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Current Opinion in Neurobiology Dec 2023Feeding behavior involves a complex organization of neural circuitry and interconnected pathways between the cortex, the brainstem, and muscles. Elevated synchronicity... (Review)
Review
Feeding behavior involves a complex organization of neural circuitry and interconnected pathways between the cortex, the brainstem, and muscles. Elevated synchronicity is required starting from the moment the animal brings the food to its mouth, chews, and initiates subsequent swallowing. Moreover, orofacial sensory and motor systems are coordinated in a way to optimize movement patterns as a result of integrating information from premotor neurons. Recent studies have uncovered significant discoveries employing various and creative techniques in order to identify key components in these vital functions. Here, we attempt to provide a brief overview of our current knowledge on orofacial systems. While our focus will be on recent breakthroughs regarding the masticatory machinery, we will also explore how it is sometimes intertwined with other functions, such as swallowing and limb movement.
Topics: Animals; Mastication; Neurons; Feeding Behavior; Movement; Brain Stem
PubMed: 37913688
DOI: 10.1016/j.conb.2023.102805 -
Annual Review of Vision Science Sep 2023As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual... (Review)
Review
As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual input are comparatively easy to measure as trajectories of eye movements, offering insight into many unconscious and conscious visual and cognitive processes. In this article, we review recent advances in predicting where we look. We focus on evaluating and comparing models: How can we consistently measure how well models predict eye movements, and how can we judge the contribution of different mechanisms? Probabilistic models facilitate a unified approach to fixation prediction that allows us to use explainable information explained to compare different models across different settings, such as static and video saliency, as well as scanpath prediction. We review how the large variety of saliency maps and scanpath models can be translated into this unifying framework, how much different factors contribute, and how we can select the most informative examples for model comparison. We conclude that the universal scale of information gain offers a powerful tool for the inspection of candidate mechanisms and experimental design that helps us understand the continual decision-making process that determines where we look.
Topics: Fixation, Ocular; Eye Movements
PubMed: 37419107
DOI: 10.1146/annurev-vision-120822-072528 -
Scientific Reports Sep 2023Accurately quantifying an animal's movement is crucial for developing a greater empirical and theoretical understanding of its behaviour, and for simulating biologically...
Accurately quantifying an animal's movement is crucial for developing a greater empirical and theoretical understanding of its behaviour, and for simulating biologically plausible movement patterns. However, we have a relatively poor understanding of how animals move at fine temporal scales and in three-dimensional environments. Here, we collected high temporal resolution data on the three-dimensional spatial positions of individual three-spined sticklebacks (Gasterosteus aculeatus), allowing us to derive statistics describing key geometric characteristics of their movement and to quantify the extent to which this varies between individuals. We then used these statistics to develop a simple model of fish movement and evaluated the biological plausibility of simulated movement paths using a Turing-type test, which quantified the association preferences of live fish towards animated conspecifics following either 'real' (i.e., based on empirical measurements) or simulated movements. Live fish showed no difference in their response to 'real' movement compared to movement simulated by the model, although significantly preferred modelled movement over putatively unnatural movement patterns. The model therefore has the potential to facilitate a greater understanding of the causes and consequences of individual variation in movement, as well as enabling the construction of agent-based models or real-time computer animations in which individual fish move in biologically feasible ways.
Topics: Animals; Fishes; Smegmamorpha; Movement
PubMed: 37666895
DOI: 10.1038/s41598-023-40420-1 -
Cell Feb 2024Behavior relies on activity in structured neural circuits that are distributed across the brain, but most experiments probe neurons in a single area at a time. Using...
Behavior relies on activity in structured neural circuits that are distributed across the brain, but most experiments probe neurons in a single area at a time. Using multiple Neuropixels probes, we recorded from multi-regional loops connected to the anterior lateral motor cortex (ALM), a circuit node mediating memory-guided directional licking. Neurons encoding sensory stimuli, choices, and actions were distributed across the brain. However, choice coding was concentrated in the ALM and subcortical areas receiving input from the ALM in an ALM-dependent manner. Diverse orofacial movements were encoded in the hindbrain; midbrain; and, to a lesser extent, forebrain. Choice signals were first detected in the ALM and the midbrain, followed by the thalamus and other brain areas. At movement initiation, choice-selective activity collapsed across the brain, followed by new activity patterns driving specific actions. Our experiments provide the foundation for neural circuit models of decision-making and movement initiation.
Topics: Brain; Movement; Neurons; Thalamus; Memory
PubMed: 38306983
DOI: 10.1016/j.cell.2023.12.035 -
Trends in Neurosciences Nov 2023The vestibular cerebellum plays an essential role in maintaining our balance and ensuring perceptual stability during activities of daily living. Here I examine three... (Review)
Review
The vestibular cerebellum plays an essential role in maintaining our balance and ensuring perceptual stability during activities of daily living. Here I examine three key regions of the vestibular cerebellum: the floccular lobe, anterior vermis (lobules I-V), and nodulus and ventral uvula (lobules X-IX of the posterior vermis). These cerebellar regions encode vestibular information and combine it with extravestibular signals to create internal models of eye, head, and body movements, as well as their spatial orientation with respect to gravity. To account for changes in the external environment and/or biomechanics during self-motion, the neural mechanisms underlying these computations are continually updated to ensure accurate motor behavior. To date, studies on the vestibular cerebellum have predominately focused on passive vestibular stimulation, whereas in actuality most stimulation is the result of voluntary movement. Accordingly, I also consider recent research exploring these computations during active self-motion and emerging evidence establishing the cerebellum's role in building predictive models of self-generated movement.
Topics: Humans; Activities of Daily Living; Movement; Cerebellum; Vestibule, Labyrinth; Space Perception
PubMed: 37739815
DOI: 10.1016/j.tins.2023.08.009 -
Neuroscience and Biobehavioral Reviews Dec 2023The brain is a remarkably complex organ responsible for a wide range of functions, including the modulation of emotional states and movement. Neuronal circuits are... (Review)
Review
The brain is a remarkably complex organ responsible for a wide range of functions, including the modulation of emotional states and movement. Neuronal circuits are believed to play a crucial role in integrating sensory, cognitive, and emotional information to ultimately guide motor behavior. Over the years, numerous studies employing diverse techniques such as electrophysiology, imaging, and optogenetics have revealed a complex network of neural circuits involved in the regulation of emotional or motor processes. Emotions can exert a substantial influence on motor performance, encompassing both everyday activities and pathological conditions. The aim of this review is to explore how emotional states can shape movements by connecting the neural circuits for emotional processing to motor neural circuits. We first provide a comprehensive overview of the impact of different emotional states on motor control in humans and rodents. In line with behavioral studies, we set out to identify emotion-related structures capable of modulating motor output, behaviorally and anatomically. Neuronal circuits involved in emotional processing are extensively connected to the motor system. These circuits can drive emotional behavior, essential for survival, but can also continuously shape ongoing movement. In summary, the investigation of the intricate relationship between emotion and movement offers valuable insights into human behavior, including opportunities to enhance performance, and holds promise for improving mental and physical health. This review integrates findings from multiple scientific approaches, including anatomical tracing, circuit-based dissection, and behavioral studies, conducted in both animal and human subjects. By incorporating these different methodologies, we aim to present a comprehensive overview of the current understanding of the emotional modulation of movement in both physiological and pathological conditions.
Topics: Animals; Humans; Emotions; Brain; Movement; Neurons
PubMed: 37996047
DOI: 10.1016/j.neubiorev.2023.105475 -
Integrative and Comparative Biology Dec 2023Motility is an essential factor for an organism's survival and diversification. With the advent of novel single-cell technologies, analytical frameworks, and theoretical... (Review)
Review
Motility is an essential factor for an organism's survival and diversification. With the advent of novel single-cell technologies, analytical frameworks, and theoretical methods, we can begin to probe the complex lives of microscopic motile organisms and answer the intertwining biological and physical questions of how these diverse lifeforms navigate their surroundings. Herein, we summarize the main mechanisms of microscale motility and give an overview of different experimental, analytical, and mathematical methods used to study them across different scales encompassing the molecular-, individual-, to population-level. We identify transferable techniques, pressing challenges, and future directions in the field. This review can serve as a starting point for researchers who are interested in exploring and quantifying the movements of organisms in the microscale world.
Topics: Animals; Movement; Single-Cell Analysis; Models, Theoretical; Cell Movement; Bacteria
PubMed: 37336589
DOI: 10.1093/icb/icad075 -
Journal of the Mechanical Behavior of... Oct 2023The periodontium is a biological structure that supports the tooth in the jaw and behave as a developmental, biological, and functional unit. Teeth may be considered to...
The periodontium is a biological structure that supports the tooth in the jaw and behave as a developmental, biological, and functional unit. Teeth may be considered to be 'suspended' in their tooth sockets which provides teeth the ability to move in response to an applied load. In terms of the protection the suspension effect of the periodontal ligament may offer dental restorations, movement in an axial direction is of interest. No device or system to measure this movement is readily available, thus a novel approach had to be developed to address the questions of this research. The device developed allowed images to be taken of the participants teeth before, during and after a participant bit down on the tooth and used to measure the displacement of the tooth in image processing software. Average maximum tooth displacement from all participants of 73.8 μm (sd = 22.5 μm) were recorded. Longer application time of bite force was associated with greater cumulative tooth displacement, for a given level of force, and female participants experienced approximately 2 μm more displacement per Newton than males. The device and methods utilised in this study has shown good potential as a measurement protocol for measurement of vertical tooth movements in vivo. The response to load the teeth in this study has shown, highlighted the visco-elastic properties of the periodontal ligament and the amount of movement recorded supports the protection that controlled tooth movement offers teeth.
Topics: Male; Humans; Female; Periodontal Ligament; Bite Force; Image Processing, Computer-Assisted; Movement; Software
PubMed: 37604099
DOI: 10.1016/j.jmbbm.2023.106059 -
Scientific Reports Oct 2023When we perform an action, self-elicited movement induces suppression of somatosensory information to the cortex, requiring a correct motor-sensory and inter-sensory...
When we perform an action, self-elicited movement induces suppression of somatosensory information to the cortex, requiring a correct motor-sensory and inter-sensory (i.e. cutaneous senses, kinesthesia, and proprioception) integration processes to be successful. However, recent works show that blindness might impact some of these elements. The current study investigates the effect of movement on tactile perception and the role of vision in this process. We measured the velocity discrimination threshold in 18 sighted and 18 blind individuals by having them perceive a sequence of two movements and discriminate the faster one in passive and active touch conditions. Participants' Just Noticeable Difference (JND) was measured to quantify their precision. Results showed a generally worse performance during the active touch condition compared to the passive. In particular, this difference was significant in the blind group, regardless of the blindness duration, but not in the sighted one. These findings suggest that the absence of visual calibration impacts motor-sensory and inter-sensory integration required during movement, diminishing the reliability of tactile signals in blind individuals. Our work spotlights the need for intervention in this population and should be considered in the sensory substitution/reinforcement device design.
Topics: Humans; Touch; Reproducibility of Results; Blindness; Touch Perception; Movement
PubMed: 37783746
DOI: 10.1038/s41598-023-43526-8 -
Nature Neuroscience Jul 2023Cells in the precentral gyrus directly send signals to the periphery to generate movement and are principally organized as a topological map of the body. We find that...
Cells in the precentral gyrus directly send signals to the periphery to generate movement and are principally organized as a topological map of the body. We find that movement-induced electrophysiological responses from depth electrodes extend this map three-dimensionally throughout the gyrus. Unexpectedly, this organization is interrupted by a previously undescribed motor association area in the depths of the midlateral aspect of the central sulcus. This 'Rolandic motor association' (RMA) area is active during movements of different body parts from both sides of the body and may be important for coordinating complex behaviors.
Topics: Motor Cortex; Movement; Brain Mapping
PubMed: 37202552
DOI: 10.1038/s41593-023-01346-z