Brain and neurotransmitters

• CNS: subcortical brain structures

  Thalamus- This is the brains relay station, it receives information from various senses such as hearing and touch. Then passes it on to the appropriate areas of the cerebral cortex for higher level processing.
• CNS: subcortical brain structures

  Hypothalamus- This controls motivational behvaiours such as hunger and sex. Has a key role on body stress response through its control of 'fight or flight'. It maintains balance in many bodily functions such as temperature and also regulates the activity of the endocrine system via its connection with the pituitary gland
• CNS: subcortical brain structures

  Limbic system- consists of several structures such as the amygdala- plays a role in regulating emotional responses. It also has a role in memory and learning
• CNS: subcortical brain structures

  Cerebellum- its primary role is to coordinate posture, balance and movement. It does this by receiving anfdintegrating information from the spinal cord and other areas .
• CNS: subcortical brain structures

  Corpus callosum- it allows communication between the hempispheres by passing signals back and forth- CRITICAL due to it integrates the activities of both sides of the body
• What is lateralisation?

  The idea that the brains left and right sides have different functions for example- language is associated with the left hemisphere
• what is localisation?

  Certain areas of the brain are responsible for specific functions and behaviours
• The cerebral cortex

  Is subdivided into four lobes- each has different fucntions

  • Frontal lobes- control high level cognitive functions such as problem solving and also contains the motor cortex
  • Parietal lobes- processes sensory information from the skin ie. temperature
  • Temporal lobes- each lobe contains an auditory cortex which deals with sounds coming mainly from the opposite ear, have a role in understanding language
  • Occipital lobes- each lobe contains a visual cortex and eevrything we see to the right of our field of vision is initially processed by the left visual cortex being shared
• Diagram of a neuron

  insert pic
• Sensory neuron:


  • tells the rest of the brain about the external and internal environment by proessing information taken from one of the five senses
• Relay neuron:


  • they carry messages from one part of the CNS to another and connect motor and sensory neuron's
• Motor neuron:


  • they carry signals from the CNS which helps both organs, including glands and muscles
• The process of synaptic transmission:

  This is the process of transmitting messages form neuron to neuron. Nerve impulses are carried across the small gap, the synapse between one neuron and another- the nerve impulse is an electrical signal which is carried by chemicals known as neurotransmitters.

  • excitatory potentials- make it more likely for the neuron to fire
  • inhibitory potentials- less likely to fire
• What is a neurotransmitter?

  It is a chemical message that carries, boost and balances signals between neuron's or nerve cells and other cells in the body. These chemical messages can affect both physical and psychological functions including heart rate, sleep and fear.
• what are recreational drugs?

  Biochemicals that have specific effects on the functioning of the bodys systems- either increases or decreases specific neurotransmitters at the synpase
• Recreational drug- Cocaine

  • cocaine has a stimulant effect on the CNS, especially on the brains reward system
  • the drug achieves its effects by altering synaptic transmission involving neurotransmitters such as noradrenaline, serotonin and acetylcholine
  • most profound impact is on the activity on DOPAMINE
  • EFFECT- It blocks the reupatake of dopamine and prevents it from being transported leaving the synapse to being flooded with dopamine causing a 'euphoric high'
• Recreational drug- Heroin

  • heroin has depressant effects on the CNS as it slows down the CNS activity which includes the neruons involved in pain
  • when usually injected and reaches the brain most of it is processed into a closely related opioid - MORPHINE
  • morphine binds to a specific opioid receptor at the synapse- enhancing the natural response of the endorphins already produced by the body
  • long term effects include downregulation
• What are agonists and antagonists?

  • agonist mimics the action of another biochemical ( heroin)
  • antagonist blocks opiate receptos (Naloxone)
• what is the process of reuptake ?

  The neurotransmitter that is not used by the receptors is taken up to be reused

  The reuptake regulates the amount of neurotransmitter in the synapse which regulates how much message there is ( message stops once transmitter has left the gap) and also recycles the neurotransmitter so it has a useful function.

  • a reuptake inhibitor works by stopping the transmitter from reaching the post synaptic neuron- meaning it will be left in the gap so the message can continue for longer
• what happens through synaptic transmission?

  • an axon terminal of one neuron reaches out to the dendrites of another
  • the gap between the terminal is synapse
  • neurons are separated by the synaptic cleft
  • the neuron where the signal is initiated is the pre synaptic neuron and post synaptic receives this
  • the pre synaptic neuron contains neurotransmitters that the axon potential causes the vesicles to fuse with the presyanptic membrane
• Brain structure - pre frontal cortex

  Is involved with self control and decision making, handling aggression. If not functioning well there is no break on aggression