About this Research Topic
Spatial orientation is a universal cognitive function, crucial for any species that locomotes in an environment, needs to find its way to a target or food, and is able to go back to its starting point. How do we know where we are and where we are going? A major goal of Neuroscience is to decipher how behaviorally relevant cognitive functions emerge from underlying neuronal circuits. Recent evidence suggests that the same brain structures are involved in spatial orientation coding in humans and other mammals. Multiple sensory input signals participate in the construction of a sense of orientation. Investigating spatial orientation in humans and animals allows to compare anatomical, physiological and behavioral data across species and dissect the underlying cellular and circuit elements.
From human studies, behavioral evidence suggests that the brain uses multiple sources of sensory information to encode spatial orientation and perform accurate goal-directed motor tasks during body movements. Representations of the environment and of the task can be ego-centered or exo-centered. Neural processing of multisensory information has been widely investigated through the study of cognitive and sensory-motor tasks. More recently the development of experimental setups using virtual environments and the coupling of cognitive and behavioral studies with brain imaging techniques are contributing to identify the neural structures involved in human spatial orientation as well as their specific roles.
From animal studies, we know that the sense of orientation depends on a network of spatially modulated cells in interconnected brain areas. Head direction cells function like a compass, discharging selectively when the animal faces a specific direction. Place cells form a spatial map and provide an internal representation of the external space, while grid cells provide metrics. The extraordinary neuronal code signaling direction and location in space relies on neuronal networks in many brain regions, including the brainstem, mammillary bodies, thalamus, retrosplenial cortex, and the entorhinal-hippocampal region. Sensory inputs, notably of vestibular and visual origin, are crucial for generating and updating these spatial signals. Despite formidable recent insight into head direction, place and grid cells, we are still far from understanding the cellular and circuit mechanisms responsible for spatially modulated neuronal firing in behaving animals.
This collection of articles will address the specific question of how the sense of orientation emerges from the integration of multisensory signals. How does the brain weight and compare vestibular, proprioceptive and visual information? How is multisensory information processed in anatomically defined circuits for head direction? What are the intrinsic and synaptic properties of neurons that enable orientation coding? How do macro-circuit properties emerge from micro-circuits composed of principal excitatory cells, and inhibitory interneurons, and finally contribute to behaviorally relevant function?
The aim of this Research Topic is to bring together experts studying spatial orientation coding and the underlying cellular and circuit elements. It is therefore open to submissions from neuroscientists at all levels of investigation, from in vivo physiology and imaging in humans and monkeys, to rodent models, in vitro anatomy, electrophysiology, electroanatomy, cellular imaging, molecular biology, disease models, computational modeling, and more.
Keywords: Multisensory processing, head direction, sensorimotor transformation, neuronal circuits, physiology
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