These results demonstrate that the PV-mediated effect on putative excitatory neuronal responses did not change with repeated presentations of the standard tone, whereas the SOM-mediated effect increased with the repeated stimulus.
The spike time and count variability of parasol (magnocellular-projecting) retinal ganglion cells was examined in isolated macaque monkey retinas stimulated with repeated presentations of high contrast, spatially uniform intensity modulation.
Moreover, there was no significant attenuation of the time biases with repeated presentations of the moving character, contrary to the notion that pairing a timing task with a concurrent well-practiced distractor leads to a systematic reduction of the time bias with repeated presentations [28].
Subjects' familiarity with the experimental stimuli may shape amygdala responses, as several studies have shown [35] [38] that the response of the human amygdala to emotional facial expressions diminishes with repeated presentations, that is, with increasing familiarity.
For example, the first presentation of a stimulus may elicit an unconditioned response (UR), but this UR will decline or habituate with repeated presentations.
The logic behind fMRI adaptation is that neurons decrease their firing rate with repeated presentations of the stimulus feature that those neurons encode.
This suggests that the strength of SOM-mediated inhibitory drive is not significant in response to the deviant but increases with repeated presentations of the standard.
These results are consistent with the interpretation that the inhibitory drive from PVs is constant throughout the stimulus regardless of tone history, whereas the effect of SOM modulation increases with repeated presentations of the standard tone.
It was examined if chemosensory evoked potentials towards pleasant and unpleasant odors change with repeated presentation.
These results suggest that SOMs may adapt at a faster time scale than PVs with repeated presentation of tones.
Our results of recordings from PVs and SOMs present a surprising finding that PVs and SOMs adapt in response to repeated tones, countering our initial hypothesis that SOMs saturate in responses to the deviant, or facilitate with repeated presentation of a tone.
