biopsych

Q: Explain the 3 different types of neurons?

Relay – connect other neurons together.

Motor – Transmit messages from the CNS to the muscles and organs

Sensory – Transmit messages towards the CNS from the muscles and organs

Explain the two main divisions of the Nervous System?

Central Nervous System – This includes the brain and spinal cord.

 

Peripheral Nervous System – This is all nerves that connect the brain and spinal cord to the rest of the body.

Explain the two main divisions of the Peripheral Nervous System?

Autonomic Nervous System – This deals with the involuntary body functions.

 

Somatic Nervous System – This is the system that deals with voluntary body movements.

Q: Explain the two main divisions of the Autonomic Nervous System?

Sympathetic Nervous System – This is the system that triggers the fight or flight response.

 

Parasympathetic Nervous System – This is the system that returns the body to a relaxed state after a stressor. 

Q: Outline 2 hormones and their functions in the body or effects on behaviour.

Testosterone: Too much of this and this can lead to risk taking or aggression.

 

Adrenaline: This hormone prepares our body for stress by triggering the fight or flight response.

Explain what is meant by the fight or flight response.  

The fight or flight response is an innate tendency for the body to prepare itself to run away (flight) or fight against something that is causing them stress.  It is triggered by the sympathetic nervous system.

Explain the structure of a neuron.

A neuron has dendrites which receive a signal at one end.  A cell body containing a nucleus.  An Axon which is covered in myelin sheath (to speed up a signal) and then axon terminals at the end to send the signal on.

Explain the difference between inhibitory and excitatory neurons.

An excitatory neurotransmitter is one that increase the positive charge of the neuron, increasing the chance it will fire (e.g dopamine)

 

Whereas an inhibitory neurotransmitter is one that increases the negative charge and therefore lowers the chance it will fire (e.g serotonin).

Q: What are neurotransmitters and give some examples?

These are chemicals which carry a signal from one neuron to another.  They are released at a synapse.  Varying levels of these can affect behaviour.

 

Serotonin – low levels have been linked with depression and OCD.

Dopamine – high levels have been linked with schizophrenia.

GABA

Q: Outline the endocrine system.

The endocrine system is a system of glands which produce hormones.  Hormones are chemical messengers that travel in the blood stream to specific organs of the body and can also affect our behaviour.

What is the purpose of myelin sheath?

It speeds up transmission by allowing the signal to jump across the Nodes of Ranvier on each segment of myelin sheath.

Explain the process of synaptic transmission

A signal is received by the pre-synaptic neuron.  This triggers the release of neurotransmitter into the synapse.  These bind to receptors on the post-synaptic neuron which triggers a signal down the post synaptic neuron.  The remaining neurotransmitter is then taken back (reuptake) into the pre-synaptic neuron.

Explain 3 things the sympathetic nervous system does in the body.

Slows digestion

• Inhibits Saliva production

• Increases Heart Rate

• Relaxes Bladder (increases urination)

• Dilates Pupils

• Dilates Bronchi of Lungs

Q: What is the master gland of the endocrine system?

Pituitary Gland

Q: Explain the process of how a signal transfers along a neuron?

A neuron is normally negatively charged.  A signal is received by the dendrites which makes the cell positively charged for a split second.  This travels down the axon as an action potential.

Q: Explain 3 things the parasympathetic nervous system does in the body.

Increases Digestion

• Increases Saliva Production

• Decreases Heart Rate

• Contracts Bladder (reduces urination)

• Constructs Pupils

• Constricts Bronchi of Lungs

Describe a motor neuron.

These transmit messages from the CNS towards organs and muscles.

 

They tend to have long axons and short dendrites.

Describe a sensory neuron.

These carry messages to the CNS from the senses processed by the PNS.

 

They tend to have long dendrites and short axons.

Describe a Relay Neuron.

These connect other neurons together.  E.g. a motor neuron to a sensory neuron.

 

They tend to have short dendrites and short axons.

 

Q: Label the brain

What is meant by Localisation?

The theory that specific areas of the brain are associated with particular physical and psychological functions

What is mean by lateralisation

The idea that certain physical or psychological functions are controlled by certain hemispheres of the brain

Describe the outer structure of the brain.

The cerebral cortex of the brain is divided into two hemispheres: the left and the right and each is responsible for specific functions.

Explain the motor cortex of the brain.

Located in the FRONTAL LOBE.

It controls our voluntary movement. Each hemisphere controls the opposite side of the body.

Different parts of the motor cortex control different parts of the body.  These are arranged logically – the region that controls the foot is next to the region that controls the leg.

Describe the Somatosensory Area of the brain.

 Located in the PARIETAL LOBE

 This is where sensory information from the skin (e.g touch, heat pressure) is represented.  

 The cortex on one side of the brain receives sensory info from the opposite side of the body

Describe the Visual Cortex of the brain.

 Located in the OCCIPITAL LOBE

 Nerve impulses from the retina travel to areas of the brain via the optic nerve

 The right hemisphere receiving its input from the left-hand side of the visual field and vice versa

 Visual cortex contains different areas that process different types of visual info.

Describe the Auditory Area of the brain.

 Located in the TEMPORAL LOBE

 In temporal lobes on both sides of brain where the auditory cortex is

 Begins in the inner ear, sound waves are converted to nerve impulses

 These travel via the auditory nerve to the auditory cortex

What are the two language areas of the brain you need to know?

Broca’s area in the Left Frontal Lobe

 

Wernicke’s area in the Left Temporal Lobe

Explain Broca’s area of the brain.

In the Left FRONTAL LOBE

 

 Deals with Speech Production

 Damage to this area leads to Broca’s Aphasia – speech is slow and not fluent.  

 E.g Broca’s patient called ‘Tan’.  Called this because that is all he could say.

Explain Wernicke’s area of the brain.

In the Left TEMPORAL LOBE

 Deals with Language comprehension

 Damage to this area leads to Wernicke’s Aphasia where patients can produce language (it is fluent but meaningless) but it is difficult to understand. They often produce nonsense words.

Describe a brain scanning study that tested the language centres of the brain.

Peterson (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task supporting the key assumptions about both of these areas.

What type of evidence would be examined to see if brain functions are localised?

 Brain Scan Evidence

 

 Neurosurgical Evidence (Lobotomies!)

 

 Case Study Evidence

Describe how Lobotomies support localisation of the brain

Lobotomies involve destruction of brain tissue in an area.  E.g   The transorbital lobotomy involved damaging the frontal lobe connections.  

 

This led to changes in personality and impulsivity, showing the localised functions of the frontal lobe.

Explain how modern neurosurgery can support localisation of function.

Modern neurosurgery (like a Cingulotomy) uses precise technology to damage a part of the brain involved in mental illness.

 The success of these procedures for some patients suggests that the symptoms and behaviours of mental illness are localised to certain areas of the brain.

Explain how case study evidence can be used to demonstrate localisation of function.

Case studies like Phineas Gage who suffered localised brain damage of the frontal lobe, show that the frontal lobe is responsible for personality and regulating mood.  This is because of the change in behaviour after the accident of Phineas gage.

 

However – it is a case study so difficult to generalise.

Q: What evaluation points of localisation of function can you use?

There is research evidence to support localisation (case studies, brain scans etc)

 Localisation is not set and fixed as the brain can recover from damage through Plasticity.

 Certain higher cognitive functions (e.g learning) are not localised and appear to be more holistic.

What is meant by Plasticity?

.

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

?

What is meant by Functional

Recovery

A form of plasticity where the brain can redistribute or transfer functions usually performed by a damaged area to another area of the brain.

Outline the Maguire Study.

Aims: to investigate structural brain differences in taxi and non-taxi drivers.

Procedures: Compared Taxi drivers to non –taxi drivers in an MRI scan.

Findings: more grey matter in the hippocampus of the taxi drivers than controls.   Also there was a positive correlation between length of time in the job and the size of differences.

Conclusions: supports plasticity as it was concluded the difference was due to learning.

What structural changes occur in the brain during functional recovery?

Axonal Sprouting – growth of new nerve endings

• Neuronal Unmasking - The unmasking of dormant synapses

• Reformation of blood vessels

• Recruitment of similar areas on the opposite side of the brain

?

What evaluation is there of plasticity and functional recovery of the brain

 There are practical applications of the research

 Plasticity can result in maladaptive consequence (e.g amputees experience phantom limb syndrome)

 The brain does have a greater propensity to reorganise in childhood and is affected by environmental factors (e.g years in education).

 There is research supporting plasticity from animal research

Outline 2 ways in that the brain recovers from trauma?

The brain can either transfer functions to a different location on the brain (neural reorganisation) or

it can repair the damage by forming new neuronal connections or blood vessels (neural regeneration).

Outline an EEG.

Used to monitor electrical (therefore neuronal) activity in the brain. The

participant wears a cap with many electrodes

Electrodes detect small electrical charges resulting from the activity of millions of neurons.

Evaluate the EEG as a way of investigating the brain.

It has been invaluable in diagnosing conditions (like epilepsy) and understanding sleep.

+ It has high temporal resolution (no lag time between the activity and it being detected by the scanner)

+ safe and non-invasive for participants

- It produces very generalised information of brain activity.

- It doesn’t provide a clear image of the brain – just the locations of the electrodes.

Outline an fMRI.

Used to examine the structure and function of the brain during tasks. More active areas of the brain need more oxygen so they have an increase in bloodflow. The MRI scanner uses magnets to pick up the iron in the haemoglobin in the blood. More iron is shown up as brighter areas on the scan. This is then used to infer which areas of the brain are active during a task.N

Evaluate fMRI as a way to investigate the Brain

+ Risk free and non-invasive

+ high quality images that shows function and structure of the brain

- Expensive and uncomfortable for people

- It has poor temporal resolution - a time lag (of approx. 5 seconds)

- It only measures blood flow not neuronal activity

Name the ways of investigating the brain you need to know.

Functional Magnetic Resonance

Imaging (MRI)

Electroencephalogram (EEG)

Event Related Potentials (ERP)

Post Mortem Investigations

Outline post mortems as a way of investigating the brain.

How is it done?

Examining structural damage to the brain after death to establish how/what damage leads to specific deficits.

What is it used for?

It usually is done on patients who have rare deficits in mental processes or behaviour (e.g HM).

Evaluate post mortems as a way of investigating the brain.

Vital before neuroimaging became possible.

+ Allows exploration of deeper areas within the brain which might not be possible through some of the scans.

 

- Difficult to establish causation of functions.

- There are so many factors that can affect the quality and variety of data

Explain what an ERP is.

It is measuring electrical activity in the brain that results from specific stimuli (events).  All the inconsistent brain activity is filtered out to leave only the ERP’s (consistent activity). Over repeat tries of presenting a stimulus - if the same brain activity is recorded consistently to this stimulus, it can be argued to be the brain’s processing of that stimulus

Evaluate ERP’s.

high temporal resolution (there is no lag time)

+ It measures the specific activity that relates to a specific task so is less generalised than EEG is normally.

- Often large repetitions of activities are required to average activity, to see the consistent activity.

- Difficult to ensure extraneous noise etc are completely eliminated

Q: Outline the procedures of the Sperry Split Brain study.

Compared split brain patients to others with no hemisphere separation.

Different activities were tried with the patients including touch of objects and visual presentation of stimuli to see how the different sides perform on tasks. A stimuli was presented to one visual field or one hand to test what the patients were able to do with that stimuli.

Outline the conclusions of the Sperry Split brain study.

It seems that in these patients the hemispheres of the brain process information separately.

Hemispheres do seem to have differing functions (e.g language left and drawing ability right)

P’s seem to have two separate streams of consciousness with their own memories and perceptions.

Explain what is meant by lateralisation.

The idea that the two halves of the brain are functionally different and certain processes or behaviours are controlled by one hemisphere rather than the other.

 

E.g Left processes language ability

E.g Right processes drawing ability and creativity

Evaluate the Maguire Study

 

Hint: Taxi drivers!

+) Control group allows us to say that there is a significant difference between taxi drivers and others (good design).

(+) Use of scientific, objective measurements (MRI)

(-) issues with cause and effect – they may have already had a larger hippocampus, it may not have gotten larger due to learning (although the positive correlation makes this less likely)

Explain who the split brain patients were.

A unique group of patients who had a Corpus Callosotomy – where the Corpus Callosum is severed so that the two hemispheres are separated and don’t communicate with each other.

This was done to control frequent and severe epileptic fits.  

Both hemispheres function independently and don’t transfer information between each other.

Outline the findings of the Sperry study on split brain patients when they were shown an image to left and right visual field.

When shown an image to their left visual field the p’s wouldn’t be able name it, but would be able to name it if shown to their right visual field.

 

If shown an image to their left visual field they could select the object with their left hand but not their right hand.

What was found with composite words (different words presented to each visual field) in split brain patients?

For example, key to left visual field and ring to the right visual field.  

 

They would say ring as that is processed by the left hemisphere and they would be able to pick up the key with their left hand as that was processed by the right hemisphere.

What was found with regards to drawing ability in the split brain patients?

A picture is shown to the left or right visual field and the patient is asked to draw it.

The drawings were consistently better when drawn by the left hand (controlled by the right hemisphere).  

This was still the case in right handed patients.

Evaluate lateralisation of the brain.

Some of the early discoveries from split brain patients have been disconfirmed by more recent discoveries. E.g language can be dealt with by the right hemispheres

- There are disadvantages to lateralisation e.g research shows left handedness is associated to poorer immunity.

+/- Lateralisation changes with age. Lateralised functions (functions dealt with by one hemisphere) found in younger individuals tend to switch to bilateral functions (dealt with by both hemispheres) in healthy older adults.

Evaluate the Sperry Study.

• It was a quasi-experiment in controlled conditions.  Good standardised procedures, good control.

• Lacks ecological validity as in real life the patients can just shift view so it is processed by each eye.

• Low population validity – sample was 11 p’s so may not be big enough to generalise.  Also difficult to make generalisation about non-split brains on the basis of these findings.