Biology subjects

Peatfield, N.

Publications and source records attributed to Peatfield, N..

3 recordsLinked to original sources

bioRxiv2024

When Attention Hurts: The Effect Of rTMS On Neural Correlates Of Time Perception

The parietal lobe plays a crucial role in the attentional networks that help shape our perception, including our perception of time. Based on neuropsychological and neurophysiological evidence, a "when" pathway including the right parietal lobe has been proposed as the critical cortical site for the discrimination of objects across time. When an oddball stimulus is presented in a stream of identical standard stimuli, it is perceived as lasting longer, even when its actual duration is shorter. While attentional capture seems to play a major role in this subjective expansion of time the cortical mechanisms responsible for this effect remain unclear. We therefore set to investigate the direct role of parietal brain areas in time perception using combined repetitive transcranial magnetic stimulation (rTMS) and electroencephalogram (EEG). We measured the perceived duration of an oddball stimulus in each participant before and after inhibitory 1-Hz rTMS stimulation at one of three scalp locations: the right intraparietal sulcus (rIPS), the right inferior parietal lobe (rIPL), or the occipital cortex as a control. EEG was recorded throughout. Stimulation over the rIPL caused a more veridical experience of times subjective expansion towards the oddball, while rTMS over the rIPS and the occipital cortex had no effect. These data provide theoretically challenging notions to the concept of the cortexes role within time perception and the mechanisms involved.

neuroscience↗

bioRxiv2019

Atypical developmental features of cortical thickness trajectories in Autism Spectrum Disorder

Neuroimaging studies have reported numerous region-specific atypicalities in the brains of individuals with Autism Spectrum Disorder (ASD), including alterations in cortical thickness (CT). However, there are many inconsistent findings, and this is probably due to atypical CT developmental trajectories in ASD. To this end, we investigated group differences in terms of shapes of developmental trajectories of CT between ASD and typically developing (TD) populations.\n\nUsing the Autism Brain Imaging Data Exchange (ABIDE) repository (releases I and II combined), we investigated atypical shapes of developmental trajectories in ASD using a linear, quadratic and cubic models at various scales of spatial coarseness, and their association with symptomatology using the Autism Diagnostic Observation Schedule (ADOS) scores. These parameters were also used to predict ASD and TD CT development.\n\nWhile no overall group differences in CT was observed across the entire age range, ASD and TD populations were different in terms of age-related changes. Developmental trajectories of CT in ASD were mostly characterized by decreased cortical thinning during early adolescence and increased thinning at later stages, involving mostly frontal and parietal areas. Such changes were associated with ADOS scores. The curvature of the trajectories estimated from the quadratic model was the most accurate and sensitive measure for detecting ASD. Our findings suggest that under the context of longitudinal changes in brain morphology, robust detection of ASD would require three time points to estimate the curvature of age-related changes.

neuroscience↗

bioRxiv2017

Rubin-vase percept is predicted by prestimulus coupling of category-sensitive occipital regions with frontal cortex

Fluctuations in what an observer perceives can be demonstrated in images that give rise to competing percepts, examples include binocular rivalry, figure-ground illusions, and other phenomena. These stimuli are an important and well-studied stimulus set in studying human conscious perception.\n\nOne such stimulus is the Rubins vase illusion, a bistable stimulus that gives rise to the perception of a vase, or the profile of two faces (hereafter referred to as the facevase stimulus). Research using this stimulus has predominately focused on the neural response whilst viewing it (Andrews et al., 2002; Hasson et al., 2001; Kleinschmidt et al., 1998). An explanation for the phenomenological switch could exist in distinct features of the on-going brain activity, Hesselmann, Kell, Eger, & Kleinschmidt (2008) showed that fluctuating BOLD levels in Fusiform Face Area (FFA) prior to presentation of the face-va ...

neuroscience↗