Biology subjects

Ladow, M. A.

Publications and source records attributed to Ladow, M. A..

2 recordsLinked to original sources

bioRxiv2024

Representations of stimulus meaning in the hippocampus

The ability to discriminate and categorize the meaning of environmental stimuli and respond accordingly is essential for survival. The ventral hippocampus (vHPC) controls emotional and motivated behaviors in response to environmental cues and is hypothesized to do so in part by deciphering the positive or negative quality of these cues. Yet, what features of the environment are represented in the activity patterns of vCA1 neurons, and whether the positive or negative meaning of a stimulus is present at this stage, remains unclear. Here, using 2-photon calcium imaging across six different experimental paradigms, we consistently found that vCA1 ensembles encode the identity, sensory features, and intensity of learned and innately salient stimuli, but not their overall valence. These results offer a reappraisal of vCA1 function, wherein information corresponding to individual stimulus features and their behavioral saliency predominates, while valence-related information is attached elsewhere.

neuroscience↗

bioRxiv2021

Complementary population codes in the dorsal and ventral hippocampus during associative learning

Animals associate cues with outcomes and continually update these associations as new information is presented. The hippocampus is crucial for this, yet how neurons track changes in cue-outcome associations remains unclear. Using 2-photon calcium imaging, we tracked the same dCA1 and vCA1 neurons across days to determine how responses evolve across phases of odor-outcome learning. We find that, initially, odors elicited robust responses in dCA1, whereas in vCA1 responses emerged after learning, including broad representations that stretched across cue, trace, and outcome periods. Population dynamics in both regions rapidly reorganized with learning, then stabilized into ensembles that stored odor representations for days, even after extinction or pairing with a different outcome. Finally, we found stable, robust signals across CA1 when anticipating reward, but not when anticipating inescapable shock. These results identify how the hippocampus encodes, stores, and updates learned associations, and illuminates the unique contributions of dorsal and ventral hippocampus.

neuroscience↗