Neural Mechanisms for Auditory Memory Sequencing and Prediction

Human and nonhuman animals rely on memories of the past to anticipate the future, weighted by the reality of the present in our ever-changing sensory world. As universal as it is for neural systems to integrate information from the past and present to forecast the future-and the striking impact on quality of life when these functions fail-fundamental empirical questions remain on how sensory, memory and predictive signalling interactions occur from neuronal levels to systems.

Substantial scientific progress has been made in studying hippocampal- and non-hippocampal-dependent learning and memory. In parallel, both the prefrontal cortex and hippocampus have now been implicated in non-classical (statistical) learning of sequential sensory dependencies separated in time, a building block for human language and intellect. Moreover, both regions relay 'top-down predictive' signals to the sensory cortex that interface with veridical input from the senses.

Integrative theoretical frameworks have emerged, raising important questions that require direct empirical evidence on how neural systems interact during sensory, memory (retrospective) and predictive (prospective) functions. A scientific roadblock has been the paucity of approaches combining memory and prediction tasks, research focusing on one or a few key nodes in the system, and the lack of parallel studies in an animal model and humans using the same task.

We propose a timely cross-species neurophysiological approach during an auditory delayed sensory predictions task. Both monkeys and humans can learn the task via statistical learning in tens of minutes, and we will leverage the capability for simultaneous neuronal recordings from the prefrontal cortex, hippocampus and auditory cortex in macaque monkeys (Aim 1) and humans (Aim 2).

The task harnesses statistical learning that can induce sensory sequence learning and predictions within minutes, using probabilistically variable sound sequences that manipulate "what" has and will happen and "when" (the delay between the sounds).

The cross-species approach will provide new knowledge into the interactions of a neural system integrating functions vital for daily life, and how these compare between the monkey brain and the human brain.