Psychology And The Brain Flashcards
What makes the human brain similar to and/or different to that of animals?
- Human brain has skills and capabilities that other animals do not have
- Example: we are able to use language to a much higher degree than other animals
- Gyri and Sulci in our cerebral cortex has shown the human brain has increased in size with evolution
- However, Animals rely on smell so their olfactory bulb is larger
Describe the broad structure of the brain
- With evolution the surface area of our brain has increased in size
- this is seen in the convulsions (gyri and sulci) in our cerebral cortex compared to other animals
- Two hemispheres communicate with each other through a bridge called the Corpus Callosum
- Explain the brain e.g lobes
- the cerebellum is involved in the execution of motor actions
- the brain stem contains networks of connections from the spinal cord
Identify some areas of the brain and their functions
1) Frontal lobe: contains areas involved in movement, attention and memory
2) Parietal lobe: somatosensory Cortex is located here
3) Temporal lobe: auditory cortex is here as well as areas involved in speech production
4) Occipital love: posterior in the brain and contains the visual cortex
Compare and contrast EEG and MEG as techniques for studying the brain
- EEG: directly measures electrical brain activity through the scalp. Attaching electrodes to the surface of the head and measuring current to record electrical currents
- MEG: measures tiny magnetic fields created by neural activity in the brain
MEG allows recordings of nearly the same brain activity as EEG but with better spatial resolution as well as excellent temporal
Compare and contrast MRI and fMRI as techniques for studying the brain
- MRI: uses strong magnetic field and radio waves to produce an image of the brain based on hydrogen ions in the body
- fMRI: uses MRI scanners to measure task related changes in blood flow.
- both have excellent spatial resolution. However, fMRI Has poor temporal resolution as it cannot track brain activity as it happens
Assess ECoG as a technique for studying the brain
• ECoG: involves placement of small electrodes on the surface of the brain
Gives direct recordings of brain activity with high spatial and temporal resolution
However, it is very dangerous for patients as a brain infection can be deadly. It is only carried out on people who have been given medical clearance for reasons such as tumours
How has Cellular Neurophysiology helped as a technique for studying the brain?
• The study of animals have provided knowledge about how the brain works. Staining examples of brain tissue to identify fine-grained neuroanatomy under microscope
Describe the structure of a neutron
Ramon y Cajal: first scientist to suggest the brain was made up of special cells called neurons
Neurons have:
- cell body with nucleus containing genetic material
Outline and describe the 5 neurotransmitter categories
1) Acetylcholine:
- neurotransmitter at the neuromuscular junctions e.g the motor system
2) Monoamines:
- Synthesised from a single amino acid
- present in the brainstem including dopamine
3) Amino acid neurotransmitters
- molecules are sub components of proteins
4) Neuropeptides
- include endorphins
- involved in meditating the systems involved in both pain and pleasure
5) Soluble Gases
- diffuse through cell membranes
- include CO2 and nitric oxide
Explain Synaptic communication
• Neurotransmitter binds with receptors and causes either:
- excitation: more depolarisation more AP - inhibition: hyperpolarisation preventing more AP
• inhibition: this will cause negatively charged ions to enter the cell and cause the menbrane to be negatively charged
How do drugs work in the brain?
• Many drugs act to alter neurotransmitter activity
- Agonists increase activity
- Antagonists decrease activity
- Some drugs interfere with mopping up of neurotransmitters
- Direct actions bind to the neurotransmitter binding site. Whereas, indirect actions bind elsewhere
Give an example of drugs and their action
Example: Benzodiazepines
- A GABA agonist
- Binds to GABA receptors
- Increases the binding of GABA to the receptor, increasing inhibition
What are hormones?
A chemical signal that is released into the bloodstream by an endocrine gland is which targets cells and other organs.
Explain the endocrine system
Secretes hormones through different glands
1) Pineal gland: secretes hormone called melatonin which regulates our daily biological cycles e.g sleep
2) Hypothalamus: hormones released are important in regulating sleep
3) Ovaries/Testes: secretes sex hormones
4) Adrenal Gland: Important for our initial stress response involved in fight/flight response
Explain the Autonomic Nervous System (ANS)
- Autonomic responses facilitate the fast mobilisation of energy required to respond to a stressful stimulus eg increase in heart rate
- Subdivided into two systems and work in opposition to each other
- PNS: internal processes of our hormones
- SNS: involved in responding to stress
• For instance, if we experience some debris in our eyes, the SNS will stimulate our tear glands to help wash our eyes. However, the PNS will cause the tear glands to be inhibited
Explain the stress response
- A physiological reaction caused by the perception of aversive situations
- First phase: ANS (very fast)
- Facilitate fast mobilisation of energy required to respond to a stressful stimulus
- fast responses through the spinal column cause increased heart rate
- adrenal medulla secretes stress hormones
- this then leads to the fight/flight response
• Second phase: Hormonal slow and sustained
- hormones have to be transported around the bloodstream hence why it’s slow
- Pituitary gland releases ACTH
- Adrenal Cortex secretes various stress hormones e.g cortisol
- stress hormones travel in blood stream to relevant organs
- this then leads to the fight/flight response
What is DNA and how does it work?
It is our genetic code packed away into chromosomes in the nucleus of our cells
1) DNA transcribed into mRNA by special enzymes releases from nucleus. A gene is an area of DNA that codes for RNA
2) RNA is translated into proteins in ribosomes
• Proteins affect the way cells work as slight differences in protein structure can alter behaviour
What is heritability and give some examples
The proportion of the entire variation in a group of individuals that is accounted for by genetic variation
Is a population estimate not for any one individual
Give some methods for studying genetic inheritance in reference to Family Studies
Case histories and genetic data collected or members of the family and control samples
Allows comparisons of genetic overlap versus similarity.
Hopper et al:
Give some methods for studying genetic inheritance in reference to Twin Studies
Mz twins are identical and share 100% genetic material
Dz twins are fraternal and share 50% of their segregating genes
Give some methods for studying genetic inheritance in reference to Adoption Studies
Compares twin pairs raised together with twins separated at birth where environmental factors are removed
Define phenotype and genotype
Phenotype:
- physical characteristics that result from the interaction of its genotype and environment
Genotype:
- genetic makeup of an individual/organism
Outline the key stages in brain development and their relative timing
1) early embryonic Life - 250,000 neurons/minute added
2) growth at 2 years after birth result into 80% of adult size
3) Almost all structure of brain is present at birth
4)
Outline the mechanisms by which the stages of brain development occur
0) Neurulation: 2-3weeks
- 2wks gestation, ectoderm folds in on itself
- 3 wks gestation, develops into neuralplate forming neural groove
- neural tube contains stem cells and forms the basis of the brain and spinal cord
1) Neurogenesis: prenatal
- within the neural tube, via mitosis
- stem cells divide until the appropriate number of progenitor cells is achieved (radial glia)
- they then differentiate into neurons
- (table of symmetrical and asymmetrical division)
2) Neuronal Migration: prenatal
- young neurons travel with similar cells along scaffolding of the radial glia towards outer layers
3) Cellular differentiation: prenatal
- Progenitor👉🏾radial glia - neurons, glia, astocytes👉🏾neurons
4) Synaptogenesis : prenatal
- forming chemical connections
- neurotransmitter release site in the presynaptic neuron
5) Apoptosis
- controlled process caused by a chemical signal that activates a genetic mechanism inside the cell
6) Synaptic Reorganisation
- usually occurs postnatally at 6yrs old
- if you don’t use certain connections they get taken away
Explain the key stages of neurodevelopment
1) Neurogenesis (mitosis)
- first the stem cells divide until the appropriate number of progenitor cells is achieved
- They differentiate into neurons which migrate to their final positions
2) Neural Migration:
- young neurons travel with similar cells along scaffolding the radial glia towards outer layers
3) Cellular Differentiation
- progenitor cells 👉🏾 radial glia : neuron, glia, astrocytes 👉🏾 neurons
How are hormones secreted?
Through the endocrine system
Give examples of different kinds of developmental disorders
Hereditary
Disorders which are passed on from parents to children
Fragile X Syndrome:
- most common inherited form of intellectual disability
- most males and 1/3 females have mild to moderate intellectual disability
- delayed speech and language development by age 2.
- widespread reductions in grey and white matter in the frontal and temporal lobe
Give examples of different kinds of developmental disorders
Genetic
Genetic disorders that are not inherited are genetic differences that have arisen spontaneously but not present in the parents genetic material
Down Syndrome:
- chromosomal condition that occurs when there are three copies of chromosome 21
- characteristic facial appearance
Williams Syndrome:
- occurs because of a deletion of material on chromosome 7
- problems with visual spatial processing
Give examples of different kinds of developmental disorders
Environmental
Foetal Alcohol Syndrome:
- environmental cause referring to alcohol intake during the mother’s pregnancy
- distinctive facial feature L’s, low height and weight
- severity depends on timing in pregnancy, volume of alcohol as well as individual differences
Give examples of different kinds of developmental disorders
Interaction between environment and genetic risk
Autism Spectrum Disorder:
• environmental risk factors:
- maternal diabetes
- paternal age
• genetic factors
- twin studies show that ASD is highly heritable within each symptom group
Dyslexia:
- neuronal Migration errors (ectopias)
- differences in white matter structure
Neural basis of reading
• left inferior frontal gyrus
- semantic processing
Discuss closed-head injuries in relation to Brian damage
mTBI:
• Caused by vehicle accidents and sports injuries.
• 2 main mechanisms
- direct strike to the head
- sudden acceleration/deceleration damaging white matter traits
Concussion: • Initial blow results into a counterblow which strikes the brain inside of the skull • brain swells and bruises •Immediate symptoms: headache, nausea •LT Symptoms: memory problems
Discuss Tumours in relation to Brain Damage.
Tumours:
• Affects brain function in 2 ways:
- Infiltration: replace normal tissue with cancerous growth
- Compression: pushing and displacing normal brain tissue
Symptoms of tumour:
• diagnosed by brain imaging eg MRI
Discuss brains damage in relation to CTE
CTE is characterised by
- mood disorders
- behaviour changes
- later result into dementia or Parkinson’s
CTE: in sport
- some sports carry high risk for concussion
- example: football players who head the ball a lot
- new guidelines for coaches are strict about when a player should be removed from the game
Discuss Cerebrovascular accidents and toxicity in relation to Brain Damage.
CVA:
- blood supply to part of brain is interrupted
Types of stoke include:
- haemorrhagic stroke caused by leaking blood vessel
- ischaemic stroke: caused by blocked artery
Risk factors include:
- high blood pressure
Describe what is neurodegeneration and provide two examples of neurodegenerative disorders and mechanisms
Hereditary and sporadic conditions which are characterised by progressive Nervous System dysfunction
- fundamentally all involve the loss of cells for example through apoptosis
Alzheimer’s Disease:
- symptoms include: memory loss, aphasia
- there’s no cure, life expectancy is usually 5-10yrs after diagnosis
- Brain changes: loss of cortex with effects on executive functions, movement
Parkinson’s Disease:
- caused by a loss of dopaminergic neurons called the basal ganglia
- cell death accompanied by accumulation of alpha-synuclein in the neurons
Explain synaptic transmission
•
Describe the sequence of events involved in the propagation of action potentials
- at rest neuron has membrane potential of -70mV
- the inside of the cell is more negative because the pump pumps out 3sodium ions for every 2potassium ions
- sodium flows back if the cell is electrically stimulated above threshold making membrane potential positive
- potassium channels open slower as membrane potential returns to -70mV
- the sweep up and down along the neuron is called AP
- myelin insulates neuron as AP jumps between the gaps travelling faster along the neuron
