Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception.

The cerebellum has an important role in the control and coordination of movement. It is now clear, however, that the cerebellum is also involved in neural processes underlying a wide variety of perceptual and cognitive functions, including the regulation of emotional responses. Contemporary neurobiological models of emotion assert that a small set of discrete emotions are mediated through distinct cortical and subcortical areas. Given the connectional specificity of neural pathways that link the cerebellum with these areas, we hypothesized that distinct sub-regions of the cerebellum might subserve the processing of different primary emotions. We used functional magnetic resonance imaging (fMRI) to identify neural activity patterns within the cerebellum in 30 healthy human volunteers as they categorized images that elicited each of the five primary emotions: happiness, anger, disgust, fear and sadness. In support of our hypothesis, all five emotions evoked spatially distinct patterns of activity in the posterior lobe of the cerebellum. We also detected overlaps between cerebellar activations for particular emotion categories, implying the existence of shared neural networks. By providing a detailed map of the functional topography of emotion processing in the cerebellum, our study provides important clues to the diverse effects of cerebellar pathology on human affective function.

(1) to determine if the acoustical parameters used by normal subjects to discriminate between different speakers vary when comparisons are made between pairs of two of the same or different vowels, and if they are different for male and female voices; (2) to ask whether individual voices can reasonably be represented as points in a low-dimensional perceptual space such that similarly sounding voices are located close to one another. Subjects were presented with pairs of voices from 16 male and 16 female speakers uttering the three French vowels "a", "i" and "u" and asked to give speaker similarity judgments. Multidimensional analyses of the similarity matrices were performed separately for male and female voices and for three types of comparisons: same vowels, different vowels and overall average. The resulting dimensions were then interpreted a posteriori in terms of relevant acoustical measures. For both male and female voices, a two-dimensional perceptual space was found to be most appropriate, with axes largely corresponding to contributions of the larynx (pitch) and supra-laryngeal vocal tract (formants), mirroring the two largely independent components of source and filter in voice production. These perceptual spaces of male and female voices and their corresponding voice samples are available at: http://vnl.psy.gla.ac.uk section Resources.

The ability to encode and update representations of heading direction is crucial for successful navigation. In rats, head-direction cells located within the limbic system alter their firing rate in accordance with the animal's current heading. To date, however, the neural structures that underlie an allocentric or viewpoint-independent sense of direction in humans remain unknown. Here we used functional magnetic resonance imaging (fMRI) to measure neural adaptation to distinctive landmarks associated with one of four heading directions in a virtual environment. Our experiment consisted of two phases: a "learning phase," in which participants actively navigated the virtual maze; and a "test phase," in which participants viewed pairs of images from the maze while undergoing fMRI. We found that activity within the medial parietal cortex-specifically, Brodmann area 31-was modulated by learned heading, suggesting that this region contains neural populations involved in the encoding and retrieval of allocentric heading information in humans. These results are consistent with clinical case reports of patients with acquired lesions of medial posterior brain regions, who exhibit deficits in forming and recalling links between landmarks and directional information. Our findings also help to explain why navigation disturbances are commonly observed in patients with Alzheimer's disease, whose pathology typically includes the cortical region we have identified as being crucial for maintaining representations of heading direction.

Landmarks play an important role in guiding navigational behavior. A host of studies in the last 15 years has demonstrated that environmental objects can act as landmarks for navigation in different ways. In this review, we propose a parsimonious four-part taxonomy for conceptualizing object location information during navigation. We begin by outlining object properties that appear to be important for a landmark to attain salience. We then systematically examine the different functions of objects as navigational landmarks based on previous behavioral and neuroanatomical findings in rodents and humans. Evidence is presented showing that single environmental objects can function as navigational beacons, or act as associative or orientation cues. In addition, we argue that extended surfaces or boundaries can act as landmarks by providing a frame of reference for encoding spatial information. The present review provides a concise taxonomy of the use of visual objects as landmarks in navigation and should serve as a useful reference for future research into landmark-based spatial navigation.

Real-life moving objects are often detected by multisensory cues. We investigated the cortical activity associated with coherent visual motion perception in the presence of a stationary or moving auditory noise source using functional magnetic resonance imaging. Twelve subjects judged episodes of 5-s random-dot motion containing either no (0%) or abundant (16%) coherent direction information. Auditory noise was presented with the displayed visual motion that was moving in phase, was moving out-of-phase, or was stationary. Subjects judged whether visual coherent motion was present, and if so, whether the auditory noise source was moving in phase, was moving out-of-phase, or was not moving. Performance was greatest for a moving sound source that was in phase with the visual coherent dot motion compared with when it was in antiphase. A random-effects analysis revealed that auditory motion activated extended regions in both cerebral hemispheres in the superior temporal gyrus (STG), with a right-hemispheric preponderance. Combined audiovisual motion led to activation clusters in the STG, the supramarginal gyrus, the superior parietal lobule, and the cerebellum. The size of the activated regions was substantially larger than that evoked by either visual or auditory motion alone. The congruent audiovisual motion evoked the most extensive activation pattern, exhibiting several exclusively activated subregions.

No abstract

Frank SM, Baumann O, Mattingley JB, Greenlee MW. Vestibular and visual responses in human posterior insular cortex.