Long-term implicit memory for sequential auditory patterns in humans

Abstract

<jats:p>Memory, on multiple timescales, is critical to our ability to discover the structure of our surroundings, and efficiently interact with the environment. We combined behavioural manipulation and modelling to investigate the dynamics of memory formation for rarely reoccurring acoustic patterns. In a series of experiments, participants detected the emergence of regularly repeating patterns within rapid tone-pip sequences. Unbeknownst to them, a few patterns reoccurred every ~3 min. All sequences consisted of the same 20 frequencies and were distinguishable only by the order of tone-pips. Despite this, reoccurring patterns were associated with a rapidly growing detection-time advantage over novel patterns. This effect was implicit, robust to interference, and persisted for 7 weeks. The results implicate an interplay between short (a few seconds) and long-term (over many minutes) integration in memory formation and demonstrate the remarkable sensitivity of the human auditory system to sporadically reoccurring structure within the acoustic environment.</jats:p>

Sustained neural activity correlates with rapid perceptual learning of auditory patterns

“…The results of Experiment I are in line with previous work and show that individuals learn regular tone patterns over a few repetitions (Agus et al, 2010;Kang et al, 2017;Bianco et al, 2020), such that they are faster in detecting the pattern when they encounter it again (Bianco et al, 2020). Participants detected a repeated regular pattern about 0.12 s earlier than a novel regular pattern.…”

“…In Experiment V, participants judged, for each sound, whether a visual disc, presented at one of several fixed times relative to pattern onset, precedes or follows the onset of the pattern. Experiment I (Figure 1) and previous work (Bianco et al, 2020) demonstrates that individuals detect a repeated pattern faster than a novel pattern. Hence, we expected that participants in Experiment V indicate an earlier disc time to correspond to the pattern onset for repeated than for novel patterns.…”

“…Sensitivity to regular patterns is thought to optimize auditory perception (Smith and Lewicki, 2006;Kluender et al, 2013) by enabling, for example, segregation of sound streams (Snyder and Alain, 2007;Bendixen, 2014), detection of acoustic changes (Schröger, 2005;Winkler et al, 2009;Herrmann et al, 2020), and recognition and prediction of sounds (Jones and Boltz, 1989;Henry and Herrmann, 2014;Nobre and van Ede, 2018). Learning of regular patterns may also benefit perception, for example, by increasing detection sensitivity and reducing detection time of recognizable sounds (Agus et al, 2010;Bianco et al, 2020). The current study is concerned with the neural substrates of processes that are related to perceptual learning of regular auditory patterns.…”

“…Perceptual learning of regular auditory patterns is typically rapid, at least in experimental contexts, indicated by faster response times and higher detection sensitivity for repeated than novel patterns after only a few pattern repetitions (Agus et al, 2010;Kang et al, 2017;Bianco et al, 2020).…”

“…We would expect sustained neural activity to increase earlier when patterns are repeated compared to novel, if sustained activity reflects perceptual learning of regular patterns. In addition, memory for regular patterns can be long-lasting -for weeks in experimental contexts (Agus et al, 2010;Bianco et al, 2020) -and such memories may also affect the magnitude of pattern-related sustained activity.…”