publications

2026

1. bioRxiv

   

   A cholinergic eligibility trace facilitates amygdala plasticity in flavour avoidance learning

   Weston Fleming Jordan L. Pauli, and 8 more authors

   bioRxiv, 2026

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   When an animal consumes a new food and consequently feels ill, it rapidly and robustly learns to avoid this food in the future, a form of learning termed conditioned flavour avoidance (CFA). Postingestive malaise often occurs long after novel food consumption, necessitating a neural mechanism that can facilitate plasticity between temporally distant events. Neuromodulators, acting through G-protein-coupled receptors (GPCRs) that can influence neuronal excitability on extended timescales, may underlie this process. The projection of parabrachial (PB) Calca neurons to the central amygdala (CeA) is critical for formation of CFA. Here, we demonstrate that these neurons overlap with a PB population that releases acetylcholine (ACh) in the CeA. ACh is released in CeA during consumption of a novel solution and subsequent visceral malaise, consistent with a role in CFA acquisition. Two-photon calcium imaging in brain slices reveals that ACh widely activates CeA neurons and enhances glutamatergic responsivity on a timescale consistent with CFA learning. CRISPR-Cas9-mediated genetic knockdown and optogenetics demonstrate that ACh from PB facilitates CFA behavior. Large-scale neuronal recordings in the CeA along with our CRISPR approach reveal that loss of ACh signaling to CeA blocks key signatures of CFA-associated plasticity. Together, these data point to the cholinergic input from PB to central amygdala as a critical neuromodulatory signal that links activity over long timespans to facilitate associative learning in CFA.

2025

1. Neuron

   

   Opioid-driven disruption of the septum reveals a role for neurotensin-expressing neurons in withdrawal

   Rhiana C Simon Weston Fleming, and 10 more authors

   Neuron, 2025

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   Opioid withdrawal is an intensively aversive experience and often drives relapse. The lateral septum (LS) is a forebrain structure that is important in aversion processing and has been linked to substance use disorders, but which LS cell types contribute to the maladaptive state of withdrawal is unknown. We used single-nucleus RNA sequencing to interrogate cell-type-specific gene expression changes induced by chronic morphine exposure and discovered that morphine globally disrupts LS cell types, but neurotensin-expressing neurons (LS-Nts) are selectively activated by naloxone. Using two-photon calcium imaging and ex vivo electrophysiology, we next demonstrate that LS-Nts neurons receive elevated glutamatergic drive in morphine-dependent mice and remain hyperactivated during withdrawal. Finally, we show that manipulating LS-Nts neurons during opioid withdrawal regulates pain coping and sociability. Together, these results suggest that LS-Nts neurons are a key neural substrate involved in opioid withdrawal and establish the LS as a crucial regulator of adaptive behaviors.

2024

1. Nat. Neurosci.

   Independent inhibitory control mechanisms for aggressive motivation and action

   Tomohito Minakuchi Eartha Mae Guthman, and 6 more authors

   Nature Neuroscience, 2024

2023

1. Nat. Neurosci.

   

   A neural substrate of sex-dependent modulation of motivation

   Julia Cox Adelaide R Minerva, and 9 more authors

   Nature neuroscience, 2023

2022

1. Thesis

   Measurement and Manipulation of Subcortical Neuromodulatory Populations during Reward Learning

   Weston Taylor Fleming

   Princeton University, 2022
2. Cell Rep

   

   Cholinergic interneurons mediate cocaine extinction in male mice through plasticity across medium spiny neuron subtypes

   Weston Fleming Junuk Lee, and 3 more authors

   Cell reports, 2022

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   Cholinergic interneurons (ChINs) in the nucleus accumbens (NAc) have been implicated in the extinction of drug associations, as well as related plasticity in medium spiny neurons (MSNs). However, since most previous work relied on artificial manipulations, whether endogenous acetylcholine signaling relates to drug associations is unclear. Moreover, despite great interest in the opposing effects of dopamine on MSN subtypes, whether ChIN-mediated effects vary by MSN subtype is also unclear. Here, we find that high endogenous acetylcholine event frequency correlates with greater extinction of cocaine-context associations across male mice. Additionally, extinction is associated with a weakening of glutamatergic synapses across MSN subtypes. Manipulating ChIN activity bidirectionally controls both the rate of extinction and the associated plasticity at MSNs. Our findings indicate that NAc ChINs mediate drug-context extinction by reducing glutamatergic synaptic strength across MSN subtypes, and that natural variation in acetylcholine signaling may contribute to individual differences in extinction.

3. Bio. Psych. GOS

   Perineuronal nets in the dorsomedial striatum contribute to behavioral dysfunction in mouse models of excessive repetitive behavior

   Brandy A Briones Miah N Pitcher, and 9 more authors

   Biological psychiatry global open science, 2022

2021

1. PLOS One

   

   Inferring spikes from calcium imaging in dopamine neurons

   Weston Fleming Sean Jewell, and 3 more authors

   PlOS One, 2021

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   Calcium imaging has led to discoveries about neural correlates of behavior in subcortical neurons, including dopamine (DA) neurons. However, spike inference methods have not been tested in most populations of subcortical neurons. To address this gap, we simultaneously performed calcium imaging and electrophysiology in DA neurons in brain slices and applied a recently developed spike inference algorithm to the GCaMP fluorescence. This revealed that individual spikes can be inferred accurately in this population. Next, we inferred spikes in vivo from calcium imaging from these neurons during Pavlovian conditioning, as well as during navigation in virtual reality. In both cases, we quantitatively recapitulated previous in vivo electrophysiological observations. Our work provides a validated approach to infer spikes from calcium imaging in DA neurons and implies that aspects of both tonic and phasic spike patterns can be recovered.

2020

1. Cell Reports

   A comparison of dopaminergic and cholinergic populations reveals unique contributions of VTA dopamine neurons to short-term memory

   Jung Yoon Choi Hee Jae Jang, and 7 more authors

   Cell reports, 2020
2. Elife

   

   Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times

   Lili X Cai Katherine Pizano, and 6 more authors

   Elife, 2020

2019

1. Nature

   

   Specialized coding of sensory, motor and cognitive variables in VTA dopamine neurons

   Ben Engelhard Joel Finkelstein, and 9 more authors

   Nature, 2019
2. ACER

   

   Withdrawal from brief repeated alcohol treatment in adolescent and adult male and female rats

   Weston Fleming Quincy Jones, and 6 more authors

   Alcoholism: clinical and experimental research, 2019