Chapter 3: Methods
Nuerons modify the functioning of other neurons
Diff pathways in the NS correspond to a different behavioral functions 1. Cell recordings
a) Single cell recordings
• Precision. Which cells do what.
• E.g., mapping out visual cortex.
a) Mass activity of neurons
• Gross behaviour.
• E.g., stages of sleep, learning,
How do you record neurons? Know what their doing?
a)We can excise a neuron, look at in a pitri dish. Now can LOOK AT NEURON
inside an alive animal and see how it fxns. But we have 10-100 billion neurons
cant measure every one of them
b)Not individual neurons but millions of neurons and their behavior Ie EEG
stages of sleep entire brain neurons changes. 1. Cell recordings
a) Single cell recordings: Wilder Penfield
• 1950s: Used mild electrical currents
to stimulate patients with seizures
• Induced movements by stimulating
primary motor cortex
• Mapped out 2 “homunculi” (little
- Clamps into animals head to keep in place. Excise a piece of the skull and
insert an electrode and monitor the neuron in question.
-Hugal and Weasel won a nobel prize for mapping out the visual cortex,our
understanding of visuals and ability to recognize images is due to single cell rec
-nuerons respond to lines moving in a direction= Visual!
A) people have a sensory relation to seizures ie- burnt food can tigger sezuire.
Only treatment was to cut out part of brain causing the seizures. Maped out 2
parts of the brain 'homunculi'. One maps out all the sensations you feel
(somatosensory strip),the other for motor control (motor strip). NOT in proportion
(huge part for hands and face not trunk/feet) 1. Cell recordings
4 1. Cell recordings
GENITALS are in the wrong place, should be beside hip. Theory thats why foot
rub feels so good hah! 1. Cell recordings
a) Single cell recordings: EEG
• Electrical activity generated by brain
& recorded at scalp.
• Minimum evasiveness.
• Depth of anesthesia, sleep, normal
brain activity, & to diagnose
neurological dis6rders like epilepsy. 1. Cell recordings
7 2. Machines
• “Computer Axial Tomography”
• No time resolution.
• Spatial resolution poor (approx. 5 mm )-
3 things to keep in mind with Machines
1-What is the temporal resolution, how close to realtime are we measuring
2-Whats the Spacial resolution, how detailed are we seeing of the brain
3-How invasive is this procedures? Will it cause damage the the person
CAT based on theory that different parts of body absorb radiation differently ie
bone is more than air. Still images 2. Machines
• “Positron Emission Tomography”
• Measures blood flow containing
radioactive atoms that emit positrons.
• Functional images. Spatial resolution
OK (approx. 2 mm ).
Pt must breath in radiocative gas or drink radioactive material. Decays rapidly so
minimal risk but still invasive
Theory that active parts of brain absorb more oxegen thats measured by the
PET scan- assume active neuron need more 02 2. Machines
• “Magnetic Resonance Imaging”
• Applies brief but powerful magnetic