Electrical Techniques

What are the 2 ways to study brain electrical potentials? (brain waves)

Spontaneous

Evoked

Evoked

brain waves are generated using a specific stimulus, look at spike

Spontaneous

no specific stimulus, how the brain is at rest, and brain waves are recorded

(ex. person just there, person asleep)

EEG

Encephalogram
electrodes are placed on scalp
non-invasive, directly measuring activity, since its measuring acidity

measures in real time
it works by measuring dipoles: difference in positive and negative charges on opposite sides of neurons due to excited ps potentials and inhibited ps potentials.

neurons of smae overall chage group together, and the difference between those charges are measured by electrodes on their respective spots → eeg signal

electrodes are paired difference are measured
aomplitude and frequency
just an idea of how it works

whats EEG used for

measuring brain waves on

consciousness, and sleep
seizures

effects of brain injury

Event related potentials (ERPS)

electrical potentials caused by an event aka evoked potential teq

you use a repetive stimulis, evoke ERP changes and average it to account for the noise of regular brain activity

EEG pros

less expensive
direct measures of activity
great temporal resolution

real time

non-invasive

Epilespy

normally, activity is unsyncrozied across different brain regions
but when seizures happen: synchronizaiton of electrical activity

looks like a spike and wave pattern

Types of seizures

depends on which brain regions are invovled

Tonic-Clonic
Absence (Simple partial)

Complex partial

Tonic-Clonic

the EEG is abnormal over the whole brain (synchonized)

becomes unsciousness

tonic phase: muscles stiffen

clonic phase: jerk movements

(classic) or grand mal

Absence (Simple partial)

spike and wave for a few secs, several times throughout the day
temporarily unware
normal muscles

Complex partial

localized in part of brain
sympotoms change w/ the area affected

may cause: inwareness, movements, sensations

what to do if someone has a seizure?

move onto side, remove anyhting that can be harmful, time the seizure, leave them be, monitor breathing and skin colour

Mind control with Optogenetics

use ion channels that respond to light. different channels respond to differens spectrums of light, so you can use different light to turn neurons on and off (hyperpolzarize, inhibit)
allow you to activate a part of the pbrain without doing something invasiv

TMS

transcranial magnetic stimulation

uses magnets to briefly stimlate cortical regions

activate areas