brain and neuropsychology

• Nervous system


  Divided into central nervous system (CNS) and peripheral nervous system (PNS). PNS is further divided into somatic nervous system (SNS) and autonomic nervous system (ANS)
• Autonomic nervous system (ANS)


  • Controls homeostasis
  • Controls glands, vital muscles and internal organs like heart, stomach, blood vessels
• Homeostasis


  The process by which the body maintains a constant and balanced internal state
• Examples of homeostasis


  • Maintaining constant blood carbon dioxide level
  • Maintaining constant body temperature around 37 degrees Celsius
• Automatic system


  Actions of the ANS cannot be brought under voluntary control, they keep going without us having to will them to do so
• Divisions of the ANS


  • Sympathetic nervous system
  • Parasympathetic nervous system
• Sympathetic nervous system


  Represents a state of physiological arousal - faster breathing, rapid heart beats, sweating. Prepares the body for fight or flight response to cope with stress
• Parasympathetic nervous system


  Counteracts the actions of the sympathetic nervous system, returns the body to its normal resting state after the threat or stress has passed
• Fight or flight response

  1. Brain detects threat

  2. Hypothalamus instructs sympathetic division of ANS to act

  3. Adrenaline released from adrenal glands

  4. Physiological changes to prepare body for action
• When threat has passed

  Parasympathetic division returns body to resting state
• The fight or flight response is an automatic response in the body designed to help confront the threat or give energy to run away
• After the threat has passed, the person may feel hungry or thirsty having used up energy during fight or flight, and because digestion is now stimulated
• Sadness


  A normal human emotion
• Depression


  An abnormal emotional state where a person feels sad about everything
• There may be no key cause for depression
• Unipolar depression


  The person only experiences one emotional state (depression)
• Symptoms of depression


  • Low mood depressed mood for most of the day, nearly everyday
  • Reduced energy levels - people with depression have reduced levels of energy, making them feel lethargic
• Bipolar depression


  People experience changes between two mood states - depression and mania. Mania is a state of euphoria or frenzied activity in which people may have an exaggerated belief that the world is theirs for the taking
• Bipolar disorder used to be called manic depression because the person alternates between mania and depression for weeks or months
• Neurotransmitters


  Brain chemicals that are released from synaptic vessels
• Serotonin


  A neurotransmitter which transmits a message from one neuron to another. If there's plenty of serotonin in the synaptic cleft, the message is transmitted and the postsynaptic neuron is stimulated, leading to improved mood
• In some people, levels of serotonin in the brain are low
• If brain levels of serotonin are low, then levels at the synapse are low and the message is not transmitted, resulting in a low mood
• Other effects of serotonin

  • Impacts memory, sleep and appetite
• Reasons for low serotonin levels

  • Genetic - a person may inherit a poor ability to produce serotonin
  • Nurture - diet low in tryptophan, which is a key ingredient in making serotonin
• There's supporting research evidence that depressed people have lower serotonin levels in their brains compared to a control group
• Depression may not be caused by abnormal levels of neurotransmitters as the explanation is too simple, because research shows that people with low levels of serotonin don't have depression
• Negative schemas


  A mental structure containing all the information we have about one aspect of the world. If you have a negative self-schema, this means you're likely to interpret all information about yourself in a negative way
• Attributions


  The process of explaining causes of behaviour. When we observe someone else's behaviour, we unconsciously think of explanations for their behaviour. We also have attributions for ourselves
• Learned helplessness


  If a person has an unpleasant experience and can't escape, they learn to give up trying
• Cognitive explanations lead to ways of treating depression, such as cognitive behaviour therapy
• Negative beliefs may simply be realistic rather than depressing, as there are occasions where life experiences are depressing and it's realistic to feel sad
• Selective serotonin reuptake inhibitor (SSRI)


  A drug that selectively targets serotonin at the synapse by inhibiting the reuptake of serotonin molecules
• Serotonin release and reuptake

  1. Serotonin is released by certain neurons in the brain and stored in vesicles at the end of the transmitting neuron

  2. The electrical signal travelling through the neuron causes the vesicles to release the neurotransmitter into the synaptic cleft

  3. The serotonin molecules convey the signal from the presynaptic neuron to the postsynaptic neuron by locking into a postsynaptic receptor

  4. Afterwards, the serotonin molecule is taken back into the presynaptic neuron where it's broken down and re-used
• If the reuptake can be blocked, then more serotonin is held in the synaptic cleft as new serotonin is released from the presynaptic neuron and added to what has been held in the synaptic cleft
• Using antidepressants have serious side effects including nausea, insomnia, weight loss or gain, and an increase in suicidal thoughts
• Patients may stop taking antidepressants as they dislike the lack of control they feel over their own behaviour and report feeling like they're in a dream
• Cognitive Behavioural Therapy (CBT)


  A therapy that focuses on what a patient thinks, as good mental health is the result of rational thinking, while poor mental health such as depression is a result of negative irrational thinking
• CBT process


  1. Therapist tries to challenge the client's irrational thoughts and help them think more rationally

  2. Client is asked to keep a thought diary to record unpleasant emotions experienced
• CBT


  • Has lasting effectiveness as it supplies the depressed person with tools to help them deal with future episodes of depression
  • Requires a considerable amount of time and thought from the client, which means many people drop out of CBT treatments as they aren't seeing benefits