# Mechanisms Regulating the Specification and Differentiation of Unique Types of Cholinergic Neurons During Development

> **NIH NIH F32** · HARVARD MEDICAL SCHOOL · 2022 · $2,500

## Abstract

PROJECT SUMMARY
The human brain is comprised of billions of diverse neuronal types. How this diversity is generated and how
these neurons are assembled into functional networks remain highly researched questions with unclear answers.
Obtaining a deep understanding of how this is achieved promises to allow us to study the functions of different
neuronal types (e.g., by gaining genetic access to them) as well as open the door to program stem cells into
specific neuronal types to study and treat neurological diseases. Work spanning the last few decades in model
organisms, such as Drosophila and mouse, has begun to unravel the underlying molecular mechanisms that
lead to the specification of different neuronal types. At the very top of this molecular hierarchy are spatial and
temporal programs that allow stem cells and their progeny to know where and when they are in space and time.
For example, adult cholinergic neurons located in the basal forebrain (BF) and striatum are all born from a
specific embryonic domain in the ventral telencephalon called the medial ganglionic eminence (MGE), which
also produces precursors for other neuronal types such as GABAergic neurons. In addition to being spatially
restricted, cholinergic neuronal types are born in overlapping temporal windows from E10-E13. Thus, the
combination of spatial (MGE restricted) and temporal (E10-E13 restricted) programs contribute to cholinergic
specification. Preliminary work in the Fishell lab has uncovered at least 8 distinct cholinergic neuronal types
located in the BF and striatum but how these subtypes are specified during development is not known. As the
specification into different cholinergic neuronal types likely occurs in the MGE upon becoming postmitotic (as is
the case for GABAergic neurons), the goal of this proposal is to determine these specification programs.
Understanding how different cholinergic neuronal types are specified will allow us to begin to understand their
functions. Indeed, cholinergic neurons in the brain modulate neurocognitive functions such as memory, attention,
and reward by regulating diverse brain circuits. Dysfunction of these neurons is linked to many neurological
disorders, including Parkinson's and Alzheimer's diseases. In Aim 1, I will annotate the 8 adult (P30) cholinergic
neuronal clusters, which I hypothesize represent the 2 interneuron types residing in different parts of the striatum
and projection neurons targeting distinct brain areas. In Aim 2, I will define the developmental programs leading
to different cholinergic classes by collecting and analyzing cholinergic precursors from E10-E13, which I will
annotate by working backwards in time from our P30 dataset. In Aim 3, I plan to use existing methods and
develop new strategies to assess the function of candidate factors in specifying cholinergic fates. The outcomes
of these manipulations will be determined by charactering the expression of cluster specific markers, projection
patterns, an...

## Key facts

- **NIH application ID:** 10458204
- **Project number:** 3F32NS120936-01S1
- **Recipient organization:** HARVARD MEDICAL SCHOOL
- **Principal Investigator:** Anthony M Rossi
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $2,500
- **Award type:** 3
- **Project period:** 2021-06-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10458204

## Citation

> US National Institutes of Health, RePORTER application 10458204, Mechanisms Regulating the Specification and Differentiation of Unique Types of Cholinergic Neurons During Development (3F32NS120936-01S1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10458204. Licensed CC0.

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