17Su11Lec7 - CS17 Neurobiology of Cognition Summer 2011...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CS17 Neurobiology of Cognition Summer 2011 Lecture 7: Sleep STAGES OF WAKEFULLNESS / SLEEP Electro-Encephalogram ( EEG ) used to characterize brain activity during different states of wakefulness/sleep - Gross average of the electrical potentials of the neurons in a general area of the brain (mostly Neocortex) - Electrodes attached to scalp record Frequency (average amplitude) - Simultaneous changes in potential (negative graphed above zero axis, positive below) summate such that. .. - Neural de-synchrony => High Frequency (w/variable Voltage) waves = Multiple sources of stimulation: “many pebbles” - Neural synchrony => Low Frequency , High Voltage waves = Coherent source of stimulation: “one big rock” Awake, active => Beta Activity = 18-24 Hz, Very high frequency - very desynchronized Awake, relaxed => Alpha Activity = 8-12 Hz, Like above, but somewhat lower frequency, somewhat desynchronized Sleep 1 => Theta Activity = 4-7 Hz, Lower freq , still quite irregular, significantly more synchronized Sleep 2 => Mostly Theta Activity, but with many interspersed Spindles and K Complexes - Spindle and K Complex = intermittent bursts of high freq or voltage, as brain settles into deeper sleep Sleep 3 => Delta Activity = < 4 Hz observed in less than 50% of this stage, Very low freq , higher voltage , very synchronized Sleep 4 => Delta Activity, in more than 50% of this stage, hardest to wake Stages 3 and 4 = Slow Wave Sleep (SWS) - SO, as move into deeper sleep, freq decreases as brain activity becomes synchronized - Heart rate and breathing rate also decrease, and brain is less responsive to external stimuli REM ( Rapid Eye Movement ) or Paradoxical Sleep because of contradictory set of conditions that occur: - EEG is desynchronized , High freq (like Sleep 1 or even Awake), Low voltage (only Sleep 1 is lower): Imaginary pebbles?! - Heart rate, breathing rate, blood pressure more variable than in other sleep stages - Eyes move , genitalia active, but postural muscles paralyzed, loss of muscle tonus thru most of body (=
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/07/2011 for the course COGS 17 taught by Professor Pineda during the Spring '06 term at UCSD.

Page1 / 2

17Su11Lec7 - CS17 Neurobiology of Cognition Summer 2011...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online