Biopsychology

• Describe the divisions of the nervous system

  Separated into the central nervous system and the peripheral nervous system.

  The peripheral nervous system divides into the autonomic nervous system and the somatic nervous system.

  The autonomic nervous system divides into the parasympathetic nervous system and the sympathetic nervous system.
• Describe the central nervous system


  The spinal cord is responsible for reflex actions.

  The brain is the centre of conscious awareness and is made up of the cerebellum, cerebrum and medulla.

  The cerebral cortex is divided into 4 lobes: frontal, parietal, temporal and occipital.
• Describe the peripheral nervous system


  It connects the central nervous system to the rest of the body

  It is divided into two parts:

  • The somatic nervous system that controls voluntary movement in the skeletal muscles. It contains sensory neurons that transmit signals from the body to the brain and motor neurons that transmit signals from the brain to the body.
  • The autonomic nervous system regulates our involuntary functions carried out by the body without conscious awareness.It recieves signals from sensory neurons to create involuntary responses in cardiac and smooth muscles
• Describe the divisions of the autonomic nervous system 


  The sympathetic nervous system controls our responses when we are in an emergency situation to provide rapid energy - the 'fight or flight response'

  The parasympathetic nervous system returns our body to its normal resting state after an emergency has passed, so it is sometimes referred to as the 'rest and digest system'.
• Describe the structure of a neuron


  Consists of a cell body (soma) which contains a nucleus that stores the genetic code.

  Dendrites branch out from the cell body and carry electrical impulses to other neurons.

  The axon projects away from the cell body and carries the signals received by the dendrites to other neurons.

  The myelin sheath is a white, fatty substance that insulates the axon and speeds up the rate of conduction of signals.

  The signal is carried away from the cell body, down the axon to its terminal, where the impulse can be transmitted to another neuron.
• Describe how an action potential occurs


  When a neuron is in a resting state the inside of the cell is negatively charged. When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second, causing an action potential. This creates an electrical impulse that travels down the axon towards the end of the neuron.
• Describe the structure of a motor neuron


  Short dendrites protrude directly from the cell body, which is at one terminal. Impulse is carried away by the long axon to the other terminal.
• Describe the location of a motor neuron


  The cell body is inside the central nervous system and the axon is inside the peripheral nervous system
• Describe the function of the motor neuron

  It controls muscles and organs (effectors)
• Describe the structure of a relay neuron

  Short dendrites carry impulses to the cell body. The impulse is carried away by the very short axon
• Describe the location of a relay neuron

  The entire neuron is inside the central nervous system
• Describe the function of a relay neuron

  Allows motor and sensory neurons to communicate
• Describe the structure of a sensory neuron

  A long dendrite carries impulses to the cell body which is at the side of the short axon|
• Describe the location of a sensory neuron

  The cell body is inside the peripheral nervous system and the axon is inside the central nervous system
• Describe the function of the sensory neuron

  It carries nerve impulses from sensory receptors to the spinal cord and brain
• Describe how neurons interact

  Sensory neurons receive impulses from receptors on the sense organs when a stimulus is presented

  They carry the impulse away from the body and into the CNS, where it is transmitted to a relay neuron

  This neuron transmits the impulse to a motor neuron, which carries the receptors on an effector, this could be a muscle

  The effector then carries out a response
• Describe synaptic transmission

  -Before action potential occurs, the activated cell changes from its negative resting state to a positive activated state

  -The electrical impulse travels down the axon on the pre-synaptic neuron and reaches the terminal button, where it triggers the release of neurotransmitters from vesicles within the terminal

  -Neurotransmitters cross the synapse and bind to receptor sites on the dendrite of the post-synaptic neuron

  -Stimulation of post-synaptic receptors by neurotransmitters results in either excitation or inhibition of the post-synaptic neuron
• Describe excitation and inhibition

  -The contents of neurotransmitters at the synapse determines where the synapse is excitatory or inhibitory

  -If it is excitatory, the post-synaptic neuron is instructed to fire (conduct an action potential)

  -If it is inhibitory, the receiving neuron is instructed not to fire

  -When a post-synaptic neuron receives inputs that are both inhibitory and excitatory at the same time, it adds them together and whichever is greater depends on whether it goes on to fire. This is called summation.
• Describe an excitatory neurotransmitter

  Increase the likelihood that a signal is sent to the post-synaptic neuron which is then more likely to fire as it becomes more positively charged.

  This is called excitatory post-synaptic potential (EPSP)

  Dopamine and noradrenaline are examples.
• Describe an inhibitory neurotransmitter

  Decrease the likelihood that a signal is sent to the postsynaptic neuron because it becomes more negatively charged.

  This is called inhibitory post-synaptic potential (IPSP)

  GABA and serotonin are examples.
• Describe the endocrine system

  Regulates cell or organ activity and control vital physiological processes

  Releases hormones from glands

  Hormones are released into the bloodstream, which have an effect on organs with receptors

  The effects on these organs influence processes such as growth, metabolism and reproduction

  An imbalance of hormones cause various dysfunctions

  The pituitary gland controls the activity of all other glands in the body
• Describe the anterior lobe

  Responsible for releasing the hormone ACTH

  Stimulates the adrenal cortex to release cortisol during times of chronic stress to give us energy
• Describe the posterior lobe

  Responsible for releasing the hormone oxytocin

  This hormone is responsible for producing contractions in the uterus during childbirth
• Describe the hormone and function of the thyroid gland

  Thyroxine

  Regulates metabolic rate
• Describe the hormone and function of the ovary gland

  Oestrogen

  Development of female sex characteristics and regulation of the menstrual cycle
• Describe the hormone and function of the testes gland

  Testosterone

  Development of male sex characteristics and regulation of aggressive behaviour
• Describe the hormone and function of the pancreas

  Insulin

  Regulates blood sugar levels
• Summarise the fight or flight response

  Hypothalamus detects stressor

  Activates sympathetic branch of the autonomic nervous system

  Adrenal glands are activated

  Adrenal medulla releases adrenaline

  Heart rate, blood pressure increases blood to the brain and non-essential systems shut down

  Parasympathetic branch reverses effects when the threat is removed
• Describe the location, function and consequence of damage of different parts of the brain

  Motor cortex - Frontal lobe, controls voluntary movement of opposite side, loss of control over motor movements

  Somatosensory cortex - parietal lobe - collects sensory information from skin, decreased sensation

  Visual cortex - occipital lobe, receives information from eyes, blindness

  Auditory cortex - temporal love, analyses speech based info, hearing loss

  Broca's area - frontal lobe, speech production, Broca's aphasia

  Wernicke's area - temporal lobe, speech comprehension, cannot comprehend language
• Use a case study to explain localisation of function

  1848 - Phineas Gage, a railroad construction worker had an iron rod driven through his skull, destroying the majority of his left frontal lobe. He underwent a change in personality and became disinhibited, couldn't show compassion or make decisions
• What does fMRI measure?

  Uses magnetic and radio waves to monitor blood flow

  fMRI measures which parts of the brain are most active during certain tasks compared to a baseline task

  It is based on:

  • Neurons that are active will be using energy in the form of glucose and oxygen, which are directed to the areas requiring it via the bloodstream (haemodynamic response)
  • Therefore, the area with the most blood flow to it during a task is the most active.
• How does fMRI work?

  A powerful magnetic field is applied to the brain

  Oxygenated blood has a different magnetic quality than deoxygenated blood

  The scanner generates a signal called a blood oxygen level dependent contrast

  This reveals which neurons are currently using up most oxygen

  fMRI produces a 3D image showing active parts of the brain in colour.
• What does EEG measure?

  EEG stands for electro-encephalogram and provides a continuous recording of brain wave activity

  EEG specifically records when there is a polarity change, caused when neurotransmitters are recieved by the dendrites of post-synaptic neurons

  EEG is not capable of recording a single neuron's activity, but records the activity if numerous neurons working together in a local field potential
• How does an EEG work?

  The subject is fitted with an EEG cap composed of electrodes placed on the scalp that measure neuronal activity directly below where they are placed

  An EEG amplifies the strength of the signals and sends the data to a data acquisition computer

  There are 4 main groups of wavelength that can be seen on the EEG recording, including Gamma, Beta, Alpha and Theta. Each has two basic properties that are examined:

  • The strength/intensity of activity which is amplification
  • The speed of activity which is the frequency
• What are ERPs?

  Stands for event related potential

  They are types of brainwave triggered by specific stimuli showing us the exact type of brain activity linked to different, specific cognitive processes
• How do ERPs work?

  A stimulus is presented to a subject during an EEG

  The stimulus is presented repeatedly at exactly the same interval, for exactly the same time

  The brain wave pattern after each presentation is added to the previous ones, and a computer program creates an average of this pattern

  This process filters out all the extraneous brain activity that is not related to the stimulus

  We can establish which wave is linked to the processing of a certain type of stimulus, as the amplitude of the ERP will be stronger after that type of stimulus is presented.
• Describe a post-mortem examination

  The analysis of a subject's brain after their deaths

  Subject's are often individuals who suffered from rare disorders and experienced deficits in mental processes/behaviour

  The brain is dissected and examined to establish cause of these deficits

  May involve comparisons with the brains of control subjects to establish the extent of the difference
• Give Broca's research example for post mortem examinations

  Tan was the subject

  He had language impairment of only speaking one word but could understand speech and instructions

  Damage was found in the base of the frontal lobe in the left hemisphere

  Broca concluded language is lateralised to the left hemisphere and speech production is lateralised to the frontal lobe (Broca's aphasia)
• Give details of HM's post mortem

  His temporal lobes were removed to reduce seizures from epilepsy

  He had memory deficits for consolidation and storing in LTM. He had procedural memory but lacked declarative

  Post mortem, when his brain was sliced to create a 3D computerised model, it was found he retained a significant amount of hippocampi and he had an additional lesion in the OFC and injuries to deep white matter.
• Define hemispheric lateralisation

  The theory that certain functions are controlled by one hemisphere rather than the other