Brain and neurospychology

• The nervous system is a specialised network of cells in the human body and is our primary internal communication system
• Two main functions of the nervous system:

  • To collect, process and respond to information in the environment
  • To co-ordinate the working of different organs and cells
• Parts of the nervous system:

  • Central nervous system (CNS) consists of the brain and the spinal cord
  • Peripheral nervous system (PNS) transmits messages to and from the CNS
• Central nervous system (CNS):

  • Brain is the centre of all conscious awareness
  • Brain's outer layer, the cerebral cortex, is highly developed
  • Brain is divided into two hemispheres where all decision making takes place
  • Spinal cord is an extension of the brain, responsible for reflex actions
• Peripheral nervous system (PNS) is further subdivided into somatic and autonomic
• Autonomic nervous system (ANS) governs vital (involuntary) functions in the body such as breathing, heart rate, digestion, and stress responses

  • Further subdivided into parasympathetic and sympathetic
• Somatic nervous system (SNS) is responsible for carrying sensory and motor information to and from the spinal cord
• Sympathetic nervous system:

  • Prepares the body for fight or flight with quick responses
  • Actions include slowing digestion, inhibiting saliva production, increasing heart rate, stimulating glucose production, stimulating urination, relaxing the bladder, dilating pupils, and dilating bronchi
• Parasympathetic nervous system:

  • Maintains and conserves energy for rest and digest with slower responses
  • Actions include increasing digestion, increasing saliva production, decreasing heart rate, stimulating bile production, inhibiting urination, constricting pupils, and constricting bronchi
• James-Lange theory:

  • Event-arousal-interpretation-emotion sequence
  • Weaknesses include being challenged by the Canon-Bard theory and the two-factor theory
• Neurones:

  • Motor neuron carries messages from the CNS to effectors
  • Sensory neuron carries messages from the PNS to the CNS
  • Relay neuron connects sensory neurons to motor neurons
• Basic structure of a neuron:

  • Cell body includes a nucleus and dendrites
  • Axon carries electrical signals away from the cell body
  • Myelin sheath protects the axon and speeds up the electrical signal
  • Terminal buttons communicate with the next neuron in the chain
• Synaptic transmission:

  • Neurons pass messages by releasing neurotransmitters into synapses
  • Neurotransmitters alter the neuron's chemistry, making it more or less likely to fire
• Donald Hebb's theory of learning:

  • Neuronal growth occurs when neurons excite each other repeatedly
  • Forms neural pathways and cell assemblies for learning and memory
• Neural plasticity:

  • Neurons change in form and function in response to environmental alterations
  • Brain experiences rapid growth in synaptic connections during infancy
• Penfield's interpretive cortex study:

  • Investigated the workings of the conscious mind through brain stimulation
  • Strengths include developing the Montreal procedure for treating epilepsy
• Tulving's gold memory study:

  • Episodic and semantic memories are separate forms of long-term memory
  • Episodic and semantic memories are located in different parts of the brain
• CT scan:

  • Reveals abnormal brain structures such as tumours
  • Requires more radiation than x-rays
• PET scan:

  • Shows brain activity and localisation of function
  • Requires injection of a radioactive substance
• fMRI scan:

  • Measures changes in blood oxygen levels in the brain
  • Shows clear images without radiation