NEUR200 Research methods

Optogenetics

• Brain stimulation using light

• Insert light sensitive protein from algae into a type of neuron

• Insert an optical fiber to shine light

• Stains just a few neurons

Brain stimulation

TMS and DBS

TMS

• magnetic stimulation to a portion of the scalp

• Activates or inactives neurons in a narrow area below the magnet

• Temporary brain activity

Limitations of TMS

• a little painful

• Only for outer cortex

• Difficult to target area (deep areas)

• Transient cognitive changes

DBS

• Electrical stimulation of the brain

• Only used in patients when medication is not working (Parkinson’s disease, depression)

• neurostimulator implanted under the skin that sends electrical impulses to the brain

Electrical recording

EEG and MEG

EEG

When millions are active at the same times, current generated is strong enough to be detected on surface of the scalp with sensitive electrodes

MEG

Measures the magnetic fields generated by brain activity

EEG AND MEG resolution

Bad spatial resolution

Very good time resolution (milliseconds)

ECOG

• Electrodes are placed directly on the brain

• Good spatial and temporal resolution

• Only used with patients who are going through brain surgery

Neuroimaging

MRI and FMRI

MRI

• Structural image of the brain.

• Doesn’t use X-rays

• Uses strong magnetic fields

fMRI

• study brain function

• Measured oxygen content in the blood flowing through each region of the brain

• Relies on the magnetic properties of the atoms

MRI and FMRI

Bad temporal resolution (2 seconds)

Good spatial resolution