Invariance of firing rate and field potential dynamics to stimulus modulation rate in human auditory cortex

• Published in: Human brain mapping 2011-08, Vol.32 (8), p.1181-1193
• Main Authors: Mukamel, Roy, Nir, Yuval, Harel, Michal, Arieli, Amos, Malach, Rafael, Fried, Itzhak
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adult; auditory cortex; Auditory Cortex - physiology; Auditory Perception - physiology; Biological and medical sciences; Brain Mapping; Cortex (auditory); Cortex (temporal); Data processing; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Electrodes, Implanted; Electrophysiological recording; Envelopes; Epilepsy - physiopathology; Female; Firing pattern; Firing rate; Fundamental and applied biological sciences. Psychology; human; Humans; Investigative techniques, diagnostic techniques (general aspects); local field potentials (LFP); Male; Medical sciences; Nervous system; Neuromodulation; Neurons - physiology; Photic Stimulation; Population levels; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Scaling; spiking activity; Vertebrates: nervous system and sense organs
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.21100

The effect of stimulus modulation rate on the underlying neural activity in human auditory cortex is not clear. Human studies (using both invasive and noninvasive techniques) have demonstrated that at the population level, auditory cortex follows stimulus envelope. Here we examined the effect of stimulus modulation rate by using a rare opportunity to record both spiking activity and local field potentials (LFP) in auditory cortex of patients during repeated presentations of an audio‐visual movie clip presented at normal, double, and quadruple speeds. Mean firing rate during evoked activity remained the same across speeds and the temporal response profile of firing rate modulations at increased stimulus speeds was a linearly scaled version of the response during slower speeds. Additionally, stimulus induced power modulation of local field potentials in the high gamma band (64–128 Hz) exhibited similar temporal scaling as the neuronal firing rate modulations. Our data confirm and extend previous studies in humans and anesthetized animals, supporting a model in which both firing rate, and high‐gamma LFP power modulations in auditory cortex follow the temporal envelope of the stimulus across different modulation rates. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.