Biological Theory Flashcards
what is biological psychology?
Psychology is about people and includes aspects of how the brain works as well as how social and environmental influences affect our behaviour.
The biological approach looks at CHEMICAL
ACTIVITY in the BRAIN, including how NEUROTRANSMITTERS ACT AT SYNAPSE to enable messages to be transmitted. Messages are also transmitted throuch HORMONES which determines what gender we are likely to be. The biological approach links to our evolutionary perspective and the inheritance of GENES and their influence on who we become.
what are the biological key assumptions and ideas for neurotransmitter functioning?
The major biological influence on our behaviour and emotions is our nervous system (consisting of the brain, spinal cord and body nerves). It is made up of special cells called neurons, specialised for communication within the body. Messages are electrical within neurones but chemical between them.
The nervous system receives external information and triggers behaviours.
The brain controls many
different functions and has specialised areas for many of these eg, memory, vision and the control of sleep. The nervous system interacts with other parts of the body and controls them, eg stimulating the release of hormones from glands.
what is hormonal transmission?
Another way that messages are passed is through hormones. These send messages more slowly than neurotransmitters and are used for different purposes.
Hormones have a large part to play in our
development of being male and female eg, androgens are “male” hormones and ostrogen is “female”.
what are genetic influences?
We inherit 50% of our genes from our genetic make-up from our mother and 50% from our father.
These genes are important in determining our individual characteristics such as personality, abilities and behaviour. The effects of genes can be seen in physical abilities such as being able and unable
This is IMPORTANT because although single genes can control individual
characteristics (such as being able to roll your tongue), this is unusual for psychological variables.
In general psychological variables are the product of a combination of genes or the interaction between genes and the environment (NATUR AND NURTURE). Understanding the relative influence of genes and the environment can help us to identify the potential influence on mental health eg, in schizophrenia.
The genes tendencies that we INHERIT seem to have PASSED down to us through the mechanism of
“survival of the fittest”. Darwin proposed that all forms of life have evolved to suit their ECOLOGICAL NICHE. This means that the ENVIRONMENT - the habitat, climate, food available etc. decides which animals survives and therefore reproduces.
do geres that are passed on should help
those to survive. If it were not for understanding these mechanisms of survival of the most suited to the particular environment, then we would probably not study non-human animals, when looking for
unaciolanaine or numans
describe what the brain is and how it functions?
The brain has many parts, for example the limbic system is linked to aggression and the medial temporal lobe and lateral cortex are thought to be where short-term memory occurs, and when it moves memory into long-term memory.
There are four lobes in the brain, temporal lobe, parietal lobe, the occipital lobe and prefrontal lobe.
Raine et al (1997) considered all four lobes when they looked for differences in the brain structure between 41 people pleading not guilty by reason of insanity to murder and 41 controls (key study later). Schmolck et al (2002) studied people with brain damage and how such damage might link to their memory problems, looking at the medial temporal lobe.
Damage to the prefrontal lobe has been
linked to aggression. For example, Phineas Gage, after an unfortunate accident, suffered damage to the prefrontal lobe, which seemed to affect his treatment.
what is lateralisation?
The brain is in two halves, called hemispheres - LATERALISATION. Some structures are the same across two hemispheres, such as the lobes, so these are BILATERAL.
Therefore, “BILATERAL”
means two sides and “UNILATERAL” means one side.
give the structure and function of the spinal cord?
structure: column of nerves between the brain and peripheral nervous system which connects the brain and brain stem and runs through the spinal canal inside the vertebrates - tube like
function: to carry info from various parts of the body to and from the brain, linking to the pns. A second function is that it is responsible for the reflect actions such as pulling your hand away from a hot plate.
what are the 3 parts of the cns?
spinal cord, brain stem, the brain
what are the nervous systems functions?
- collects processes and response to info. in the environment
- it coordinates the working of different organs and cells in the body
so info. comes from the external environment which the nervous system receives and coordinates from within the body to produce a response.
this is done through the nerve tissues which control the activities of the mind and body, the brain interprets the info and is a communication system.
structure and function of the brain stem:
structure: connects the brain to the spinal cord. The brain stems structure is made up of the midbrain, pons, medulla.
Function: is to control messages from the brain to body, controls breathing, swallowing, heart rate etc
structure and function of the brain:
structure: two near symmetrical hemispheres which are connected by “corpus callosum”. The outer layer of the brain the “cerebral cortex” is hihgly developed in humans which distinguishes human mental thinking/functioning to animals - 3mm think covers inner area of the brain
So cortex is outer and subcortical is below the cortex.
function:
to control contralateral in which the left hemisphere controls activity on the right side of the body and the right hemisphere control the left side movement.
it also the source of conscious awareness and decision making - it controls many of the brain functions including sensation, thought, movement, awareness and memory.
describe lateralisation and localisation:
lateralisation:
2 halves of brain are functionally diff. and each hemisphere has functional specialisations for e.g. the left is dominant of lang. and the right excels in visual motor skills.
localisation:
involves the idea that certain functions e.g. memory, language etc have certain localisations and or areas of the brain. So, a particular function or process taking place in an area of the brain e.g. visual, auditory etc
historical overview of the brain and cns:
Historical overview: there’s evidence that early humans understood some basic qualities of the brain. Fossil evidence shows trepanning was used in connection with migraines & epilepsy - humans had knowledge of brain functioning 10 000 years ago. Hippocrates, a Greek physician (father of medicine) was familiar with brain injuries and put forward the idea that each side, or hemisphere, of the brain served a distinct function. However, there was little development in our understanding of the role of brain structure until the early 1gth century when the since of phrenology was introduced by Franz Joseph Gall. The ‘science’ was mistaken in its belief that you could tell someone’s character by mapping the bumps on their head, but it at least reflected the idea that behavior was in some way linked to the brain.
structure and function of the cerebral cortex:
The structure of the cerebral cortex involves both hemispheres being divided into 4 lobes - each named after the bones beneath it. So you have in your brain 8 lobes in total - 4 on each side.
Localisation theory suggests that each lobe has a different function (*these will be discussed later).
The cerebral cortex looks like a big walnut and appears wrinkly. It has many different
CONVOLUTIONS or ridges called GYRI (singular gyrus) and valleys called SULCI (singular sulcus).
The convolutions’ function increase the surface area, giving the cortex more processing power. The surface area of the cortex is estimated to be roughly 4 sides of A4 paper.
structure and function of frontal lobe:
Structure - situated at the front of the brain, the frontal lobe makes up about 40% fo the cerebral Function - reasoning and higher-level cognitive functioning (executive functions) for example thinking, planning, decision-making, problem-solving, reasoning, emotional traits, speaking, voluntary
motor aciviv.
The BROCA AREA found by Pierre Paul Broca a surgeon working in the 1860s found a small area in the left frontal lobe responsible for speech production. Damage to this area causes APHASIA - slow, laborious speech which lacks fluency.
The frontal lobes also contain the MOTOR CORTEX. Structure - long strip of neurons that run down alongside the central sulcus on both hemispheres.
Function — each motor contex controls voluntaly
movements so the opposite side of the body (contralateral).
The SOMATOSENSORY CORTEX lies directly beside the sulcus (structure) and its function is to process sensory information from the skin. For example, touch, temperature, pressure - again in a
contralateral way
Neurons processing sensory information take up over half of th area of the sensory
somatosensory cortex.
cerebellum structure and function:
The cerebellum is also known as the “little brain” with its structure having two hemispheres which are highly convoluted (wrinkly). Its function is to coordinate posture, balance and movement. It receives and integrates information from the spinal cord and other areas i.e., motor neurons.
It is 10% of
the brains entire weight but has almost 50% of its neurons.
structure and function of corpus callosum:
describe the example of vision as well
The structure of the corpus callosum involves a collection of nerve cells (sense) which physically connect the two hemispheres below the cerebral cortex. Its function involves allowing communication between the two hemispheres. Key to collateral control of the body is that it integrates the activities of both sides of the body.
Control of the body is mostly contralateral - left hemisphere controls the right and right the left.
Vision is an area that needs communication between both hemispheres. The left eye sends
nesscoes one tomoan a me roneve sens messaoes oreleroran.
someone with a split corpus callosum would not have a message from the left going to the right
side of the brain, and the right eye would send information to the left side of the brain.
HOWEVER, there would be no communication between the two sides - as the corpus callosum is split. Speech is usually on the left side of the brain, someone would be able to say what they saw in the right eye, as the message goes to the left side of the brain, but what they saw in the left eye would not be communicated - as the corpus callosum to transfer to the left side (language) is split.
structure and function of parietal lobe:
Structure - situated on the other side of the central sulcus, further back in the brain.
Function - somatosensory cortex function of processing sensory information. Also deals with visual information but is more to do with using spatial awareness and physical actions that require visual information. Plays a part in understanding geometry, maths (visualise spatial problems), knowing right from left,
structure and function of occipital lobe:
Structure - located at the back of the brain, each lobe contains a primary visual cortex and several secondary areas (left/right/right-left).
Function - the primary visual cortex receives information first from the eyes and begins to process it.
The secondary visual cortex then sends the information to other parts of the brain, this helps understand colour and movement so we can then determine what we are seeing.
structure of temporal lobe:
Structure - lie beneath the lateral sulcus of each hemisphere.
Function - each lobe contains an auditory cortex which deals with sound information coming mainly
trom the opposite cal
They process the location, volume and pitch or sounds and therefore have a
role in understanding language.
Inside the temporal lobe is the hippocampus - deals with memory
behaviour, spatial processing.
Karl Wernicke found the “Wernicke Area” when he was describing patients who had difficulty understanding language, producing fluent but meaningless speech - Wernicke’s aphasia, he located the area within the left temporal lobe.
role and parts of limbic system:
(hypothalamus, thalamus, amygdala, hippocampus)
Consists of several structures for example, the amygdala which play a role in regulating emotional responses eg, aggression.
It also plays a role in memory and learning.
The limbic system is highly
interconnected with areas of the cortex, integrating cortical and subcortical parts.
structure and function of thalamus: (limbic system)
Brains reply station.
It receives information from various senses (i.e., hearing. fight, touch but not
smell) and passes it on to the appropriate areas of the cerebral cortex for high-level processing. The thalamus is active, as it carries out some processing on its own.
So, it acts as a “gate” or filter of
information, it is thought to play a role in sleep, wakefulness and OCD.
structure and function of hypothalamus (limbic system):
Sits below the (hypo) the thalamus and is the size of your finger. It controls motivational behaviours such as hunger, thirst and sex.
Key role in body “fight-or-flight”, response when stress occurs it
maintains balance of body function ie, temperature (homeostasis) It also regulates the activity of the endocrine system (hormones) via its connection with the pituitary gland and even secrete hormones.
structure and function of scn (superchiasmatic nucleus):
Is a tiny region in the hypothalamus above the optic chiasm. It is responsible for controlling circadian rhythms (24-hour cycle).
structure and function of hippocampus (limbic system):
Located in medial temporal lobe. Part of limbic system and is important in memory (LTM) and spatial
navigation
describe the orbital frontal delayed gratification, delayed and immediate and the ventro-medical cortext.
1) being aware patience is needed for bigger award at end.
2) only looking at short term comfort and not looking at the long term.
3) is associated with emotions, decision making and regulating behaviour
structure and function of amygdala (limbic system):
Almond shaped set of neurons within the medial temporal lobe. Involved in emotions. Part of the limbic system.
structure and function of pons:
Contain mainly ascending and descending fibre tracts and fibres linked to the cerebellum.
structure and function of medulla:
Contain important nuclei responsible for regulation of breathing and cardiac functions.
describe the prefrontal cortex and aggression:
The prefrontal cortex is involved in depression, the lower the activity in the prefrontal cortex the more likely depression will occur. So, we know that the prefrontal cortex relates to emotions, a lack of regulation in the prefrontal cortex could lead to traits like aggression because our emotions are out of control and aggression results.
The prefrontal cortex has connections with many neurotransmitters like serotonin, dopamine and norepinephrine - these also link to emotions and so being connected to the prefrontal cortex seems logical.
The prefrontal cortex in the left hemisphere seems to be involved in positive emotions the right negative emotions - this means that the different parts of the brain have different functions as do the different hemispheres.
difference between cortex and prefrontal cortex:
cortex is outer layer of the brain, the prefrontal is made up of diff parts involved heavily in our emotions.
evidence of brain and aggression:
There is evidence suggesting that damage to the prefrontal has been linked to aggression for example, Phineas Gage, was a railway worker in the mid-west in USA. In 1948 he suffered an unfortunate accident when a tamping iron (an iron rod used for pushing explosives into drilled holes in rock in order to blow them up) set off the explosive and blew the iron rod up through Gage’s face and out of the top of his head. For the remaining 11 years of his life after the accident, his personality had a fundamental change from being a reliable person he became irresponsible and aggressive. His doctor concluded that the change done to his brain, which included severing the PREFRONTAL CORTEX, had led to the change in his character.
Bechara and van der Linden (2005) looked at several studies focusing on the prefrontal cortex and concluded that the area seems to be involved in the regulation of behaviour especially planning - suggested it is involved in regulating emotions and damage so some may not be able to control their aggression.
raine et al 1998 - researchers concluded that the offenders who had shown emotional impulsive aggression had not been able to regulate their behaviour because of low prefrontal cortex functioning, which fits with the explanation about prefrontal cortex functioning. (* contemporary study in full later).
Heinz et al (2011) looked at aggression and alcohol and suggests that environmental factor like stress are as important as genetic variations eg, serotonin.
These environmental stress and genetic
predispositions increase activity in the amygdale and lower activity in the prefrontal cortex.
These two
effects on activity in the brain link with alcohol use and also with impulsive aggression. Also as alcohol is drunk more, this can affect executive control more (in the prefrontal cortex), leading to more aggressive tendencies.
Evaluation - this seems to be a more holistic approach to looking at aggression compared to Raine et al who selects a reductionist standpoint - they are supposing that both nature and nurture are at play within aggression is involved.
what is the limbic system:
involved in self preservation and body controls e.g. temp or fight/flight.
describe hypothalamus and aggression:
The hypothalamus helps us balance the body (HOMEOSTASIS), it regulates temperature, hunger, thirst as well as our responses to anger, pain, aggression and sexual satisfaction. It is involved with regulating blood pressure, pulse, breathing and arousal levels through the autonomic part of the nervous system. It can detect leptin in the body, which is released if we overeat, therefore controlling appetite in addition to transferring lots of information. It regulates hormones including those that regulate sex functions, this is linked to aggressive behaviour in males via the production of TESTOSTERONE.
Hermans et al (1993) showed that electrical stimulation of the hypothalamus incites aggression.
Andy and Velamati (1978) carried out a study on cats by stimulating their hypothalamus and basil ganglia (part of limbic system) they had aggressive seizures. The aggression was measured by the amount of hissing and growling as the cat walked around freely.
describe amygdala and aggression:
The structure within the limbic system most associated with aggression is the amygdala.
Downer (1961) removed one amygdala from monkeys brains and cut the optic nerve; the monkeys who had visual input that connected to the intact amygdala behaved normally to humans ie, aggressively whereas the other monkey group who did not have an intact amygdala they were much calmer which indicates the amygdala being involved in an aggressive response to perceived threat.
Coccaro et al (2007) studied people with intermittent explosive disorder (IED) a major feature of which is a tendency for outbursts of extreme reactive aggression ie hot blooded, impulsive.
Using fMRI they found an association between amygdala reactivity and aggression to images of angry faces.
- Swantje et al (2012) in Germany carried an MRI scanning of 20 healthy volunteers who were all women and right-handed. Each participants amygdala was measured and an aggressive score worked out.
They all scored in the normal lifetime aggressive range; those with a higher
aggressive score 16-18% had an amygdale of lower volume. They concluded that the volume of the amygdala can predict the personality trait of aggression in “normal” people.
describe PAG and Aggression:
The midbrain contains an area called the PAG (periaqueductal grey matter) which links the
AMYGDALA and HYPOTHALAMUS with the prefrontal cortex. It has a role in coordinating and integrating behaviour responses to perceived internal and external stressors such as pain and threat.
Lonstein and Stern 1998 found that Lesions to the PAG in rats that have recently given birth show an increase in aggression when the rats are confronted with potential threat in the form of unfamiliar male rats being introduced to the cage.
describe serotonin and dopamine (includes studies):
Serotonin in a neurotransmitter which dampens and downs down neural activity in the brain.
denson 20212 found normal levels of S are linked with self control therefore disruption to serotonin levels may be responsible for impulsive behaviour including aggression.
virkk unen et al 1994 compared levels of S production in violent impulsive and violent non impulsive offenders, they found S was lower in the impulsive offenders suggesting that disruption to serotonin is linked with impulsive behaviour.
Dopamine has inhibitory effects in some areas of the brain and also excites others.
It is important in
regulating motivation and our experience of rewards, Dongju Seo et al (2008) found that serotonin under activity stimulates dopamine over activity. They interact together in terms of impulsive and aggressive behaviour.
2 strengths of brain and aggression:
link between certain areas of the brain, specifically the limbic system and hypothalamus of ind
aggression is supported by Andy and Velamati who showed that electrical stimulation of the hypothalamus gives an aggressive response in cats, so the hypothalamus is associated with aggression.
A link between certain areas of the brain, specifically the limbic system and the prefrontal cortex and aggression is supported by Swantje et al (2012) who showed that there is a negative correlation between the volume of the amygdale and self-reported lifetime aggression in humans.
2 weaknesses of brain and aggression:
andy and velamati 1978 used cats in their study on the hypothalamus which cannot be directly generalised to human brain structures e.g. they do not have the same prefrontal cortex as humans and animals so application to human brain and aggression limited.
gorka et al 2013 asked people to look happy, angry or fearfull faces and tested their prefrontal cortex to amygdala connectivity under the influence of alcohol which does not represent everyday functioning therefore reduces validity as the scan has to take place while someone is processing info. in some way and this processing task is artificial - so not all brain aggression is valid.
give an overview of hormones:
Hormones have many different roles, they can regulate the sleep wake cycle, metabolism and even eating habits. They affect people around puberty, affecting mood during the menstrual cycle and around menopause. Hormones are linked to diabetes which in itself affects behaviour. They can help to regulate stress.
Hormones are chemical messengers based within the body, unlike neurotransmitters they take
time to relay their message and they work on the body over time.
They work by combining to
receptor proteins in target cells and changing cell functions, cells then respond in different ways trigger
to the hormones.
“Behaviour is affected by hormones based on when they are released, and they
are received at the cell level and the receptors reached, and also how concentrated they are, which refers to their levels, The environment can also affect the release of hormones eg, stress/ or light can release hormones at different times.
Hormones travel via the circulatory system of the body via the bloodstream. The endocrine system is a chemical messaging system consisting of hormones that travel via the blood.
The endocrine which is made of thyroid, adrenal, thymus and pituitary glands make
hormones. In men they come from testes and women ovaries.
Each hormone affects certain target organs for example, the adrenal glands secrete hormones adrenaline and noradrenaline, which affect cells in organs throughout the body eg, heart. They have a crucial role in the fight-or-flight response to perceived stressors eg increasing heart rate, helping to fuel the aggressive response that may be needed to respond to a threat.
The pituitary gland is found in the brain and is important in hormone development,
y chromosome triggers release of oestrogen, foetus develops sexual characteristics,
anaregin insensitivity disorder - xy developing female characteristics