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Distinguishing animate from inanimate objects is fundamental for social perception in humans and animals. Visual motion cues indicative of self-propelled object motion are useful for animacy perception: they can be detected over a wide expanse of visual field, at distance and in low visibility conditions, can attract attention and provide clues about object behaviour. However, the neural correlates of animacy perception evoked exclusively by visual motion cues, i.e. not relying on form, background or visual context, are unclear. We aimed to address this question in four psychophysical experiments in humans, two of which performed during neuroimaging. The stimulus was a single dot with constant form that moved on a blank background and evoked controlled degrees of perceived animacy through parametric variations of self-propelled motion cues. BOLD signals reflecting perceived animacy in a graded manner irrespective of eye movements were found in one intraparietal region. Additional whole-brain and region-of-interest analyses revealed no comparable effects in brain regions associated with social processing or other areas. Our study shows that animacy perception evoked solely by visual motion cues, a basic perceptual process in social cognition, engages brain regions not primarily associated with social cognition. • Self-propelled motion cues evoked graded percepts of animacy from motion only. • Occipital regions were sensitive to the amount of cues evoking animacy. • Only one cluster in right IPS was sensitive to percept changes. • IPS response may reflect accumulation of evidence about animacy. • No effects of perceived animacy were found in ventral or lateral temporal regions. [ABSTRACT FROM AUTHOR]

The vestibular system constitutes the silent sixth sense: It automatically triggers a variety of vital reflexes to maintain postural and visual stability. Beyond their role in reflexive behavior, vestibular afferents contribute to several perceptual and cognitive functions and also support voluntary control of movements by complementing the other senses to accomplish the movement goal. Investigations into the neural correlates of vestibular contribution to voluntary action in humans are challenging and have progressed far less than research on corresponding visual and proprioceptive involvement. Here, we demonstrate for the first time with event-related TMS that the posterior part of the right medial intraparietal sulcus processes vestibular signals during a goal-directed reaching task with the dominant right hand. This finding suggests a qualitative difference between the processing of vestibular vs. visual and proprioceptive signals for controlling voluntary movements, which are pre-dominantly processed in the left posterior parietal cortex. Furthermore, this study reveals a neural pathway for vestibular input that might be distinct from the processing for reflexive or cognitive functions, and opens a window into their investigation in humans. [ABSTRACT FROM AUTHOR]

Abstract: Our experience with a dynamic environment has tuned our visual system to use form and motion as complementary sources of information for object recognition. To identify the neural systems involved in integrating form and motion information during dynamic object processing, we used an fMRI adaptation paradigm which factorially manipulated form and motion repetition. Observers were sequentially presented with pairs of rotating novel objects in which the form or rotation direction in depth could be repeated. They were required to discriminate either dimension of the second target object, while the first object served as a form and/or motion prime. At the behavioural level, observers were faster to recognize the target or discriminate its direction when primed by the same form. Importantly, this form priming effect was enhanced when prime and target objects rotated in the same direction. At the neural level, the two priming effects (i.e., the main effect of form repetition and the interaction between form and motion repetition) were associated with reduced activations in distinct brain regions. Bilateral lateral occipital regions exhibited reduced activation when form was repeated irrespective of rotation direction. In contrast, bilateral anterior fusiform and posterior middle temporal regions (overlapping with hMT+/V5) regions showed an adaptation effect that depended on both form and motion direction. Thus, the current results reveal a visual processing hierarchy with lateral occipito-temporal cortex representing an object''s 3D structure, and anterior fusiform and posterior middle temporal regions being involved in spatio-temporal integration of form and motion during dynamic object processing. [Copyright &y& Elsevier]

Abstract: Seemingly effortless, we adjust our movements to continuously changing environments. After initiation of a goal-directed movement, the motor command is under constant control of sensory feedback loops. The main sensory signals contributing to movement control are vision and proprioception. Recent neuroimaging studies have focused mainly on identifying the parts of the posterior parietal cortex (PPC) that contribute to visually guided movements. We used event-related TMS and force perturbations of the reaching hand to test whether the same sub-regions of the left PPC contribute to the processing of proprioceptive-only and of multi-sensory information about hand position when reaching for a visual target. TMS over two distinct stimulation sites elicited differential effects: TMS applied over the posterior part of the medial intraparietal sulcus (mIPS) compromised reaching accuracy when proprioception was the only sensory information available for correcting the reaching error. When visual feedback of the hand was available, TMS over the anterior intraparietal sulcus (aIPS) prolonged reaching time. Our results show for the first time the causal involvement of the posterior mIPS in processing proprioceptive feedback for online reaching control, and demonstrate that distinct cortical areas process proprioceptive-only and multi-sensory information for fast feedback corrections. [Copyright &y& Elsevier]