Title: A role for ventral hippocampus in hidden state inference

Speaker: Andrew MackAskill (Professor of Cellular and Systems Neuroscience, Department of Neuro, Physiology & Pharmacology)

Location: In person at 12 Queen Square & online via Zoom

Abstract: We routinely infer hidden states in everyday life. When a friend’s messages come late, short, or full of emojis, we use these indirect cues to judge whether they are happy, stressed, or distracted, even though we cannot observe those feelings directly. This capacity to infer what are called 'hidden states' and use them to guide behaviour is essential for adaptive decision making, yet we still know little about how the brain performs it.

In my talk, I will present recently published data showing that the ventral hippocampus is crucial for mice to perform hidden state inference. I will show that ventral hippocampal neurons use incoming observations to distinguish the abstract, ‘hidden' contexts required for this strategy in a way that parallels the differentiation of spatial locations in dorsal hippocampus. I will then share unpublished findings suggesting that acetylcholine dynamics in the ventral hippocampus may signal uncertainty during this process - a key component of this mechanism. Together, these results provide cellular insight into how otherwise hidden contextual information shapes decisions and highlight a central, often underappreciated role for the hippocampus in hidden state inference.