Cross-frequency coupling

Cross-frequency coupling

Bernhard Staresina

CONIG 09/06/11

I. What is CFC?Definition and functional significance

II. How is CFC calculated?PLV-MI, KL-MI

III. Example CFC during sleep

Talk Outline

Terminology

Cross Frequency Coupling (CFC)

Terminology

Phase Amplitude Coupling (PAC)Cross Frequency Coupling (CFC)

Terminology


Cross Frequency Phase Amplitude Coupling (CFPAC)

Terminology


Cross Frequency Phase Amplitude Coupling (CFPAC)

Terminology

I. What

I. What

Oscillatory interactions of two signalsI. What

Oscillatory interactions of two signalsI. What

I. What

(Canolty and Knight, 2010)

Definition

I. What

(i) an observed statistical dependence between filtered signals derived from electrical brain activity.


Definition

I. What

(i) an observed statistical dependence between filtered signals derived from electrical brain activity.

(ii) a transient but mechanistic coupling (mediated by spikes and synaptic activity) between the functionally distinct neuronal subpopulations that give rise to recorded electrical activity.


Definition

low frequencies high frequencies

I. What

coordination of cortical excitability (global states, sensory input)

coordination of local information processing

low frequencies high frequencies

CFC

I. What

coordination of cortical excitability (global states, sensory input)

coordination of local information processing

transfer of information from large-scale brain networks to local processing required for effective computation and synaptic modification

ExampleEffective LTP induction - high frequency bursts, repeated at a ~3-5 Hz inter-burst interval

I. What


I. What


I. What

I. What

Links with behaviour

I. What

theta:gamma CFC increases with working memory load in humans

(Axmacher et al., 2010)


I. What

theta:gamma CFC increases with working memory load in humans

(Axmacher et al., 2010)

theta:gamma CFC increases with navigation task performance in rodents

(Tort et al., 2009)


II. How

II. How

II. How

II. How

II. How

Interlude: different ways of representing phasesII. How

Interlude: different ways of representing phasesII. How

Interlude: different ways of representing phases

peak (0 deg)

trough(180 deg)

II. How


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2

-pi

pi

0


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2

-pi

pi

0

-pi

pi

0


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2

-pi

pi

0


peak (0 deg)

trough(180 deg)

II. How

0pi

pi/2

3pi/2

II. HowPhase locking and some of its applications


1. Alignment of phase values at time t across trials inter-trial phase locking [Phase Locking Index (PLI)]




2. Alignment of phase difference values between two regions at time t across trials inter-region inter-trial phase locking [Phase Locking Value (PLV)]



3. Alignment of phase difference values between (i) low frequency phase and (ii) high frequency envelope/power at time t across trials inter-frequency inter-trial phase locking [Cross-Frequency Coupling (CFC)]


II. HowCalculation of phase locking


PLI = 0 PLI = .5 PLI = .75





3. Alignment of phase difference values between (i) low frequency phase and (ii) high frequency envelope/power at time t across trials inter-frequency inter-trial phase locking [Cross-Frequency Coupling (CFC)]

II. How1. Phase Locking Index (inter-trial coupling)

II. How

freq

uency

1. Phase Locking Index (inter-trial coupling)

II. How

freq

uency


II. How

freq

uency


II. How2. Phase Locking Factor (inter-region inter-trial coupling)

region A

region Btrial 1

region A

region Btrial 2

...


region A

region Btrial 1

region A

region Btrial 2

...


II. How3. CFCa (inter-frequency inter-trial coupling)

low frequency signal“phase-providing”



high frequency signal“amplitude (power)-providing”



Envelope of high frequency signal

high frequency signal“amplitude (power)-providing”



Envelope of high frequency signal


II. HowCFCb – II. Based on ‘Kullback-Leibler Distance’Tort et al., 2010







III. Example

BackgroundIII. Example

Background

Memories are initially stored in the hippocampus.

III. Example

Background


Slow-wave sleep (SWS) facilitates memory consolidation.

III. Example

Background



Cross-frequency-coupling (CFC) has been related to synaptic plasticity and memory.

III. Example

Cross-frequency-coupling (CFC) has been related to synaptic plasticity and memory.

Is there evidence for hippocampal cross-frequency-coupling during SWS in humans?


Background


III. Example

III. ExampleMethods

Methods

iEEG recordings from MTL contralateral to the epileptic focus (n=10)

III. Example

Methods


classification of sleep stages based on Cz scalp electrode, EOG and EMG

III. Example

Methods



III. Example

sleep architecture

Methods



power spectrum sleep:wake

III. Example

Methods




III. Example

Results

CFC in hippocampus, SWS vs. wake

III. Example

Results


III. Example

Results


III. Example

Results


III. Example

complementary analysis: display of gamma power locked to theta peak

ResultsIII. Example

Results


III. Example

Results


III. Example

raw data example

ResultsIII. Example

Results

raw data example

III. Example

~200 ms

Results

raw data example

III. Example

theta:gamma CFC across sleep stages

ResultsIII. Example

Results

theta:gamma CFC across sleep stages

III. Example

Results

control: phase-scrambled surrogate data

III. Example


Results


III. Example

power spectrum sleep:wake theta:gamma CFC across sleep stages

Results


III. Example

SummaryIII. Example

Strong theta:gamma CFC in hippocampus during SWS

SummaryIII. Example

Strong theta:gamma CFC in hippocampus during SWS

Evidence for effective LTP during SWS?

SummaryIII. Example

Thank You!

Documents

Cross-frequency coupling