1,720,999 research outputs found
Level of M1 GABAB predicts micro offline consolidation of motor learning during wakefulness
Full text linkThe consolidation process stabilizes a new initially labile memory. This consolidation could operate on a shorter timescale during wakefulness after initial motor learning. Within micro-offline learning states, sequences of simple individual actions learned through interleaved practice are condensed into a unified skill through a time-dependent consolidation process occurring during wakeful periods. While emerging evidence links Glutamate and GABA modulations in the primary motor cortex (M1) to motor learning, its relationship with micro-offline consolidation processes in brief resting states during motor learning is unclear. To investigate this issue, we employed Transcranial magnetic stimulation (TMS) to evaluate whether interindividual variation of different neurotransmitters at rest influences motor learning consolidation in humans. Our results point to the role of GABAB in micro-offline motor consolidation processes during motor learning in M1. This finding could have an important impact on planning neuropharmacology or non-invasive brain stimulation approaches in clinical domains, such as post-stroke rehabilitation
Please, don't do it! Fifteen years of progress of non-invasive brain stimulation in action inhibition
Full text linkThe ability to inhibit prepotent responses is critical for survival. Action inhibition can be investigated using a stop-signal task (SST), designed to provide a reliable measure of the time taken by the brain to suppress motor responses. Here we review the major research advances using the combination of this paradigm with the use of non-invasive brain stimulation techniques in the last fifteen years. We highlight new methodological approaches to understanding and exploiting several processes underlying action control, which is critically impaired in several psychiatric disorders. In this review we present and discuss existing literature demonstrating i) the importance of the use of non-invasive brain stimulation in studying human action inhibition, unveiling the neural network involved ii) the critical role of prefrontal areas, including the pre-supplementary motor area (pre-SMA) and the inferior frontal gyrus (IFG), in inhibitory control iii) the neural and behavioral evidence of proactive and reactive action inhibition. As the main result of this review, the specific literature demonstrated the crucial role of pre-SMA and IFG as evidenced from the field of noninvasive brain stimulation studies. Finally, we discuss the critical questions that remain unanswered about how such non-invasive brain stimulation protocols can be translated to therapeutic treatments
Early motor reactivity to observed human body postures is affected by body expression, not gender
No full textThe early response to emotional stimuli involves a transient suppression of motor reactivity to favor monitoring of emotionally relevant information. Using transcranial magnetic stimulation (TMS), we have previously shown that viewing emotional body postures induces an early and transient reduction in motor excitability. Yet, it remains unclear whether early motor responses to emotional bodies are automatic or influenced by top-down factors such as task- or gender-related effects. To address these issue, we administered TMS over the right motor cortex (M1) during observation of still pictures of fearful expressions, happy expressions, neutral movements and neutral static body postures, and recorded motor-evoked potentials (MEPs) at an early phase of processing (i.e., at 100–125 ms from stimulus onset). To test gender-related effects, we presented male and female models to male and female participants. To test task-related effects, we asked participants to categorize the different body postures into either four (4AFC: fearful, happy, neutral movements, or static postures) or two distinct categories (2AFC: emotional or neutral postures). Results showed a reduction of MEPs for fearful and happy body postures relative to neutral movements and static postures. This motor suppression was not influenced by the gender of the actor, the gender of the observer, or the task performed. These findings indicate that early motor responses to observed human body postures are affected by the type of expression displayed by the observed model more than by task- or gender-related effects, suggesting these responses may be relatively automatic
Visual, sensorimotor and cognitive routes to understanding others' enjoyment: An individual differences rTMS approach to empathic accuracy
Full text linkFunctional imaging studies suggest that accurate understanding of others' emotional feelings (i.e., empathic accuracy, EA) recruits high-order visual, sensorimotor and mentalizing brain networks. However, the behavioral relevance of these findings is unclear. To fill in this gap, we used repetitive transcranial magnetic stimulation (rTMS) to interfere with the right superior temporal sulcus (STS), inferior frontal gyrus (IFG) and temporoparietal junction (TPJ) during an EA task requiring participants to infer the enjoyment felt by a social target while smiling/laughing. Relative to a baseline condition (sham rTMS), active rTMS of STS, IFG and TPJ (but not of a control site) disrupted the efficiency of EA task performance, mainly by lowering task accuracy; rTMS of IFG and TPJ also slowed down response speeds. Importantly, the effects of rTMS on EA task efficiency were predicted by baseline EA performance, with high-performers showing a performance decrease when the TPJ was targeted, and low-performers showing a performance decrease when the STS or the IFG was targeted. The double dissociation in the effect of rTMS between low- and high-performers suggests distinct roles of STS, IFG and TPJ in efficient understanding of the enjoyment felt by others. These findings provide causal evidence of distinct visual, sensorimotor and cognitive routes to EA and suggest that individual differences in EA are underpinned by differential recruitment of these routes
Frozen in (e)motion: How reactive motor inhibition is influenced by the emotional content of stimuli in healthy and psychiatric populations
Full text linkEfficient inhibitory control is vital. However, environmental cues can influence motor control especially in an emotional context. One common task to measure inhibitory control is the stop-signal task (SST), which asks participants to respond to go stimuli knowing that on some trials a stop signal will be presented, requiring them to inhibit their response. This paradigm estimates the ability to inhibit already-initiated responses by calculating participants' stop-signal reaction times (SSRT), an index of inhibitory control. Here, we aim to review the existing, often contradictory, evidence on the influence of emotional stimuli on the inhibitory process. We aim to discuss which factors may reveal an interference as well as an advantage of emotional stimuli on action inhibition performance. Finally, we review the existing evidence that has investigated the effect of such stimuli on action inhibition in the psychiatric population. Important factors are the relevance, the intensity and the valence of the emotional stimulus, as well as the affected component of the motor control. From all this evidence, it is clear that understand precisely how emotion is integrated into core executive functions, such as inhibitory control, is essential not only for cognitive neuroscience, but also for refining neurocognitive models of psychopathology
Memories are not written in stone: Re-writing fear memories by means of non-invasive brain stimulation and optogenetic manipulations
Full text linkThe acquisition of fear associative memory requires brain processes of coordinated neural activity within the amygdala, prefrontal cortex (PFC), hippocampus, thalamus and brainstem. After fear consolidation, a suppression of fear memory in the absence of danger is crucial to permit adaptive coping behavior. Acquisition and maintenance of fear extinction critically depend on amygdala-PFC projections. The robust correspondence between the brain networks encompassed cortical and subcortical hubs involved into fear processing in humans and in other species underscores the potential utility of comparing the modulation of brain circuitry in humans and animals, as a crucial step to inform the comprehension of fear mechanisms and the development of treatments for fear-related disorders. The present review is aimed at providing a comprehensive description of the literature on recent clinical and experimental researches regarding the noninvasive brain stimulation and optogenetics. These innovative manipulations applied over specific hubs of fear matrix during fear acquisition, consolidation, reconsolidation and extinction allow an accurate characterization of specific brain circuits and their peculiar interaction within the specific fear processing
"Action simulation plays a critical role in deceptive action recognition" Poster Presentation - 8th IBRO Conference, Florence-Italy, July 14-18, 2011.
No full textEarly right motor cortex response to happy and fearful facial expressions: A tms motor-evoked potential study
Full text linkThe ability to rapidly process others’ emotional signals is crucial for adaptive social interactions. However, to date it is still unclear how observing emotional facial expressions affects the reactivity of the human motor cortex. To provide insights on this issue, we employed single-pulse transcranial magnetic stimulation (TMS) to investigate corticospinal motor excitability. Healthy participants observed happy, fearful and neutral pictures of facial expressions while receiving TMS over the left or right motor cortex at 150 and 300 ms after picture onset. In the early phase (150 ms), we observed an enhancement of corticospinal excitability for the observation of happy and fearful emotional faces compared to neutral expressions specifically in the right hemisphere. Interindividual differences in the disposition to experience aversive feelings (personal distress) in interpersonal emotional contexts predicted the early increase in corticospinal excitability for emotional faces. No differences in corticospinal excitability were observed at the later time (300 ms) or in the left M1. These findings support the notion that emotion perception primes the body for action and highlights the role of the right hemisphere in implementing a rapid and transient facilitatory response to emotional arousing stimuli, such as emotional facial expressions
Don't Hurt Me No More: State-dependent Transcranial Magnetic Stimulation for the treatment of specific phobia
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