Biology subjects

Kellendonk, C.

Publications and source records attributed to Kellendonk, C..

11 recordsLinked to original sources

bioRxiv2026

Striatal acetylcholine enables latent-state creation during reversal learning

Like dopamine, acetylcholine is modulated in the striatum by reward-predicting cues and outcomes, yet its computational role remains unclear. Here, we manipulated dorsomedial striatal acetylcholine in mice performing a reversal learning task using genetic and physiologically guided optogenetic approaches. Inhibiting phasic acetylcholine modulation impaired reversal learning, while enhancing modulation during non-rewarded trials facilitated reversal learning. Trial-by-trial acetylcholine dynamics were best explained by a reinforcement learning model in which new latent states are created when experience is poorly explained by existing states. A circuit-constrained model further suggested that acetylcholine promotes plasticity when reward-omission is ambiguous, leading to a surprising prediction: making reward omission explicit should reduce the need for acetylcholine. We confirmed this in a new experiment in which an auditory omission cue substantially reduced the reversal-learning deficit caused by genetic acetylcholine knockdown. These findings suggest that striatal acetylcholine supports reversal learning by promoting state construction in reinforcement learning.

neuroscience↗

bioRxiv2025

Altered striatal dopamine regulation in ADGRL3 knockout mice

Dopaminergic signaling is essential for regulating movement, learning, and reward. Disruptions in this system are linked to neuropsychiatric disorders such as ADHD. ADGRL3, an adhesion G protein-coupled receptor highly expressed in the brain, is genetically associated with increased ADHD risk. ADGRL3 knockout in animals alters expression of dopaminergic markers and induces dopamine-related behavioral changes. However, its precise role in modulating dopamine signaling remains unclear. We investigated how ADGRL3 knockout affects striatal dopamine release in mice using ex vivo fast-scan cyclic voltammetry and in vivo fiber photometry with a dopamine sensor. Ex vivo measurements showed increased electrically-evoked dopamine release across the striatum. Conversely, in vivo recordings revealed reduced task-induced dopamine signals in the nucleus accumbens during an operant fixed interval task. This reduction was not due to impaired dopamine availability, as amphetamine-evoked release was unchanged. These findings suggest ADGRL3 modulates dopamine release in complex ways via different pre- and postsynaptic mechanisms.

neuroscience↗

bioRxiv2025

A corticostriatal learning mechanism linking excess striatal dopamine and auditory hallucinations

1Auditory hallucinations are linked to elevated striatal dopamine, but their underlying computational mechanisms have been obscured by regional heterogeneity in striatal dopamine signaling. To address this, we developed a normative circuit model in which corticostriatal plasticity in the ventral striatum is modulated by reward prediction errors to drive reinforcement learning while that in the sensory-dorsal striatum is modulated by sensory prediction errors derived from internal belief to drive self-supervised learning. We then validate the key predictions of this model using dopamine recordings across striatal regions in mice, as well as human behavior across various tasks including a new hybrid learning task. Finally, we find that changes in learning resulting from optogenetic stimulation of the sensory-dorsal striatum in mice and individual variability in hallucinations in humans are best explained by selectively enhancing dopamine levels in the model sensory-dorsal striatum. These findings identify plasticity mechanisms underlying biased learning of sensory expectations as a biologically plausible link between excess dopamine and hallucinations.

neuroscience↗

bioRxiv2024

Prefrontal representations of retrospective spatial working memory in a rodent radial maze task

Working memory is the cognitive capacity for temporarily holding information in mind for processing or use. It has been theorized to depend upon executive and mnemonic subcomponents, although the contextual mapping of these subcomponents is not complete. Perturbations of prefrontal cortex (PFC) delay activity disrupt spatial working memory performance in rodent tasks. However, recordings of unperturbed PFC delay activity do not consistently contain mnemonic representations of spatial information in these tasks, calling into question the role that mnemonic PFC representations play in freely-moving spatial working memory. We hypothesized that increasing task complexity might increase the likelihood of mnemonic PFC representation emergence. We therefore used an automated eight-arm radial maze to implement a novel match-to-sample rodent spatial working memory task with seven options on each trial, and recorded calcium activity in PFC neurons during task performance. We found that the delay-phase activity of PFC neurons indeed contained mnemonic representations of spatial information at the population level. These representations were retrospective rather than prospective, and--surprisingly--were more evident on error trials. Together with previous results, these observations suggest that in freely-moving spatial working memory tasks, PFC mnemonic representations emerge to empower deviation from a routine behavioral strategy. Significance StatementPrefrontal cortex (PFC) activity is necessary for optimal performance of freely-moving spatial working memory tasks in rodents. Despite this, PFC representations of retrospective actions or stimuli--one quintessential working memory hallmark--are only variably observed during task delays, complicating our understanding of the PFCs role in spatial working memory. Here, we examine cellular-resolution PFC activity in a high-optionality match-to-sample radial maze task and find retrospective delay representations. Strikingly, these delay representations are more evident in error trials. This suggests that in the freely-moving context, explicit PFC representations of retrospective information support deviations from an entrained behavioral strategy, rather than equally supporting all spatial working memory-based behavior.

animal behavior and cognition↗

bioRxiv2024

Inhibition of striatal indirect pathway during second postnatal week leads to long lasting deficits in motivated behavior

Schizophrenia is a neuropsychiatric disorder with postulated neurodevelopmental etiology. Genetic and imaging studies have shown enhanced dopamine and D2 receptor occupancy in the striatum of patients with schizophrenia. However, whether alterations in postnatal striatal dopamine can lead to long lasting changes in brain function and behavior is still unclear. Here, we approximated striatal D2R hyperfunction in mice via designer receptor mediated activation of inhibitory Gi-protein signaling during a defined postnatal time window. We found that Gi-mediated inhibition of the indirect pathway during postnatal day 8-15 led to long lasting decreases in locomotor activity and motivated behavior measured in the adult animal. In vivo photometry further showed that the motivational deficit was associated with an attenuated adaptation of cue-evoked dopamine levels to changes in effort requirements. These data establish a sensitive time window of D2R-regulated striatal development with long lasting impacts on neuronal function and behavior.

animal behavior and cognition↗

bioRxiv2023

Adolescent Thalamocortical Inhibition Alters Prefrontal Excitation-Inhibition Balance.

Adolescent inhibition of thalamo-cortical projections from postnatal day P20-50 leads to long lasting deficits in prefrontal cortex function and cognition in the adult mouse. While this suggests a role of thalamic activity in prefrontal cortex maturation, it is unclear how inhibition of these projections affects prefrontal circuit connectivity during adolescence. Here, we used chemogenetic tools to inhibit thalamo-prefrontal projections in the mouse from P20-35 and measured synaptic inputs to prefrontal pyramidal neurons by layer (either II/III or V/VI) and projection target twenty-four hours later using slice physiology. We found a decrease in the frequency of excitatory and inhibitory currents in layer II/III nucleus accumbens (NAc) and layer V/VI medio-dorsal thalamus projecting neurons while layer V/VI NAc-projecting neurons showed an increase in the amplitude of excitatory and inhibitory currents. Regarding cortical projections, the frequency of inhibitory but not excitatory currents was enhanced in contralateral mPFC-projecting neurons. Notably, despite these complex changes in individual levels of excitation and inhibition, the overall balance between excitation and inhibition in each cell was only changed in the contralateral mPFC projections. This finding suggests homeostatic regulation occurs within subcortically but not intracortical callosally-projecting neurons. Increased inhibition of intra-prefrontal connectivity may therefore be particularly important for prefrontal cortex circuit maturation. Finally, we observed cognitive deficits in the adult mouse using this narrowed window of thalamocortical inhibition (P20-P35). Significance StatementConnectivity between two brain regions, the thalamus and the prefrontal cortex, has been found to be reduced in patients with schizophrenia. Neuronal activity in thalamo-cortical projections is important for the proper development of sensory cortices. How thalamo-cortical activity regulates prefrontal cortex development is less well understood. Here, we show that decreasing activity in thalamo-prefrontal projections in mice during early adolescence alters synaptic connectivity to distinct neuronal projections within the prefrontal cortex that are already evident in adolescence. While some of these changes can be explained by reduced thalamo-cortical projections, other adaptations are intrinsic to the prefrontal cortex. These findings implicate adolescence as a critical period of cortical development and demonstrate this period as a potential target for therapeutic intervention.

neuroscience↗

bioRxiv2021

Dopamine D2Rs Coordinate Cue-Evoked Changes in Striatal Acetylcholine Levels

In the striatum, acetylcholine (ACh) neuron activity is modulated co-incident with dopamine (DA) release in response to unpredicted rewards and reward predicting cues and both neuromodulators are thought to regulate each other. While this co-regulation has been studied using stimulation studies, the existence of this mutual regulation in vivo during natural behavior is still largely unexplored. One long-standing controversy has been whether striatal DA is responsible for the induction of the cholinergic pause or whether D2R modulate a pause that is induced by other mechanisms. Here, we used genetically encoded sensors in combination with pharmacological and genetic inactivation of D2Rs from cholinergic interneurons (CINs) to simultaneously measure ACh and DA levels after CIN D2R inactivation. We found that CIN D2Rs are not necessary for the induction of cue induced dips in ACh levels but regulate dip lengths and rebound ACh levels. Importantly, D2R inactivation strongly decreased the temporal correlation between DA and Ach signals not only at cue presentation but also during the intertrial interval. This points to a general mechanism by which D2Rs coordinate both signals. At the behavioral level D2R antagonism increased the latency to lever press, which was not observed in CIN-selective D2R knock out mice. This latency correlated with the cue evoked dip length supporting a role of the ACh dip and its regulation by D2Rs in motivated behavior. Overall, our data indicate that striatal DA coordinate phasic ACh and DA signals via CIN D2Rs which is important for the regulation of motivated behavior.

neuroscience↗

bioRxiv2021

Mature parvalbumin interneuron function in prefrontal cortex requires activity during a postnatal sensitive period

In their seminal findings, Hubel and Wiesel identified sensitive periods in which experience can exert lasting effects on adult visual cortical functioning and behavior via transient changes in neuronal activity during development. Whether comparable sensitive periods exist for non-sensory cortices, such as the prefrontal cortex, in which alterations in activity determine adult circuit function and behavior is still an active area of research. Here, we demonstrate that inhibition of prefrontal parvalbumin-expressing interneurons during the juvenile and adolescent period, results in persistent impairments in adult prefrontal circuit connectivity, in vivo network function and behavioral flexibility that can be reversed by targeted activation of parvalbumin interneurons in adulthood. In contrast, transient suppression of parvalbumin interneuron activity in adulthood produces no lasting effects. These findings identify an activity-dependent sensitive period for prefrontal circuit maturation and highlight how abnormal parvalbumin interneuron activity during development alters adult prefrontal circuit function and cognitive behavior.

neuroscience↗

bioRxiv2020

Dopamine D2 receptors modulate the cholinergic pause and inhibitory learning

Cholinergic interneurons (CINs) in the striatum respond to salient stimuli with a multiphasic response, including a pause, in neuronal activity. Slice physiology experiments have shown the importance of dopamine D2 receptors (D2Rs) in regulating CIN pausing yet the behavioral significance of the CIN pause and its regulation by dopamine in vivo is still unclear. Here, we show that D2R upregulation in CINs of the nucleus accumbens (NAc) lengthens the pause in CIN activity ex vivo and enlarges a stimulus-evoked decrease in acetylcholine (ACh) levels during behavior. This enhanced dip in ACh levels is associated with a selective deficit in the learning to inhibit responding in a Go/No-Go task. Our data demonstrate, therefore, the importance of CIN D2Rs in modulating the CIN response induced by salient stimuli and points to a role of the pause in inhibitory learning. This work has important implications for brain disorders with altered striatal dopamine and ACh function, including schizophrenia and attention-deficit hyperactivity disorder (ADHD).

neuroscience↗

bioRxiv2020

Dopamine D2R upregulation in nucleus accumbens indirect pathway does not affect Pavlovian and Go/No-Go Learning

Ventral striatal dopamine is thought to be important for associative learning. Dopamine exerts its role via activation of dopamine D1 and D2 receptors in the ventral striatum. Upregulation of dopamine D2R in the indirect pathway of the nucleus accumbens (NAc) impairs incentive motivation via inhibiting synaptic transmission to the ventral pallidum. Here, we determined whether upregulation of D2Rs and the resulting impairment in indirect pathway function modulates associative learning in an auditory Pavlovian reward learning task as well as Go/No-Go learning in an operant based reward driven Go/No-Go task. We found that upregulation of D2Rs in indirect pathway neurons of the NAc did not affect Pavlovian learning or the extinction of Pavlovian responses, and neither did it alter No-Go learning. A delay in the Go component of the task however could indicate a deficit in learning though it may be attributed to locomotor hyperactivity of the mice. In combination with previously published findings our data suggest that D2Rs in the NAc core play a specific role in regulating motivation by balancing cost/benefit computations but do not necessarily affect associative learning.

animal behavior and cognition↗

bioRxiv2019

Cortical Overgrowth in a Preclinical Forebrain Organoid Model of CNTNAP2-Associated Autism Spectrum Disorder

Autism spectrum disorder (ASD) represents a major public health burden but translating promising treatment findings from preclinical non-human models of ASD to the clinic has remained challenging. The recent development of forebrain organoids generated from human induced pluripotent stem cells (hiPSCs) derived from subjects with brain disorders is a promising method to study human-specific neurobiology, and may facilitate the development of novel therapeutics.\n\nIn this study, we utilized forebrain organoids generated from hiPSCs derived from patients from the Old Order Amish community with a rare syndromic form of ASD, carrying a homozygous c.3709DelG mutation in CNTNAP2 and healthy controls to investigate the effects of this mutation on cortical embryonic development.\n\nPatients carrying the c.3709DelG mutation in CNTNAP2 present with an increased head circumference and brain MRI reveals an increase in gray matter volume. Patient-derived organoids displayed an increase in total volume that was driven by an increased proliferation in neural progenitor cells, leading to an increase in the generation of cortical neuronal and non-neuronal cell types. The observed phenotypes were rescued after correction of the pathogenic mutation using CRISPR-Cas9. RNA sequencing revealed 339 genes differentially expressed between patient- and control-derived organoids of which a subset are implicated in cell proliferation and neurogenesis. Notably, these differentially expressed genes included previously identified ASD-associated genes and are enriched for genes in ASD-associated weighted gene co-expression networks.\n\nThis work provides a critical step towards understanding the role of CNTNAP2 in human cortical development and has important mechanistic implications for ASD associated with brain overgrowth. This CNTNAP2 organoid model provides opportunity for further mechanistic inquiry and development of new therapeutic strategies for ASD.

neuroscience↗