# Basal Forebrain Modulation of Olfactory Bulb Function

> **NIH NIH R01** · UNIVERSITY OF MARYLAND BALTIMORE · 2020 · $630,487

## Abstract

PROJECT SUMMARY
 Sensory systems, including olfaction, are heavily dependent on signals from higher brain regions that
regulate behavioral states of alertness and attention. A major center for these modulatory inputs is the basal
forebrain. The basal forebrain (BF) sends axonal projections throughout the brain and has been implicated in
dynamic modulation of cortical as well as sensory circuits during behavior. BF is classically thought of as a
center for cholinergic projections throughout the brain, whose chief functional role is to mediate attentional
modulation of information processing. However, the recent advent of novel tools for probing neural circuits in
vivo has enabled a deeper and more nuanced understanding of basal forebrain organization and role in
cognition. BF projections to neocortex are in fact neurochemically diverse and precisely organized with respect
to projection target. Further, different BF subpopulations are linked to distinct aspects of behavior and are
implicated in diverse cognitive functions including reward signaling, behavioral responding to sensory cues and
task learning. Despite these advances, however, we still know little about BF impact on the initial processing of
sensory inputs on their way to cortex.
 The olfactory bulb (OB) is advantageous for investigating basal forebrain function, as it is the only primary
(pre-cortical) sensory processing area receiving BF inputs and because olfaction is a primary modality driving
behavior in rodents. BF sends massive projections to the OB, with terminations in all OB layers. Many of these
projections are cholinergic. However, as for neocortex, BF projections to OB are neurochemically diverse with
substantial numbers of GABAergic neurons. The importance of this diversity has only recently begun to be
appreciated for cortex, but almost entirely unexamined with respect to OB circuitry. A recent study showed that
GABAergic basal forebrain projections to the olfactory bulb target distinct neuronal subpopulations and can,
independent of cholinergic projections, modulate OB circuits to affect odor perception. However, our
understanding of the respective roles played by BF cholinergic and GABAergic in modulating OB circuits and
odor perception remains rudimentary. Fundamental unanswered questions include whether cholinergic and
GABAergic basal forebrain projections target distinct components of olfactory bulb circuits, whether they have
complementary or opposing effects on odor representations at the level of olfactory bulb output, what are the
activity patterns of cholinergic and GABAergic basal forebrain neurons during behavior, and what role these
projections play in odor perception or odor-guided behaviors?
 The overall goal of this proposal is to investigate how the basal forebrain neuromodulatory inputs affect
olfactory bulb function in a multi-disciplinary study spanning investigation at the level of single neurons through
to animal behavior utilizing advances in electro...

## Key facts

- **NIH application ID:** 9989101
- **Project number:** 5R01DC010915-08
- **Recipient organization:** UNIVERSITY OF MARYLAND BALTIMORE
- **Principal Investigator:** ADAM C PUCHE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $630,487
- **Award type:** 5
- **Project period:** 2011-02-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9989101

## Citation

> US National Institutes of Health, RePORTER application 9989101, Basal Forebrain Modulation of Olfactory Bulb Function (5R01DC010915-08). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9989101. Licensed CC0.

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