Dynamic spatial representation of self and others' actions in the macaque frontal cortex.

Modulation of neuronal firing rates by the spatial locations of physical objects is a widespread phenomenon in the brain. However, little is known about how neuronal responses to the actions of biological entities are spatially tuned and whether such spatially tuned responses are affected by social contexts. These issues are of key importance for understanding the neural basis of embodied social cognition, such as imitation and perspective-taking.

Decoding social rewards via inter-areal coordination frequency in the brain.

Vicarious reward plays a pivotal role in shaping altruism and prosociality. However, neural circuit mechanisms underlying the distinction between vicarious reward and experienced reward are poorly understood. Putnam et al.

Chemogenetic dissection of a prefrontal-hypothalamic circuit for socially subjective reward valuation in macaques.

The value of one's own reward is affected by the reward of others, serving as a source for envy. However, it is not known which neural circuits mediate such socially subjective value modulation. Here, we chemogenetically dissected the circuit from the medial prefrontal cortex (MPFC) to the lateral hypothalamus (LH) while male macaques were presented with visual stimuli that concurrently signaled the prospects of one's own and others' rewards.

Tuning in to real-time social interactions in macaques.

Movement synchronization between individuals has been implicated in reinforcing their cohesion. How might such interindividual motor entrainment be controlled by the social brain? The answer remains elusive owing largely to the lack of suitable animal models in which direct neural recordings are available. Here, we show that macaque monkeys exhibit social motor entrainment without human prompting.

Cognitive genomics of learning delay and low level of social performance monitoring in macaque.

Cognitive skills and the underlying neural architecture are under the influence of genetics. Cognitive genomics research explores the triadic relationship between genes, brain, and cognition, with its major strategy being genotype-driven. Here we show that an inverse strategy is feasible to identify novel candidate genes for particular neuro-cognitive phenotypes in macaques.

Live agent preference and social action monitoring in the macaque mid-superior temporal sulcus region.

Mentalizing, the ability to infer the mental states of others, is a cornerstone of adaptive social intelligence. While functional brain mapping of human mentalizing has progressed considerably, its evolutionary signature in nonhuman primates remains debated. The discovery that the middle part of the macaque superior temporal sulcus (mid-STS) region has a connectional fingerprint most similar to the human temporoparietal junction (TPJ)-a crucial node in the mentalizing network-raises the possibility that these cortical areas may also share basic functional properties associated with mentalizing.

The Role of the Medial Prefrontal Cortex in Moderating Neural Representations of Self and Other in Primates.

As a frontal node in the primate social brain, the medial prefrontal cortex (MPFC) plays a critical role in coordinating one's own behavior with respect to that of others. Current literature demonstrates that single neurons in the MPFC encode behavior-related variables such as intentions, actions, and rewards, specifically for self and other, and that the MPFC comes into play when reflecting upon oneself and others. The social moderator account of MPFC function can explain maladaptive social cognition in people with autism spectrum disorder, which tips the balance in favor of self-centered perspectives rather than taking into consideration the perspective of others.

Subcortical encoding of agent-relevant associative signals for adaptive social behavior in the macaque.

Primates are group-living creatures that constantly face the challenges posed by complex social demands. To date, the cortical mechanisms underlying social information processing have been the major focus of attention. However, emerging evidence suggests that subcortical regions also mediate the collection and processing of information from other agents.

Socially relative reward valuation in the primate brain.

Reward valuation in social contexts is by nature relative rather than absolute; it is made in reference to others. This socially relative reward valuation is based on our propensity to conduct comparisons and competitions between self and other. Exploring its neural substrate has been an active area of research in human neuroimaging.

A causal role for frontal cortico-cortical coordination in social action monitoring.

Decision-making via monitoring others' actions is a cornerstone of interpersonal exchanges. Although the ventral premotor cortex (PMv) and the medial prefrontal cortex (MPFC) are cortical nodes in social brain networks, the two areas are rarely concurrently active in neuroimaging, inviting the hypothesis that they are functionally independent. Here we show in macaques that the ability of the MPFC to monitor others' actions depends on input from the PMv.

Representation of distinct reward variables for self and other in primate lateral hypothalamus.

The lateral hypothalamus (LH) has long been implicated in maintaining behavioral homeostasis essential for the survival of an individual. However, recent evidence suggests its more widespread roles in behavioral coordination, extending to the social domain. The neuronal and circuit mechanisms behind the LH processing of social information are unknown.

Multiple neuronal circuits for variable object-action choices based on short- and long-term memories.

At each time in our life, we choose one or few behaviors, while suppressing many other behaviors. This is the basic mechanism in the basal ganglia, which is done by tonic inhibition and selective disinhibition. Dysfunctions of the basal ganglia then cause 2 types of disorders (difficulty in initiating necessary actions and difficulty in suppressing unnecessary actions) that occur in Parkinson's disease.

Social reward monitoring and valuation in the macaque brain.

Behaviors are influenced by rewards to both oneself and others, but the neurons and neural connections that monitor and evaluate rewards in social contexts are unknown. To address this issue, we devised a social Pavlovian conditioning procedure for pairs of monkeys. Despite being constant in amount and probability, the subjective value of forthcoming self-rewards, as indexed by licking and choice behaviors, decreased as partner-reward probability increased.

Development of social systems neuroscience using macaques.

This paper reviews the literature on social neuroscience studies using macaques in the hope of encouraging as many researchers as possible to participate in this field of research and thereby accelerate the system-level understanding of social cognition and behavior. We describe how different parts of the primate brain are engaged in different aspects of social information processing, with particular emphasis on the use of experimental paradigms involving more than one monkey in laboratory settings. The description begins with how individual neurons are used for evaluating socially relevant information, such as the identity, face, and focus of attention of others in various social contexts.

Performance monitoring in the medial frontal cortex and related neural networks: From monitoring self actions to understanding others' actions.

Action is a key channel for interacting with the outer world. As such, the ability to monitor actions and their consequences - regardless as to whether they are self-generated or other-generated - is of crucial importance for adaptive behavior. The medial frontal cortex (MFC) has long been studied as a critical node for performance monitoring in nonsocial contexts.

Direct and indirect pathways for choosing objects and actions.

A prominent target of the basal ganglia is the superior colliculus (SC) which controls gaze orientation (saccadic eye movement in primates) to an important object. This 'object choice' is crucial for choosing an action on the object. SC is innervated by the substantia nigra pars reticulata (SNr) which is controlled mainly by the caudate nucleus (CD).

Understanding intentional actions from observers' viewpoints: A social neuroscience perspective.

When we see others, we also try to 'see' their unobservable states of minds, such as beliefs, desires, and intentions. We carefully monitor others' actions, as we assume that those actions are outward manifestations of their internal states. Actors and observers can have divergent views on the cause of the same actions.

Single-neuron and genetic correlates of autistic behavior in macaque.

Atypical neurodevelopment in autism spectrum disorder is a mystery, defying explanation despite increasing attention. We report on a Japanese macaque that spontaneously exhibited autistic traits, namely, impaired social ability as well as restricted and repetitive behaviors, along with our single-neuron and genomic analyses. Its social ability was measured in a turn-taking task, where two monkeys monitor each other's actions for adaptive behavioral planning.

A Primary Role for Nucleus Accumbens and Related Limbic Network in Vocal Tics.

Inappropriate vocal expressions, e.g., vocal tics in Tourette syndrome, severely impact quality of life.

Common therapeutic mechanisms of pallidal deep brain stimulation for hypo- and hyperkinetic movement disorders.

Abnormalities in cortico-basal ganglia (CBG) networks can cause a variety of movement disorders ranging from hypokinetic disorders, such as Parkinson's disease (PD), to hyperkinetic conditions, such as Tourette syndrome (TS). Each condition is characterized by distinct patterns of abnormal neural discharge (dysrhythmia) at both the local single-neuron level and the global network level. Despite divergent etiologies, behavioral phenotypes, and neurophysiological profiles, high-frequency deep brain stimulation (HF-DBS) in the basal ganglia has been shown to be effective for both hypo- and hyperkinetic disorders.

What makes the dorsomedial frontal cortex active during reading the mental states of others?

The dorsomedial frontal part of the cerebral cortex is consistently activated when people read the mental states of others, such as their beliefs, desires, and intentions, the ability known as having a theory of mind (ToM) or mentalizing. This ubiquitous finding has led many researchers to conclude that the dorsomedial frontal cortex (DMFC) constitutes a core component in mentalizing networks. Despite this, it remains unclear why the DMFC becomes active during ToM tasks.

Pharmacological animal models of tic disorders.

This review summarizes animal models of Tourette syndrome (TS) and associated tic disorders that have been developed through pharmacological manipulation. These models provide a useful platform to explore the pathophysiology and the therapeutic interventions available for these disorders. The current pharmacological models, primarily using rodents and nonhuman primates, are classified in this review into two major categories depending on the methodology used for administration, that is, systemic and focal (intracerebral) injection protocols.

[Recent advances in social neuroscience research using macaques].

The last decade has seen a surge of interest in the study of social brain functions. Research in this field, called social neuroscience, has been mostly carried out on human subjects by using a functional neuroimaging technique. This is largely because of the fact that humans have sophisticated social abilities and are capable of performing various demanding tasks in a scanner.