Additionally, we found a task-related Caspase inhibitor modulation, namely, in the P2 component solely in YA: only YA showed stronger P2 amplitudes in the speech compared to the nonspeech task. The P2 component in OA revealed the same activation level, irrespective of the task. With respect to latencies, OA demonstrated generally longer latencies of the N1 and P2 components. We will discuss the implications of these results comprehensively in the following section. N1 and P2 latencies Response latencies have been shown to reflect neural conduction time (Lister et al. 2011). Notably aging delays neural conduction Inhibitors,research,lifescience,medical and decreases neural precision (Iragui et al. 1993; Anderson et al. 2012; Kim et al. 2012).

Therefore, longer N1 and P2 latencies in OA compared to YA may suggest age-related decrease Inhibitors,research,lifescience,medical in synchronous firing among the neural ensembles that generate N1 and P2 components (Walton et al.

1998, 2002; Walker et al. 2008). This finding implies that the auditory system in older adults is less able to precisely synchronize the neural activity to the onset of the speech stimuli, regardless of the focus of attention. Assuming that some of the neuronal ensembles contributing to the generation of the N1 component overlap with those ensembles Inhibitors,research,lifescience,medical that elicit the P2 component, the prolonged latencies would represent a slower recovery process from the first, initial response, namely, the N1. Therefore, there might be an age-related difference in the refractory time exhibited by neurons in the auditory cortex of OA, leading to a longer recovery period before neurons are able to respond to a succeeding Inhibitors,research,lifescience,medical stimulus (Walton et al. 1998; Tremblay et al. 2003). This proposal receives further support by numerous studies that confirm an age-related decrease in speed of information processing in general, (Salthouse 1996, 2000) as well as for different cognitive functions, such as working memory (Sander et al. 2012) and divided attention (Park et al. 1989). In addition to the measured differences in AEP latencies between YA and OA, a Inhibitors,research,lifescience,medical general attention-modulated pattern could be observed in both age samples.

Both YA and OA showed prolonged latencies in the nonspeech compared to the speech task. The fact that this N1 and P2 latency pattern—representing an early level of auditory perception—is comparable in both age groups may indicate that the preliminary encoding of the stimuli is not Rutecarpine affected by the aging process (i.e., aging of the auditory system and/or required cognitive functions). In contrast, the subsequent analysis of inflowing auditory information, as indexed by the P2 peak amplitude may be impoverished in older adults. Accordingly, Ostroff et al. (2003) suggest that precise encoding of sound duration declines after the fifth decade of life. N1 peak We found a general pattern of stronger N1 amplitude in OA as compared to YA, regardless of their focus of attention.