BOLD signals correlate with ensemble unit activities in rat's somatosensory cortex.
Evoked neural activity (ensemble single-unit activity and evoked field potential) and functional magnetic resonance imaging (fMRI) changes of the primary somatosensory cortex in response to electrical stimulation of the hind paw were studied in rats under anesthesia. The effects of stimulation frequency (ranging from 0.3 to 10 Hz) and types of anesthetics (alpha-chloralose and sodium pentobarbital) on blood oxygen level dependent (BOLD) activation and neural activation were compared. Both ensemble single-unit activity and BOLD signal changes achieved maximal activation at 3 Hz of stimulation and responses were significantly stronger under alpha-chloralose anesthesia. The maximal activation of the integral evoked potential (sigmaEP), in contrast, was the highest at 10 Hz; and the values were similar for alpha-chloralose and pentobarbital. These analyses revealed that fMRI image changes were better correlated with ensemble single-unit activity than with sigmaEP during somatosensory stimulations.
Institute of Zoology, National Taiwan University, Taipei.
Chung-Chih
CC
Kuo
Jyh-Horng
JH
Chen
Chin-Yen
CY
Tsai
Keng-Chen
KC
Liang
Chen-Tung
CT
Yen
D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D002698:Chloralose; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005528:Foot; D006614:Hindlimb; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000097:blood*; D010424:Pentobarbital; D051381:Rats; D020318:Rats, Long-Evans; D013003:Somatosensory Cortex / Q000502:physiology*
D002698:Chloralose; D010424:Pentobarbital; D010100:Oxygen