Biological Psychology Flashcards
Describe Role of Neuron
Neuron- Specialised cell for the purpose of communicating
Describe Components of Neuron
◦Cell body- Main part of cell, contains nucleus and mitochondria
○ The nucleus-Houses genetic material for cell
◦The mitochondria- Site of aerobic respiration where energy is released from glucose. Provides cells with energy
◦Dendrites branches at top end of neuron, attached to cell body and receives messages from other neurons to trigger action potential (Electrical impulse) within cell.
◦The axon long, branch extension of cell body, passes electrical impulse down to end of neuron to allow communication with other neurons .
◦The axon hillock axon hillock triggers nerve impulse and connects cell body to axon
◦The myelin sheath- Fatty deposit that surrounds and electrically insulates axon to help speed up message transmission rate, and allows for electrical nerve impulses to bce passed along. Insulates (Keeps in impulses)
◦The nodes of Ranvier breaks between cells along adjacent myelin sheath
◦The axon terminal and the axon terminal buttons-Axon terminals are at end of axon, at end of these are terminal buttons/boutons. Axon terminals pass nerve impulses from cell body to parts of the body they control/activate (Muscle, gland, Another neuron.)
○ Terminal buttons/Boutons- Very end of neuron where nerve impulse becomes a chemical message that can be passed to dendrite of other neuron
○ Vesicles- Tiny sacs that contain molecules of neurotransmitter chemicals
◦Neurotransmitters- Chemicals that passes messages between neurons
Describe what is meant by Action Potential
Beginning of one cell communicating with another, leads to synaptic transmission
Actual method by which nerve impulse travels down axon of neuron to stimulate release of neurotransmitters, tiny electrical impulse triggered by change of neuron’s electrical potential.
Describe the process of Action Potential
Neurons have resting membrane potential of about -70mV meaning that inside of neuron has slight negative charge in relation to outside. When neuron receives message from another neuron, this chemical message can either stimulate an excitatory postsynaptic potential (reducing neuron charge by depolarisation)where the sodium channels (S-, NEGATIVE CHARGE) play a role in generating the action potential in excitable cells and activating a transmission along the axon. Or Inhibitory postsynaptic potential (Increasing Neuron charge by hyperpolarisation). Potassium ions reach equilibrium when the membrane voltage is below -70 mV (Millivolts), so a period of hyperpolarization occurs while the K+ channels are open. Those K+ (POSITIVE CHARGE)channels are slightly delayed in closing, accounting for this short overshoot.
When neuron has received enough more excitatory messages that are sufficiently strong to reach neuron’s own threshold, action potential triggered (Impulse sent down axon via axon hillock), usually happens when neuron charge reaches approximately -55mV
POSITIVE=Inhibitory, Polarised, split between + and -, NEGATIVE=Excitatory, depolarisation, neutralisation, lower negative charge
How does Action Potential Work?
Starts at presynaptic neuron and axon hillock, electrical signals then jump through nodes of ranvier (Gaps in Mylein sheath) and passes faster due to insulation
What is Synaptic Transmission?
Cell’s electrical impulse/action potential starts as small electrical impulses generated at axon hillock, but once message reaches terminal button it turns into chemical message. When impulse reaches axon terminal, neuron can pass chemical message to further neurons across synaptic gap/cleft (space between two). Message sender= Presynaptic neuron, message receiver= Postsynaptic neuron
Each neuron is responsible for producing certain chemical/neurotransmitter, when the action potential reaches axon terminal, calcium channels will obey, flooding terminal buttons with calcium ions. Vesicles containing neurotransmitter substance will then be released and travel down to outer membrane of terminal button where vesicle casing will fuse with membrane and allow for neurotransmitter to be released from vesicle into synaptic cleft.
Receptors on postsynaptic neuron designed to bind to specific neurotransmitter and when detected, the neurotransmitter molecule will then be absorbed by postsynaptic neuron. Any neurotransmitter molecules not absorbed by receptors of postsynaptic neuron then will either diffuse away (be destroyed), or neurotransmitters will be absorbed again by presynaptic neuron (Reuptake) and they are recycled, ready to be fired again. Reabsorbed molecules will be destroyed by enzymes within neuron to “Turn off” neuron in preparation for future action potential.
Describe Effect of Drugs on Synaptic Transmission
Recreational drugs change function of neurotransmitters is brain, by preventing enzymes from breaking down dopamine neurotransmitter, leading to more dopamine being in synaptic cleft and going through reuptake via pre-synaptic neuron, this causes intense feeling of euphoria while dopamine remains. The body responds by down-regulating (reducing) the amount of dopamine naturally in body, and so eventually, when drug has worn off, less dopamine in brain then there was before.
natural activities make a smoother curve, dopamine level increases and decreases at lower difference
With drugs, spiking occurs (Euphoria), down-regulation of dopamine leads to severe drop of dopamine levels (Dysphoria)
Therefore, person becomes dependent on drug to take away negative feelings, (Dysphoria) and they also become tolerant (Meaning that more of the drug is needed to cause same feeling), leads to addiction.
Describe Effect of Brain Structure On Aggression
Midbrain-Contains an area called periaqueductal grey matter (PAG, area of grey matter within midbrain which plays a role in pain modulation and defensive behaviour) which links amygdala and hypothalamus with prefrontal cortex (Seen before in Phineas Gage). Has a role in co-ordinating and integrating behavioural responses to perceived internal and external stressors such as pain and threat , can be images, and sounds also (Detecting whether something is threatening). Regulating pain and external behaviour. Responses are co-ordinated in prefrontal cortex. Lesions to PAG in rats that have recently given birth (Protective) show increase in aggression when rats confronted with potential threat i.e. unfamiliar male rats (who may kill babies who are not there’s) in cage (Lonstein and Stern 1998).
Amygdala- linked to PAG, Centre for Emotions, emotional behaviour, motivation. Integrates internal and external stimuli, and every sensory modality has input, which when combined gives us an instinctive feeling/reaction to environment that will include aggression. Prefrontal cortex also connects to amygdala and may lead to expression of aggression. Prefrontal cortex weighs out pros and cons of expressing aggression.
Hypothalamus-Maintains homeostasis (Response which maintains human body in reaction to change in external conditions) through hormone regulation (Including sexual function), linked to aggressive behaviour in males via testosterone production.
Prefrontal cortex-Sits right behind forehead, at front of forehead governs behavioural regulation and social interaction (Is this acceptable, how am I going to look?) , delays gratification (Want for satisfaction), impulse control and has connections to amygdala and hypothalamus, damage normally results in problems with anger management, irritability, impulse control.
Frontal lobe aids in consideration of right and wrong
Evaluate Brain Structure and Aggression
- Support for the link between brain function/structure and aggression comes from human case studies i.e Phineas Gage whose social behaviour was largely affected by prefrontal cortex damage, from calm, well-mannered, social, to aggressive, irritable, and using profanity
- However, he’s a single case and unique, so effects of brain damage may not represent all humans (Idiographic- Focuses on specific person), although other case studies also support involvement of prefrontal cortex and relation to aggressive behaviour (Adds credibility)
- More specific support comes from Raine et al (1997) who used a sample of 41 murderers and found lower prefrontal cortex activity in PET scans
- Raine conducted research on Prisoners from New Mexico, and found that they had smaller amygdala (Responsible for emotions and emotional responses)
- Biological approach to explain aggression supports genetic basis because our genetic information determines are brain structure, therefore males are predisposed to be more aggression compared to females.
Explain Effect Of Evolution on Aggression
In evolutionary terms, success is measured by production of offspring that survive to reproductive maturity. In the EEA, successful males physically bigger and stronger so would be those most capable of providing of and protecting mates and offspring. Psychologically, males would have adaptive advantage as they were naturally more aggressive when resources were threatened.
Gave advantage of mate choice. Successful females chose mates who provided good genes, big, strong men favoured. Such men were also more likely to provide better resources in terms of food (Hunting and keeping food safe) and protection towards offspring and women against predators and other males who may kill wife or offspring, suggesting that those who displayed aggressive traits would be more successful than those who didn’t, competition for mates has driven masculine aggression.
Theory would also suggest that females would be less physically aggressive in EEA as it’d be an evolutionary disadvantage for females who’d spend long time-periods pregnant, breastfeeding, looking after vulnerable young children to ensure their survival and gathering foods such as fruit and berries. According to evolutionary psychology, this is why female aggression is more verbal/emotional instead of physical. Buss (1999) proposed that females would still be in competition for best mates but achieved victory by criticising other females to potential mates to make them appear less attractive. Hypothesis has been experimentally tested and found support.
If these ideas are valid, we may expect physical difference in brain structure/chemistry of males and females, which would lead to greater expression of aggression in males. We would also expect to see greater degree of aggression among males than among females and those animals to which we are more closely genetically related would show similar behaviour.
Evaluate Effect of Evolution and Aggression
Credibility- Strength of evolutionary theory is so that it can explain gender differences in aggression i.e. more co-operative females naturally selected as can protect self +Offspring. More aggressive males naturally selected due to better hunting and protection. Chimpanzee studies support gender differences/patterns in aggression, can be generalised to humans due to close genetic relation, increases credibility of idea (Manson + Wrangham 1991)
Objections- Some people reject evolutionary explanation of aggression (Natural Selection) , in favour of psychodynamic theory which suggests that gender differences in aggression may be determined by innate personality aspects, such as Id (Pleasure Principle, some males may find hurting others to be pleasurable) and Thanatos (Death + Destruction), males may be more destructive + Impulsive due to stronger Id and Thanatos in comparison to females who may have stronger Super Ego.
Differences- Theory doesn’t explain individual differences such as culture in aggressive behaviour, for example among the Kung San people of the Kalahari aggression is discouraged from childhood so is rare, in contrast, the Yanomami of Venezuela and Brazil have been described as fierce people , aggression is a socially acceptable behaviour to gain status in society (Wolfgang and Feracuti 1967)
Application- Theory has application to reproductive behaviour and human relationships (Buss 1999) found that, across 33 countries, males preferred younger, more attractive women and this enhances reproductive success due to more female fertility.
Ultimately, theory is credible due to research evidence (Manson and Wrangham) and high applicability (Reproductive behaviour), however is limited in credibility due to being objected by psychodynamic theory and not acknowledging effect of individual differences such as culture on aggression.
Explain effect of hormones on Aggression
Hormones are chemical messengers carried in the blood that travel around whole of body and affect long-term changes. Produced and excreted by glands, system of glands is called endocrine system.
Affect behaviour and cause physical changes in the body i.e., oxytocin is released by pituitary gland and increases trust between people.
Testosterone is an androgen (Develops or maintains male characteristics) and is more prominent in males.
Antenatal exposure to testosterone increases spatial ability and competitive aggression. There’s a critical period where testosterone sensitises neural circuits: Stimulates cell growth in areas of hypothalamus and amygdala (Naftoli, Garcia-Segura, Keefe 1990)
Supporting evidence comes from rodent research, male rodents castrated (Stops testosterone production by removing testicles and behaviour will be compared with control under aspects such as threat and competition for mates, castrated rodents show little-to-no aggression, however if testosterone injections are used, typical aggressive behaviour shown. Injecting neonatal female rodents with testosterone made them act much more aggressively when given testosterone as adults compared to control females (Edwards, 1968), supports the idea that testosterone is implicated in aggressive behaviour and sensitisation of neural circuitry after birth is an important factor in the effect of testosterone release.
Evaluate effect of hormones on Aggression=
Credibility- Idea has research credibility from testosterone research in females, James Dabbs and Marian Hargrove (1997) measured testosterone in saliva of 87, female prison inmates. Degree of criminal violence positively correlated with testosterone level, as well as testosterone levels also correlated with aggressive dominance within prison. Aggression-testosterone link also found in male prisoners in replications, increasing validity of association.
Objections- Objecting theories such as idea of brain structure effect on aggression suggests that brain damage such as prefrontal cortex and amygdala may result in increased aggression due to causing behaviours such as irritability, impulsivity, lack of self-control, brain structure idea has more credibility than Hormone idea as has generalisable, supporting research evidence such as Phineas Gage (1954) who suffered prefrontal cortex damage and became more aggressive.
Differences- Differences in hormone levels, species, morals with humans and animals such as rats may result in limited generalisability of research of animal studies to aggression, which can suggest that humans may be affected differently by hormones in terms of aggression.
Application- Understanding the effects of hormones on aggression could lead to real practical benefits, for example, if aggression is chemically controlled it should be possible to manufacture a drug that influences the hormonal mechanism and reduces aggressive behaviour preferably without widespread effects on bodily effects and behaviours. Anti-testosterone drugs may have positive consequences for individuals, communities and societies.
To conclude, idea of hormones and aggression is credible due to supporting research evidence from Hargrove (1997) and having high applicability to hormone-influencing drugs as method of reducing aggression, however has been objected by more credible brain structure explanation of aggression and, as the research primarily uses animals, doesn’t acknowledge the differences animals and humans have (Species, Morals, Hormone levels) and can suggest these differences limit generalisability of idea of hormones and aggression to humans
Explain Psychodynamic Theory of Aggression
Two innate drives (Eros and Thanatos) would come together to form first part of personality from birth-2 years (The ID). The unconscious ID is most primitive part of personality that’s completely driven by impulses of Eros and Thanatos with no thought for consequences. ID operates on pleasure principle, demanding immediate gratification of urges.
Around age 3-4+ , new aspect emerged, the ego (Part of personality that attempts to satisfy the id within restrictions of reality). This is driven by reality principle (Rule of what’s socially acceptable). The norms and rules of society are learned and, although the ego doesn’t understand right from wrong, it understands when it’s appropriate to show behaviours such as aggression. Satisfies ID urges indirectly and symbolically, has no moral sense, doesn’t try judge ID, but tries to direct and control all their urges.
At some time between ages 5-6+ , the third and final aspect of personality emerged (Superego) and this operates morality principle (Understanding what’s right from what’s wrong), delays ID urges until appropriate time and place and allows child to feel pride for acting correctly (The ego ideal) or feel guilty for inappropriate behaviour (The conscience). Aggressive impulses should be well controlled if superego is properly developed.
Any issues in development of ego or superego will result in problems managing urges of id and aggressive behaviour could be frequent, for most people, ego and superego are well developed so id urges remain in unconscious mind and we’re unaware of violent urges, however may be aware of them through catharsis behaviours (Love of violent films and/or boxing), Ego balances out superego (Restricts, ID and thinks about consequences of doing action for pleasure)
When Ego fails to balance out demands of ID and superego, psychological difficulties can occur, if people have strong ID, this means that impulsive/aggressive behaviour is likely to satisfy these urges. Usually, these urges are managed by the other components of the personality and therefore are in the unconscious. The only time we may be aware of them is when we engage in aggressive activities such as sports by watching violent films (Catharsis).
Evaluate Effect of Psychodynamic on Aggression
Credibility comes from: Stephanie Gorka et al. (2013) used MRI scans to study activity of pre-frontal cortex and the amygdala. Showed that alcohol interferes with the brain’s ability to pass information between the two. This also backs up Freud’s idea that one part of the psyche generates aggression, and another part decides what to do about it.
Objected by Albert Bandura in his 1961 study makes a big point of the fact that the children who observed the aggressive role models displayed more aggression themselves, not less. This goes against what catharsis would suggest.
Doesn’t acknowledge role of individual differences such as brain damage on three parts aspects of the personality, for example prefrontal cortex damage may result in impulsivity, does this mean that the Id has become more dominant over the superego?
Freud’s theory has applicability to everyday life, for example catharsis which may be seen in boxing, playing violent video games and has no effect on self, adds to credibility of theory.
To conclude, Psychodynamic explanation has high credibility from research evidence such as Gorka et al’s MRI scans and the high applicability of concepts i.e., Catharsis in playing violent video games however lacks credibility due to being objected by research evidence (Bandura 1961) and Lacks explanation into individual differences i.e. brain damage inti aspects of personality.
