Indeed, a recent study based on neuronal recordings and evoked local field potentials (eLFP) in the awake rat found enhanced responses to deviants in eLFP but did not find the late deviant response component that would have been the equivalent to the human MMN [12].
Moreover, independently of the nature of the deviant faces, the P3a component shows an earlier latency in the HP group as compared to the LP group, whereas the reversed pattern was shown for the P3b component.
In particular, reduced amplitude of the duration deviant mismatch negativity (MMN) component is one of the most robust and reliable findings in schizophrenia [ 2].
The results clearly and consistently indicated that infrequent, physically deviant tones elicited larger negative components than frequent tones did, irrespective of the combination of stimulus tones.
To assess this, mean MMN and LDN amplitudes across the six electrodes were calculated and a series of one-tailed Pearson product moment correlations were performed between the amplitudes of the two components for each deviant.
Physiologically, the MMN is the first measurable brain response component that differentiates between standard and deviant auditory stimuli [ 8], as no MMN component is elicited by the repeated standard stimuli.
Of these, the P1 and N1 components were evoked by deviant as well as standard notes that is, they were unmodulated by melodic abnormalities in controls and TD subjects.
In contrast, the hippocampal response did not differentiate between the standard and the deviant tones (p ≥ 0.10 for all components).
These components were not present the in the deviant ERPs, confirming that deviant stimuli were not directly attended to.
The MMN is an event-related potential (ERP) component that occurs when infrequent "deviant" stimuli are inserted in a series of "standard" stimuli (Näätänen, Gaillard, & Mäntysalo, 1978).
When calculating mismatch effect between standard and deviant AEP, we focused on the middle-latency components only (N40, P60 and P110).
