Residual motion of upper limbs in individuals who experienced cervical spinal cord injury (CSCI) is vital to achieve functional independence. Several interventions were developed to restore shoulder range of motion (ROM) in CSCI patients. However, shoulder ROM assessment in clinical practice is commonly limited to use of a simple goniometer. Conventional goniometric measurements are operator-dependent and require significant time and effort. Therefore, innovative technology for supporting medical personnel in objectively and reliably measuring the efficacy of treatments for shoulder ROM in CSCI patients would be extremely desirable. This study evaluated the validity of a customized wireless wearable sensors (Inertial Measurement Units—IMUs) system for shoulder ROM assessment in CSCI patients in clinical setting. Eight CSCI patients and eight healthy controls performed four shoulder movements (forward flexion, abduction, and internal and external rotation) with dominant arm. Every movement was evaluated with a goniometer by different testers and with the IMU system at the same time. Validity was evaluated by comparing IMUs and goniometer measurements using Intraclass Correlation Coefficient (ICC) and Limits of Agreement (LOA). inter-tester reliability of IMUs and goniometer measurements was also investigated. Preliminary results provide essential information on the accuracy of the proposed wireless wearable sensors system in acquiring objective measurements of the shoulder movements in CSCI patients.

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 male 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 (LFPs) recorded from the dorsolateral 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 negativepositive waves (N70 and P130). The EEG potential was symmetrical and maximal at the scalp vertex, highly reminiscent of 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 LFPs recorded from deep rather than superficial cortical layers. These results disclose a phylogenetically preserved corticomotor mechanism supporting adaptive behavior in response to salient sensory events. Significance Statement Survival in the natural world depends on an animals capacity to adapt ongoing behavior to abrupt unexpected events. To study the neural mechanisms underlying this capacity, we trained monkeys to apply constant force on a joystick while we recorded their brain activity from the scalp and the prefrontal cortex contralateral to the hand holding the joystick. Unexpected auditory stimuli elicited a biphasic force modulation: a transient reduction followed by a corrective adjustment. The same stimuli also elicited EEG and LFP responses, dominated by a biphasic wave that predicted the magnitude of the behavioral adjustment. These results disclose a phylogenetically preserved corticomotor mechanism supporting adaptive behavior in response to unexpected events.

Interpersonal coordination is fundamental to social evolution. We investigate its phenomenology and neural underpinnings in humans and macaques, examining the behavioral adaptations required for mutual coordination during motor interactions and the extent to which the underlying brain mechanisms are shared across species. Using a common interpersonal coordination paradigm, we conducted functional magnetic resonance imaging (fMRI) in humans and intracranial local field potential (LFP) recordings in macaques. Despite between-species behavioral discrepancies, both monkeys and humans coordinate through adjustments that proved to be based on proactive adaptation of motor planning and execution. Evidence from fMRI and time-resolved decoding analysis of LFPs converged to show modulation of premotor brain activity associated with interpersonal coordination and its effectiveness. Moreover, a dynamic sequential coding emerged, whereby the action context is represented early during planning, and coordination features near movement onset. Our findings reveal an evolutionarily conserved cortical architecture across primates that supports cooperative motor behavior.

In behavioral neuroscience, research in nonhuman primates often relies on video-game–like paradigms, including studies of social interaction and joint action. In social studies, establishing whether animals monitor their partner and are aware of their reciprocal interactions in these abstract laboratory settings is essential for interpreting the processes underlying cooperative performance. Here, we examined spontaneous head-orienting behavior in two macaques performing a cooperative visuomotor task under highly controlled conditions. The animals sat side by side with their heads unrestrained and used isometric joysticks to control their respective cursors displayed on a shared screen. Depending on trial instructions, they performed either individual actions (SOLO action, SA) or joint actions (JA) to obtain a reward. We quantified spontaneous head rotations toward the partner as an ethologically relevant behavioral indicator of social monitoring. Partner-directed head turns occurred more frequently during JA than during SA trials. Crucially, their rate increased with the number of errors made by the partner during JA trials. Together, these findings indicate that macaques monitor their partner during abstract, computer-mediated cooperative interactions and that this monitoring is driven by the partner’s performance. Such spontaneous, context-specific orienting toward the partner supports the interpretation that macaques are aware of their dyadic engagement, even in video-game-like settings. Our results therefore highlight the suitability of controlled visuomotor paradigms for investigating the cognitive-motor processes underlying joint action in nonhuman primates.

The appreciation of music is a universal trait of humankind. Evidence supporting this notion includes the ubiquity of music across cultures and the natural predisposition towards music that humans display early in development. Are we musical animals because of species-specific predispositions? This question cannot be answered by relying on cross-cultural or developmental studies alone, as these cannot rule out enculturation. Instead, it calls for cross-species experiments testing if homologous neural mechanisms underlying music perception are present in non-human primates. We present music to two rhesus monkeys, reared without musical exposure while recording electroencephalography (EEG) and pupillometry. Monkeys exhibit higher engagement and neural encoding of expectations based on the previously seeded musical context when passively listening to real music, as opposed to shuffled controls. We then compare human and monkey neural responses to the same stimuli and find a species-dependent contribution of two fundamental musical features – pitch and timing– in generating expectations: whilst timing- and pitch-based probabilistic expectations are similarly weighted in humans, monkeys rely on timing rather than pitch. These results highlight a conserved auditory mechanism underlying music perception, i.e. a primitive sensitivity to temporal regularities that may have served as an intermediate step towards the evolution of human musicality. This work further sets the stage for future cross-species and developmental comparative studies to non-invasively track neural encoding of naturalistic musical stimuli.