Transcript Language & Brain Lecture 120110

Phrenology
Wrong!
Outer Surface of Human Brain
Axial Slice through Human Brain
Front
Gray Matter
Gyri
= Neuron cell bodies
& dendrites
Cortex
= Outer layer of
gray matter
Sulci
White Matter
= Myelin (=fat)covered axons
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)
- This is how it was first discovered that different parts
of the brain have different functions
But we can't get the full story on normal function from damage
- Lack of control
- Involvement vs responsibility
- Compensation & reorganization
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)