Sensitivity to Complex Statistical Regularities in Rat Auditory Cortex

Abstract

Neurons in auditory cortex are sensitive to the probability of stimuli: responses to rare stimuli tend to be stronger than responses to common ones. Here, intra- and extracellular recordings from the auditory cortex of halothane-anesthetized rats revealed the existence of a finer sensitivity to the structure of sound sequences. Using oddball sequences in which the order of stimulus presentations is periodic, we found that tones in periodic sequences evoked smaller responses than the same tones in random sequences. Significant reduction in the responses to the common tones in periodic relative to random sequences occurred even when these tones consisted of 95% of the stimuli in the sequence. The reduction in responses paralleled the complexity of the sound sequences and could not be explained by short-term effects of clusters of deviants on succeeding standards. We conclude that neurons in auditory cortex are sensitive to the detailed structure of sound sequences over timescales of minutes.

Rapid and Direct Encoding of Numerosity in the Visual Stream

“…One potential explanation for this greater effect of total item perimeter is that, because area ranged 16-fold as perimeter ranged 4-fold, there could be a context effect whereby greater attention is implicitly given to the visual property with a larger range of sampling. This explanation is consistent with findings in the large body of literature showing that the brain is capable of implicitly picking up statistical regularities of the stimuli (Bonte et al 2005;TurkBrowne et al 2010;Yaron et al 2012). According to this explanation, a particular visual property may appear to modulate the ERPs more than numerosity if the range (and perhaps resolution) of change in that visual property far exceeds that in numerosity which appears to be the case in some previous studies Reynvoet 2012, 2013).…”

Hierarchy of prediction errors for auditory events in human temporal and frontal cortex

“…We did not find sensitivity to periodic structure in auditory cortex contacts, such as it was shown for the rat or macaque auditory cortex (37,38). Yaron et al (37) found neurons responding differently to fully predictable and unpredictable standards and deviants. However, the largest fraction of neurons in the rat auditory cortex responded similarly in the fully unpredictable condition.…”

Auditory System

“…This finding suggests that SRAF (Te3) has an important role in recognition memory process of familiarity discrimination. In support of this, recent studies on SSA have demonstrated the presence to true deviance detection in the auditory cortex (Taaseh et al, 2011) and neurons in the AC are sensitive to the detailed structure of sound sequences over timescales of minutes (Yaron et al, 2012).…”