Biopsychology

What does the Central Nervous system do?

Consists of the brain and the spinal cord. It receives information from the senses and controls the body’s responses

What does the Peripheral Nervous System do?

Sends information to the CNS from the outside world and transmits messages from the CNS to muscles and glands in the body

What does the autonomic nervous system do?

A division of the peripheral nervous system: Governs vital functions in the body such as

• Breathing

• Heart Rate

• Sexual arousal

• Stress responses (involuntary movement)

What does the somatic nervous system do?

• Governs muscle movement and receives information from sensory receptors.

• Controls voluntary movement and deals with external environment: It is made up of sensory and motor neurons

What does the sympathetic nervous system do?

Increases activity: Prepares for fight or flight

a division of the autonomic system

What does the parasympathetic nervous system do?

Restores body to resting levels ie rest and digest

A division of the autonomic nervous system

What are motor neurons

They have long axons extending from the cell body to connect to the CNS to effectors such as muscles and glands

What are sensory neurons

Carry messages from the PNS to the CNS. They have long dendrites

What are relay neurons

Connect sensory neurons to motor or other relay neurons

What are the different components of a neuron

• Cell body

• Dendrites

• Axon

• Terminal Buttons

What is the cell body

Included nucleus containing genetic material of the cell

What are dendrites

Branch like structures that protrude from cell body. These carry nerve impulses from neighbouring neuron’s towards cell body

What is the Axon

carried the electrical impulses away from the cell body down the length of the neuron. It is covered by a fatty layer of myelin sheath that protects the axon. Gaps in the axon called Nodes of Ravier speed up the transmission of the impulse

What are terminal buttons

At the end of the axon, communicate with the next neuron in the chain gap across the synapse

What is The firing of a neuron

When a neuron is activated the inside of the cell becomes positively charged for a split second causing action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron

What is Synaptic Transmission

• Electrical impulse reaches the end of the neuron, triggering the release of neurotransmitter from vesicles

• Once the neurotransmitters cross the gap, it is taken up by post- synaptic receptor on the next neuron

• The Chemical message is converted back into an electrical impulse (action potential)

What is the endocrine system

One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target sites in the body. Communicates via chemicals

What is the Pituitary Gland

• Produces growth

• ‘Master gland’

• Located in the top of the head

• Controlled by Hypothalamus which releases ACTH as a response to stress

Robert Waldow case study

He was the tallest man in history, 8ft 11, 119kg and died at 22. This was due to hypertrophy of his pituitary gland which results in abnormal high Human Growth Hormone.

What is the Pancreas

• Produces insulin

• regulates blood sugar

What is the Thyroid Gland

• Produces Thyroxine

• Regulates metabolism

What is the Adrenal Gland

• Produces Adrenaline

• Fight or flight

What are the reproductive glands

• Ovaries produce oestrogen

• Testes produce testosterone

• Responsible for puberty

What is the fight or flight response

The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or in some cases flight

What are stressors

Either

• Acute (Short Term)

• Chronic (long term)

What are the steps of stress response

• The stress response is triggered by the amygdala (an area of the brain)

• The Amygdala sends a distress signal to the hypothalamus

• The hypothalamus activates the sympathetic nervous system

• The SNS sends a signal to the adrenal medulla

• Adrenaline causes an increase in heart rate breathing and blood pressure

• The parasympathetic nervous system dampens down the stress response (rest and digest)

Limitations of The Fight or Flight Response

-Females may show a ‘tend and befriend’ response rather than a fight or flight: They tend for young and befriend other animals for help. Suggests previous research has obscured patterns of stress response (all male samples: Beta Bias)

-The first response may be freeze: Gray argued the initial response is ‘stop, look, listen’ when the animal is hyper vigilant. The adaptive response for humans is that freezing focuses attention making them look for better information in how to respond to the threat

What is localisation of function

The idea that certain functions have certain locations or areas within the brain

What is the motor cortex

A region of the frontal lobe involved in regulating movement- damage here results in a loss of muscle movement

What is the Somatosensory Cortex

An area of the parietal lobe that processes sensory information such as touch

What is the visual cortex

A part of the occipital lobe that receives and processes visual information

Each eye sends information from right visual field to left cortex and vice versa

What is the Auditory Cortex

Located in the temporal lobe and concerned with the analysis of speech based information

What is Broca’s area

An area of the frontal lobe of the brain in the left hemisphere responsible for speech production

Damage causes Brocas Alphasia (impairment of language)

What is Wernickes area

An area of the temporal lobe in the left hemisphere responsible for speech comprehension

Damage here results in Wernicke’s alphasia (impairment of comprehending language

What is the Phinneas Gage Case Study

An explosion hurled a metre length pole through Gages left cheek passing through his skull.

The damage to his brain changed his personality from calm to rude and short tempered. This suggests the frontal lobe may be responsible for regulating mood

Strengths of localisation of function

-Brain scan evidence of localisation: Peterson et al used brain scans to measure activity in the brain during a reading and a listening task. They found activity in Wernicke’s area in the listening task and Broca’s area in the reading task

-Neurological Evidence: Dougherty et al reposted on 44 OCD patients who had a cingulomoty (resonating the cingulate gyrus) after 32 weeks 1/3 met the criteria for successful response to surgery and 14% partial response. The success of the procedures suggests that symptoms and behaviours associated with serious mental disorders are localised

Limitations of localisation of function

-Lashley’s work suggests higher cognitive functions are not localised but distributed in a holistic way: Lashely removed between 10-50% of the cortex in rats learning a maze. No one area was more important then any other in terms of the rats ability to learn the maze. As learning requires every part of the cortex it suggests learning is too complex and cannot be localised

What is Hemispheric lateralisation

The idea that the two hemispheres of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemispheres rather than the other, as in the example of language (which is localised as well as lateralised)

What is the Corpus Callosum

Connects the two hemispheres

What are ‘Split Brain Patients’

Patients who’s corpus callosum are severed in a treatment for severe epilepsy- commissurotomy- so communication between the two hemispheres was removed

What was Sperry’s procedure

Studied a group who had to undergo a commissurotomy. He devised a procedure where an image would be projected to a patients right visual field (processed by the left hemisphere) and a different image to the left vf (right hemisphere).

What was Sperry’s findings

When a picture was shown to the right visual field patients could easily describe it. If the same object was shown to the left visual field the patient could not verbally describe what was seen. This is because language was processed in the left hemisphere and the right could not communicate what it sees. When asked to draw with their left hand patients were able to draw what they’d seen

Strengths of Lateralisation and Split-brain research

-Sperry’s Methodology: Sperry’s procedure was standardised. The image was flashed up for 0.1 seconds while participants stared at a fixed point so patient had no time to move eyes and spread across both visual fields. Very useful controlled procedure

-Lateralisation linked to increased neural processing capacity: By only using 1 hemisphere to engage in a particular task, the other would be free to negate in another function. Thus finding provides some evidence that brain lateralisation enhances efficiency in cognitive tasks

Limitations of Lateralisation and Split-brain research

-Issues with generalising case studies: many researchers said these findings cannot be widely accepted as ‘split brain patients’ are such an unusual sample. This may have caused changes in the brain that influences these findings. This limits the extent of generalisably, reducing validity of conclusions

What is Plasticity

This describes the brains tendency to change and adapt (functionally and physically) as a result of experience and new learning

What is synaptic prooning

Rarely used connections are deleted and frequently used connections are strengthened

Maguire’s Study

Studied brains of london taxi drivers and found a greater volume of grey matter in the hippocampus than in the matched control group. This part of the brain is associated with spatial and navigation skills:

-Assesses their recall of the city streets and possible routes

-Altered stricter of the taxi drivers brain

-Longer job= more pronounced structures: positive correlation

Limitations of Plasticity

-Negative plasticity: The brain’s ability to rewrite itself can sometime have maladaptive consequences: prolonged drug use=poor cognitive functioning and increased dementia

-Playing video games: Kühn compared a control group with a video game tracking group (2 months, 30 mins on super mario) They found a significant increase in grey matter in various brain areas. Increase was not evident in the control group

What is functional recovery

A form of plasticity. Following damage through brain injury or disease, the brains ability to redistribute or transfer functions ideally performed by a damaged area to other, undamaged area

What is Neural Unmasking

Wall identified ‘dormant’ (inactive) synapses in the brain but their function is blocked. However they can become unmasked when surrounding brain areas become damaged

What are Stem cells

Injected into damaged area replacing or rescuing the injured cells

Strengths of Functional Recovery

-Supporting Evidence: Tahiti randomly assigned rays with traumatic brain injury to either: Group refiner transplant of stem cells or a group received a soloution infused containing no stem cells. 3 month later the brains of the stem cells showed clear development of neuron like cells in an area of injury

Limitations of Functional Recovery

-The concept of cognitive reserve: Schneider et al discovered that the more time brain unity patients had spent. in education, which was taken as an indication of their ‘cognitive reserveM the greater chance of a disability- free recovery

What is an fMRI

A method used to measure brain activity while a person is performing a task nah uses MRI technology. This enables researchers to detect which region a of the brain areas rich in oxygen and thus active through producing an image

Strengths of fMRI

-Risk free: Unlike other scans it doesn’t rely on radiation: If administered correctly it is risk free non invasive and straightforward

-High resolution: Very high spatial resolution depicting detail by mm provides clear picture of localised activity

Limitations of FMRI

-Expensive compared to other neuroimaging techniques

-Can be blurry: Can only capture image if person stays perfectly still. Has poor temporal resolution because there is a 6 sec time lag behind the image on the screen and initial firing of neural activity

What are EEGs

A record of the tiny electrical impulses produced by the brains activity. By measuring characteristic wave patterns the EEG can help diagnose certain conditions of the brain

Strengths of EEGS

-Help diagnose conditions: EEGs provided invaluable on conditions like epilepsy characterised by random bursts of activity in the brain that can be detected on the screen

-High temporal resolution: today EEG technology can accurately detect brain activity as a resolution of a single millisecond

Limitations of EEGs

-not accurate at pinpointing source: EEG signal is not useful. The pinpointing exact source of neural activity doesn’t allow distinguish between activities or originating indifferent but adjacent locations

What are ERPs

The brains electrophysiological response to a specific sensory cognitive or motor event can be isolated through statistical analysis of EEG data

Strengths of ERPs

-accurate and specific measurements: have excelled temporal resolution compared to neuroimaging techniques led to wide use in measuring cognitive functions and deficits. Researchers have been able to identify many types of ERP and describe precise role of these incognito functions.

Limitations of ERPs

background noise and extraneous material in order to establish pure data and ERP studies: This material must be completely eliminated which is not easy to achieve.

What are Post-Mortem Examinations

The brain is analysed after death to determine whether certain observed behaviours during patient’s lifetime can be linked to abnormalities in the brain.

Jacopo Anis‘s post-mortem of HM confirmed his inability to store new memories, was linked to lesions in the hippocampus.

Strengths of Post-Mortems

Foundation of early understanding Broca and Wernicke both relied on post-mortems and establishing link between brain and language and behaviour decades before Neo imaging ever became possibility. Most post-mortem studies improve medical knowledge and generate hypothesis for further studies.

Limitations of Post-Mortems

-issues with course and effect observed damage to brain may not be linked to deficits but unrelated to trauma or decay

-ethical issues patients may not be able to provide informed consent before death. HM lost his abilities to form memory so cannot give such consent

What are Circadian Rhythms

A type of biological rhythm subject to a 24 hour cycle which regulates a number of body processes such as the sleep/wake cycle and changes in core body temperature

What are Biological Rhythms

Governed by (endogenous pacemakers: the bodies internal clock) exogenous site external changes in environment (that can help tell us what time it is affects endogenous pacemakers) e.g. sunlight

Siffres Cave Study

procedure: spent two months in the dark southern Alps with no light to examine the effects of free running biological rhythms

findings his free running circadian rhythm settle down to one that was around 25 hours though he did continue to fall asleep and wake up on a regular schedule

Strengths of Circadian Rhythms

-practical application to shift work: boyfriend at our found shift workers experience a lapse of concentration around 6 am so mistakes and accidents are more likely research also suggests between shift work and poor health with shift workers three times more likely to develop heart disease (knutson 2003)

-practical applications to drug treatments: understanding circadian rhythms have revealed there are peak times where drugs are most effective. This has led to a development of guidelines to do with the timing of drug dosing for a whole range of medication including anti cancer cardiovascular respiratory antiulcer and anti-epileptic drug

What is an Infradian Rhythm

A type of biological rhythm with a duration of over 24 hours this may be weekly monthly or annually example examples include menstruation and seasonal affective disorder

Processes of The Menstrual Cycle

-Rising levels of oestrogen cause ovary to develop an egg

-Gets released (ovulation)

-Progesteronenhelosnlononf grow thicker to prepare for pregnancy

-Egg gets absorbed by womb lining

-It all leaves the body (menstrual flow)

Stern and McClintock procedure

29 women with a regular history samples (via a cotton pad under armpit for eight hours) and placed an upper lip of other participants

Stern and McClintock Findings

68% of women experienced changes to their cycle, bringing them closer to the cycle of their older donor

What is Seasonal Affective Disorder

A depressive disorder has a seasonal pattern of onset: low mood, lack of activity and interest in life particularly during winter months

it is hypothesised during night penal glands secrete melatonin until Dawn-increase of light-winter = lack of light meaning serotonin continues longer

What are Ultradian Rythms

A type of biological rhythm with a frequency of more than one cycle in 24 hours, such as the stages of sleep

What are The Stages of Sleep

-Stage 1+2- Light sleep: brain wave pattern starts become slower and rhythmic

-Stages 3+4: deep sleep – involve slower delta waves difficult to wake someone

-Stage five: REM brackets opened (rapid eye movement) body is paralysed get brain activity speeds up significantly in a manner that resembles the awake brain – experience dreaming

Strengths of Ultradian and Infradian Rhythms

-Menstrual cycle shows its evolutionary value (Infradian rhythms): our ancestors it may have been advantageous for female so menstruate together and fall pregnant together this means newborns could be cared for collectively within a social group increasing chances of offspring survival

-supporting evidence for stages in sleep (ultradian rhythms): Dermot and Klietman monitored sleep patterns of nine adults in a sleep lab brain where activity was recorded through EEG’s and research is controlled with the effects of caffeine and alcohol. REM activity was highly correlated with dreaming.

Limitations of Ultradian and Infradian Rhythms

-Menstrual synchrony is disputed (infradian rhythms): shank found no reliable evidence arguing synchrony could just happen by chance (small sample size). This reduces the validity of synchrony research as it may be based on statistical error rather than real biological rhythms.

What are Endogenous Pacemakers

internal body clocks that regulate many of our biological rhythms such as the influence of the suprachiasmatic nucleus (SCN)on the sleep cycle

What is the Suprachiasmatic Nucleus

A bundle of nerves in the hypothalamus: nerve fibres connected to the eye cross in an area called optic chiasm on their way to the visual area of the cerebral cortex

it receives information about light directly from the structure continuing when our eyes are closed enabling the biological clock to adjust changing patterns of daylight while we sleep

Decoursey’s research into influence of SCN

Procedure: decoursey destroyed the SCN connections in the brains of 30 chipmunks who are returned to natural habitat and observed for 80 days

Findings: their sleep wake cycle disappeared and by the end of the study a significant amount were killed by predators (presumably because they were awake and vulnerable to attack when they should’ve been asleep)

Secretion of Melatonin

The SCN passes the information on day length and light that it receives to the pineal gland (structure behind the hypothalamus)

during the night the pineal gland increases a production of melatonin (chemical that induces sleep and is inhibited during periods of wakefulness). melatonin has been suggested as a factor in SAD

What are Exogenous Zeitgebers

External cues that may affect or entrain our biological rhythms such as the influence of light on our sleep/week cycle

Campbell+Murphy Research

15 participants working at various times and had a light pad shown on the back of their knees. The researchers managed to produce a deviation in the participant usual sleep/wake cycle of up to 3 hours. This suggests that light is a powerful exogenous site subscriber that need not necessarily rely on the eyes to exert its influence on the brain.

Sleep/Wake Cycle in parents

As every parent knows infants are rarely on the same sleep/week cycle as the rest of the family in human infants the initial sleep/week cycle is pretty much random at six weeks the circadian rhythms begin and by 16 weeks most babies are entrained

How to entrain circadian rhythms and beat jet lag

research also suggests adapting local times for eating and sleeping is an effective way of entraining circadian rhythms and beating jet lag

strengths of endogenous pacemakers and exogenous zietgebers

-Better understanding of dangers of disruptive rhythms Toutou argued exposure to artificial light at night disrupt circadian rhythms – adverse effects on health – increase rates of cardiovascular disorders and mood disorders such depression

Limitations of endogenous pacemakers and exogenous zeitgebers

-Case study of a blind person: Miles recounted the story of a young man blind from birth with a circadian rhythm of 24.9 hours despite exposure to social cues his sleep wake cycle could not be adjusted and consequently he had to take sedatives at night and stimulants in the morning to keep pace with 24 hour world. This suggests that there are occasions where exogenous site scribers may have little impact on our biological rhythms

-Influence of Exogenous Zeitgebers may be overstated: studies of individuals who live in Arctic regions show normal sleep patterns despite prolonged exposure to light