A5007386321- Visual perception and processing mechanisms
- Neural dynamics and brain function
- Functional Brain Connectivity Studies
- Cognitive and developmental aspects of mathematical skills
- Advanced MRI Techniques and Applications
- Mathematics Education and Teaching Techniques
- Aesthetic Perception and Analysis
- Glaucoma and retinal disorders
- Statistical Methods in Clinical Trials
- Pain Mechanisms and Treatments
- Sleep and Wakefulness Research
- Mental Health Research Topics
- Advanced Neuroimaging Techniques and Applications
- Color Science and Applications
- Neuroscience and Music Perception
- Visual Attention and Saliency Detection
- Retinal Development and Disorders
- Vestibular and auditory disorders
Spinoza Centre for Neuroimaging
2018-2025
Royal Netherlands Academy of Arts and Sciences
2025
Netherlands Institute for Neuroscience
2025
Utrecht University
2018-2022
University College London
2015-2018
National Hospital for Neurology and Neurosurgery
2015-2016
University College Lahore
2015-2016
Abstract Perception is subjective. Even basic judgments, like those of visual object size, vary substantially between observers and also across the field within same observer. The way in which system determines size objects remains unclear, however. We hypothesize that inferred from neuronal population activity V1 predict idiosyncrasies cortical functional architecture should therefore explain individual differences judgments. Here we show results novel behavioural methods magnetic resonance...
Population receptive field (pRF) analysis is a popular method to infer spatial selectivity of voxels in visual cortex. However, it remains largely untested how stable pRF estimates are over time. Here we measured the intersession reliability parameter for central and near periphery, using combined wedge ring stimulus containing natural images. Sixteen healthy human participants completed two scanning sessions separated by 10–114 days. Individual showed very similar maps V1-V4 on both...
Visual spatial attention concentrates neural resources at the attended location. Recently, we demonstrated that voluntary attracts population receptive fields (pRFs) toward its location throughout visual hierarchy. Theoretically, both a feed forward or feedback mechanism could underlie pRF attraction in given cortical area. Here, use sub-millimeter ultra-high field functional MRI to measure across depth and assess contribution of signals attraction. In line with previous findings, find...
Abstract Numerosity, the set size of a group items, helps guide behaviour and decisions. Non-symbolic numerosities are represented by approximate number system. However, distinct behavioural performance suggests that small numerosities, i.e. subitizing range, implemented differently in brain than larger numerosities. Prior work has shown neural populations selectively responding (i.e. hemodynamic responses) to organized into network topographical maps. Here, we investigate how respond large...
Abstract The contrast sensitivity function (CSF) characterizes visual function, and is widely used in research on perception ophthalmological disorders. CSF describes the lowest level that participants can perceive as a of spatial frequency. Here, we present new method to estimate neural equivalent how population neurons responds Using functional magnetic resonance imaging (fMRI) at 7 Tesla, measured responses while viewed gratings varied systematically We modeled (nCSF) using an asymmetric...
Abstract A fundamental assumption of nearly all functional magnetic resonance imaging (fMRI) analyses is that the relationship between local neuronal activity and blood oxygenation level dependent (BOLD) signal can be described as following linear systems theory. With advent ultra-high field (7T higher) MRI scanners, it has become possible to perform sub-millimeter resolution fMRI in humans. novel promising application measuring responses across cortical depth, i.e. laminar imaging. However,...
Painful burning sensations can be elicited by a spatially-alternating pattern of warm and cold stimuli applied on the skin, so called "Thermal Grill Illusion" (TGI). Here we investigated whether TGI percept originates spinally or centrally. Since inhibition nociceptive input concomitant non-nociceptive somatosensory has strong spinal component, reasoned that, if afferent underlying at level, then should inhibited input. Conversely, is result supraspinal processing, no effect touch would...
Abstract Perception is subjective. Even basic judgments, like those of visual object size, vary substantially between observers and also across the field within same observer. The way in which system determines size objects remains unclear, however. We hypothesize that inferred from neuronal population activity V1 predict idiosyncrasies cortical functional architecture should therefore explain individual differences judgments. Indeed, using novel behavioral methods magnetic resonance imaging...
Abstract Advancements in ultra-high field (7 T and higher) magnetic resonance imaging (MRI) scanners have made it possible to investigate both the structure function of human brain at a sub-millimeter scale. As neuronal feedforward feedback information arrives different layers, functional MRI has potential uncover processing between cortical micro-circuits across depth, i.e. laminar fMRI. For nearly all conventional fMRI analyses, main assumption is that relationship local activity blood...
Numerosity is the set size of a group items. perception trait shared across numerous species. Numerosity-selective neural populations are thought to underlie numerosity perception. These neurons have been identified primarily using electrical recordings in animal models and blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) humans. Here we use intracranial investigate tuning humans, focusing on high-frequency transient activations. combine high spatial temporal...