Publications by authors named "Bruno Nazarian"

In a functional magnetic resonance imaging study, we examined speech error monitoring in a cortico-cerebellar network for two contrasts: (a) correct trials with high versus low articulatory error probability and (b) overtly committed errors versus correct trials. Engagement of the cognitive cerebellar region Crus I in both contrasts suggests that this region is involved in overarching performance monitoring. The activation of cerebellar motor regions (superior medial cerebellum, lobules VI and VIII) indicates the additional presence of a sensorimotor driven implementation of control.

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Addictions often develop in a social context, although the influence of social factors did not receive much attention in the neuroscience of addiction. Recent animal studies suggest that peer presence can reduce cocaine intake, an influence potentially mediated, among others, by the subthalamic nucleus (STN). However, there is to date no neurobiological study investigating this mediation in humans.

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Article Synopsis
  • The planum temporale (PT) area in the left hemisphere is crucial for language development and is found to be asymmetrical in both humans and newborn baboons, indicating a possible pre-wired language readiness in the brain.
  • Research showed that 27 newborn baboons with a larger left PT were more likely to develop right-handed communication gestures as they matured, suggesting a link between early brain structure and future communicative behavior.
  • This study implies that PT asymmetry might represent an evolutionary trait that underlies shared gestural communication in both monkeys and humans.
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Biscriptuality is the ability to read and write using two scripts. Despite the increasing number of biscripters, this phenomenon remains poorly understood. Here, we focused on investigating graphomotor processing in French-Arabic biscripters.

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The left ventral occipito-temporal cortex (left-vOT) plays a key role in reading. Interestingly, the area also responds to speech input, suggesting that it may have other functions beyond written word recognition. Here, we adopt graph theoretical analysis to investigate the left-vOT's functional role in the whole-brain network while participants process spoken sentences in different contexts.

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Article Synopsis
  • - The human action observation network (AON) in the brain is responsible for processing observed actions and is present from childhood, but its sensitivity to social versus object-related actions may differ between adolescents and adults.
  • - A study using fMRI scanned teenagers and adults while they watched videos of actions differing in sociality and transitivity, revealing that both groups engaged similar brain areas; however, adolescents showed lower accuracy in processing these actions.
  • - The results suggest that adolescent representation of social actions in the AON is less robust compared to adults, indicating ongoing development in how individuals understand social interactions.
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Epidural electrical stimulation (EES) targeting the dorsal roots of lumbosacral segments restores walking in people with spinal cord injury (SCI). However, EES is delivered with multielectrode paddle leads that were originally designed to target the dorsal column of the spinal cord. Here, we hypothesized that an arrangement of electrodes targeting the ensemble of dorsal roots involved in leg and trunk movements would result in superior efficacy, restoring more diverse motor activities after the most severe SCI.

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Manual gestures and speech recruit a common neural network, involving Broca's area in the left hemisphere. Such speech-gesture integration gave rise to theories on the critical role of manual gesturing in the origin of language. Within this evolutionary framework, research on gestural communication in our closer primate relatives has received renewed attention for investigating its potential language-like features.

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Cognitive control and social perception both change during adolescence, but little is known of the interaction of these 2 processes. We aimed to characterize developmental changes in brain activity related to the influence of a social stimulus on cognitive control and more specifically on inhibitory control. Children (age 8-11,  = 19), adolescents (age 12-17,  = 20), and adults (age 24-40,  = 19) performed an antisaccade task with either faces or cars as visual stimuli, during functional magnetic resonance brain imaging.

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How the evolution of speech has transformed the human auditory cortex compared to other primates remains largely unknown. While primary auditory cortex is organized largely similarly in humans and macaques, the picture is much less clear at higher levels of the anterior auditory pathway, particularly regarding the processing of conspecific vocalizations (CVs). A "voice region" similar to the human voice-selective areas has been identified in the macaque right anterior temporal lobe with functional MRI; however, its anatomical localization, seemingly inconsistent with that of the human temporal voice areas (TVAs), has suggested a "repositioning of the voice area" in recent human evolution.

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An event-related functional magnetic resonance imaging study examined how speakers inspect their own speech for errors. Concretely, we sought to assess 1) the role of the temporal cortex in monitoring speech errors, linked with comprehension-based monitoring; 2) the involvement of the cerebellum in internal and external monitoring, linked with forward modeling; and 3) the role of the medial frontal cortex for internal monitoring, linked with conflict-based monitoring. In a word production task priming speech errors, we observed enhanced involvement of the right posterior cerebellum for trials that were correct, but on which participants were more likely to make a word as compared with a nonword error (contrast of internal monitoring).

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The basal ganglia (BG) have long been known for contributing to the regulation of motor behaviour by means of a complex interplay between tonic and phasic inhibitory mechanisms. However, after having focused for a long time on phasic reactive mechanisms, it is only recently that psychological research in healthy humans has modelled tonic proactive mechanisms of control. Mutual calibration between anatomo-functional and psychological models is still needed to better understand the unclear role of the BG in the interplay between proactive and reactive mechanisms of control.

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The "language-ready" brain theory suggests that the infant brain is pre-wired for language acquisition prior to language exposure. As a potential brain marker of such a language readiness, a leftward structural brain asymmetry was found in human infants for the Planum Temporale (PT), which overlaps with Wernicke's area. In the present longitudinal in vivo MRI study conducted in 35 newborn monkeys (Papio anubis), we found a similar leftward PT surface asymmetry.

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While the brain network supporting handwriting has previously been defined in adults, its organization in children has never been investigated. We compared the handwriting network of 23 adults and 42 children (8- to 11-year-old). Participants were instructed to write the alphabet, the days of the week, and to draw loops while being scanned.

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There is a growing interest in understanding functional brain decline with aging. The dataset provides raw anatomical and functional images recorded in a group of 20 young volunteers and in another group of 19 older volunteers during a 10-minute period of resting state followed by four consecutive task-related runs. During each task-related run, the participants were exposed to two types of sensory stimulation: a tactile stimulation consisting in a textured-disk rotation under the palm of their right hand or a muscle proprioceptive stimulation consisting in a mechanical vibration applied to the muscle tendon of their wrist abductor.

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Article Synopsis
  • - This study explored age-related changes in how the brain processes sensory information about self-motion, using fMRI to create illusions of hand movements through tactile and proprioceptive stimulation.
  • - Results indicated that while younger and older adults showed similar brain activations during these illusions, older adults had less deactivation in specific frontal brain regions and exhibited a more evenly distributed activity pattern in the sensorimotor areas.
  • - The findings suggest that older individuals experience a decline in proprioceptive perception linked to aging, potentially due to weakened inhibitory brain processes, but they may benefit from improved connectivity between different brain networks.
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Background: Recent studies suggest that Posttraumatic Stress Disorder (PTSD) might be associated with dysfunctional reward circuitry. However, further research is needed to understand the key role of the reward system in PTSD symptomatology.

Methods: Twenty participants with PTSD and 21 Trauma-Exposed matched Controls (TECs) completed the Monetary Incentive Delay (MID) task during an MRI session.

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The left ventral occipitotemporal cortex (vOT) is considered the key area of the visuo-orthographic system. However, some studies reported that the area is also involved in speech processing tasks, especially those that require activation of orthographic knowledge. These findings suggest the existence of a top-down activation mechanism allowing such cross-modal activation.

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We present a novel functional magnetic resonance imaging paradigm for second-person neuroscience. The paradigm compares a human social interaction (human-human interaction, HHI) to an interaction with a conversational robot (human-robot interaction, HRI). The social interaction consists of 1 min blocks of live bidirectional discussion between the scanned participant and the human or robot agent.

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Handedness, one of the most prominent expressions of laterality, has been historically considered unique to human. This noteworthy feature relates to contralateral inter-hemispheric asymmetries in the motor hand area following the mid-portion of the central sulcus. However, within an evolutionary approach, it remains debatable whether hand preferences in nonhuman primates are associated with similar patterns of hemispheric specialization.

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Current models of writing assume that the orthographic processes involved in spelling retrieval and the motor processes involved in the control of the hand are independent. This view has been challenged by behavioral studies, which showed that the linguistic features of words impact motor execution during handwriting. We designed an experiment coupling functional magnetic resonance imaging and kinematic recordings during a writing to dictation task.

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Disruption of fear conditioning, its extinction and its retrieval are at the core of posttraumatic stress disorder (PTSD). Such deficits, especially fear extinction delay, disappear after alternating bilateral stimulations (BLS) during eye movement desensitization and reprocessing (EMDR) therapy. An animal model of fear recovery, based on auditory cued fear conditioning and extinction learning, recently showed that BLS facilitate fear extinction and fear extinction retrieval.

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The neural mechanisms underlying response inhibition and related disorders are unclear and controversial for several reasons. First, it is a major challenge to assess the psychological bases of behaviour, and ultimately brain-behaviour relationships, of a function which is precisely intended to suppress overt measurable behaviours. Second, response inhibition is difficult to disentangle from other parallel processes involved in more general aspects of cognitive control.

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The planum temporale (PT) is a critical region of the language functional network in the human brain showing a striking size asymmetry toward the left hemisphere. Historically considered as a structural landmark of the left-brain specialization for language, a similar anatomical bias has been described in great apes but never in monkeys-indicating that this brain landmark might be unique to Hominidae evolution. In the present in vivo magnetic resonance imaging study, we show clearly for the first time in a nonhominid primate species, an Old World monkey, a left size predominance of the PT among 96 olive baboons (Papio anubis), using manual delineation of this region in each individual hemisphere.

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Exploration of the body representation system (BRS) from kinaesthetic illusions in fMRI has revealed a complex network composed of sensorimotor and frontoparietal components. Here, we evaluated the degree of maturity of this network in children aged 7-11 years, and the extent to which structural factors account for network differences with adults. Brain activation following tendon vibration at 100Hz ('illusion') and 30Hz ('no illusion') were analysed using the two-stage random effects model, with or without white and grey matter covariates.

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