Auditory cortical and hippocampal local-field potentials to frequency deviant tones in urethane-anesthetized rats: An unexpected role of the sound frequencies themselves

Criteria for determining whether mismatch responses exist in animal models: Focus on rodents

“…Indeed a recent study in urethane-anesthetised rats demonstrated that responses to the deviant are significantly altered by the frequency of the deviant tone (Ruusuvirta et al, 2015).The deviant-alone sequence can be used to control for the difference in the presentation rate of deviants and standards. Even when using a flip-flop control, when comparing the deviant response from one oddball sequence to the standard (an identical stimulus physically) response from the reversed sequence, one is comparing the response to a common, predicted event to a rare, unpredicted event.…”

“…Indeed, depending on the location of recording and the state of consciousness, epidural recordings in rats have demonstrated that MMRs in rats can be both positive and negative in polarity. Recordings made under anaesthesia, whether it be via urethane, isoflurane or pentobarbital sodium, tend to report ERPs with a large, single positive peak, that exhibits a positive shift in response to the deviant (Ahmed et al, 2011;Astikainen et al, 2014;Astikainen et al, 2006;Astikainen et al, 2011;Jung et al, 2013;Nakamura et al, 2011;Ruusuvirta et al, 2015;Tikhonravov et al, 2008Tikhonravov et al, , 2010, whereas studies using awake recordings report a more complex ERP morphology with a combination of negative and positive peaks. Of such studies using awake recordings, some report that the deviant induces negative shifts in the ERP (Cabungcal et al, 2013;Nakamura et al, 2011;Roger et al, 2009;Sivarao et al, 2014;Witten et al, 2014), but at least one other studyreports both negative and positive shifts, depending on the component (Harms et al, 2014).…”

“…However, expected responses to changes in deviant probability (Jung et al, 2013;Sivarao et al, 2014), difference between deviant and standard stimuli (Ruusuvirta et al, 2015;Shiramatsu et al, 2013) and stimulus history (Nakamura et al, 2011) have been demonstrated for deviance detection in rats.…”

Balanced Noise-Evoked Excitation and Inhibition in Awake Mice CA3

“…It is similar as previous results (Abe et al, 2014a , b ) that neuronal acoustic responses were largely reduced and even abolished for a short time by general anesthesia. However, anesthetized hippocampal acoustic responses have been reported in many studies (Miller and Freedman, 1995 ; Ruusuvirta et al, 1995a , b , 2013 , 2015 ; Krause et al, 2003 ; Dissanayake et al, 2008 , 2009 ). This discrepancy might be mainly due to the different anesthetic, sodium pentobarbital, used in this study.…”

“…Identifying the basic features of CA3 auditory response will be crucial for understanding the auditory information processing in the hippocampus. Hippocampal acoustic responses have been investigated in anesthetized animals mainly focusing on auditory gating (Miller and Freedman, 1995 ; Krause et al, 2003 ; Dissanayake et al, 2008 , 2009 ) and deviations of sound frequency (Ruusuvirta et al, 1995a , b , 2015 ) or duration (Ruusuvirta et al, 2013 ). However, the sub-threshold responses induced by sound could be abolished by general anesthesia (Abe et al, 2014b ).…”