• Other techniques
o Electrophysiology
o EEG(ERP)
o Brain imaging
o (f)MRI scan and PETscan
ERP =averaged over multiple EEG measurements van zelfde events.
Left and right halve are mostly symmetrical. Lateralization = assymetry of functions over the
two halves. The localization of functions just refers to which functions (e.g., vision, planning
etc.) are where in the brain. Language = left hemisphere. Corpus callosum is een soort
bandje
Dus als er in een ruimte aan linkerkant een woord wordt gepresenteerd, kan je dat als split-
brain patient niet lezen, want left hemisphere doet language. Maar ze
kunnen wel met left hand correct item oppakken, want is controlled by right
hemisphere.
representation heeft niet te maken met grootte maar met sensitivity
Somatosensory homunculus: man you would get ->
Lecture 3: consciousness
experiment Libet: readiness potential was prior to awareness of decision. Free will?
Variations in ‘normal’ consciousness occur as a result of: 1 attention 2 sleep 3 drugs
Stimulants: side effects: insomnia, anxiety and weight-loss.
o Cocaine. Triple reuptake inhibitor: blocks reuptake of dopamine, serotonin and
norepinephrine, so acts as an agonist for these neurotransmitters.
o Long term use: limbic system, subcortical structures are harmed, including those
structures important for memory and emotion.
