Physiological Psych, Neuroscience, and Comparative Psych

Explain behavior and cognitive processes in terms of their biological foundations
Builds upon knowledge of the central nervous system
Signaled further decline of behaviorism
- Consider internal causes of behavior

Influenced by Pavlov’s work
Followed Gestalt psychology
- Studied under Lashley
Questions
- How neurons in brain organized?
- When will neurons fire?
Cell Assemblies
- Group of neurons fire when person experiences objext
  - Newborn’s brain → Random neural connections
  - Through experience → neurons become organized

Neurons receive…
- Excitatory Signals
  - Neuron fires more often
- Inhibitory Signals
  - Neuron fires less often
Neural Threshold
- Excitatory signals outnumber inhibitory signals at or above threshold for neuron to fire
Neuron 1 → 2
- Excitatory signals → +4
- Inhibitory signals → -3
- Will it fire? (NO!)
Can Neural Threshold Change?
- Neuron A fires → Neuron B fires
  - Happens many times
- Neurons that fire together, wire together
If Neuron A keeps firing, it’s easier for Neuron B to fire
- Neuron B’s neural threshold will decrease
Hebbian Learning
- Decrease of neural threshold
- Easier for neurons to fire

Studied under Donald Hebb
Researched memory, amnesia, and brain damage
Patient H.M.
- Hippocampus surgically removed
  - Involved in memory formation
- Couldn’t remember anything after surgery
H.M. Experiment
- Learned to draw star by looking in mirror
- 2 Memory Systems
  - Explicit System
    - Personal events
  - Implicit System
    - Procedures
- Hippocampus was involved with explicit memories, not implicit
  - Could still draw the star

Influenced by George Miller
Old views on memory → Singular construct
- Procedural and semantic memories are similar
- Same brain parts associated with all types of memories
Proposed third memory system
3 Memory systems:
- Separate
- Different parts associated with each type of memory
- Procedural Memory
  - How to do something
    - Ride a bike
- Semantic Memory
  - Knowledge of general facts
    - Who is President
- Tulvings 3rd memory system
- Episodic Memory
  - Memory of personal experiences
    - High school graduation
    - Sense of self
    - Only humans have this type of memory
    - Appeared late in evolution
    - Evidence?
      - Amnesics
        Forget episodic memory
        Remember procedural memory

Influenced by George Miller
Father of cognitive neuroscience
- Started world’s first computerized psych lab
Measured how quickly cognitive events take place in brain
- AA → Same → Faster response
- Aa → Same → Slower response
Used neuroimaging
- How quickly could cognitive processes occur?
- Where in the brain do cognitive processes occur?
FMRI
- Function Magnetic Resonance Imaging
- Uses water’s magnetic properties
  - Tracks blood flow through brain
- Participants performed cognitive task while brain is imaged

Studied with Lashley
Won Nobel Prize in medicine
How does info travel from left hemisphere to right hemisphere
Corpus Callosum
- Fibers connecting both hemispheres
- If severed, the hemispheres can’t communicate and operate independently
Split-Brain Procedure
- Patients suffering from severe epilepsy
- Severed corpus callosum has less severe seizures
- If seizure begins in one hemisphere, it can’t spread to other hemisphere
- Each hemisphere has its own functions
  - Left → Analytical thinking and language abiltiies
  - Right → Spatial thinking
  - Very popular research
  - People aren’t left/right brain dominant
  - People with normal brains have both hemispheres that work together