Research Methods & Strategies

Research Methods & Strategies

1. Experimental Ablation

   • Not just scooping out parts
   • Can cause lesions and examine the damage & effects they have
     • Excitotoxic - chemical lesion
     • Radiofrequency - burn
     • Antibody conjugates
     • Sham lesion for control group
   • Stereotaxic apparatus
     • Works on a 3D spherical grid to map the brain; many use bregma as a reference point
   • Histology - study of microscopic structure of cells, tissue
     • Perfusion - process where animal's blood is replaced by a fluid (bc blood is sticky and coagulates)
     • Creating brain slides
       • Formalin - formaldehyde (aq) which makes jelly-like brain easy to handle
       • Microtome - meat slicer
       • Cryostat - freezer with a microtome in it
     • Types of microscopes
       • Electron
         • Transmission
           • shows interior of cell body
         • Scanning
           • small 3D images of a surface/neuron
       • Confocal Laser Scanning Microscope - for thick tissue

2. Neural Activity

   • Tracing circuits
     • Anterograde - for efferent axons; shows what's next; going forward down path
     • Retrograde - for afferent axons; shows what came before
   • Structure of a living brain
     • CT - X-ray
     • MRI - high-res images; differences in water content changes contract in image
     • DTI - w/MRI can detect small fiber tracts
   • Electro
     • Micro - one single neuron's activity
     • Macro - covers thousands of action potentials / neurons
   • Functional Imaging
     • PET - localization of radioactive tracer in living brain
     • FMRI - BOLD

3. Genetic Methods

   • Twin studies - genetic influences
     • Monozygotic vs. dizygotic
   • Adoption studies - environmental influences
   • Genomic studies - evaluate all genetic material of a person, incl. alleles
     • Target mutations
     • Determine function

4. Neurochemical Methods

   • Metabolic activity / neural activity positively correlated
   • 2-DG -> 2-deoxyglucose
     • Imitates glucose to detect activity
     • Don't need live subjects for autoradiographs
     • PET scan for living subject