Tilburg University – Bachelor Program
Content ::
- Chris Chandler – Psychobiology (2015)
- Crash Course – Videos
- Assigned Articles
Topics ::
- Lectures 1 – 5 :: book + videos
o Evolution
o Communication
o Development
o Immune System
o Homeostasis
- Lectures 6 – 10 :: book + videos + articles
o Psychopharmacology
o Motivation
o Emotions
o Socio-biology
o Sexual Differentiation
- Lectures 11 – 14 :: book + videos + articles
o Stress and Anxiety
o Vascular system
o Personality
o Depression
(bonus :: Motor behaviour and control [book])
,BIOLOGICAL PSYCHOLOGY
LECTURES 1 – 5
Evolution
Communication
Development
Immune System
Homeostasis
, GENETICS AND EVOLUTION CHAPTER 2 + VIDEOS
Stephen Jay Gould
- Facts are the worlds data. Theories are structures of ideas that explain and interpret facts.
They don’t disappear when a new theory gets adopted
Evolution
- Theory of descent and modification
o Modern organisms successful adaptations of previous generations
(the unsuccessful ones go extinct)
- Charles Darwin
o Transmission of genetic material is the meaning of life
“we are machines built by DNA whose purpose is to make more copies of the
same DNA”
o Any species lacking this drive will go extinct
- Evidence
o Biogeography (natural barriers)
o Fossil records
o Structural similarity
o Embryology
o Molecular biology (similarities in DNA)
Human evolution
- 600 million years ago, start of life on earth
o 450mil, start of vertebrae (spine evolved before brain)
o 180mil, start of mammals (in utero development of offspring)
Hominines family
Australopithecus
Homo
o Homo sapiens
o Homo erectus
- Can be traced back from Africa (i.e. ‘out-of-Africa hypothesis)
o And traced even further we hail from Asia
,Behavioral genetics
- Quantitative traits :: affected by multiple genes
o E.g. ADHD with degrees of severity along a continuum
Nearly all cognitive factors are Quantitative traits
- Qualitative traits :: affected by single gene (follow pattern of inheritance)
o Also called ‘Mendelian inheritance’
o Typically unaffected by environmental factors
- In some individuals with inherited disease-associated alleles, the alleles might penetrate into
becoming a disorder
Mosaicism :: i.e. not all cells in individual are genetically identical
- E.g. ‘Turner-syndrome’ i.e. deletion of X-chromosome in a portion of cells
Phenocopies :: variation in phenotype, as result of environmental conditions
- Non-hereditary (not a form of mutation)
- Most often during organism’s development
Mendelian genetics :: dichotomous traits i.e. ‘yes-no’ traits
- Dominant vs. recessive traits
o Genetical construct :: genotype
o Observable effect :: phenotype
- Alleles :: possible genes which affect the same phenotypes
e.g. gene ‘x’ and gene ‘y’ both affect eye color
- Example Huntington’s disease
o Behavioural changes (early stage)
Lack of emotions – both personal and failure to recognize them in others
Alternating emotions – aggression, excitement, depression, apathy, antisocial
Short-term memory lapses
Orientation problems
Slight uncontrollable movements of face – limbs
PKU :: Phenylketonuria
- Delayed cognitive maturation
- Due to recessive allele (requires two of the genotypes to show effects)
o Therefore, if both parents have a PKU-gene present, in regards to offspring
50% will be a carrier of the disease
25% will express the disease
- Miss the enzyme phenylalanine hydroxylase
o Needed to break down amino acid phenylalanine
Leads to buildup of two toxic substances in body which damage CNS
, - Symptoms
o Delayed mental – social skills
o Smaller headsize
o Hyperactivity
o Jerking movements of extremities
o Mental impairment
o Seizures
o Skin rashes
o Tremors
o Unusual positioning of hands
Mitosis :: cellular duplication
Meiosis :: cellular division
- Reduces chromosome diploid number (46) to the haploid number (23)
Allows for formation of a zygote (fertilized egg)
- Steps of mitosis
1. Chromosomes duplicate (from 1 karyotype to 2 karyotypes in cell)
2. Cells duplicate
If between these steps, the 2 karyotypes interfere with each other, it creates
mutation in the two karyotypes (definition; see below)
o i.e. called ‘crossing over’
o leading to diversity in species
Chromosomes
- Karyotype :: all the chromosomes in cell ‘x’
i.e. 23 chromosome pairs in humans
- One set of chromosomes :: haploid e.g. egg/sperm cells
- Pair of chromosomes :: diploid
o Humans :: 23 pairs
- Ordered by size
o Chromosome 1 = largest
o Chromosome 21 = smallest (was previously #22)
First 22 chromosomes :: autosomes
23rd chromosome pair :: sex-chromosome
,Deoxy-ribonucleic acid :: DNA
- ‘building block of life’
o Made out of
Sugar i.e. ribose
Carbon
Nitrogenous base i.e. adenine – cytosine // guanine – thymine
Phosphate group
o Two functions
Replication
Creation of proteins (thereby determining function of cell)
o Proteins contain 50% of dry-weight of cell
- Nucleic acid
o Most important part = nucleotides
Deoxy-ribonucleic acid :: Creation of proteins
- Basis for the phrase “DNA as a building block of life”
o Nucleotide bases :: code that permits construction of amino-acids
Which later make up
o Enzymes
o Proteins
o Polypeptides (small proteins)
- DNA-code to proteins
o Based of sequences of three nucleotides i.e. ‘codon’
Beginning: Start codon
Mid-section: Amino-acid coding codons
End: Stop codon
1. Transmitting DNA-code outside of cell-nucleus using mRNA
(mRNA substitutes thymine for uracil)
2. Transcription – process i.e. Reading of DNA-
code
Contains exons – introns
Exons :: sequences that code for proteins
Introns :: non-coding sequences
o mRNA removes all the introns
3. Translation – process
Done by using ribosomes
o Add amino-acids as the codons instruct
Amino-acids taken to ribosome by tRNA
,DNA :: Polymorphism
- Variations in DNA sequences that are present in more than 1% of population
o Single nucleotide polymorphisms (SNP)
Long stretches of DNA
Provide vulnerability factors on a scale
- Mutation
o change in single gene that is rare, random, independent of needs of organism
often leads to a disorder; following binary presence (yes-no)
often follows mendelian hereditary pattern
DNA :: variations
- Satellite DNA :: Non-coding DNA
o Large parts organized in repeated sequences i.e. tandem repeat
Microsatellites :: 2-4 pairs of tandem-repeats; present in high levels
with
inter-intra specific polymorphisms
- Deletions / insertions :: loss/addition of nucleotides
o Especially in meiosis (piece of chromosome breaks off)
e.g. Williams-Beuren syndrome (deletion in chromosome 7)
- Inversions i.e. segments of chromosome turned around (180 degrees)
o Typically show no phenotypic effects
- Translocations i.e. movement of segment to a non-homologous chromosome
o Two types
Balanced :: equal parts are exchanged between chromosomes
Unbalanced :: unequal portions are exchanged (extra/missing
genes)
- Duplication i.e. doubling/enlarging of chromosome (or unequal crossing over)
Associated with some leukemia’s
- Number of chromosomes
o Monosomy :: only one particular type of chromosome (e.g. Turner’s syndrome)
o Polyploidy :: more than two sets of chromosomes
Trisomy :: an extra chromosome (e.g. Down’s syndrome)
Tetraploidy :: four of each chromosome (most often fatal)
Epigenetics i.e. modifications of genome which doesn’t involve the DNA sequence
- Can switch genes on – off // determine which proteins are transcribed
o E.g. the phenotypical differences between monozygotic twins
, Psychology – biology combination :: behavioural genetics
- Understanding genetic contributions to behaviour
Important for nature-nurture debate
- Heritability estimate in population
o Generally estimated to lie around 0,5 (i.e. 50% of variation caused by genetics)
And other half being environment
o Differs per context – individual
E.g. schizophrenia is 75% genetics
E.g. height is 88% genetics
- Most often twin-studies are performed to find out hereditary factors
o Comparing dizygotic with monozygotic twins
If there’s no hereditary constituent, no significant difference should appear
o However, people often marry those who are similar to them
o Critique
Twins often have close emotional bonds; thereby sharing the same
environment
Have same friends
Treated the same by others
More likely to have identity confusion
o i.e. twin-studies is at most circumstantial evidence
adoptive studies
their environment is different than those with biological care-takers
Turkheimer :: three laws of behavioural genetics
1. All human behavioural traits are genetic
2. Effect of being raised in same family is smaller than the effect of genes
3. Substantial portion of behavioural traits unexplained by genes
Endophenotype :: intermediate account of genes – environment
- Difficult to link genes with behavioural/cognitive disorders
o Shortcomings of DSM-criteria – complexity of genetics
- Endophenotype adapted
o Alternative to shed light on gene-descriptors – elusive disease processes
- Criteria for endophenotypes
o Association between illness and phenotype (in population)
o Heritability
o State independent i.e. manifests whether or not individual is
symptomatic
o Co-occurrence of endophenotype and illness within families
o Non-affected family members show endophenotype in higher rates than population