Pre-attentive Auditory Memory Research Articles

Simultaneous pitches are encoded separately in auditory cortex: an MMNm study

This study examined whether two simultaneous pitches have separate memory representations or an integrated representation in preattentive auditory memory. Mismatch negativity fields were examined when a pitch change occurred in either the higher-pitched or the lower-pitched tone at 25% probability each, thus making the total deviation rate of the two-tone dyad 50%. Clear MMNm was obtained for deviants in both tones confirming separate memory traces for concurrent tones. At the same time, deviants to the lower-pitched, but not higher-pitched, tone within the two-tone dyad elicited a reduced MMNm compared to when each tone was presented alone, indicating that the representations of two pitches are not completely independent.

The effects of interstimulus interval on sensory gating and on preattentive auditory memory in the oddball paradigm: Can magnitude of the sensory gating affect preattentive auditory comparison process?

P50, and mismatch negativity (MMN) are components of event-related potentials (ERP) reflecting sensory gating and preattentive auditory memory, respectively. Interstimulus interval (ISI) is an important determinant of the amplitudes of these components and N1. In the present study the interrelation between stimulus gating and preattentive auditory sensory memory were investigated as a function of ISI in 1.5, 2.5 and 3.5 s in 15 healthy volunteered participants. ISI factor affected the N1 peak amplitude significantly. MMN amplitude in 2.5 s ISI was significantly smaller compared to 1.5 and 3.5 s ISI. ISI X stimuli interaction on P50 amplitude was statistically significant. P50 amplitudes to deviant stimuli in 2.5 s ISI were larger than the P50 amplitudes in other ISIs. P50 difference (P50d) waveform amplitude correlated significantly with MMN amplitude. The results suggest that: (i) auditory sensory gating could affect preattentive auditory sensory memory by supplying input to the comparator mechanism; (ii) 2.5 s ISI is important in displaying the sensory gating and preattentive auditory sensory memory relation.