# Integration of seasonal cues to modulate neuronal plasticity

> **NIH NIH K99** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2023 · $105,731

## Abstract

Project Summary
 Organisms adapt to seasonal changes in environmental conditions to survive. These adaptations rely
predominantly on photoperiod (i.e., daylength), but are also influenced by temperature. Recent studies indicate
that photoperiodic changes affect the neuronal composition of brain areas involved in circadian (i.e., daily)
timekeeping and modulate the number of dopaminergic neurons, in a process known as neurotransmitter
switching. Other studies show that the brain also undergoes profound structural changes across seasons.
However, the relationship between these functional and structural changes in the brain and seasonal adaptations
remains a major gap in knowledge. Moreover, whether other relevant seasonal cues, in particular temperature,
contribute to these changes is not known. The overall goal of this project is to understand the nature and role
of neuronal plasticity in the integration of seasonal cues to promote seasonal adaptations. My hypothesis is
that seasonal adaptations are mediated by functional and structural plasticity in neurons from circadian
and aminergic circuits in response to environmental cues. To test this, I propose 3 specific aims: investigate
structural and functional plasticity of (1) the circadian clock neuronal network and of (2) aminergic circuits in
response to seasonal cues and its impact on social and locomotor behavior, and (3) determine how the plastic
changes in the circadian clock and aminergic circuits regulate brain connectivity and encode the behavioral
output of these circuits. I will accomplish this project in the genetically tractable Drosophila model and will
leverage a combination of versatile neurogenetics, high-resolution microscopy, and well-established behavioral
analysis.
 Thus far in my postdoctoral career in the Chiu lab at UC Davis, I obtained training in molecular genetics
and biochemistry, which I used to explore the role of circadian peptides in modulating seasonal adaptations in
Drosophila. Moving forward, I will build on my current research to study the neuronal mechanisms of seasonal
plasticity and behavior. During the K99 training period, I will use available tools in Drosophila to assess the
functional and structural changes in the circadian clock neurons and aminergic circuits in response to seasonal
cues. Moreover, I will test the functional consequences of these changes by using available genetically encoded
sensors and by generating new, more sensitive, sensors to assess aminergic function in vivo under the guidance
of Dr. Lin Tian. I will expand the use of these tools in the R00 stage to determine how the interaction between
these two circuit systems modulate their functions and how they affect seasonal behavior concertedly. I believe
that the mentorship of Drs. Chiu and Tian, together with the support provided by the K99/R00 award, will allow
me to build a strong foundation that will enable my success as an independent investigator. The results of the
proposed studies...

## Key facts

- **NIH application ID:** 10723977
- **Project number:** 1K99NS133470-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Sergio Ignacio Hidalgo Sotelo
- **Activity code:** K99 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $105,731
- **Award type:** 1
- **Project period:** 2023-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10723977

## Citation

> US National Institutes of Health, RePORTER application 10723977, Integration of seasonal cues to modulate neuronal plasticity (1K99NS133470-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10723977. Licensed CC0.

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