Notes topic 1: genes and evolution
- In the early 90’s people thought that genes caused (Violent) behavior, but today we know that
genes <-> environment <-> (Violent) behavior
- Each cell contains a nucleus → contains 46 chromosomes → carry
instructions for how to build and operate a booty → made Up of
Collect strand Of DNA (double helix) → backbone is made of
phosphates and sugar → each sugar has 1/4 Nitrogen
- The rungs of the double helixes are made up of
complementary chains of adenine (A), thymine (T), guanine (G) and
cytosine (C)
o G&C and T&A are always a pair
- The sequence of these pairs encodes biological information
- Genes: meaningful sectors of the DNA molecule
o govern the cell’s functioning by providing instructions for making proteins
- Gene expression: whether a gene is turned 'on' or 'off'; the
extent to which a gene is transcribed into a sequence of
amino acids (protein)
o If not turned on, the protein won’t be produced
o methylation: process by which methyl groups are
added to the DNA molecule to turn the gene off
- In each cell, some gems are expressed at any point in time
and others are not. This is controlled by the biochemical environment inside the cell
o the biochemical environment inside the cell is influence by e.g., the environment outside
the cell, timing in development, experience, behavior
- The body part in which the cell is in determines if protein will be produced
o for example: If you don't exercise regularly, the genes in your muscles will turn off → stop
making proteins
- Genotype: an organism’s specific set of genes
- Phenotype: the covert trans and behavior of an organism (the outside layer, what we look like)
o is determined by genotype × environment (Experience, past and present)
- Each gene is paired with another gene → they are located at correspondent positions on pairs of
chromosomes
- Alele Is one specific variant of a gene
o dominant (1), recessive (needs 2 Aleles)
- Distinction between allele and gene: Along sequences of
nitrogen bases → meaningful sequence = gene → protein.
- On a specific Area on a chromosome are different types of
codes
o For example, at the place of the Gene 'eye' could be a code for blue or brown
allele
- A specific trait or behavior is determined by the interaction between the environment (past and
present) and:
o One gene pair
, o multiple gene pairs: polygenetic inheritance
- Heritability: H = genetic variance: phenotypic variance
- The genome is shaped by evolution over the years → Darwin 's evolution theory
o an organism's complete set of DNAS
- Key mechanisms of evolution are Natural Selection
o 3 conditions:
Variation among individuals of populations
Individuals with certain traits survive and reproduce at higher rates than others
The associated trait it passed from parents to offspring
o Specific traits will be better represented in the next generation
- What matters is the survival of genes, not individuals
- Nature vs Nature debate has become increasingly irrelevant
o Instead, there is a continuous interaction between genres and environment
- Is it correct to claim that ' 'a Violent person has Violent genres?"
o MAOA allele for low MAO activity <-> severe mat treatment <-> higher probability or being
convicted of violent crimes
, Topic 2: The brain and the nervous system
- The nervous system contains of the central nervous system (brain + spinal cord) and the peripheral
nervous system (consisting mainly of nerves)
o Made up of 2 basic kind of cells
Glia: supportive function
Neurons: receive information and transmit info to other cells by
means of electrical pulses
- Different types of neurons:
o Sensory receptors: able to change
pressure signal into electrical pulses
o Sensory (afferent) neurons carry
information into the CNS
o Motor (efferent) neurons carry
information out of the CNS to e.g., muscle
cells
o Interneurons: connects efferent and
afferent neurons
- The neuron is covered by a membrane: only some substances can go in and out. There are different
numbers of negatively and positively charged molecules inside and outside of the cell.
o Can be measured with a voltage meter
o 70 millivolts = resting potential
o + 40 millivolts = when a membrane is stimulated, the millivolts may change, could also
change when that neuron fires (action potential)
- Sodium irons are pumped out and potassium irons are seeped in. the relative concentration of irons
inside and outside determine the difference in electrical charge.
- Action potential is only generated from – 55 millivolts and higher
- The sum of the positively and negatively charged irons at the outside is more positive than the sum
of the positively and negatively charged irons on the inside
o Implies that the inside is negatively charged relevant to the outside -> resting potential
- Iron channels in membrane can be selectively opened and closed
- The sodium potassium pump is a mechanism in the membrane that ensures that the polarization is
maintained.
o Increases potassium and reduces the sodium concentration in the neuron, which help
maintain the resting membrane potential
- Action takes place: sodium channels open causing depolarization -> sodium -> potassium channels
open and potassium flows out -> sodium channels are closed causing repolarization -> neuron is
negatively charged -> potassium channels close -> neuron regains original negative resting
potential.
- Neurons either fire or do not fire (all or none law)
- Intensity variations by:
o Variations in the number of neurons firing
, o Variations in firing rate
- Neurons interact (each neuron is affected by other neurons)
o Via synapses: the place where a signal passes from one nerve cell to another
o Through chemical substances (released from synaptic vessels): neurotransmitter travels to
receptors of postsynaptic neurons
Different types of neurotransmitters like dopamine, serotonin etc.
- Presynaptic neuron: sends the signal
- Postsynaptic neuron: receives the signal
- When the action potential has reached the terminal button, the vessel adheres to the presynaptic
membrane and releases the neurotransmitters into the synaptic cleft. These neurotransmitters bind
to the receptors on the postsynaptic neuron.
- When a neurotransmitter binds to a receptor, it blocks new signals until the influence of the
neurotransmitter is over.
- The nervous system uses a ‘key-and-lock-system’ to keep the actions apart
- The effect of a neurotransmitter is terminated by:
o Auto receptors: sends a
signal when the release
needs to be stopped (if
it reaches a certain
amount)
o Synaptic reuptake:
recycling! They are
taken up by the
presynaptic neuron
o Enzymes: deactivate
the transmitters in the
synapse
- The binding of a neurotransmitter with a receptor produces an excitatory (increase in actions) or
inhibitory (decrease in actions) signal.
Drugs
- Agonists are drugs/toxins that enhance the actions of the neurotransmitters by e.g., mimicking the
neurotransmitters and binding with receptors
o Increase of precursor (= a substance from which another is formed)
o Counteracting the clear-up enzymes
o Blocking the re-uptake
o Mimicking the transmitter’s action
- Antagonists are drugs/toxins that prevent the action of the neurotransmitters
o Decrease precursor (or neurotransmitter)
o Increase effectiveness clean-up enzyme
o Enhance the re-uptake
o Blocking of receptors
History and ways of brain imaging
- 19th century -> phrenology = bumps on skull were interpreted in terms of personality traits
- In the early 90’s people thought that genes caused (Violent) behavior, but today we know that
genes <-> environment <-> (Violent) behavior
- Each cell contains a nucleus → contains 46 chromosomes → carry
instructions for how to build and operate a booty → made Up of
Collect strand Of DNA (double helix) → backbone is made of
phosphates and sugar → each sugar has 1/4 Nitrogen
- The rungs of the double helixes are made up of
complementary chains of adenine (A), thymine (T), guanine (G) and
cytosine (C)
o G&C and T&A are always a pair
- The sequence of these pairs encodes biological information
- Genes: meaningful sectors of the DNA molecule
o govern the cell’s functioning by providing instructions for making proteins
- Gene expression: whether a gene is turned 'on' or 'off'; the
extent to which a gene is transcribed into a sequence of
amino acids (protein)
o If not turned on, the protein won’t be produced
o methylation: process by which methyl groups are
added to the DNA molecule to turn the gene off
- In each cell, some gems are expressed at any point in time
and others are not. This is controlled by the biochemical environment inside the cell
o the biochemical environment inside the cell is influence by e.g., the environment outside
the cell, timing in development, experience, behavior
- The body part in which the cell is in determines if protein will be produced
o for example: If you don't exercise regularly, the genes in your muscles will turn off → stop
making proteins
- Genotype: an organism’s specific set of genes
- Phenotype: the covert trans and behavior of an organism (the outside layer, what we look like)
o is determined by genotype × environment (Experience, past and present)
- Each gene is paired with another gene → they are located at correspondent positions on pairs of
chromosomes
- Alele Is one specific variant of a gene
o dominant (1), recessive (needs 2 Aleles)
- Distinction between allele and gene: Along sequences of
nitrogen bases → meaningful sequence = gene → protein.
- On a specific Area on a chromosome are different types of
codes
o For example, at the place of the Gene 'eye' could be a code for blue or brown
allele
- A specific trait or behavior is determined by the interaction between the environment (past and
present) and:
o One gene pair
, o multiple gene pairs: polygenetic inheritance
- Heritability: H = genetic variance: phenotypic variance
- The genome is shaped by evolution over the years → Darwin 's evolution theory
o an organism's complete set of DNAS
- Key mechanisms of evolution are Natural Selection
o 3 conditions:
Variation among individuals of populations
Individuals with certain traits survive and reproduce at higher rates than others
The associated trait it passed from parents to offspring
o Specific traits will be better represented in the next generation
- What matters is the survival of genes, not individuals
- Nature vs Nature debate has become increasingly irrelevant
o Instead, there is a continuous interaction between genres and environment
- Is it correct to claim that ' 'a Violent person has Violent genres?"
o MAOA allele for low MAO activity <-> severe mat treatment <-> higher probability or being
convicted of violent crimes
, Topic 2: The brain and the nervous system
- The nervous system contains of the central nervous system (brain + spinal cord) and the peripheral
nervous system (consisting mainly of nerves)
o Made up of 2 basic kind of cells
Glia: supportive function
Neurons: receive information and transmit info to other cells by
means of electrical pulses
- Different types of neurons:
o Sensory receptors: able to change
pressure signal into electrical pulses
o Sensory (afferent) neurons carry
information into the CNS
o Motor (efferent) neurons carry
information out of the CNS to e.g., muscle
cells
o Interneurons: connects efferent and
afferent neurons
- The neuron is covered by a membrane: only some substances can go in and out. There are different
numbers of negatively and positively charged molecules inside and outside of the cell.
o Can be measured with a voltage meter
o 70 millivolts = resting potential
o + 40 millivolts = when a membrane is stimulated, the millivolts may change, could also
change when that neuron fires (action potential)
- Sodium irons are pumped out and potassium irons are seeped in. the relative concentration of irons
inside and outside determine the difference in electrical charge.
- Action potential is only generated from – 55 millivolts and higher
- The sum of the positively and negatively charged irons at the outside is more positive than the sum
of the positively and negatively charged irons on the inside
o Implies that the inside is negatively charged relevant to the outside -> resting potential
- Iron channels in membrane can be selectively opened and closed
- The sodium potassium pump is a mechanism in the membrane that ensures that the polarization is
maintained.
o Increases potassium and reduces the sodium concentration in the neuron, which help
maintain the resting membrane potential
- Action takes place: sodium channels open causing depolarization -> sodium -> potassium channels
open and potassium flows out -> sodium channels are closed causing repolarization -> neuron is
negatively charged -> potassium channels close -> neuron regains original negative resting
potential.
- Neurons either fire or do not fire (all or none law)
- Intensity variations by:
o Variations in the number of neurons firing
, o Variations in firing rate
- Neurons interact (each neuron is affected by other neurons)
o Via synapses: the place where a signal passes from one nerve cell to another
o Through chemical substances (released from synaptic vessels): neurotransmitter travels to
receptors of postsynaptic neurons
Different types of neurotransmitters like dopamine, serotonin etc.
- Presynaptic neuron: sends the signal
- Postsynaptic neuron: receives the signal
- When the action potential has reached the terminal button, the vessel adheres to the presynaptic
membrane and releases the neurotransmitters into the synaptic cleft. These neurotransmitters bind
to the receptors on the postsynaptic neuron.
- When a neurotransmitter binds to a receptor, it blocks new signals until the influence of the
neurotransmitter is over.
- The nervous system uses a ‘key-and-lock-system’ to keep the actions apart
- The effect of a neurotransmitter is terminated by:
o Auto receptors: sends a
signal when the release
needs to be stopped (if
it reaches a certain
amount)
o Synaptic reuptake:
recycling! They are
taken up by the
presynaptic neuron
o Enzymes: deactivate
the transmitters in the
synapse
- The binding of a neurotransmitter with a receptor produces an excitatory (increase in actions) or
inhibitory (decrease in actions) signal.
Drugs
- Agonists are drugs/toxins that enhance the actions of the neurotransmitters by e.g., mimicking the
neurotransmitters and binding with receptors
o Increase of precursor (= a substance from which another is formed)
o Counteracting the clear-up enzymes
o Blocking the re-uptake
o Mimicking the transmitter’s action
- Antagonists are drugs/toxins that prevent the action of the neurotransmitters
o Decrease precursor (or neurotransmitter)
o Increase effectiveness clean-up enzyme
o Enhance the re-uptake
o Blocking of receptors
History and ways of brain imaging
- 19th century -> phrenology = bumps on skull were interpreted in terms of personality traits
