Please enable JavaScript.

Coggle requires JavaScript to display documents.

Week 1: Research Methods - Coggle Diagram

- - - - Brighter voxels => larger number
      - voxel intensity meaning
        defined by image modality
- - - - Surgical Removal
      - Heat :fire:
        
        Microelectrode is surgically inserted
        
        Heat generated at electrode tip to kill nearby cells
      - Chemicals
        
        applying neurotoxins through a surgically implanted micropipette
        
        selectively harm cell bodies or nerve fibres
    - - Cooling :snowflake:
        
        neurons unable to function when cooled
        
        Able to resume normal activity when temperature is normal
- - - - also known as
        T1-weighted imaging
      - white matter :bulb:
        
        grey matter :dark_sunglasses:
      - primarily used to
        study grey matter
        
        Volume
        
        Cortical thickness
      - face may be cut out as the MRI
        may contain facial features
    - - cortical thickness
    - - primarily used to study
        white matter microstructure
        
        Fractional Anisotropy
        
        directionality of
        water movements
        
        High in WM
        
        WM fibre tracts only allow
        water to flow unidirectionally
        
        Low FA in WM tracts may mean
        compromised microstructural integrity
        
        Eg.multiple sclerosis
        
        Low in GM
        
        Lowest in ventricles
        
        Mean DIffusivity (MD)
        
        Overall magnitude of water diffusion
        
        :chart_with_downwards_trend: in WM tracts
        
        High FA can indicate compromised
        microstructural integrity
        
        Highest :chart_with_upwards_trend: in ventricles
      - aka Diffusion Tensor Imaging
  - - - Characteristics
        
        Higher detection depth
        to subcortical regions
        
        Statistical models may be needed to separate subcortical signals from cortical surface signals
        
        Higher temporal resolution
        than fMRI or PET (1ms)
        
        requires a magnetically
        shielded room
        
        Variable spatial resolution (10ms)
        
        Silent
        
        High cost
      - records the weak electromagnetic fields generated by neurons
        
        use of superconducting quantum interference devices (SQUIDs)
        
        recordings are superimposed on 3D MRI images
    - - requires injection of radioactive tracers
      - restricted diet and physical activity 24 hours before scan
    - - How
        
        oxygenated and deoxygenated
        blood provide different magnetic signals
        
        Blood-oxygen-level-dependent (BOLD) levels
        
        multiple brain scans taken over short intervals (1 to 3 seconds)
        
        each voxel contains time series data
        
        4D image because
        its across time
        
        Measures brain
        activity by blood flow
      - Functions
        
        used for comparisons
        between 2 conditions
        
        important to mention
        control task as well
        
        Functional
        Connectivity
        
        correlations between
        brain activity in 2 regions
      - Characteristics
        
        Unable to measure short-duration events
        
        Eg. Priming event
        
        Priming event can be repeated
        but may reduce the effect of priming
        
        Contraindication of ferromagnetic
        or metallic implants
        
        High spatial resolution
        
        Ability to identify brain
        activity changes
        
        High costs
        ($1000 / hour)
        
        :chart_with_downwards_trend: Statistical power
        
        :chart_with_downwards_trend: Reproducibility
    - - detect changes across
        very short time intervals
      - Characteristics
        
        Higher temporal resolution then fMRI (1ms)
        
        Poor spatial
        resolution
        
        Different head shapes
        and hair volumes
        
        cannot be sure if the signal is originating
        from the desired brain area
        
        Low detection depth
        (slightly more than fNIRS)
      - Uses
        
        Brain waves
        
        frequency related to level of coordination in neuron activity
        
        :chart_with_downwards_trend: brain activity
        
        :chart_with_upwards_trend: coordination :arrow_right: :chart_with_downwards_trend: frequency
        
        Eg. Deep sleep :sleeping:
        
        :chart_with_upwards_trend: brain activity
        
        :chart_with_downwards_trend: coordination :arrow_right: :chart_with_upwards_trend: frequency
        
        Eg. Problem solving / concentration :male-student::skin-tone-3:
        
        Event-related
        Potentials
        
        changes in cortical neuronal activity associated with stimuli
        
        Recordings from multiple readings averaged out to reduce noice
        
        Average wave has
        polarity and latency
        
        Abnormalities in P300 wave associated with alcohol dependence and Alzheimer's
        
        possible due to high
        temporal resolution
    - - measures blood flow and blood oxygenation levels using infrared light
      - Characteristics
        
        Poor spatial
        resolution (10mm)
        
        May measure different brain areas
        across different participants
        
        Low detection depth
        (up to 4cm deep)
        
        Lower cost than fMRI
        
        Better temporal resolution than fMRI
        
        Can be obstructed by
        dark or thick hair
        
        Relatively higher mobility
      - Composed of infrared
        emitters and detectors
        
        Emitters emit infrared signal
        
        Reflected infrared signal is
        detected by infrared detectors
    - - Characteristics
        
        :chart_with_upwards_trend: invasiveness
        
        :chart_with_upwards_trend: cost
        
        :chart_with_upwards_trend: spatial resolution
        
        :chart_with_upwards_trend: temporal resolution
      - surgical insertion of
        microelectrode into the skull
      - used in discovery of mirror neurons
    - - simultaneous recording of brain activity from more than one person
      - records information about synchrony of neural activity during social interactions
      - fNIRS preferred due to its relative mobility
- - - - changes occuring
        during TCDS
      - Eg. altered resting membrane potential
    - - prolonged stimulation can result
        in semi-permanent changes
      - aftereffects post-TCDS
    - - Itching and burning
        sensation on scalp
      - Non-invasive
      - Smaller range
        
        Skull bones obstruct
        electricity better
  - - - Smoking cessation
      - MDD
      - OCD
  - - - Genetic material that produces opsins inserted in virus
        
        Virus is injected into animal brain and infects many cells
- - - - 400 BCE
        
        Hippocrates
        
        correctly identified epilepsy as originating in the brain
        
        Galen
        
        believed ventricles transported messages to and from the brain
        
        error affected neuroscience for another 1500 years
        
        Josef Gall
        
        Phrenology
        
        shift towards idea that functions are localised in the brain
        
        bumps in skull structure can predict personality traits
      - Edwin Smith
        Surgical Papyrus
        
        oldest known medical
        writing in history
        
        understood nervous system damage as the cause of paralysis or lack of sensation
        
        understanding of relative permanence of damage
- - - - sweat creates differences in skin conductance
- - - - Linkage
        
        identify locations
      - Genome-Wide
        Association Study
        
        finds correlations between genes and specific phenotypes
        
        used to identify genetic correlations for disorders like schizophrenia
      - Candidate
        
        find correlations between specific genes and traits
        
        genes selected due to logical relationships with a trait