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last updated:

March 09, 2021

[Brain Image]    

PSY 340 Brain and Behavior

Class 13:  Research Methods (OUTLINE)

   


How do we learn about how the brain works?

Brain vs. Behaviors

1. Look at the Effects of Brain Damage

2. Stimulate Some Brain Area and Analyze the Resulting Behavioral Change

3. Record Brain Activity during Behavior

4. Correlate Brain Anatomy with Behavior




1. Look at the Effects of Brain Damage


Broca Tan  Stereotaxic
                  Instrument   Transcranial Magnetic Stimulation


Paul Pierre Broca (1824-1880)

Animal Brain Research

Transcranial Magnetic Stimulation (TMS) causes temporary "damage" by turning off neural transmissions

BBC The Brain: A Secret History

Michael Mosley has areas of his brain turned off by TMS (YouTube)





2. Stimulate Some Brain Area and Analyze the Resulting Behavioral Change

Originally, electrical stimuli applied to the brain to see the resulting behavior

Rat (Optogenetics)     Optogenetics = Using light to control a limited group of neurons










3. Record Brain Activity during Behavior


EEG (Electroencephalograph)

EEG Berger 1929   EEG Child with
          Petit Mal Epilepsy



PET Scan (Positron Emission Tomography)

Pet scan working

PET ScanPET Temporal Lobe
            Hypoactivity







Functional Magnetic Resonance Imaging (fMRI)

fMRI of occipital lobe   Default Mode Network




4. Correlate Brain Anatomy with Behavior

CAT ScanCAT Scan - hemorrhage

MRIMRI (1319-25)

In the MRI image on the right, the patient appears to have a large tumor growing in the mid-portion of the brain. This has compressed the cingulate cortex and is pressing down on the corpus callosum.




Brain vs. Body MassBrain Size and Intelligence

  • Humans do not have the largest brains across animal species
  • Humans: Brains vs. IQ (Intelligence)
    • There is a moderate correlation between brain size and IQ tests (r = ~0.30-0.40, that is, 9-16% of IQ scores related to brain size).
    • CAUTION: IQ test scores may not be adequate to evaluate "intelligence" which is a notoriously difficult concept to quantify.
    • Hevern: Intelligence involves those abilities to cope successfully with whatever environments (physical, interpersonal, or cultural) individuals find themselves in.
  • Males generally do have larger brains than females (roughly 8-10%). However, there are no overall IQ differences between men and women.
  • Males vs. Females
    • Women have deeper & more sulci than men and, despite females brains being roughly 8-10% smaller in volume, there is equal cortical surface for men and women.
    • Some structural differences have been found in the wiring between female and male brains. The significance of these findings is not yet clear.
    • Structural differences ≠ behavioral differences, for example, Males > Females in face processing cortical area, yet, Females > Males in actual face processing tasks




This page was first posted February 3, 2005