Grasping Neurons in the Ventral Premotor Cortex of Macaques Are Modulated by Social Goals.

Although it is established that F5 neurons can distinguish between nonsocial goals such as bringing food to the mouth for eating or placing it in a container, it is not clear whether they discriminate between social and nonsocial goals. Here, we recorded single-unit activity in the ventral premotor cortex of two female macaques and used a simple reach-to-grasp motor task in which a monkey grasped an object with a precision grip in three conditions, which only differed in terms of their final goal, that is, a subsequent motor act that was either social (placing in the experimenter's hand ["Hand" condition]) or nonsocial (placing in a container ["Container" condition] or bringing to the mouth for eating ["Mouth" condition]). We found that, during the execution of the grasping motor act, the response of a sizable proportion of F5 motor neurons was modulated by the final goal of the action, with some having a preference for the social goal condition. Our results reveal that the representation of goal-directed actions in ventral premotor cortex is influenced by contextual information not only extracted from physical cues but also from cues endowed with biological or social value. Our study suggests that the activity of grasping neurons in the premotor cortex is modulated by social context.

Simultaneous scalp recorded EEG and local field potentials from monkey ventral premotor cortex during action observation and execution reveals the contribution of mirror and motor neurons to the mu-rhythm.

The desynchronization of alpha and beta oscillations (mu rhythm) in the central scalp EEG during action observation and action execution is thought to reflect neural mirroring processes. However, the extent to which mirror neurons (MNs) or other populations of neurons contribute to such EEG desynchronization is still unknown. Here, we provide the first evidence that, in the monkey, the neuronal activity recorded from the ventral premotor cortex (PMv) strongly contributes to the EEG changes occurring in the beta band over central scalp electrodes, during executed and observed actions. We simultaneously recorded scalp EEG and extracellular activity, Multi Unit Activity (MUA) and Local Field Potentials (LFP), from area F5 of two macaques executing and observing grasping actions. We found that MUA highly correlates with an increase in high gamma LFP power and, interestingly, such LFP power increase also correlates to EEG beta - and in part also to alpha - desynchronization. In terms of timing of signal changes, the increase in high gamma LFP power precedes the EEG desynchronization, during both action observation and execution, thus suggesting a causal role of PMv neuronal activity in the modulation of the alpha and beta mu-rhythm. Lastly, neuronal signals from deeper layers of PMv exert a greater contribution than superficial layers to the EEG beta rhythm modulation, especially during the motor task. Our findings have clear implications for EEG studies in that they demonstrate that the activity of different populations of neurons in PMv contribute to the generation of the mu-rhythm.

Mirror Neurons of Ventral Premotor Cortex Are Modulated by Social Cues Provided by Others' Gaze.

Mirror neurons (MNs) in the inferior parietal lobule and ventral premotor cortex (PMv) can code the intentions of other individuals using contextual cues. Gaze direction is an important social cue that can be used for understanding the meaning of actions made by other individuals. Here we addressed the issue of whether PMv MNs are influenced by the gaze direction of another individual. We recorded single-unit activity in macaque PMv while the monkey was observing an experimenter performing a grasping action and orienting his gaze either toward (congruent gaze condition) or away (incongruent gaze condition) from a target object. The results showed that one-half of the recorded MNs were modulated by the gaze direction of the human agent. These gaze-modulated neurons were evenly distributed between those preferring a gaze direction congruent with the direction where the grasping action was performed and the others that preferred an incongruent gaze. Whereas the presence of congruent responses is in line with the usual coupling of hand and gaze in both executed and observed actions, the incongruent responses can be explained by the long exposure of the monkeys to this condition. Our results reveal that the representation of observed actions in PMv is influenced by contextual information not only extracted from physical cues, but also from cues endowed with biological or social value. SIGNIFICANCE STATEMENT: In this study, we present the first evidence showing that social cues modulate MNs in the monkey ventral premotor cortex. These data suggest that there is an integrated representation of other's hand actions and gaze direction at the single neuron level in the ventral premotor cortex, and support the hypothesis of a functional role of MNs in decoding actions and understanding motor intentions.

Neuroanatomical correlates of gross manual dexterity in children with unilateral spastic cerebral palsy.

Unilateral spastic Cerebral Palsy (UCP) results from congenital brain injury, and Magnetic Resonance Imaging (MRI) has a role in understanding the etiology and severity of brain insult. In UCP, functional impairment predominantly occurs in the upper limb (UL) of the more affected side, where manual ability and dexterity are typically reduced. Also, mirror movements (MMs), are often present in UCP, with a further possible negative functional impact. This study aims to investigate the relationships among neuroanatomical characteristics of brain injury at MRI, manual functional impairment and MMs, in children with UCP. Thirty-five children with UCP participated in the study (20, M = 15, F, mean age 9.2 ± 3.5 years). Brain lesions at MRI were categorized according to the Magnetic Resonance Classification System (MRICS) and by using a semi-quantitative MRI (sqMRI) scale. Gross manual performance was assessed through Manual Ability Classification System (MACS) and the Box and Block Test (BBT), and MMs by Woods and Teuber scale, for both hands. Non-parametric correlation analyses were run to determine the relationship between neuroanatomical and functional features. Regression models were run to explore the contribution of neuroanatomical features and MMs to UL function. Correlation analyses revealed moderate to strong associations between sqMRI scores contralateral to the more affected side and UL functional impairment on MACS and BBT, with more severe brain injuries significantly correlating with poorer function in the more affected hand. No association emerged between brain lesion severity scores and MMs. MRICS showed no association with MACS or BBT, while a significant correlation emerged between MRICS category and MMs in the more affected hand, with brain lesion category that are suggestive of presumed earlier injury being associated with more severe MMs. Finally, exploratory regression analyses showed that neuroanatomical characteristics of brain injury and MMs contributed to the variability of UL functional impairment. This study contributes to the understanding of the neuroanatomical and neurological correlates of some aspects of manual functional impairment in UCP by using a simple clinical brain MRI assessment.

Implementation of Listening Visits with Parents of Preterm Infants in an Italian Neonatal Intensive Care Unit.

PURPOSE: To assess the feasibility of implementing Listening Visits (LV) in an Italian neonatal intensive care unit (NICU). STUDY DESIGN AND METHODS: This feasibility implementation of LV included empathic listening and problem-solving sessions provided by a psychologist to 26 parents of hospitalized preterm newborns. Using the RE-AIM implementation framework, three facets of feasibility were assessed: reach, adoption, and implementation. RESULTS: It is feasible to integrate LV into the NICU: 76% of families were willing to try LV (reach). Listening Visits recipients reported high satisfaction. Twelve of the 16 families (75%) received six or more LV sessions (adoption), with mothers attending more sessions. Implementation fidelity, defined here as the percentage of LV recipients that received at least four sessions, was 94% among mothers and 30% among fathers. CLINICAL IMPLICATIONS: The LV intervention for parental support during the NICU stay is feasible and deemed helpful by parents. Parents were motivated to participate even though their levels of depression, stress, and anxiety were not high. In addition to the use of standardized screening questionnaires, parental requests and clinical team indications should be included in the decision-making for the provision of parental support services.

Oxytocin promotes prosocial behavior and related neural responses in infant macaques at-risk for compromised social development.

Although positive effects of oxytocin (OT) on social functioning are well-demonstrated, little is known about the mechanisms through which OT may drive early social development, or its therapeutic efficacy in infancy. To address these critical issues, we investigated the effects of exogenous OT on neural (EEG) and behavioral responses during observation of live facial gestures in infant macaques with limited social exposure (i.e. nursery-reared). Three key findings were revealed. First, OT increased alpha suppression over posterior scalp regions during observation of facial gestures but not non-biological movement, suggesting that OT targets self-other matching and attentional cortical networks involved in social perception from very early infancy. Second, OT increased infant production of matching facial gestures and attention towards the most socially-relevant facial stimuli, both behaviors typically silenced by early social deprivation. Third, infants with higher cortisol levels appeared to benefit the most from OT, displaying greater improvements in prosocial behaviors after OT administration. Altogether, these findings suggest that OT promotes prosocial behaviors and associated neural responses likely impacted by early social adversity, and demonstrate the potential of OT administration to ameliorate social difficulties in the context of neurodevelopmental and early-emerging psychiatric disorders, at a developmental stage when brain plasticity is greatest.

Intranasal oxytocin enhances EEG mu rhythm desynchronization during execution and observation of social action: An exploratory study.

Intranasal administration of oxytocin (OT) has been found to facilitate prosocial behaviors, emotion recognition and cooperation between individuals. Recent electroencephalography (EEG) investigations have reported enhanced mu rhythm (alpha: 8-13 Hz; beta: 15-25 Hz) desynchronization during the observation of biological motion and stimuli probing social synchrony after the administration of intranasal OT. This hormone may therefore target a network of cortical circuits involved in higher cognitive functions, including the mirror neuron system (MNS). Here, in a double-blind, placebo-controlled, between-subjects exploratory study, we investigated whether intranasal OT modulates the cortical activity from sensorimotor areas during the observation and the execution of social and non-social grasping actions. Participants underwent EEG testing after receiving a single dose (24 IU) of either intranasal OT or placebo. Results revealed an enhancement of alpha - but not beta - desynchronization during observation and execution of social grasps, especially over central and parietal electrodes, in participants who received OT (OT group). No differences between the social and non-social condition were found in the control group (CTRL group). Moreover, we found a significant difference over the cortical central-parietal region between the OT and CTRL group only within the social condition. These results suggest a possible action of intranasal OT on sensorimotor circuits involved in social perception and action understanding, which might contribute to facilitate the prosocial effects typically reported by behavioral studies.

EEG beta desynchronization during hand goal-directed action observation in newborn monkeys and its relation to the emergence of hand motor skills.

Previous developmental research suggests that motor experience supports the development of action perception across the lifespan. However, it is still unknown when the neural mechanisms underlying action-perception coupling emerge in infancy. The goal of this study was to examine the neural correlates of action perception during the emergence of grasping abilities in newborn rhesus macaques. Neural activity, recorded via electroencephalogram (EEG), while monkeys observed grasping actions, mimed actions and means-end movements during the first (W1) and second week (W2) of life was measured. Event-related desynchronization (ERD) during action observation was computed from the EEG in the alpha and beta bands, two components of the sensorimotor mu rhythm associated with activity of the mirror neuron system (MNS). Results revealed age-related changes in the beta band, but not the alpha band, over anterior electrodes, with greater desynchronization at W2 than W1 for the observation of grasping actions. Additionally, desynchronization to observed grasping actions at W2 was associated with infants' motor skills - measured by a separate behavioral task - such that more grasping attempts were associated to greater beta ERD. These findings suggest the emergence of an early action-perception system, that relies on motor experience, shortly after birth.