Biology subjects

McKendrick, A. M.

Publications and source records attributed to McKendrick, A. M..

3 recordsLinked to original sources

bioRxiv2025

Multimodal lesion mapping in affective blindsight reveals dual amygdala and superior temporal sulcus contributions to nonconscious emotion processing

Affective blindsight, the capacity to discriminate emotional stimuli despite bilateral damage to the primary visual cortex (V1) and without conscious awareness, offers a unique model of non-conscious visual processing. Subcortical pathways involving the pulvinar and amygdala have been proposed, but putative cortical contributions remain unclear. We examined 182 patients, including 31 with bilateral V1 lesions. Among these, 15 had cortical visual loss and 7 showed affective blindsight. Using behavioral testing, lesion symptom mapping, and tractography, we found that preserved pulvinar connectivity with both the posterior superior temporal sulcus (STS) and the amygdala is necessary for affective blindsight. These findings provide causal evidence for a multi-route architecture, identifying the pulvinar-STS pathway, alongside the pulvinar-amygdala pathway, as a critical substrate for non-conscious affective processing.

neuroscience↗

bioRxiv2021

The Open Perimetry Initiative: a framework for cross-platform development for the new generation of portable perimeters

The Open Perimetry Initiative is fully open source and consists of the Open Perimetry Interface (OPI) and an accompanying package (visualFields) with analytical tools. The OPI package contains an ever-growing number of drivers for commercially available perimeters, head-mounted devices, and virtual reality headsets. The visualFields package contains tools for the analysis and visualization of visual field data, including methods to compute deviation values and probability maps. The use of the OPI and visualFields is shown through a custom static automated perimetry test for the full visual field (up to 50{degrees} nasally and 80{degrees} temporally) developed with the OPI driver for the Octopus 900 and using visualFields for statistical analysis. Its potential for the development of cross-platform apps for driving and testing portable devices is demonstrated with an OPI driver for an Android-based headset. With more than 55 citations in clinical and translational science as listed in Scopus, this initiative has contributed significantly to expanding the knowledge base in perimetry and clinical vision research at large, and with clinical translation. The continued support of researchers, clinicians, industry, and public institutions are key in transforming perimetry research from closed to open science. The Open Perimetry Initiative provides framework to achieve this.

bioinformatics↗

bioRxiv2018

Relating excitatory and inhibitory neurochemicals to visual perception: a magnetic resonance study of occipital cortex between migraine events.

Certain perceptual measures have been proposed as indirect assays of brain neurochemical status in people with migraine. One such measure is binocular rivalry, however, previous studies have not measured rivalry characteristics and brain neurochemistry together in people with migraine. This study compared spectroscopy-measured levels of GABA and Glx (glutamine and glutamate complex) in visual cortex between 16 people with migraine and 16 non-headache controls, and assessed whether the concentration of these neurochemicals explains, at least partially, inter-individual variability in binocular rivalry perceptual measures. Mean Glx level was significantly reduced in migraineurs relative to controls, whereas mean occipital GABA levels were similar between groups. Neither GABA levels, nor Glx levels correlated with rivalry percept duration. Our results thus suggest that the previously suggested relationship between rivalry percept duration and GABAergic inhibitory neurotransmitter concentration in visual cortex is not strong enough to enable rivalry percept duration to be reliably assumed to be a surrogate for GABA concentration, at least in the context of healthy individuals and those that experience migraine.

neuroscience↗