Phrenology

Wrong!

Outer Surface of Human Brain

Gray Matter = Neuron cell bodies & dendrites

White Matter = Myelin (=fat)- covered axons

Cortex = Outer layer of gray matter

Gyri

Sulci

Axial Slice through Human BrainFront

Back

Major Lobes of the Brain

Ways to Find Out About Brain Function

Most of what we know about the brain comes from brain damage - Damage to specific regions often produces specific deficits  - e.g., In the 1800s, Broca observed that damage to the left frontal lobe led to language deficits (aphasia)

But we can't get the full story on normal function from damage - Lack of control- Involvement vs responsibility- Compensation & reorganization

- This is how it was first discovered that different parts of the brain have different functions

Some Regions Involved in Language(Evidence from Brain Damage)

Function in the Normal Brain Ways to monitor brain activity non-invasively, as it’s

happening Measure: 1. Electrical and magnetic fields generated by neurons - Electroencephalography (EEG, ERP) - Magnetoencephalography (MEG) - Event-related Optical Signal (EROS)

2. Blood flow to active regions  - Positron Emission Tomography (PET) - Functional Magnetic Resonance Imaging (fMRI) - Other optical methods (Near-Infrared Spectrometry – NIRS)

3. Consequences of temporary disruption (Not so non-invasive!) - Electrical stimulation - Magnetic stimulation (Transcranial Magnetic Stimulation - TMS)