BACKGROUND: To what extent is activity of individual neurons coupled to the local field potential (LFP) and to blood-oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI)? This issue is of high significance for understanding brain function and for relating animal studies to fMRI, yet it is still under debate. RESULTS: Here we report data from simultaneous recordings of isolated unit activity and LFP by using multiple electrodes in the human auditory cortex. We found a wide range of coupling levels between the activity of individual neurons and gamma LFP. However, this large variability could be predominantly explained (r = 0.66) by the degree of firing-rate correlations between neighboring neurons. Importantly, this phenomenon occurred during both sensory stimulation and spontaneous activity. Concerning the coupling of neuronal activity to BOLD fMRI, we found that gamma LFP was well coupled to BOLD measured across different individuals (r = 0.62). By contrast, the coupling of single units to BOLD was highly variable and, again, tightly related to interneuronal-firing-rate correlations (r = 0.70). CONCLUSIONS: Our results offer a resolution to a central controversy regarding the coupling between neurons, LFP, and BOLD signals by demonstrating, for the first time, that the coupling of single units to the other measures is variable yet it is tightly related to the degree of interneuronal correlations in the human auditory cortex.
BACKGROUND: To what extent is activity of individual neurons coupled to the local field potential (LFP) and to blood-oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI)? This issue is of high significance for understanding brain function and for relating animal studies to fMRI, yet it is still under debate. RESULTS: Here we report data from simultaneous recordings of isolated unit activity and LFP by using multiple electrodes in the human auditory cortex. We found a wide range of coupling levels between the activity of individual neurons and gamma LFP. However, this large variability could be predominantly explained (r = 0.66) by the degree of firing-rate correlations between neighboring neurons. Importantly, this phenomenon occurred during both sensory stimulation and spontaneous activity. Concerning the coupling of neuronal activity to BOLD fMRI, we found that gamma LFP was well coupled to BOLD measured across different individuals (r = 0.62). By contrast, the coupling of single units to BOLD was highly variable and, again, tightly related to interneuronal-firing-rate correlations (r = 0.70). CONCLUSIONS: Our results offer a resolution to a central controversy regarding the coupling between neurons, LFP, and BOLD signals by demonstrating, for the first time, that the coupling of single units to the other measures is variable yet it is tightly related to the degree of interneuronal correlations in the human auditory cortex.
Authors: Antonello Baldassarre; Christopher M Lewis; Giorgia Committeri; Abraham Z Snyder; Gian Luca Romani; Maurizio Corbetta Journal: Proc Natl Acad Sci U S A Date: 2012-02-06 Impact factor: 11.205
Authors: Tomas Ossandón; Juan R Vidal; Carolina Ciumas; Karim Jerbi; Carlos M Hamamé; Sarang S Dalal; Olivier Bertrand; Lorella Minotti; Philippe Kahane; Jean-Philippe Lachaux Journal: J Neurosci Date: 2012-03-07 Impact factor: 6.167
Authors: Mélanie Boly; Vincent Perlbarg; Guillaume Marrelec; Manuel Schabus; Steven Laureys; Julien Doyon; Mélanie Pélégrini-Issac; Pierre Maquet; Habib Benali Journal: Proc Natl Acad Sci U S A Date: 2012-03-26 Impact factor: 11.205
Authors: Marieke L Schölvinck; Alexander Maier; Frank Q Ye; Jeff H Duyn; David A Leopold Journal: Proc Natl Acad Sci U S A Date: 2010-05-03 Impact factor: 11.205