biopsych

• Nervous system


  A specialised network of cells making up our internal communication system. It helps to collect, process and respond to information in our environment and co-ordinate the working of organs and cells
• Central nervous system (CNS)


  Division of the human nervous system that is responsible for complex commands and decisions. It integrates incoming information and co-ordinates activity across the whole body. It is made up of the brain and spinal cord

  
• Brain


  An organ made up of a mass of nerve tissues. It is our centre of conscious awareness and allows us to have higher mental processes
• Spinal cord


  Extension of the brain which passes messages to and from the brain. It connects nerves to the peripheral nervous system
• Peripheral nervous system (PNS)


  Division of the human nervous system that sends messages to and from the CNS. It links the outside world with the CNS and controls muscles and glands
• Somatic nervous system


  A voluntary part of the peripheral nervous system, controlling muscle movement and receives information from sensory receptors on the body. Works with the CNS to direct muscles to act
• Autonomic nervous system


  Involuntary part of the PNS that transmits information to and from internal organs and helps control vital functions

  
• Sympathetic nervous system


  The fight and flight response which prepares the body to respond to threat
• Parasympathetic nervous system


  The rest and digest response which restores the body back to its usual state of relaxation
• Parasympathetic vs Sympathetic


  • Parasympathetic: constrict pupils, increase saliva production, decrease heart rate, dilate blood vessels, constrict bronchi, increase stomach and intestine motility, contract bladder
  • Sympathetic: dilate pupils, decrease saliva production, increase heart rate, constrict blood vessels, dilate bronchi, reduce stomach and intestine motility, relax bladder
• Endocrine system


  An information system in the body that instructs glands to release hormones into the bloodstream. Slower but more powerful than the nervous system, with longer lasting effects
• Gland


  Organ in the body that produces hormones
• Hormones


  Chemical substances that circulate in the bloodstream and only affect target organs
• Fight or flight response

  1. Stress perceived in the hypothalamus

  2. Activates the pituitary gland to trigger activity in the autonomous nervous system

  3. Stress hormone adrenaline is released from the adrenal gland

  4. The ANS switches to the sympathetic state

  5. Adrenaline causes physiological changes in the body which produces arousal needed for fight or flight

  6. When threat passes, the parasympathetic branch of the ANS returns the body to its resting state
• Neuron


  Building blocks of the nervous system. Nerve cells which process and transmit messages chemically and electrically. Transmits impulses from a receptor to the spinal cord or brain
• Types of neurons


  • Sensory neuron: long dendrites, short axons, allows sensory and motor neurons to communicate
  • Relay neuron: short dendrites, short axons, sends impulses from the CNS to a muscle, organ or gland
  • Motor neuron: short dendrites, long axons, sends impulses from the CNS to a muscle, organ or gland

  
• Synaptic transmission


  1. Electrical impulse (action potential) travels down the presynaptic neuron towards the synapse

  2. This triggers the release of neurotransmitters from the vesicles and into the synapse

  3. The neurotransmitters diffuse across the synapses and bind with receptor sites on the post synaptic neuron

  4. The chemical signal is converted back to an electrical signal to continue the process again in the post synaptic neuron

  5. Unused neurotransmitters are taken back up to the presynaptic neuron via reuptake valves and they go back to the vesicles to be reused on the next transmission
• Excitation


  A neurotransmitter that increases the positive charge of the presynaptic neuron, increasing the likelihood that it will fire (e.g. adrenaline)
• Inhibition


  A neurotransmitter that increases the negative charge of the presynaptic neuron, decreasing the likelihood that it will fire (e.g. serotonin)
• Summation


  The process which determines whether a neuron will fire: 1. Sum up the excitatory and inhibitory influences, 2. If overall effect is inhibitory - less likely to fire, 3. If overall effect is excitatory - more likely to fire. Action potential will only be triggered if the sum meets the threshold
• Localisation of function


  The idea that certain functions have certain locations within the brain

  
• Localised brain functions


  • Motor cortex: controls voluntary movements, in the back of the frontal lobe
  • Somatosensory cortex: receives information from touch receptors, in the parietal lobe
  • Visual cortex: processes visual information, in the occipital lobe
  • Auditory cortex: processes sound, in the temporal lobe
  • Broca's area: main centre of speech production, in the frontal lobe
  • Wernicke's area: concerned with speech comprehension, in the temporal lobe

  
• The motor cortex in the left controls movement in the right hand side of the body, and the motor cortex in the right controls movement in the left hand side of the body
• The right hemisphere's visual cortex processes visual information received by the left eye and vice versa

  
• Neurons on one side of the auditory cortex detect high frequency sounds, but neurons on the other side detect low frequency sounds
• Broca's aphasia


  A language disorder caused by damage in a specific area of the brain that controls language expression and comprehension. Patients struggled with language production, couldn't speak full sentences and took a long time to get words out
• Wernicke's aphasia


  Language was easily formed but the sentences were not comprehensive, with impaired meaning and poor comprehension. Suggests that damage to Wernicke's area causes damage to language interpretation
• Hemispheric lateralisation


  The idea that the two halves of the brain are functionally different and that each hemisphere has functional specialisation

  
• Contralateral


  Where each hemisphere controls the opposite side of the body
• Problems of causation in Sperry's research - all patients had epilepsy and there was no control group, so it cannot be certain that non-epileptic people have the same level of lateralisation in their brains

  
• Fink et al used PET scans and found that areas in the right hemisphere were more active during visual processing tasks

  
• Brain plasticity


  The brain's ability to alter its structure and function in reaction to the environment and through experience
• How brain plasticity works

  1. Impulses travel along neurons and travel to the next neuron via a synapse

  2. Neural pathways are created as new information is passed from one neuron to another
• Objects placed in the left hand


  • Processed in the right hemisphere
  • Couldn't be spoken about but the participant could find a similar object
• Objects placed in the right hand

  • Processed in the left hemisphere
  • Could be spoken about
  • Could also find a similar object
• Left hand drawings


  • Clearer and better, showing superiority of right hemisphere for visual motor tasks

  
• Problems of causation - all patients had epilepsy and there was no control group so it cannot be certain that non-epileptic people have the same level of lateralisation in their brains
• Neural pathways


  1. Impulses travel along neurons and travel to the next neuron via a synapse

  2. New information is passed from one neuron to another

  3. The more the neural pathways are used, the stronger the pathway becomes

  4. If the pathway is not used regularly, the connection weakens
• Pruning


  Connections are lost due to a lack of use
• Bridging


  • New connections are created due to use and new stimulus
  • Pathways that are used more are strengthened