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Kevin Whittingstall, Ph.D.

Address: Spemannstr. 38
72076 Tübingen
Room number: 251
Phone: +49 7071 601 1606
Fax: +49 7071 601 652
E-Mail: kevin.whittingstall

 

Picture of Whittingstall, Kevin, Ph.D.

Kevin Whittingstall

Position: Postdoctoral Fellow  Unit: Alumni Logothetis

Pharmacological dissociation of EEG and LFP: Effects of neural synchrony

 

Introduction and Scientific Aims

Electroencephalography (EEG) is one of the most commonly used methods to measure brain activity in humans. However, despite its widespread use, we still lack a clear understanding of how EEG signals are related to the spatio-temporal organization of underlying neuronal activity.  The dominant theory is that the surface EEG is not only dependent on the magnitude of LFP actvivity, but also on the degree of its temporal synchronization across space.  It is therefore theoretically possible that increases in cortical neural synchrony alone can enhance surface EEG signals without concomitant changes in the amplitude of LFP activity [1].  However, experimental confirmation of this hypothesis remains elusive, partly due to the difficulty in reliably separating intracortical measures of signal amplitude and spatial synchrony. 

The aim of this study is establish the contribution of local neural synchrony to measured surface EEG signals.  More specfically, can increases in EEG activity be detected when concomitant LFP activity is supressed?

Methods

In this study, we made simultaneous intracortical recordings of local field potentials (LFPs) with simultaneous surface EEG measurements in the primary visual cortex of two behaving non-human primates.  We made local injections of lidocaine, which has previously been shown to reduce LFP, though paradoxically increase EEG. Monkeys were trained to fixate during the presentation of a 5-second movie clip.  In each trial, we computed the EEG and LFP signal power, along with the temporal synchrony between micro-electrode pairs (LFP Spatial Coherence or SC).  These three measures where then normalized to their respective trial-average.

Results and Initial Conclusions

Figure 1 shows the relationship between high-gamma (60-100Hz) EEG, LFP and SC in the drug-free condition (no injection).  The upper left quadrant of this graph shows that in trials where LFP is negatively modulated, both EEG and SC are significantly positively modulated (p<0.01).  This result is more obvious during pharmacological manipulation (Figure 2).  Here, strong increases in EEG better follow SC compared to LFP, especially in the high-gamma frequency range.  In both drug and drug-free conditions, we found that SC explained a portion of the EEG which could not be explained by LFP alone. 

Figure 1 – Trial-to-Trial variations in EEG, LFP and SC.  EEG and LFP are represented as % change from the trial-average and SC is represented as a difference. Figure 2 – With lidocaine, LFP power (green) is suppressed while SC (red) and high-frequency EEG (blue) is enhanced.

Figure 1 – Trial-to-Trial variations in EEG, LFP and SC.  EEG and LFP are represented as % change from the trial-average and SC is represented as a difference.
Figure 2 – With lidocaine, LFP power (green) is suppressed while SC (red) and high-frequency EEG (blue) is enhanced.


Our work provides the first experimental evidence demonstrating that the surface EEG signal is strongly influenced by the degree of underlying neural synchrony.  Of particular interest, is that robust EEG signals can be observed even though LFP is unchanged or even suppressed.  This finding is extremely important for the interpretation of EEG signals in both basic and clinical research, especially when they are compared to other neuroimaging modalities (e.g. fMRI [2,3]).



Supervises Students and Collaborators

For this project, I supervised Simon Musall (M.Sc. student) and collaborated with Dr. Alexander Rauch (MPI for Biological Cybernetics)

References

1. Cosandier-Rimele, D., Merlet, I., Badier, J.M., Chauvel, P., and Wendling, F. (2008). The neuronal sources of EEG: modeling of simultaneous scalp and intracerebral recordings in epilepsy. Neuroimage 1, 135-46.

2. Nunez, P.L., and Silberstein, R.B. (2000). On the relationship of synaptic activity to macroscopic measurements: does co-registration of EEG with fMRI make sense? Brain Topogr 2, 79-96.

3. Musall, S.F., VPfostl, V.,  I., Rauch, A., Logothetis N.K., Whittingtsall K., (submitted).  Effects of neural synchrony on surface EEG

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Articles (11):

Musall S Person, von Pföstl V Person, Rauch A Person, Logothetis NK Person and Whittingstall K Person (April-2014) Effects of neural synchrony on surface EEG Cerebral Cortex 24(4) 1045-1053.
Goense J Person, Whittingstall K Person and Logothetis NK Person (January-2012) Neural and BOLD responses across the brain Wiley Interdisciplinary Reviews: Cognitive Science 3(1) 75–86.
Reichenbach A Person, Whittingstall K Person and Thielscher A Person (January-2011) Effects of transcranial magnetic stimulation on visual evoked potentials in a visual suppression task Neuroimage 54(2) 1375-1384.
Whittingstall K Person, Bartels A Person, Singh V Person, Kwon S Person and Logothetis NK Person (October-2010) Integration of EEG source imaging and fMRI during continuous viewing of natural movies Magnetic Resonance Imaging 28(8) 1135-1142.
Mazzoni A , Whittingstall K Person, Brunel N , Logothetis NK Person and Panzeri S Person (September-2010) Understanding the relationships between spike rate and delta/gamma frequency bands of LFPs and EEGs using a local cortical network model NeuroImage 52(3) 956-972.
Goense JBM Person, Whittingstall K Person and Logothetis NK Person (March-2010) Functional magnetic resonance imaging of awake behaving macaques Methods 50(3) 178-188.
Yesilyurt B Person, Whittingstall K Person, Ugurbil K , Logothetis NK Person and Uludag K Person (February-2010) Relationship of the BOLD signal with VEP for ultrashort duration visual stimuli (0.1 to 5 ms) in humans Journal of Cerebral Blood Flow and Metabolism 30(2) 449-458.
Whittingstall K Person and Logothetis NK Person (October-2009) Frequency-Band Coupling in Surface EEG Reflects Spiking Activity in Monkey Visual Cortex Neuron 64(2) 281-289.
Magri C Person, Whittingstall K Person, Singh V Person, Logothetis NK Person and Panzeri S Person (July-2009) A toolbox for the fast information analysis of multiple-site LFP, EEG and spike train recordings BMC Neuroscience 10(81) 1-24.
Thielscher A Person, Reichenbach A Person and Whittingstall K Person (July-2008) Effects of TMS on visual evoked potentials in a visual suppression task Brain Stimulation 1(3) 275-276.
Petkov CI Person, Kayser C Person, Steudel T Person, Whittingstall K Person, Augath M Person and Logothetis NK Person (March-2008) A voice region in the monkey brain Nature Neuroscience 11(3) 367-374.
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Contributions to books (1):

Whittingstall K Person and Logothetis NK Person: Physiological Foundations of Neural Signals, 3-14. In: Principles of Neural Coding, (Ed) R. Quian Quiroga, CRC Press, Boca Raton, FL, USA, (May-2013).

Posters (15):

Zaldivar D Person, Li J Person, von Pföstl V Person, Whittingstall K Person, Goense J Person, Rauch A Person and Logothetis NK Person (July-2012): The Modulatory Role Of Dopamine In The Early Visual System Of Macaques Investigated By Fmri, Neurochemistry And Neurophysiology, 8th Forum of European Neuroscience (FENS 2012), Barcelona, Spain.
Schridde U Person, Whittingstall K Person, Murayama Y Person and Logothetis NK Person (November-2010): Cross-frequency coupling of neural signals within and between early visual areas V1 and V2, 40th Annual Meeting of the Society for Neuroscience (Neuroscience 2010), San Diego, CA, USA.
Musall S Person, Logothetis NK Person and Whittingstall KS Person (November-2010): Predicting surface EEG power through fluctuations in intracortical signals during different behavioral and pharmacological conditions, 40th Annual Meeting of the Society for Neuroscience (Neuroscience 2010), San Diego, CA, USA.
Kapoor V Person, Whittingstall K Person, Panagiotaropoulos T Person, Keliris G Person and Logothetis NK Person (November-2009): Comparing inter-ocular switch and classical binocular rivalry in the human brain using EEG, 10th Conference of Junior Neuroscientists of Tübingen (NeNa 2009), Ellwangen, Germany.
Musall S Person, Logothetis NK Person and Whittingstall K Person (November-2009): Frequency-band coupling in surface EEG reflects spiking activity in monkey V1 during passive fixation, 10th Conference of Junior Neuroscientists of Tübingen (NeNa 2009), Ellwangen, Germany.
Kapoor V Person, Whittingstall K Person, Panagiotaropoulos T Person, Keliris GA Person and Logothetis NK Person (October-2009): Comparing inter-ocular switch and classical binocular rivalry in the human brain using eeg, 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009), Chicago, IL, USA.
Whittingstall KS Person, Bartels A Person, Kwon S , Singh V Person and Logothetis NK Person (October-2009): EEG source imaging during continuous viewing of natural movies, 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009), Chicago, IL, USA.
Musall S Person, Logothetis NK Person and Whittingstall KS Person (October-2009): Frequency-band coupling in surface EEG reflects spiking activity in monkey V1 during passive fixation, 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009), Chicago, IL, USA.
Magri C Person, Whittingstall K Person, Singh V Person, Logothetis NK Person and Panzeri S Person (September-2009): Information breakdown analysis of simultaneous neural recordings: tools for the study of neural codes, 2nd INCF Congress of Neuroinformatics, Pilsen, Czech Republic, Frontiers in Neuroinformatics(Conference Abstract: Neuroinformatics 2009).
Thielscher A Person, Reichenbach A Person and Whittingstall K Person (July-2009): Effects of TMS on visual evoked potentials in a visual suppression task, 15th Annual Meeting of the Organization for Human Brain Mapping (HBM 2009), Melbourne, Australia, NeuroImage, 47(Supplement 1) S63.
Whittingstall KS Person and Logothetis NK Person (November-2008): Simultaneous recordings of multi-unit activity (MUA) and surface EEG in alert macaques during presentation of movie clips, 38th Annual Meeting of the Society for Neuroscience (Neuroscience 2008), Washington, DC, USA.
Petkov CI Person, Kayser C Person, Whittingstall K Person, Steudel T Person, Augath M Person and Logothetis NK Person (September-2007): A voice-area in the primate brain: Enhanced representation of the "voice" of conspecifics, International Symposium on Evolution of Emotional Communication (EEC 2007), Hannover, Germany.
Yesilyurt B Person, Whittingstall K Person, Sengupta B Person, Ugurbil K and Uludag K Person (June-2007): The Dynamics of ERP and Hemodynamic Responses at Very Short Stimulus Durations, 13th Annual Meeting of the Organization for Human Brain Mapping (HBM 2007), Chicago, IL, USA, NeuroImage, 36(Supplement 1) S47.
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Yesilyurt B Person, Whittingstall K Person, Ugurbil K and Uludag K Person (May-2007): Insights into the dynamics of hemodynamic response to millisecond stimulus duration: A fMRI and VEP combination study, 2007 Joint Annual Meeting ISMRM-ESMRMB, Berlin, Germany.
Whittingstall KS Person and Logothetis NK Person (October-2006): High-frequency oscillations in the macaque visual evoked potential, 36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006), Atlanta, GA, USA.

Talks (3):

Whittingstall K Person (December-12-2010) Invited Lecture: Multi-modal imaging, ESMRMB-Lectures on Magnetic Resonance, Functional Magnetic Resonance Imaging: from Neurophysiology to Cognitive Neuroscience, Maastricht, The Netherlands.
Whittingstall K Person (September-10-2009) Invited Lecture: Multi-modal imaging, ESMRMB-Lectures on Magnetic Resonance, fMRI – From Neurophysiology to Cognitive Neuroscience, Tübingen, Germany.
Yesilyurt B Person, Whittingstall K Person, Ugurbil K and Uludag K Person (May-2007) Abstract Talk: Insights into the dynamics of hemodynamic response to millisecond stimulus duration: A fMRI and VEP study, 2007 Joint Annual Meeting ISMRM-ESMRMB, Berlin, Germany.
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Last updated: Friday, 17.01.2014