, 1987a and Kraus et al., 1987b). Thus, the maturation of central processing is delayed relative to peripheral processing and is, in many cases, more closely correlated in time with perceptual development. The relationship between

the stimulus duration and optimal performance on an auditory task, called temporal integration, differs with age. The most common assay of temporal integration measures a subject’s thresholds for detecting a sound Proteases inhibitor as its duration increases. Temporal integration differs markedly in infants and adults; to determine whether a sound is coming from the right or left side, infants must listen for about 1 s, whereas adults need only a few milliseconds (Clarkson buy Pifithrin-�� et al., 1989). Studies suggest that children are particularly poor when stimulus duration is < 20 ms, although temporal integration is adult-like above this duration (Figure 2) (Maxon and Hochberg, 1982, Berg and Boswell, 1995, He et al., 2010 and Moore et al., 2011). Using behavioral findings like this to guide experiments, a relatively simple comparison of the time constant for optimal performance

could be used to correlate perceptual skills to neural coding over the course of development. Children often display a more gradual improvement in performance as stimulus magnitude increases (Figure 3). The position and shape of these functions can be used to make inferences about the underlying neural processing. Megestrol Acetate Figure 5A (top) shows a hypothetical psychometric function for an adult (red dashed), and a second for a juvenile with a shallower slope (blue dashed). These behavioral data can be used to generate

hypothetical internal neural responses that represent the target stimuli using signal detection theory (see figure legend for details). Using this framework, Figure 5A (top) illustrates one simple model to account for poor performance in developing animals: for a given stimulus magnitude, the juvenile mean internal response has a larger variance (blue distributions) and overlaps more with the mean internal signal when no stimulus is present (gray distributions), as compared to the adult (red distributions). That is, the juvenile internal responses are more difficult to discriminate from one another. For comparison, Figure 5B presents an alternative model that could account for poor performance in developing animals: for a given stimulus magnitude, the juvenile mean internal responses (blue distributions) increase less as stimulus magnitude gets larger, as compared to the adult (red distribution). If psychometric functions were available from developing and adult animals, then credible comparisons could be made to neurometric analyses of the putative internal signal (solid blue and red lines). Of course, the more rigorous the experiment (e.g., recording responses while animals perform the task), the more plausible the analysis.