Biology Of Behaviour Flashcards
Chromosome
Cellular structure that holds out genetic information in threadlike strands of DNA
DNA (deoxyribonucleic acid)
Genetic material that makes up chromosomes
Large coiled molecule that contains genes
Genes
Small segments of DNA that contain information for producing proteins
Genome
All genetic information contained in our DNA
Alleles
Different forms of genes
Dominant genes
Show their effect even if there is only one allele
Recessive genes
Show effects only when both alleles are the same (recessive form)
Genotype
Specific collection of genes that we carry as a part of our genetic makeup
Phenotype
Observable characteristics with relation to genetics
Behavioural genetics
3 principles of behavioural genetics that are relevant to psychology
- Relationship between specific genes and behaviour is complex; behaviours derive from dozens or hundreds of genes, not one or two
- by studying human twins and adoptees, or manipulating genes in animals, behavioural geneticists may disentangle the contributions of heredity and environment to behaviour
- Environment influences how and when genes affect behaviour
Monogenetic transmission
Hereditary passing on of traits determined by a single gene
Polygenic transmission
Many genes interacting to create a single characteristic
Heritability coefficient
Ranges from 0-1
1 being solely due to genetics
0 being solely due to environment
Fraternal twins
Develop from 2 different eggs fertilized by 2 different sperm
Aka dizygotic twins
Identical twins
Develop from a single fertilized egg that splits into two independent cells… aka monozygotic twins
Twin studies
- fraternal twins share half as many genes as identical twins (50% vs 100%)
- if a trait is genetically influenced, identical twins should be more similar in that trait than fraternal twins
- if genetics play no role, identical twins will be no more alike than fraternal twins in that specific trait
Adoption studies
- studying adopted individuals and comparing them to biological parents and adoptive parents
- if environment is more influential on a trait, the child will be more like adoptive parents
- if genetics are more influential on a trait the child will be more like the biological parents
Twin-adoption studies
-study twins, both identical and fraternal, who were raised apart and those who were raised together
Gene by environment studies
- assess how genetic differences interact with environment to produce a certain behaviour in some people but not in others.
- studies directly measure genetic variation in parts of the genome and examine how such variations interacts with different kinds of environments to produce different kinds of behaviours
- differs not in whether an individual has the gene, but how the gene presents itself
- some genes may vary in length of DNA sequence (genetic marker)
Genetic markers
- differences in length of DNA sequences for a particular gene
- researchers take a DNA sample then assess crucial environmental factors such as trauma, stress, in people with and without the genetic marker
- determine whether individuals raised in a particular environment are more or less likely to develop some trait (violence, high intelligence etc)
Gene manipulation in non-human animals
- genetically engineering of genes in experimental animals
- conditional manipulation of gene expression or permanent alteration of the genome
- involves inactivation or over expression of specific gene
Antisense injection
Form of genetic engineering where a gene (antisense) is injected to block the gene from being translated into protein
- if that gene plays a role in a particular behaviour, then inactivation should lead to observable changes
- eg. Brain-derived neurotrophic factor is a protein thought to support memory process, so inactivation will produce memory impairments
Viral mediated gene transfer
Genome alteration
- involve changing genetic material BEFORE conception (unlike genetic manipulation which is done to adult animals)
- genome alteration are present not only in adulthood, but also throughout prenatal and postnatal development
- knockout vs transgenic
Knockout (genome manipulation)
Inactivation of a gene
Transgenic (genome manipulation)
Introduction of a novel gene (usually human origin)
Epigenetics
- how the environment changes gene expression
- genes can be changed by an individuals behaviour, or behaviours can by modified by genetic expression
- food we eat, drugs we take, exposure to certain chemicals are a few things that can have epigenetic consequences
DNA methylation
- when we eat or drink certain things, exercise, or are exposed to particular chemicals in the environment, molecular tags known as methyl groups can get attached to specific nucleotides in the DNA, often targeting cytosines
- these tags turn off particular genres, regardless of the actual genetic sequence around them
Diversity of cells in the NS
- neuron types for three regions of the NS: the cortex and cerebellum (CNS) and the retina (PNS)
- neurons that communicate with other distant regions are usually larger that’s those that communicate locally.
Glial cells
- glia = glue
- glial cells hold the CNS and PNS together, providing structural support, promoting efficient communication between neurons, and removing cellular debris.
- also play important role in communication between neurons
- 90% of cells in the brain are glial cells
Acetylcholine
Slows ANS activity; eating, drinking, neuromuscular junction; involved in learning, memory, sleeping and dreaming
-Alzheimer’s disease results at least partially from a decrease in ACh
Dopamine
Plays and important role in arousal, mood (especially positive mood); oversupply correlates with schizophrenia; voluntary muscle control
- released in response to behaviours that feel good or rewarding
- cocaine blocks reuptake of dopamine to that it stays in synaptic clef longer before binding to receptors in postsynaptic neurons
- Parkinson’s related to dopamine - losing ability to control muscles and shake involuntarily
- dopamine producing neurons die in Parkinson’s and eventually loss of motor control can cause death
Epinephrine
Increases ANS activity; fight or flight response
- also called adrenaline
- produced in adrenal gland on kidney
Norepinephrine
- affects CNS activity
- plays role in increasing alertness and attention
Serotonin
- plays role in mood, sleep, eating, temp regulation
- undersupply correlates with anxiety and depression
- involved in dreaming and controlling emotional states
- drugs that block reuptake of serotonin are used to treat anxiety and depression
- MDMA (ecstasy) makes people feel social, affectionate and euphoric, stimulates extremely high levels of serotonin
GABA
- major inhibitory neurotransmitter
- slows CNS function
- correlates with anxiety and intoxication
- tells postsynaptic neurons NOT to fire
- GABA doesn’t function properly in people with epilepsy
- depressants (alcohol, anxiety drugs etc.) increase GABA activity to relax people
Glutamate
- most common excitatory neurotransmitter in the brain
- involved in memory
- may be involved in schizophrenia
- facilitates growth and change in neurons
Australopithecus
- 4 million years ago
- brain capacity ranges from 450 to 650 cubic centimetres
Homo erectus
- 1.6 million to 100000 years ago
- further development of skull and jaw are evident
- brain capacity about 900 cc
Neanderthal
- 350000 to 28000 years ago
- human skull now taken shape
- skull case has elongated to hold complex brain
- 1450 cc
Homo sapien
-200000 years ago to present
-deeply convoluted brain reflects growth in areas concerned with higher mental processes
1300cc
Hindbrain
- regulates breathing, heart rate, arousal and other basic survival function
- medulla regulates breathing, heart rate, BP, and involved in various reflexes like coughing, swallowing, sneezing, vomiting
- Pons serves as bridge between lower brain and higher midbrain and forebrain
- cerebellum contains more neurons than any other single part of the brain and is responsible for body movement, balance, coordination, and fine motor skills like typing and piano playing and is also important in cognitive activities such as learning and language
Midbrain
Controls eye muscles, processes auditory and visual information and initiatives voluntary movement
- Parkinson’s disease results from malfunction of midbrain
- reticular formation: network of nerves running through hindbrain and midbrain which is crucial to waking up, sleeping and arousal
Forebrain
Controls cognitive, sensory, and motor function and regulates temperature, reproductive function, eating, sleeping and emotions
- highly folded surface (cerebral cortex)
- Thalamus receives input from ears, eyes, skin and taste nudes and relays this info to associated part of cerebral cortex
- limbic system consists of hypothalamus, hippocampus and amygdala and cingulate gyrus
Bilateral
Left and right version of each structure in the brain
Hypothalamus
- master regulator of all major drives and motives including, thirst, hunger, temperature and sexual behaviour
- controls pituitary gland
Hippocampus
- wrapped around thalamus
- plays role in learning and memory
- if events are important enough, they’re processed in the hippocampus and eventually established as lasting memories
Amygdala
- small almond shaped structure located directly in front of the hippocampus
- plays key role in determining the emotional significance of stimuli, especially when they evoke fear
Cingulate gyrus
- means belt ridge
- belt like structure in the middle of the brain
- play important role in attention and cognitive control
- seems to malfunction in people with schizophrenia who have major problems focusing their attention
Basal ganglia
- collection of interconnected structures involved in voluntary motor control
- located between cingulate gyrus and surround the thalamus and have connections with the cerebral cortex, thalamus and brain stem
- because voluntary movement is an important part of emotional and motivated behaviour, the basal ganglia are often considered part of the limbic system
Nucleus accumbens
- animals would deliver stimulation to electrodes placed in a certain region of the basal ganglia called nucleus accumbens
- animals appeared to find the electrical self stimulation rewarding and later studies showed that this part of the brain is activated by natural rewards like food and sex
Cerebral cortex
- approx 80% of the brain
- much of human though, planning and perception and consciousness take place
Cortical localization
Different parts of the cortex are responsible for different function
Insula
- small structure that resides deep within the cortex in the area that separates the temporal lobe from the parietal lobe
- active in perception of bodily sensations, emotional states, empathy and addictive behaviour
- communicates with structures of the limbic system and higher brain areas involved in decision making
- plays role in awareness of our body as our own
Association cortex
- silent areas that are involved in the integration of information that comes from other cortical areas and the rest of the brain
- large degree of asymmetry between hemispheres
- left hemisphere processes info in a more focused and analytic manner. Language and comprehension production
- right hemisphere integrates information in. A broader, more holistic manner. Spatial arrangements, facial expressions etc.
- these functions are lateralized because they are biased toward one side of the brain
Aphasia
-a deficit in the ability to speak or comprehend language.
Broca’s area
Area associated with persons ability to speak
Wernicke’s area
Are in brain responsible for speech comprehension
Contralateral neglect
- damage to association cortex in the right parietal lobe can cause contralateral neglect, where individuals ignore the left side of their world
- eat only from left side of plate, dressing only one half of body etc
Prosopagnosia
Damage to areas in right occipital and temporal lobe which play roles in facial recognition
-face blindness where affected individuals have difficulty recognizing faces
Neurogenesis
-process of developing new neurons
Arborization
-growth and formation of new dendrites
Synaptogenesis
-formation of entirely new synapses or connection with other neurons that is the basis of learning
Electroencephalography (EEG)
- record electrical activity of the brain from electrodes placed on a persons scalp.
- the electrodes, metal disks attached to wires are usually mounted in a fabric cap
Event-related potential (ERP)
- special technique that extracts electrical activity from raw EEG data to measure cognitive processes
- raw EEG data provides a summary of all the electrical activity in the brain that happened at a particular time
- because they are based on EEG, ERPs provide excellent temporal resolution but poor spatial resolution
MRI
- magnetic resonance imagine
- uses magnetic fields to produce very finely detailed images of the structure of the brain and other soft tissues
- provides static pictures and useful for looking at abnormalities in structures
- doesnt give info about activity
FMRI
- functional MRI
- gives info on brain activity
- tells us where activity is occurring in the brain during particular tasks by tracking blood oxygen use
- very expensive and doesnt provide precise measures of when activation occurs in response to particular task
Positron Emission Tomography (PET)
- measure blood flow to brain areas in active brain
- can determine which brain areas are active during certain situations
- inject participant with radioactive form of oxygen or glucose, which the brain takes up during cel metabolism
