A Case Report of Perceptual Disturbances with Incidental Calcifications in the Cerebellum

Background. The cerebellum has extensive connections with motor and nonmotor areas of the nervous system. These nonmotor areas include the cognitive, affective, and perceptual areas of the central nervous system. Extensive literature has emerged cognitive documents and mood disorders in patients with cerebellar dysfunction. Perceptual disturbances consistent with cerebellar connections with perceptual areas have not been as widely documented. Case Presentation. We present the case of a 58-year-old female presenting with new onset isolated auditory hallucinations and incidental findings of cerebellar calcifications. Conclusion. In light of this case, we discuss an expanding body of evidence that suggests the likely role of the cerebellum in perceptual functioning.

Pathways of Perceptual Primacy: ERP Evidence for Relationships Between Autism Traits and Enhanced Perceptual Functioning

Autistic individuals show enhanced perceptual functioning on many behavioral tasks. Neurophysiological evidence also supports the conclusion that autistic individuals utilize perceptual processes to a greater extent than neurotypical comparisons to support problem solving and reasoning; however, how atypicalities in early perceptual processing influence subsequent cognitive processes remains to be elucidated. The goals of the present study were to test the relationship between early perceptual and subsequent cognitive event related potentials (ERPs) and their relationship to levels of autism traits. 62 neurotypical adults completed the Autism Spectrum Quotient (AQ) and participated in an ERP task. Path models were compared to test causal relationships among an early perceptual ERP (the P1 component), a subsequent cognitive ERP (the N400 effect), and the Attention to Detail subscale of the AQ. The size of participants’ P1 components was positively correlated with the size of their N400 effect and their Attention to Detail score. Model comparisons supported the model specifying that variation in Attention to Detail scores predicted meaningful differences in participants’ ERP waveforms. The relationship between Attention to Detail scores and the size of the N400 effect was significantly mediated by the size of the P1 effect. This study revealed that neurotypical adults with higher levels of Attention to Detail show larger P1 differences, which, in turn, correspond to larger N400 effects. Findings support the Enhanced Perceptual Functioning model of autism, suggesting that early perceptual processing differences may cascade forward and result in modifications to later cognitive mechanisms.

Brain Dynamics Altered by Photic Stimulation in Patients with Alzheimer’s Disease and Mild Cognitive Impairment

Individuals with mild cognitive impairment (MCI) are at high risk of developing Alzheimer’s disease (AD). Repetitive photic stimulation (PS) is commonly used in routine electroencephalogram (EEG) examinations for rapid assessment of perceptual functioning. This study aimed to evaluate neural oscillatory responses and nonlinear brain dynamics under the effects of PS in patients with mild AD, moderate AD, severe AD, and MCI, as well as healthy elderly controls (HC). EEG power ratios during PS were estimated as an index of oscillatory responses. Multiscale sample entropy (MSE) was estimated as an index of brain dynamics before, during, and after PS. During PS, EEG harmonic responses were lower and MSE values were higher in the AD subgroups than in HC and MCI groups. PS-induced changes in EEG complexity were less pronounced in the AD subgroups than in HC and MCI groups. Brain dynamics revealed a “transitional change” between MCI and Mild AD. Our findings suggest a deficiency in brain adaptability in AD patients, which hinders their ability to adapt to repetitive perceptual stimulation. This study highlights the importance of combining spectral and nonlinear dynamical analysis when seeking to unravel perceptual functioning and brain adaptability in the various stages of neurodegenerative diseases.

Processes

Crossmodal perceptual illusions such as ventriloquism, the McGurk effect, the rubber hand, and the sound-induced flash demonstrate that one sense can causally impact perceptual processing and experience that is associated with another sense. This chapter argues that such causal interactions between senses are not merely accidental. Interactions between senses are part of typical perceptual functioning. Unlike synesthesia, they reveal principled perceptual strategies for dealing with noisy, fallible sensory stimulation from multiple sources. Recalibrations resolve conflicts between senses and weight in deference to the more reliable modality. Coordination between senses thus improves the coherence and the reliability of human perceptual capacities. Therefore, some perceptual processes of the sort relevant to empirical psychology are multisensory.