NEUR1020 W6

• What are brain lesions?


  Explains normal brain function by examining what changes when parts of the brain is damaged. Includes stroke or brain injury in humans and induced lesions in animals
• What is an assumption we make about brain lesion?

  Whatever changes in behaviour or cognition, it must rely on that part of the brain that's damaged
• What is single neuron recording?

  Placing a thin electrode into an animal's brain to record action potentials firing from a single neuron, measuring what the neurone encodes or detects
• What are the positives and negatives of single neuron recording?

  Positive: Best localisation and timing of brain function as it directly measures action potentials from individual neurons.

  Negatives: Highly invasive and are mostly conducted on animals only
• What is EEG?

  Electroencephalography, where it measures voltage changes from electrodes placed on the scalp. This is done by the summed activity from action potentials of neurons in the cortex
• What is displayed when doing an EEG?

  Oscillations (brain waves), usually seen in sleep, alertness and arousal
• What are some clinical uses of EEG?


  Detecting stages of sleep and monitoring epileptic seizures
• What are ERPs?


  Event-Related Potentials, which measure brain activity related to a specific stimulus from an average of over 100 trials of EEG
• What do the peaks represent in ERPs?


  Represents different stages of processing of the stimulus
• What is one clinical use of ERPs?


  Detecting deafness in babies
• What are the positives and negatives of ERPs?

  Positives: Shows precise time of information processing in brain.

  Negatives: Poor spatial resolution, difficult to accurately localise activity to a brain area
• What is functional brain imaging?

  Change in blood flow associated with neural activity
• What is the PET brain imaging?

  Positron Emission Tomography (1980-1990s), which used to map neurotransmitters or receptors in the brain by using radioactive substances injected into the bloodstream
• What does MRI stand for?

  Magnetic Resonance Imaging
• What is the difference between MRI and fMRI brain imaging?

  MRI studies brain anatomy while fMRI studies brain function
• What does fMRI detect?

  Detects changes in blood oxygen level (BOLD signal). Neurons use oxygen, hence brain activity increases
• What are the positives and negatives of fMRI?

  Positives: good localisation of brain activity.

  Negatives: Very expensive, not precise timing, indirect measure of brain activity as BOLD signal is from the change in blood oxygen level
• What can you NOT infer from measuring brain activity?

  Cannot infer what people are thinking/doing/feeling
• What are the MRI "brain decoding" methods potentially for the future?

  Using MRI to reconstruct what people are seeing based on activity in their visual cortex
• What is brain plasticity?


  Capability of the brain to alter its functional organisation as a result of experience (learning)
• What is neurogenesis and synaptogenesis?

  Generation of new neurons and synapses (new connections)
• What do neurons encode?

  Neurons encode concepts. Memory may be represented by groups of neurons each encoding specific concepts or objects
• What is the theory of Spreading Activation Model?

  Neurons represent a specific concept, and neurons share connection that represent related concepts. Hence, activation (firing) of one neuron leads to spreading activation to related neurons (concepts)
• What can we way about learning and memory in terms of neurons and concepts?

  Making and strengthening connections between neurons that represent associated concepts
• What did Ramon y Canal propose about neurons?

  Neurons do not regenerate
• What does neurogenesis suggest, opposed to Cajal's thoughts?

  New neurons are constantly born throughout life from neural stem cells, but only in 2 areas in the adult brain: hippocampus and sub ventricular zone
• What do "enriched" conditioned of the environment lead to for synaptogenesis?


  Leads to growth of dendrites and more extensive synaptic connections
• What is LTP?

  Long-Term Potentiation, which is the change in the structure of synapses to give stronger signal from pre-synaptic to post-synaptic neuron
• What is Hebb's Law of "Hebbian Learning"?

  "Neurons that fire together wire together". Brain pathways that are used often are strengthened
• What is an example of neuroplasticity with experience and learning?

  Sensory cortex finger areas of musicians who played stringed instruments expanded with the use of experience
• What is an example of neuroplasticity after damage?

  With rehabilitation of an injured hand, motor cortex can re-organise with use to recover its function
• What is an example of neuroplasticity in blind people?

  Visual cortex changed in blind people while reading Braille, while it didn't for sighted people, thus brain areas lacking their normal function input can take new functions with use