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Frontiers of Neurology and Neuroscience 2021Hypothalamic hypocretin/orexin neurons have been initially conceptualized as slow, modulatory controllers of behavior. Furthermore, their behavioral effects have been... (Review)
Review
Hypothalamic hypocretin/orexin neurons have been initially conceptualized as slow, modulatory controllers of behavior. Furthermore, their behavioral effects have been assumed to be a secondary consequence of their impact on arousal. However, cellular-resolution calcium imaging and optogenetic studies show that orexin neurons regulate self-generated and sensory-evoked movement on rapid, subsecond timescales. Orexin cell activity rapidly and transiently peaks before and during movements. Optogenetic prevention of this activation reduces the probability of locomotion initiation, and optogenetic mimicry of orexin cell activation rapidly causes locomotion. Neural ensemble calcium imaging experiments reveal that the same orexin cells whose activity underlies movement initiation display subsecond-latency responses to diverse sensory stimuli. These findings establish orexin neurons as rapid and strong sensorimotor controllers that are in many ways operationally similar to classic subcortical movement controllers, such as midbrain dopamine neurons. While a scientific definition of "arousal" is still lacking, the subsecond-scale sensorimotor control by orexin neurons could be viewed as reminiscent of a motor rather than an arousal system.
Topics: Animals; Humans; Hypothalamus; Locomotion; Motor Activity; Neurons; Orexins; Sensation
PubMed: 34052808
DOI: 10.1159/000514957 -
Developmental Psychobiology Apr 2019There is growing evidence that activation of the motor system during observation of actions, a phenomenon first observed in non-human primates, underlies action... (Review)
Review
There is growing evidence that activation of the motor system during observation of actions, a phenomenon first observed in non-human primates, underlies action understanding and even communication. This review (a) examines the evidence on motor system activity as an underlying neural correlate of action understanding; (b) reviews the theoretical and empirical work linking action understanding and the development of communication, with a specific focus on the role that gestures play as an intermediary; and (c) discusses the research on and existing opportunities for understanding the link between the motor system and communication in both humans and non-human primates, through the lens of action perception. Bringing together findings and perspectives from developmental social cognition in both humans and non-human primates and applying recent neuroscientific perspectives will help to elucidate the processes underlying the ability to understand and communicate with others.
Topics: Animals; Communication; Comprehension; Humans; Infant; Mirror Neurons; Motor Activity; Primates
PubMed: 30315570
DOI: 10.1002/dev.21779 -
Philosophical Transactions of the Royal... Aug 2009In this article we discuss both merits and limitations of the ideomotor approach to action control and action imitation. In the first part, we give a brief outline of... (Review)
Review
In this article we discuss both merits and limitations of the ideomotor approach to action control and action imitation. In the first part, we give a brief outline of ideomotor theory and its functional implications for imitation and related kinds of behaviours. In the subsequent sections, we summarize pertinent experimental studies on action imitation and action induction. These studies show that action perception modulates action planning in a number of ways, of which imitation is but one. In the last part, we move from regular actions to tool-use actions, raising the issue of whether and how watching others' tool-use actions leads to corresponding behaviours in observers. Here, we discuss experiments aimed at dissociating the relative roles of environmental targets, bodily movements and target-to-movement-mappings (action rules) in the observation of tool-use actions. Our findings indicate a strong role for action rules in the observation and imitation of tool-use actions. We argue that, in order to account for these findings, ideomotor theory needs to be extended to take mappings between bodily movements and environmental effects into account.
Topics: Humans; Imitative Behavior; Motor Activity; Movement; Tool Use Behavior
PubMed: 19620106
DOI: 10.1098/rstb.2009.0059 -
Neuropsychopharmacology : Official... Jan 2010Recent behavioral studies in both humans and rodents have found evidence that performance in decision-making tasks depends on two different learning processes; one... (Review)
Review
Recent behavioral studies in both humans and rodents have found evidence that performance in decision-making tasks depends on two different learning processes; one encoding the relationship between actions and their consequences and a second involving the formation of stimulus-response associations. These learning processes are thought to govern goal-directed and habitual actions, respectively, and have been found to depend on homologous corticostriatal networks in these species. Thus, recent research using comparable behavioral tasks in both humans and rats has implicated homologous regions of cortex (medial prefrontal cortex/medial orbital cortex in humans and prelimbic cortex in rats) and of dorsal striatum (anterior caudate in humans and dorsomedial striatum in rats) in goal-directed action and in the control of habitual actions (posterior lateral putamen in humans and dorsolateral striatum in rats). These learning processes have been argued to be antagonistic or competing because their control over performance appears to be all or none. Nevertheless, evidence has started to accumulate suggesting that they may at times compete and at others cooperate in the selection and subsequent evaluation of actions necessary for normal choice performance. It appears likely that cooperation or competition between these sources of action control depends not only on local interactions in dorsal striatum but also on the cortico-basal ganglia network within which the striatum is embedded and that mediates the integration of learning with basic motivational and emotional processes. The neural basis of the integration of learning and motivation in choice and decision-making is still controversial and we review some recent hypotheses relating to this issue.
Topics: Animals; Cerebral Cortex; Corpus Striatum; Goals; Habits; Humans; Motor Activity; Neural Pathways; Psychomotor Performance; Rats
PubMed: 19776734
DOI: 10.1038/npp.2009.131 -
Comprehensive Physiology Jan 2013Scientific evidence based on neuroimaging approaches over the last decade has demonstrated the efficacy of physical activity improving cognitive health across the human... (Review)
Review
Scientific evidence based on neuroimaging approaches over the last decade has demonstrated the efficacy of physical activity improving cognitive health across the human lifespan. Aerobic fitness spares age-related loss of brain tissue during aging, and enhances functional aspects of higher order regions involved in the control of cognition. More active or higher fit individuals are capable of allocating greater attentional resources toward the environment and are able to process information more quickly. These data are suggestive that aerobic fitness enhances cognitive strategies enabling to respond effectively to an imposed challenge with a better yield in task performance. In turn, animal studies have shown that exercise has a benevolent action on health and plasticity of the nervous system. New evidence indicates that exercise exerts its effects on cognition by affecting molecular events related to the management of energy metabolism and synaptic plasticity. An important instigator in the molecular machinery stimulated by exercise is brain-derived neurotrophic factor, which acts at the interface of metabolism and plasticity. Recent studies show that exercise collaborates with other aspects of lifestyle to influence the molecular substrates of cognition. In particular, select dietary factors share similar mechanisms with exercise, and in some cases they can complement the action of exercise. Therefore, exercise and dietary management appear as a noninvasive and effective strategy to counteract neurological and cognitive disorders.
Topics: Animals; Brain; Cognition; Cognition Disorders; Humans; Motor Activity
PubMed: 23720292
DOI: 10.1002/cphy.c110063 -
Biological Psychiatry. Cognitive... Sep 2019Corollary discharge (CD) signals are motor-related signals that exert an influence on sensory processing. They allow mobile organisms to predict the sensory consequences... (Review)
Review
Corollary discharge (CD) signals are motor-related signals that exert an influence on sensory processing. They allow mobile organisms to predict the sensory consequences of their imminent actions. Among the many functions of CD is to provide a means by which we can distinguish sensory experiences caused by our own actions from those with external causes. In this way, they contribute to a subjective sense of agency. A disruption in the sense of agency is central to many of the clinical symptoms of schizophrenia, and abnormalities in CD signaling have been theorized to underpin particularly those agency-related psychotic symptoms of the illness. Characterizing abnormal CD associated with eye movements in schizophrenia and their resulting influence on visual processing and subsequent action plans may have advantages over other sensory and motor systems. That is because the most robust psychophysiological and neurophysiological data regarding the dynamics and influence of CD as well as the neural circuitry implicated in CD generation and transmission comes from the study of eye movements in humans and nonhuman primates. We review studies of oculomotor CD signaling in the schizophrenia spectrum and possible neurobiological correlates of CD disturbances. We conclude by speculating on the ways in which oculomotor CD dysfunction, specifically, may invoke specific experiences, clinical symptoms, and cognitive impairments. These speculations lay the groundwork for empirical study, and we conclude by outlining potentially fruitful research directions.
Topics: Brain; Electrophysiological Phenomena; Eye Movements; Humans; Motor Activity; Schizophrenia; Sensation; Visual Perception
PubMed: 31105039
DOI: 10.1016/j.bpsc.2019.03.009 -
The Neuroscientist : a Review Journal... Aug 2019Animals and humans continuously engage in small, spontaneous motor actions, such as blinking, whisking, and postural adjustments ("fidgeting"). These movements are... (Review)
Review
Animals and humans continuously engage in small, spontaneous motor actions, such as blinking, whisking, and postural adjustments ("fidgeting"). These movements are accompanied by changes in neural activity in sensory and motor regions of the brain. The frequency of these motions varies in time, is affected by sensory stimuli, arousal levels, and pathology. These fidgeting behaviors can be entrained by sensory stimuli. Fidgeting behaviors will cause distributed, bilateral functional activation in the 0.01 to 0.1 Hz frequency range that will show up in functional magnetic resonance imaging and wide-field calcium neuroimaging studies, and will contribute to the observed functional connectivity among brain regions. However, despite the large potential of these behaviors to drive brain-wide activity, these fidget-like behaviors are rarely monitored. We argue that studies of spontaneous and evoked brain dynamics in awake animals and humans should closely monitor these fidgeting behaviors. Differences in these fidgeting behaviors due to arousal or pathology will "contaminate" ongoing neural activity, and lead to apparent differences in functional connectivity. Monitoring and accounting for the brain-wide activations by these behaviors is essential during experiments to differentiate fidget-driven activity from internally driven neural dynamics.
Topics: Animals; Behavior, Animal; Blinking; Brain; Deglutition; Humans; Motor Activity; Respiration; Sensorimotor Cortex; Tongue; Vibrissae
PubMed: 30311838
DOI: 10.1177/1073858418805427 -
Sports Medicine (Auckland, N.Z.) May 2014Accumulating evidence suggests that diet and lifestyle can play an important role in delaying the onset or halting the progression of age-related health disorders and... (Review)
Review
Accumulating evidence suggests that diet and lifestyle can play an important role in delaying the onset or halting the progression of age-related health disorders and can improve cognitive function. Exercise has been promoted as a possible prevention for neurodegenerative diseases. Exercise will have a positive influence on cognition and it increases the brain-derived neurotrophic factor, an essential neurotrophin. Several dietary components have been identified as having effects on cognitive abilities. In particular, polyphenols have been reported to exert their neuroprotective actions through the potential to protect neurons against injury induced by neurotoxins, an ability to suppress neuroinflammation, and the potential to promote memory, learning, and cognitive function. Dietary factors can affect multiple brain processes by regulating neurotransmitter pathways, synaptic transmission, membrane fluidity, and signal-transduction pathways. Flavonols are part of the flavonoid family that is found in various fruits, cocoa, wine, tea and beans. Although the antioxidant effects of flavonols are well established in vitro, there is general agreement that flavonols have more complex actions in vivo. Several cross-sectional and longitudinal studies have shown that a higher intake of flavonoids from food may be associated with a better cognitive evolution. Whether this reflects a causal association remains to be elucidated. Several studies have tried to 'manipulate' the brain in order to postpone central fatigue. Most studies have clearly shown that in normal environmental circumstances these interventions are not easy to perform. There is accumulating evidence that rinsing the mouth with a carbohydrate solution will improve endurance performance. There is a need for additional well controlled studies to explore the possible impact of diet and nutrition on brain functioning.
Topics: Animals; Brain; Cognition; Diet; Exercise; Fatigue; Humans; Motor Activity; Sports Nutritional Physiological Phenomena
PubMed: 24791916
DOI: 10.1007/s40279-014-0150-5 -
Neuropsychologia Oct 2019To investigate the neural preparation and awareness of an intention to act, neuroscientists typically examine spontaneous movements: self-paced flexions of the hand or...
To investigate the neural preparation and awareness of an intention to act, neuroscientists typically examine spontaneous movements: self-paced flexions of the hand or foot. However, these movements may not present a straightforward case of intended action as they are performed in absence of reasons to act and without the evaluation of action consequences. Therefore, a common criticism of these studies is that they lack ecological validity, because the results do not generalize to the more societally relevant deliberate actions that we perform in daily life. We agree that research on intended action should include reason-based deliberate actions in order to be more relevant for debates about human agency and free will. Therefore, we have developed a computer game called "Free Wally", which invites players to perform deliberate actions to achieve a goal. Free Wally provides a controlled environment for studying deliberate intended action, by presenting information for deciding whether or not to act, what action to perform and when to perform it, incorporating all basic components of an ecologically valid intended act. As a first step to validate our setup, we compare this game to a second computer game that measures spontaneous actions in a traditional way. While playing either game, the timing of the experienced intentions to act is measured using a real-time probing method. Moreover, the neural preparation for action is measured in terms of the (lateralized) readiness potential and alpha/beta event-related desynchronization across the motor cortex. No differences were found between the games in these last stages of action preparation, suggesting that the Free Wally game can be used to study intended action. However, differences in earlier stages during intention formation are to be expected. With Free Wally as a tool, we hope to encourage further research into the formation and content of ecologically valid motor intentions.
Topics: Adolescent; Adult; Contingent Negative Variation; Electroencephalography; Electroencephalography Phase Synchronization; Electromyography; Evoked Potentials; Eye Movement Measurements; Female; Humans; Intention; Male; Motor Activity; Motor Cortex; Video Games; Young Adult
PubMed: 31394108
DOI: 10.1016/j.neuropsychologia.2019.107156 -
Developmental Medicine and Child... Apr 2015This paper focuses on the key function of imitation in motor and social development of typically developing infants and low-functioning children with autism spectrum... (Review)
Review
This paper focuses on the key function of imitation in motor and social development of typically developing infants and low-functioning children with autism spectrum disorder (ASD). We suggest that it might also be a developmental cornerstone for other neurodevelopmental disorders. Why this suggestion? First, imitation just requires relating one's motor patterns to perceived motor patterns. This is always possible if the actions seen are not beyond the individual's motor scope; for instance, newborn infants can already imitate tongue protrusion, eye blinking, or mouth opening, because these movements are part of their foetal repertoire. Second, imitation is a 'use it or lose it' capacity: the more it is used, the more the repertoire grows (plasticity). Finally, imitation is an efficient tool for two main adaptive functions: learning and communication. Imitation-based communication is available through the use of the two facets of imitation: imitating and being imitated. The two facets afford two roles that the partners can exchange as a turn-taking while they synchronize matched activities. Neuroimaging studies of interactive imitation have shown that such communicative systems involve a coordination of bottom-up and top-down processes. In this line, imitation is a booster of development that can also be of benefit for children with neurodevelopmental disorders.
Topics: Child Development; Child Development Disorders, Pervasive; Humans; Imitative Behavior; Infant; Learning; Motor Activity; Visual Perception
PubMed: 25690119
DOI: 10.1111/dmcn.12689