Biology subjects

Procyk, E.

Publications and source records attributed to Procyk, E..

11 recordsLinked to original sources

bioRxiv2026

Quantitative evaluation of enrichment protocols on rhesus macaques welfare in laboratory environment.

Non-human primates are crucial animal models in biomedical research including neurosciences. Legal frameworks ensure that participation of monkeys in biomedical research follows an ethical assessment, driven by specific guidelines for ensuring animal well-being. Those guidelines promote continued refinement of practices to improve animal wellbeing, yet quantitative data to inform such refinements is limited. In this context, we investigated the impact of modifications to the housing that created either navigational complexity or visual access to neighbouring animals on the behaviour of rhesus macaques. Then we quantified the value of different enrichment programmes based on manipulable objects. We showed that making navigation within a modular housing more complex, or adding transparent separations between housing units is associated with significant reduction of severe aggression, stereotypical behaviours and a significant increase of appeasing behaviours. We also observed a positive effect of manipulable objects with an increase in the expression of appeasing behaviours and a decrease in abnormal or stereotypical behaviours. Finally, our study revealed significant inter-individual variability that was not explained by sex, age, social network size or social status. Overall, our results point to the importance and benefits of environmental changes and enrichment protocols, and of the critical need for personalised enrichment programmes.

animal behavior and cognition↗

bioRxiv2026

Prefrontal mechanisms of goal progress inference and monitoring in macaque monkeys

Primates pursue goals over extended periods and over multiple steps. The ability to track progress and its rate is critical for such pursuit, yet the neural mechanisms of this tracking are unclear. We recorded single-unit activity from macaque midcingulate cortex (MCC) and lateral prefrontal cortex (LPFC) whilst animals worked for immediate rewards and checked a gauge showing progress towards a larger reward. MCC expressed a temporally extended progress rate signal linked to the long timescale neurons in the region. LPFC expressed progress rate only when inferences on that property were required. In MCC, independent feedback-valence information was also preserved, enabling both readout of work success and rate-specific progress updating. An RNN trained under the same constraints showed that progress rate representations emerge spontaneously, and are critical for tracking goal progress. These results demonstrate a frontal mechanism for inferring and predicting goal progress by extracting progress rate information.

neuroscience↗

bioRxiv2025

Neural dynamics reveal foraging-like computations in the frontal cortex

The prefrontal cortex has a central role in flexible behavior. Computations for weighing alternatives, committing to an option, integrating evidence, and abandoning an option are dominantly formalized in reinforcement learning (RL). Yet, ecological considerations showcase foraging as a competing account. Identifying how the brain actually solves efficient weighing of options requires the identification of the neural representation of this abstract yet precise computation. We recorded neural populations from three areas of the primate frontal cortex involved in decision making to characterize neural dynamics while animals performed a standard RL task. By combining behavioral and neuron population analysis, we found a neural subspace in midcingulate (MCC) and ventrolateral prefrontal cortex (vLPFC) that precisely tracked value computations. We demonstrated that MCC dynamics showed signatures of foraging-like computation but conflicted with RL requirements. Our study thus provides a detailed neural account of foraging-like flexibility in the primate frontal cortex.

neuroscience↗

bioRxiv2025

Motivational control is implemented by a cingulo-prefrontal pathway

The neuronal connections between the midcingulate cortex (MCC) and the dorsolateral prefrontal cortex (dlPFC) are associated with multiple cognitive functions, including rapid and long-term adaptive processes. Here we show that DREADD-mediated activation of MCC to dlPFC projection in macaques led to increased engagement in a foraging task, but did not alter their trial-to-trial adaptive strategy. We conclude that a critical role for MCC-dlPFC pathway is in the temporally extended control of behaviour rather than in rapid adaptation.

neuroscience↗

bioRxiv2023

Frontal oscillatory beta bursts have rhythmically distinct regimes with differing functional relevance

Beta band rhythms often appear as brief bursts, but how variations in burst properties impact neural function is unclear. We probed beta burst heterogeneity by developing two complementary detection algorithms. One isolates brief high amplitude events (bursts of power, BoP) and another that identifies consistent oscillations that span multiple cycles (bursts of consistency, BoC). Examining frontal LFP and ECoG recordings from mice and macaques, these two burst types occupied the same 15 to 30 Hz frequency band yet showed minimal temporal overlap, indicating independent phenomena probably with distinct neural generators. Crucially, when task demands shifted between high and low cognitive control states, BoC bursts were enriched during demanding phases, whereas BoP bursts dominated routine phases. These results demonstrate that frontal beta activity comprises at least two rhythmically distinct regimes linked to different levels of cognitive control. Our dual mode framework refines mechanistic models of transient oscillations and underscores the significance of burst waveform diversity for flexible brain function.

neuroscience↗

bioRxiv2021

Frontal cortical functional connectivity is impacted by anaesthesia in macaques

AO_SCPLOWBSTRACTC_SCPLOWA critical aspect of neuroscience is to establish whether and how brain networks evolved across primates. To date, most comparative studies have used resting-state functional Magnetic Resonance Imaging (rs-fMRI) in anaesthetized non-human primates and in awake humans. However, anaesthesia strongly affects rs-fMRI signals. The present study investigated the impact of the awareness state (anaesthesia vs. awake) within the same group of macaque monkeys on the rs-fMRI functional connectivity (FC) organization of a well characterized network in the human brain, the cingulo-frontal lateral network. Results in awake macaques revealed a similar FC pattern to that previously uncovered in the human brain. Rostral seeds in the cingulate sulcus exhibited stronger correlation strength with rostral compared to caudal lateral frontal cortical areas while caudal seeds in the cingulate sulcus displayed stronger correlation strength with caudal compared to anterior lateral frontal cortical areas. Critically, this inverse rostro-caudal functional gradient was abolished under anaesthesia. This study demonstrates that the FC pattern of cingulo-frontal cortical networks is preserved from macaque to human but some of its properties can only be observed in the awake state, warranting significant caution when comparing FC patterns across species under different states.

neuroscience↗

bioRxiv2021

Feedback-related potentials and oscillations during trial and error learning in Parkinson's disease

Electrophysiological markers of performance monitoring are thought to reflect functioning of dedicated neural networks and neuromodulatory systems. Whether and how these markers are altered in neurological diseases and whether they can reflect particular cognitive deficits remains to be confirmed. Here we first tested whether the frontal medial feedback-related potential, evoked during a trial and error learning task, is changed in early Parkinsons disease patients compared to control subjects. The potential was not changed in amplitude and discriminated negative and positive feedback as in controls. Feedback-related markers in Parkinsons patients also appeared in time-frequency analyses, unaltered in theta (3-7 Hz) band but reduced in beta (20-30 Hz) oscillations for positive feedback. Beta oscillations power appeared to be dramatically globally reduced during the task. Overall, our results show that Beta oscillation markers of performance monitoring captured by EEG are selectively altered in Parkinsons disease patients, and that they are accompanied by changes in task-related oscillatory dynamics. Significance StatementFrontal neural activity evoked by outcomes reveal the functioning of neural systems devoted to flexible behaviours. Modulations of such activity in Parkinsons disease (PD) patients could reflect specific alterations of neural systems and cognitive processing. The goal is to evaluate whether such activity can serve as markers of the disease. Here, using EEG and a trial and error learning protocol, we show that mid-frontal midline performance feedback-related potentials for different types of feedback were similar in controls and early diagnosed PD patients. However, task-related oscillations revealed alterations in the beta range accompanied by more global beta activity alteration in PD compared to controls subjects. This study provides data relevant to the search for non-motor biomarkers in early stages of PD.

neuroscience↗

bioRxiv2020

Neural stem cells restore motor and cognitive function in a macaque model of Parkinson's disease

Parkinsons disease (PD) evolves over an extended and variable period in humans; several years prior to the onset of classical motor symptoms, cognitive deficits as well as sleep and biological rhythm disorders develop and worsen with disease progression, significantly impacting the quality of life of patients. The gold standard MPTP macaque model of PD recapitulates the progression of motor and non-motor symptoms over contracted periods of time. Here, this multidisciplinary and multiparametric study follows, in five animals, the steady progression of motor and non-motor symptoms and describes their reversal following bilateral grafts of neural precursors in diverse functional domains of the basal ganglia. Results show unprecedented recovery from cognitive symptoms in addition to a strong clinical motor recuperation. Both motor and cognitive recovery and partial circadian rhythm recovery correlate with the degree of graft integration into the host environment as well as with in-vivo levels of striatal dopaminergic innervation and function. Given inter-individuality of disease progression and recovery the present study underlines the importance of longitudinal multidisciplinary assessments in view of clinical translation and provides empirical evidence that integration of neural precursors following transplantation efficiently restores function at multiple levels in parkinsonian non-human primates. One Sentence SummaryEmpirical evidence that cell therapy efficiently reverts cognitive and clinical motor symptoms in the non-human primate model of Parkinsons disease.

neuroscience↗

bioRxiv2020

Local inhibitory control of frontal network metastability underlies the temporal signature of cognitive states

Cortical neural dynamics organizes over multiple anatomical and temporal scales. The mechanistic origin of the temporal organization and its contribution to cognition remain unknown. Here we demonstrate the cause of this organization by studying a specific temporal signature (autocorrelogram time constant and latency) of neural activity. In monkey frontal areas, recorded during flexible cognitive decisions, temporal signatures display highly specific area-dependent ranges, as well as anatomical and cell-type distributions. Moreover, temporal signatures are functionally adapted to behaviorally relevant timescales. Fine-grained biophysical network models, constrained to account for temporal signatures, reveal that after-hyperpolarization potassium and inhibitory GABA-B conductances critically determine areas specificity. They mechanistically account for temporal signatures by organizing activity into metastable states, with inhibition controlling state stability and transitions. As predicted by models, state durations non-linearly scale with temporal signatures in monkey, matching behavioral timescales. Thus, local inhibitory-controlled metastability constitutes the dynamical core specifying the temporal organization of cognitive functions in frontal areas.

neuroscience↗

bioRxiv2019

Investigating Confidence Judgments using Reviews in Human and Monkeys

Confidence judgments are self-assessments of the quality of ones own performance, and are a crucial aspect of metacognitive abilities. The underlying neurobiological mechanisms are poorly understood. One approach to understanding these mechanisms would be to take advantage of putative metacognitive abilities in non-human models. However, many discrepancies exist between human and non-human studies on metacognition due to the mode of reporting judgements. We here present an attempt to directly compare human and non-human primates metacognitive abilities using a protocol assessing confidence judgments. After performing a categorization test, subjects could either validate their choice or review the test. We could assess whether subjects detected their errors and how they corrected them according to their confidence, and importantly did so in both human and non-human primates. 14 humans and 2 macaque monkeys were tested. Humans showed a well-adapted use of the review option by reviewing more after incorrect choices or difficult stimuli. Non-human primates did not demonstrate a convincing use of the review or validate opportunity. In both species, reviewing did not improve performance. This study shows that decisions to review under uncertainty are not naturally beneficial to performance and is rather perturbed by biases and alternative low-cognitive cost strategies.

neuroscience↗

bioRxiv2019

Sulcal organization in the medial frontal cortex reveals insights into primate brain evolution

Although the relative expansion of the frontal cortex in primate evolution is generally accepted, the nature of the human uniqueness, if any, and between-species anatomo-functional comparisons of the frontal areas remain controversial. To provide a novel interpretation of the evolution of primate brains, sulcal morphological variability of the medial frontal cortex was assessed in old-world monkeys (macaque, baboon) and Hominoidea (chimpanzee, human). We discovered that both Hominoidea do possess a paracingulate sulcus, which was previously thought to be uniquely human and linked to higher cognitive functions like mentalizing. Also, we revealed systematic sulcal morphological organisations of the medial frontal cortex that can be traced from multiple old-world monkey to Hominoidea species, demonstrating an evolutionary conserved organizational principle. Our data provide a new framework to compare sulcal morphology, cytoarchitectonic areal distribution, connectivity, and function across the primate order, leading to clear predictions on how other primate brains might be anatomo-functionally organized.

neuroscience↗