Biopsychology Flashcards
what is the nervous system + functions
a specialised network of cells
primary internal communication system
- to collect, process and respond to information
- to coordinate the workings of different organs and cells
(CNS & PNS (peripheral nervous system)
what is the CNS
brain receives information from sensory receptors and sends messages to muscles and glands. It is the centre of all conscious awareness
- brain
-spinal cord (responsible for reflex actions)
connected to the rest of the body by the PNS
comtrols reflex actions
what is the PNS
transmits messages via neurones to and from the central nervous system
divided into:
-somatic nervous system (transmits sensory information from the body/sense receptors to the brain/CNS, sensory neurones
transmits information from the brain via spinal cord to the muscles/effectors to produce movements) motor neurones
controls muscle movements
* actions that are voluntary and conscious
-autonomic nervous system (governs vital functions in the body such a breathing , heart rate , digestion + stress responsive)
control organs and gland
* involuntary
parasympathetic system
sympathetic system
complementary functions to maintain homeostasis
what is the endocrine system
in charge of body processes that happen slowly
triggers glands to produce hormones which are secreted into the bloodstream
Edocrine system and ANS working together: flight or fight
when a stressor is perceived
hypothalamus triggers activity in the sympathetic branch of ANS
ANS changes for parasympathetic (resting sate) to physiologically aroused
adrenaline is released from adrenal medulla into bloodstream
adrenaline triggers physiological changes in the body
once the threat has passed the parasympathetic nervous system returns the body to it resting state
biological changes in sympathetic state
increased heart rate
increased breathing
dilated pupils
inhibits digestions
inhibits saliva
biological changes in the parasympathetic state
energy conservation
decreased heart rate
decreased breathing
constricts pupils
stimulates digestions
stimulates saliva production
neurones
transmit signals electrically + chemically
- motor
- sensory
-relay
cell body contains a nucleus
branch like structures - dendrites : carry nerve impulses to next neurone
axon carries impulse from the cell body down the neurone - covered in a myelin sheath (protects + speeds up)
firing of a neurone
when a neurone is in resting state the inside of the cell is negatively charged compared to the outside of the cell
activated by stimulus neurone inside of cells becomes positively charged = action potential
= electrical impulse that travels down axon of neurone towards the end of neurone
synaptic transmission
- electrical impulses reach presynamptic terminal
- trigger release of neurotransmitters from synaptic vesseles
- neurotransmitters diffuse across synaptic celft
- neurotransmitters bind to receptors of post synaptic transmision
neurotransmitters
chemicals that diffuse across the synapse
taken up by postsynaptic receptor sites
each neurotransmitter has its own specific molecular structure that fits perfectly into post synaptic receptor site and own specialised function
excitation and inhibition
neurotransmitters have either excitatory or inhibitory effect on neurone
inhibition - neurone becomes negatively charged and less likely to fire
excitatory- increasing its positive charge
summation
summation is a process to decide if postsynaptic neurone will fire
if net effect is excitatory= more likely to fire
localisation of function
different tasks and fucntions are involved with different parts of the brain . = if a certain are of the Brian become damaged through illness or injury the associated function with also be affected
hemispheres of the brain
the cerebrum is divided into two halves
some of our psychical and psychological functions are controlled or dominated by a particular hemisphere - lateralisation
CONTRALATERAL
Right hand side of the body + language - controlled by left hemisphere
Left hand side of the body + spatial relationships + recognising emotions- control by right hemisphere
motor area of brain
back the the frontal lobe (in both hemispheres) is the motor area which controls voluntary movements in the opposite side of the body
damage = loss of control over fine movements
somatosensory area if Brain
sepereatedd from the motor area by the central sulcus
area where sensory information from the skin is represented
amount of somatosensory area devoted to a particular body part denoted its sensitivity
visual area of brain
located in occipital lobe
each eye sends information from the right visual field to the left visual Corte and from the left visual field to the right visual cortex
damage to left hemisphere can produce blindness in the right visual field of both eyes
auditory area of brain
located in temporal loves
analyse speech based information
damage can produce hearing loss
and may effect ability to comprehend language
language centres of the brain
Brocas area
language is restricted to the left side of the brain
Broca identified a small area in the left ftronsl lobe responsible for speech production
damage to Broca’s area= Brocas aphasia- speech tha tis slow, laborious and lacks fluency
language centre of the Brian
Wernickes area
left temporal lobe
no problem producing speech but had difficulties understanding it - speech comprehension
Wernickes aphasia damaged = produce nonsense words
define 3 types of neurones
**Sensory neurons: **Transmit information from the senses (e.g. the eyes or fingertips) to the central nervous system
Motor neurons: Transmit information between the central nervous system and the organs and muscles (e.g. an instruction to the adrenals to produce adrenaline)
**Relay neurons: **Connect neurons to other neurons (e.g. motor neurons to sensory neurons) and transmit information within the central nervous system (also called interneurons)
split brain research
two hemispheres are connected via corpus callosum
- can be cut in rare cases of epilepsy, reduced to only one side of the brain
shown images in right visual field they were able to describe what they saw but couldnt when shown in left visual field
- visual information from left side is procsessed in right hemisphere but language processing in the right hemisphere
BUT were able to pick up assocaited object of what they saw
strenght of split brain research
Evidence supporting hemispheric lateralisation: Sperry’s experiments demonstrate that brain functions are lateralised.
EG, if images processed in the right hemisphere can’t be spoken of, this suggests that the image processing and language processing do indeed happen in different hemispheres.
weakness of split brain research
oerly simplified: Sperry’s research often leads to the exaggeration and oversimplification of the different functions of the left and right hemispheres. In reality, functions associated with one hemisphere (e.g. the left) can be carried out or shared by the other hemisphere when necessary.
evaluation of localisation
brain scans
Brain scans: fMRI scans demonstrate correlations between different mental activities and different areas of the brain. For example, Ovaysikia et al (2011) demonstrates increased blood flow in different areas of the brain depending on whether a person is reading words or recognising facial expressions.
weakness of lateralisation of function
complex cognition
higher cognitive processes: Higher cognitive processes such as learning, language, and memory are seemingly too complex to be localised within a single area.
For example, Lashley (1950) removed different parts of rats brains while they were learning a maze but found no single area was most important.
This suggests higher cognitive processes (e.g. learning) are distributed in a holistic way within the brain, rather than being localised in a single area.
weakness of localisation of function
brain plasticity
The fact that the brain can recover functions after damage to areas associated with that function suggests that mental activities are not localised in these areas.
For example, language is supposedly localised within the the left hemisphere, but Danelli et al (2013) – see functional recovery after trauma below – describes the case study of a boy who had his entire left hemisphere removed and yet learned to speak.
define neuroplasticity
the ability of the brain to changes its physical structure to perform different functions
in childhood brain is highly plastic = enables child to learn new skills, learn new skills and recovery from brain injury
- reduces with age
- unused apthways are removed , used pathways are strenghtened and new ones can be formed with age
neuroplasticity
recovery after brain trauma
Neuroplasticity enables people to recover function after trauma (e.g. brain damage caused by stroke or accident). To recover function, the brain restructures itself in the following ways:
* Denervation supersensitivity-Unused neural pathways that do similar jobs are recruited and aroused to a higher level to compensate for lost
* Axon sprouting: - growth of nerve endingd which connect with other undamaged nerve cells
* Recruitment of homologous- similar areas of the brain on opposite side of the brain adapt to take over the function of damaged areas
evaluation of brain plasticity
supporting evidence
brain’s ability to change its physical structure to perform different functions.
brain scans by Maguire et al (2000)
found that London taxi drivers had a higher volume of grey matter in the posterior hippocampus (an area associated with spatial memory and navigation) compared to controls.
This suggests this area of the brain adapted in cab drivers to help them with their work.
evaluation of brain plasticity
variations
variations between people and brains plasticity
depends on age and gender (Ratcliffe suggests that women are better at recovery
functional recovery after brain damage
other areas take over
For example, Danelli et al (2013) describes a case study of a boy who had his entire left hemisphere removed at age 2 and a half. As described above, language function is primarily localised in this hemisphere, and the boy was initially unable to speak. However, his language skills recovered after 2 years, suggesting the right hemisphere adapted to take over this function.
functional recovery after brain damage
unused neural pathways recruited
Wall (1977) observed that the brain contains many dormant neural connections. When healthy neural connections are damaged, these previously dormant synapses activate and form new connections to compensate for the damaged ones.
functional recovery after brain damage
axon sprouting
Axon sprouting: Damage to the axon of a neuron can break its connections to neighbouring neurons. When this happens, the neighbouring intact neurons may grow (‘sprout’) extra nerve endings to reconnect with these damaged neurons.
define fMRI and evaluate
Functional magnetic resonance imaging (fMRI) is a form of brain scanning.
It uses magnetic fields to measure blood flow and oxygenation in the brain.
When an area of the brain is highly active, that area needs more oxygen and greater blood flow to provide this oxygen. By measuring blood flow and oxygenation, fMRI scanners enable researchers to identify which areas of the brain are activated during certain tasks.
Dynamic: fMRI scans record brain activity as it happens, which enables researchers to see activity in the brain over time (unlike post-mortem).
Expensive: fMRI scanners are expensive to buy and maintain (compared to EEG). This limits their use as psychological research tools, with studies that do use fMRI scanners often consisting of small sample sizes in order to reduce costs.
Low temporal resolution: It takes several seconds between recording brain activity using fMRI and converting it into an image. This means fMRI generates fewer images per minute (compared to e.g. EEG) and brain activity between each image is not recorded.
define EEG and ERPs
EEG scan is performed by attaching electrodes to the scalp or by using a hat with electrodes attached.
The electrodes detect electrical activity in the brain cells beneath them
**Event related potentials: **
use statistical techniques to measure changes in brain activity in response to a stimulus. For example, the EEG could initially provide a baseline picture of brain activity, then researchers could introduce a stimulus (e.g. giving a subject some food to eat) and use ERPs to determine how brain activity changed in response.
evaluate EEG and ERPs
Lower cost: EEG brain scans are much less expensive than fMRI brain scans.
Higher temporal resolution: EEG can record several pictures of the brain per second, unlike fMRI.
**Low spatial resolution: **The electrodes of EEG only measure general electrical activity and are unable to provide a detailed view of what is happening in the brain (unlike fMRI).
define post mortum and evaluate
physical examination of the brain after a person has died.
By physically analysing a brain (for example, by weighing it, dissecting parts of it, and comparing it to neurotypical (‘normal’) brains) and cross-referencing this with the person’s behaviour in life
Post-mortems enable researchers to study deeper areas of the brain that cannot be reached, for example, by EEG.
** No brain activity:** As the person is dead, a post-mortem does not enable researchers to measure dynamic brain activity = speculate about connections between the person’s physical brain and their psychological character
define endogenous pacemakers
Things within the body that regulate biological rhythms (your ‘body clock’).
E.g. The suprachiasmatic nucleus of the hypothalamus
define exogenous zeitgebers
Cues in the external environment that inform endogenous pacemakers to regulate biological rhythms.
E.g. Sunlight and darkness prompt the body to release hormones that control sleep and wake cycles
define circadian rythms
are biological cycles lasting approximately 24 hours. An example of a circadian rhythm is the sleep/wake cycle: sleep for 8 hours and awake for 16
endogenous pacemakers- release hormones such as melatonin, systems that regulate body temperature, and systems that control metabolism and digestion.
- suprachiasmatic nucleus (SCN).
internal processes are influenced by exogenous zeitgebers – perhaps the most obvious of which is sunlight.
For example, the darkness of night is thought to trigger melatonin release, which makes you feel tired and want to go to bed.
research support of circadian rythms
Aschoff and Wever (1976) conducted an experiment where participants were kept in a World War 2 bunker without any natural light for four weeks. All participants (except one) maintained a circadian rhythm very close to 24 hours, despite the absence of natural light.
real life application of circadian rythms
help improve the sleep and health of shift workers,
for example. Czeisler et al (1982) found that employees whose shifts were stable over 21 days or more had greater employee satisfaction, improved health estimates, and were less likely to leave their job than employees whose work schedules changed every week.
21 days or more allowed workers’ circadian rhythms to adjust to their work schedules.
= businesses that employ workers on shifts to improve employee satisfaction and reduce employee turnover.
define infradian rhythms
biological cycles lasting more than 24 hours. An example of an infradian rhythm is the human menstrual cycle: Women typically ovulate once every 28 days.
controlled by endogenous pacemakers
and influenced by exogenous zeitegbers eg woman exposed to anothers pheromones
define ultradian rhythms
biological cycles lasting less than 24 hours. An example of an ultradian rhythm is the different stages of sleep: During the night, a sleeping person will typically cycle between five stages:
influence of endogenous pacemakers on sleep wake cycle
suprachiasmatic nucleus (SCN) located in the hypothalamus in optic area
-receive information about light directly. The SCN passes the information about day length/light to the pineal gland.
- pineal gland release melotonin
- During the night, the pineal gland increases melatonin production. With more daylight, less melatonin. The SCN is therefore to a degree regulated by light from our outside world.
- even in the absence of any light (trapped in a cave). The SCN generates a rhythm related to its production of protein. When it reaches a certain level of protein it passes a message to the pineal gland and melatonin will still be released or inhibited.
influence of exogenous zeitgebers on sleep wake cycle
light is an important factor that resets pur biological clock- entrainment
Light enters the eye through the retina and this information is passed onto the SCN.
1. Low levels of light (retina) goes via the optic area to SCN
3. SCN sends signals to pineal gland
4.Pineal gland releases melatonin
5.Induces sleep
Research supporting exogenous zeitgebers: Campbell and Murphy (1998)
15 participants were woken up at various times and a light pad was shone on the back of their knees. The researchers found a change in their sleep/wake cycle of up to 3 hours in some cases.
showed that light may be detected by skin receptor sites on the body, even when the same information is not received by the eyes.
Research supporting the SCN- Endogenous Pacemakers: Morgan’s hamster study
Hamsters were bred so that they had a circadian rhythm of 20 hours rather than 24. The SCN cells from these abnormal hamsters were transplanted onto the brains of normal hamsters.
These normal hamsters began to adopt the same abnormal circadian rhythm as their 20 hour donor.
Furthermore, when hamsters with nocturnal patterns of activity (usual) had their SCNs replaced with SCNs from mutated hamsters which slept through the night and were active during the day (unusual), the hamsters followed the new daytime activities of the donor’s patterns.
the transplanted SCN had imposed its pattern onto the hamsters and shows the significance of the SCN and how endogenous pacemakers are important for biological rhythms.
Ultradian Rhythms: The cycles of sleep
repeats itself over a period of less than 24 hours. cycle of sleep typically lasts about 90 minutes - repeat this cycle four or five times
* Stages 1 and 2 are ‘light sleep’ stages: Brain patterns become slower starting with alpha waves, progressing to theta waves.
* Stages 3 and 4 are ‘deep sleep’ associated mainly with delta waves.
* Stage 5 (REM sleep). The body is ‘paralysed’ to prevent acting out our dreams. The eyes rapidly move from side to side (Rapid eye movement- REM). The brain activity resembles a person who is awake.
supporting evidence of stages of sleep
Dement
monitored sleep of adults in lab
brainwaves activity was recorded on an EEG and researchers controlled effects of caffeine and alchohol
REM activity was highly correlated with experience of dreaming and brain activity varied
- study suggests that REM sleep is an important factor of ultradian sleep cycle
infradian rhythms - menstrual cycle and exogenous zeitegbers (research support)
lasts 28 days
goverened by changes in hormone levels that regualte ovulation.
rising le els of oestrogeon cause ovary to develop an egg and realse it .
progesterone thickens the womb lining
research study:
influenceed by exogenous factorts such as cycle of other women.
Stem and McClintock- cycles can sinchronise due to phermones
