Biological Approach - Brain and Behaviour

Techniques used to study the brain in relation to  behaviour:

MRI

• Structural MRI reveals brain anatomy   
• Magnetic resonance imaging
• The gradient – adjusts the magnetic field 
• Isolate different body parts -> Radio waves move at the same frequency as the magnetic fields. 

fMRI

• Measures brain function
• Big magnet inside
• Can see the electrical activity to see how the brain works.
• Added Atomic level – stronger magnet – faster scan 
• Oxygenated blood moves to the area of the brain that is more active*
• Talk, experience pain, etc. 
• How brain changes when learning new things – visible

Localisation:

• Localisation - the theory that specific parts of the brain have specific functions that are related to specific behaviours
• Sometimes multiple parts of the brain can be involved  within the same behaviour because the complexity of the behaviours can be often very high
• Even though some parts of the brain have different functions to others - they work together with other parts of the brain to form and create certain behaviours
• The idea that functions have different areas of localisation within the brain - functions such as speech, hearing, memory etc. have different areas of the brain dedicated to them.
• What impact do specific parts of the brain have on specific behaviours? Eg. how the hippocampus affected memory - HM case study

Neuroplasticity:

• Neural pruning - dendrites shrink if not in use
• Use it to Localisation of function
• Area dense because of the process of brain plasticity 
• Density - neurons have more branches on their dendrites

Formation of Neural Networks:

• When neural networks are formed, it is called neuroplasticity 
• When neuron is stimulated, an electrical charge travels down the axon
• Neural networks are created when chemicals are repeatedly stimulated. 
• This repeated firing causes neurons to sprout new dendrites - dendrite branching 
• Increases the number of synapses available for the behaviour

Neural Pruning:

• Neural pruning is the process by which neurons and synaptic connections that are not often used are eliminated 
• This is done to increase efficiency of the neural transmissions that are still in use.
• Neural pruning happens when synapses are not straightened in a long time
• Neural pruning results in neuroplasticity - which is the ability of the brain to change its structure

Neurotransmitters:

• Neuron contains electrical and chemical signals 
• The electrical signals are only within the neuron and the chemical signals are in the synapse and are used to communicate between neurons 
• Neurotransmitter - the chemical that is released when a signal is sent to the axon terminal. 
• The neurotransmitter travels through the gap into another neuron
  •  that is called synapse, this process is repeated once the neurotransmitter has reached its destination.

Agonists

• Neurotransmitters are agonists 
• Specific to post synaptic receptor sights only.

Antagonists:

• Chemicals that are brought to the receptors of the post synaptic neurone 
• They block the receptor sights and dont allow the agonist to actually bind to it.

Excitatory and Inhibitory synapses:

• Excitatory neurotransmitters increase the likelihood of a neuron firing by depolarizing the neuron 

  • Acetylcholine and glutamate

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• Inhibitory neurotransmitters decrease the likelihood of a neuron firing by hyperpolarizing the neuron

  • GABA

• Neural pathway is not inhabited 

• E.g. sleeping, calming/relaxing down after a stressful event