Research Methods I

How Do We Compare Tools?

What questions can I answer using a specific method? What are its strengths and weaknesses? Invasiveness x Resolution

• Ethical constraints?
  • Syphilis study
• Public registration (post methods and hypothesis)
• p-hacking
  • Much less than .5
  • Long term behaviors dont equal short term
• File drawer problem
  • Journals dont publish null results

Research Methods: Animals

Cartesian Dualism: animals didnt have a soul or mind (couldnt feel like we feel)

Reduce: Minimize the number of animals

use our best statistical estimates of power and so on to use the fewest numbers of animals possible.

Refine: Use humane methods

look at our methodologies and make sure that we're being as humane as possible.

Replace: don't use animals unless you absolutely have to

If you can do a computer simulation or grow something in a Petri dish,  that's preferable. We also replace by using the simplest organisms, like these fruit flies  who went to the International Space Station, rather than more sentient animals like  monkeys.

Peripheral Methods

• Measure emotional and arousal of whole body
  Key Focus: Compare and contrast tools based on:
  Research questions they answer.
  Strengths and weaknesses (e.g., invasiveness, spatial/temporal resolution).
  Ethical constraints, especially in non-beneficial procedures for participants.

  Concepts of Resolution:
  Spatial resolution: Detail level of structures (e.g., MRI > EEG or SPECT).
  Temporal resolution: Precision of timing (e.g., EEG > fMRI).

Peripheral Methods (Non-Invasive, High Temporal Resolution)

Facial Electromyography:
Measures facial muscle movements linked to emotions (e.g., anger, positive affect).
Heart Rate Variability (HRV):
Indicates balance between sympathetic and parasympathetic systems; lower HRV = stress.
Eye Tracking and Pupil Dilation:
Eye tracking reveals focus; pupil dilation signals arousal.

Microscopic Methods

- Types:
Light microscope: Magnifies ~1,000x; suitable for living samples.
Electron and fluorescent microscopes: Magnify ~1,000,000x; require fixed, non-living samples.
Infrared microscopy: Visualizes tissues without stains.

Stains and Historical Advances:
E.g., Golgi stain used by Santiago Ramon y Cajal to identify single neurons.
Innovations include transparent brain imaging methods.
- Golgi good for ident. of cellular structure
- Meiylin (spelled wrong prob) good for visuallising connections between the neurons

Modern Brain Imaging Techniques

CT Scans (Computerized Tomography):
Structural imaging based on X-rays with dye contrast.
Strengths: Good resolution, low cost, fast.
Weaknesses: No activity data, moderate risks from contrast dye.

PET (Positron Emission Tomography):
Tracks brain activity via radioactive tracers.
Strengths: First technology to measure activity.
Weaknesses: Ethical concerns due to radioactivity, no structural resolution.

MRI (Magnetic Resonance Imaging):
Produces high-resolution structural images.
Functional MRI (fMRI): Time series of images showing brain activity via blood flow.
Challenges: Expensive, noisy, and restrictive for participants with tattoos or piercings.
- A team of neurobiologists is investigating the possibility that lack of vitamin produces structure damage in a region of the brain.

Diffusion Tensor Imaging (DTI):
Tracks water flow in nerve fibers to map pathways (e.g., corpus callosum).

fNIRS (Functional Near-Infrared Spectrometry):
Combines advantages of fMRI with:
Lower cost, better mobility, improved temporal resolution.
Limitation: Reduced spatial resolution compared to fMRI.