Miah Pitcher

A huge thanks to everyone in the Feller Lab and the UC Berkeley Neuroscience community for their continued feedback on this project. Special shoutout to @mfeller.bsky.social, and Feller lab contributors Aanica Gonzales and Raul Habib. ⭐️💥 (11/11)

We are excited about this result because it illustrates that a dendritic computation, long studied for its role in sensory processing, acts to convert network-level activity patterns into compartment-specific dendritic growth! (10/11)

In a mouse model with decreased propagation bias (brought to us by @keisukeyonehara.bsky.social), nasal and temporal quadrants were equally activated by waves, and were morphologically more symmetric! This suggests that SACs dendrites respond to biases in propagation with asymmetric growth. (9/11)

SACs with decreased wave activity were smaller and less complex, suggesting that SAC dendrites show activity-dependent growth! (8/11)

To test this, we used genetic mouse models with altered waves. SACs undergo tremendous growth during this period (as described by @julielefebvrelab.bsky.social). First, we examined SAC morphology in a mouse model with severely disrupted waves in the first postnatal week. (7/11)

We show that waves with a nasal propagation bias preferentially activate SAC dendrites oriented in the nasal direction. Interestingly, we also found that the nasal SACs have more dendrites. We hypothesized that propagation bias instructs accelerated nasal SAC dendrite growth. (6/11)

Adult SAC dendrites are known to compute the direction of moving visual stimuli (see work by Feller lab alum @annaintegrated.bsky.social). We found SACs use the same property to compute the direction of waves! Dendrites aligned with the direction of wave propagation show the highest response. (5/11)

To show this, we used dual colored 2-photon calcium imaging to simultaneously measure calcium activity from the dendrites of SACs (green) and retinal waves (red). (4/11)

Propagation bias is thought to instruct neural circuit formation (for example see PMID: 39146415), but how do neurons in the retina decode wave direction? We found that this computation happens in the dendrites of interneurons called starburst amacrine cells (SACs). (3/11)

Before mice open their eyes at two weeks old, the retina exhibits spontaneous retinal waves. Waves at the start of the second postnatal week show a bias to propagate in the nasal direction (or right to left in the movie below). (2/11)

I’m very excited to announce that a part of my PhD thesis project is now a preprint! In this paper, we show how spontaneous activity prior to visual experience shapes neural circuits in the retina. (1/11)