Biology subjects

Lacal, I.

Publications and source records attributed to Lacal, I..

4 recordsLinked to original sources

bioRxiv2025

COSTS AND BENEFITS OF ACTING TOGETHER: A NON-HUMAN PRIMATE MODEL OF COOPERATIVE DECISION-MAKING

Cooperation is a crucial aspect of social behavior, allowing individuals to achieve goals unattainable alone. However, collective actions require costly inter-individual coordination, making continuous cost-benefit evaluation essential before engaging in cooperation. Non-human primate models can help uncover the evolutionary foundations of human cooperation and its underlying neural mechanisms. To this aim, we developed a novel paradigm to analyze the dyadic behavior of two macaques, who took turns in choosing between individual and cooperative actions to obtain variable rewards. Each monkey used a joystick to guide a cursor toward one of two targets, each indicating both the reward magnitude and the action type (i.e. solo action or joint action) required to obtain their payoff. We first observed a linear improvement in dyadic performance with the expected reward magnitude. Although macaques tended to prefer individual actions, they selected to act jointly under favorable payoff conditions, indicating that voluntary cooperation in macaques can emerge as a reward-driven process. Logistic models of their choices revealed the subjective cost monkeys assigned to cooperation, which was consistent across subjects. Nonetheless, the gain rate across different sessions increased over time, suggesting that macaques possess the cognitive ability to optimize their dyadic strategies, by estimating not only the coordination costs but also the benefits of cooperation. We observed a progressive reduction in the subjective cost assigned to joint action, which was not directly dependent on performance improvements. Our findings suggest that non-human primates can weigh the costs and benefits of cooperation, highlighting their ability to dynamically adjust social strategies based on reward contingencies. HIGHLIGHTS- Expected reward magnitude enhances cooperative performance in macaques - Monkeys evaluate the cost-benefit trade-off of cooperative actions in social contexts - In macaques, the subjective cost of cooperation decreases over time, promoting a gradual shift toward a pro-social strategy that maximizes outcomes - Cooperative behavior in macaques can emerge as a reward-driven, cost-benefit decision process - Macaques may exhibit metacognitive dynamics, using internal evaluations of expected outcomes to guide collective behavior

neuroscience↗

bioRxiv2024

Freely foraging macaques value information in ambiguous terrains

Among non-human primates, macaques are recognized for thriving in a wide range of novel environments. Previous studies show macaques affinity for new information. However, little is known about how information-seeking manifests in their spatial navigation pattern in ambiguous foraging terrains, where the location and distribution of the food are unknown. We investigated the spatial pattern of foraging in free-moving macaques in an ambiguous terrain, lacking sensory cues about the reward distribution. Rewards were hidden in a uniform grid of woodchip piles spread over a 15 sqm open terrain and spatially distributed according to different patchy distributions. We observed Levy-like random walks in macaques spatial search pattern, balancing relocation effort with exploration. Encountering rewards altered the foraging path to favor the vicinity of discovered rewards temporarily, without preventing longer-distance travels. These results point toward continuous exploration, suggesting that explicit information-seeking is a part of macaques foraging strategy. We further quantified the role of information seeking using a kernel-based model, combining a map of ambiguity, promoting information seeking, with a map of discovered rewards and a map of proximity. Fitting this model to the foraging paths of our macaques revealed individual differences in their relative preference for information, reward, or proximity. The model predicted that a balanced contribution of all three factors performs and adapts to an ambiguous terrain with semi-scattered rewards, a prediction we confirmed using further experimental evidence. We postulate an explicit role for seeking information as a valuable entity to reduce ambiguity in macaques foraging strategies, suggesting an ecologically valid way of foraging ambiguous terrains. Author SummaryIn a novel and ambiguous terrain lacking sensory information about the location or distribution of food, foragers obtain information by sampling. This process is crucial for animals thriving in a new habitat. We allowed free-roaming macaques to forage at their own pace in a controlled terrain to which they had limited prior exposure. Based on their foraging paths, we developed a computational model representing an individuals drive for reward-seeking, information-seeking, or energy preservation. These drives were represented as superimposing maps from the foragers perspective. We found that information-seeking, continuous exploration of unknown areas, is crucial for foraging under ambiguity. This finding is consistent with a theory suggesting that animals, specifically humans and other primates, seek information to reduce their uncertainty about the environment. Our study suggests that the statistical properties of primates random foraging patterns reveal their complex decision-making process, including adaptation to novel environments.

animal behavior and cognition↗

bioRxiv2023

A cortical mechanism linking saliency detection and motor reactivity in rhesus monkeys

Sudden and surprising sensory events trigger neural processes that swiftly adjust behavior. To study the phylogenesis and the mechanism of this phenomenon, we trained two rhesus monkeys to keep a cursor inside a visual target by exerting force on an isometric joystick. We examined the effect of surprising auditory stimuli on exerted force, scalp electroencephalographic (EEG) activity, and local field potentials (LFP) recorded from the dorso-lateral prefrontal cortex. Auditory stimuli elicited (1) a biphasic modulation of isometric force: a transient decrease followed by a corrective tonic increase, and (2) EEG and LFP deflections dominated by two large negative-positive waves (N70 and P130). The EEG potential was maximal at the scalp vertex, in all respects similar to the human vertex potential. Electrocortical potentials and force were tightly coupled: the P130 amplitude predicted the magnitude of the corrective force increase, particularly in the EEG electrodes contralateral to the limb exerting force, and in the LFP recorded from deep rather than superficial cortical layers, suggesting a direct effect of the vertex potential on the motor output determining the behavior. These results disclose a phylogenetically-preserved cortico-motor mechanism supporting adaptive behavior in response to salient sensory events.

neuroscience↗

bioRxiv2021

Evidence Of We-Representation In Monkeys When Acting Together

A hallmark of successful evolution resides in the ability to adapt our actions to those of others, optimizing collective behaviour, to achieve goals otherwise unattainable by individuals acting alone. We have previously shown that macaques constitute a good model to analyse joint behavior, since they are able to coordinate their actions in a dyadic context. In the present work, we investigated whether monkeys could improve their joint-action performance, under special visuomotor conditions. The behavior of 5 monkeys was analyzed in isometric center-out tasks, requiring hand force application in different directions, either individually or together with a partner. Manipulating the presence or absence of a pre-instruction about the future action condition (SOLO or TOGETHER), allowed us to investigate on the existence of a "we-representation" in macaque monkeys. We found that pre-cueing the future action context increased the chances of dyadic success, also thanks to the emergence of an optimal kinematic setting, that ultimately facilitates inter-individual motor coordination. Our results offer empirical evidence in macaques of a "We-representation" during collective behavior, that once is cued in advance has an overall beneficial effect on joint performance.

animal behavior and cognition↗