Papers by Francis McGlone
Experimental Brain Research, 2000
Inhibition of return' (IOR) refers to the delayed detection often found for targets at the same l... more Inhibition of return' (IOR) refers to the delayed detection often found for targets at the same location as a preceding event. We examined whether IOR reflects a truly supramodal phenomenon, in an experiment designed to avoid criticisms of previous crossmodal research. We presented a random sequence of visual, tactile, and auditory targets to either the left or right of central fixation, and tested for IOR between targets in all three modalities when presented successively to the same versus different side. Speeded detection for targets in all three modalities was indeed slower if the preceding target had been presented from the same position, regardless of the modality of this preceding target. These results demonstrate for the first time that IOR is truly supramodal.
Experimental Dermatology, 2015
The skin senses serve a discriminative function, allowing us to manipulate objects and detect tou... more The skin senses serve a discriminative function, allowing us to manipulate objects and detect touch and temperature, and an affective/emotional function, manifested as itch or pain when the skin is damaged. Two different classes of nerve fibre mediate these dissociable aspects of cutaneous somatosensation; i) myelinated A-beta and A-delta afferents that provide rapid information about the location and physical characteristics of skin contact, and ii) unmyelinated, slow conducting Cfibre afferents that are typically associated with coding the emotional properties of pain and itch. However, recent research has identified a third class of C-fibre afferents that code for the pleasurable properties of touch-c-tactile afferents or CTs. Clinical application of treatments that target pleasant, CT mediated-touch (such as massage therapy) could, in the future, provide a complementary, non-pharmacological means of treating both the physical and psychological aspects of chronic skin conditions such as itch and eczema.
Perception & Psychophysics, 2003
There has been a rapid growth of interest in issues related to crossmodal selective attention and... more There has been a rapid growth of interest in issues related to crossmodal selective attention and multisensory integration in the last few years (see
Journal of neurophysiology, Jan 12, 2015
It is not known how changes in skin mechanics affect the responses of cutaneous mechanoreceptors ... more It is not known how changes in skin mechanics affect the responses of cutaneous mechanoreceptors in the finger pads to compression forces. We used venous occlusion to change the stiffness of the fingers and investigated whether this influenced the firing of low-threshold mechanoreceptors to surfaces of differing stiffness. Unitary recordings were made from 10 SAI, 10 FAI and 9 SAII units via tungsten microelectrodes inserted into the median nerve at the wrist. A servo-controlled stimulator applied ramp-and-hold forces (1, 2, 4 N) at a constant loading and unloading rate (2 N/s) via a flat 2.5 cm-diameter silicone disc over the centre of the finger pad. Nine silicone discs (objects), varying in compliance, were used. Venous occlusion, produced by inflating a sphygmomanometer cuff around the upper arm to 40 ± 5 mmHg, was used to induce swelling of the fingers and increase the compliance of the finger pulp. Venous occlusion had no effect on the firing rates of the SAI afferents, nor on...
Neuroimage, Mar 31, 2000
Three studies were carried out to assess the applicability of fMRI at 3.0 T to analysis of vibrot... more Three studies were carried out to assess the applicability of fMRI at 3.0 T to analysis of vibrotaction in humans. A novel piezoelectric device provided clean sinusoidal stimulation at 80 Hz, which was initially applied in separate runs within a scanning session to digits 2 and 5 of the left hand in eight subjects, using a birdcage RF (volume) coil.
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques, 2018
Frontiers in Psychology, 2013
Tactile perception is inhibited during movement execution, a phenomenon known as tactile suppress... more Tactile perception is inhibited during movement execution, a phenomenon known as tactile suppression. Here, we investigated whether the type of movement determines whether or not this form of sensory suppression occurs. Participants performed simple reaching or exploratory movements. Tactile discrimination thresholds were calculated for vibratory stimuli delivered to participants' wrists while executing the movement, and while at rest (a tactile discrimination task, TD). We also measured discrimination performance in a same vs. different task for the explored materials during the execution of the different movements (a surface discrimination task, SD). The TD and SD tasks could either be performed singly or together, both under active movement and passive conditions. Consistent with previous results, tactile thresholds measured at rest were significantly lower than those measured during both active movement and passive touch (that is, tactile suppression was observed). Moreover, SD performance was significantly better under conditions of single-tasking, active movements, as well as exploratory movements, as compared to conditions of dual-tasking, passive movements, and reaching movements, respectively. Therefore, the present results demonstrate that when active hand movements are made with the purpose of gaining information about the surface properties of different materials an enhanced perceptual performance is observed. As such, it would appear that tactile suppression occurs for irrelevant tactual features during both reaching and exploratory movements, but not for those task-relevant features that result from action execution during tactile exploration. Taken together, then, these results support a context-dependent modulation of tactile suppression during movement execution.
Attention, Perception, & Psychophysics, 2011
No comprehensive language exists that describes the experience of touch. Three experiments were c... more No comprehensive language exists that describes the experience of touch. Three experiments were conducted to take steps toward establishing a touch lexicon. In Experiment I, 49 participants rated how well 262 adjectives described sensory, emotional and evaluative aspects of touch. In Experiment II, participants rated pairwise dissimilarities of the most descriptive words of the set. Multidimensional scaling (MDS) solutions representing semanticperceptual spaces underlying the words resulted in a touch perception task (TPT) consisting of 26 'sensory' attributes (e.g., bumpiness) and 14 'emotional' attributes (e.g., pleasurable). In Experiment III, 40 participants used the TPT to rate unseen textured materials that were moved actively or received passively against the index fingerpad, volar forearm, and two underarm sites. MDS confirmed similar semantic-perceptual structures in Experiments II and III. Factor analysis of Experiment III data decomposed the sensory attribute ratings into factors labeled Roughness, Slip, Pile and Firmness, and the emotional attribute ratings into Comfort and Arousal factors. Factor scores varied among materials and sites. Greater intensity of sensory and emotional responses were reported when participants passively, as opposed to actively, received stimuli. The sensitivity of the TPT in identifying body site and mode of touch-related perceptual differences affirms the validity and utility of this novel linguistic/perceptual tool.
Recent advances in the development of neuroimaging techniques capable of combining, in real-time,... more Recent advances in the development of neuroimaging techniques capable of combining, in real-time, electroencephalographic (EEG) and functional MRI (fMRI) data, enable the localization of areas of increased blood flow associated with specific EEG events, and will find applications in both clinical neurological and basic neuroscience areas (Zijlmans et al., 2007; Ritter P. & Villringer A., 2006)). The traditional approach to removing the two main sources of induced noise: a) scanner induced eg radio frequency (RF) and switching ...
NeuroImage, 2001
The technique of intraneural microneurography/ microstimulation has been used extensively to stud... more The technique of intraneural microneurography/ microstimulation has been used extensively to study contributions of single, physiologically characterized mechanoreceptive afferents (MRAs) to properties of somatosensory experience in awake human subjects. Its power as a tool for sensory neurophysiology can be greatly enhanced, however, by combining it with functional neuroimaging techniques that permit simultaneous measurement of the associated CNS responses. Here we report its successful adaptation to the environment of a high-field MR scanner. Eight median-nerve MRAs were isolated and characterized in three subjects and microstimulated in conjunction with fMRI at 3.0 T. Hemodynamic responses were observed in every case, and these responses were robust, focal, and physiologically orderly. The combination of fMRI with microstimulation will enable more detailed studies of the representation of the body surface in human somatosensory cortex and further studies of the relationship of that organization to short-term plasticity in the human SI cortical response to natural tactile stimuli. It can also be used to study many additional topics in sensory neurophysiology, such as CNS responses to additional classes of afferents and the effects of stimulus patterning and unimodal/crossmodal attentional manipulations. Finally, it presents unique opportunities to investigate the basic physiology of the BOLD effect and to compare the operating characteristics of fMRI and EEG as human functional neuroimaging modalities in an unusually specific and well-characterized neurophysiological setting.
Experimental Brain Research, 2000
'Inhibition of return' (IOR) refers to the delayed detection often found for targets at the same ... more 'Inhibition of return' (IOR) refers to the delayed detection often found for targets at the same location as a preceding event. We examined whether IOR reflects a truly supramodal phenomenon, in an experiment designed to avoid criticisms of previous crossmodal research. We presented a random sequence of visual, tactile, and auditory targets to either the left or right of central fixation, and tested for IOR between targets in all three modalities when presented successively to the same versus different side. Speeded detection for targets in all three modalities was indeed slower if the preceding target had been presented from the same position, regardless of the modality of this preceding target. These results demonstrate for the first time that IOR is truly supramodal.
Journal of The Acoustical Society of America, 2009
Using a 100-element tactile stimulator on the fingertip during functional-magnetic-resonance imag... more Using a 100-element tactile stimulator on the fingertip during functional-magnetic-resonance imaging, brain areas were identified that were selectively activated by a moving vibrotactile stimulus (the sensation of a moving line being dragged over the fingertip). Activation patterns elicited by tactile motion, contrasted to an equivalent stationary stimulus, were compared in six human subjects with those generated by a moving visual stimulus, contrasted to an equivalent stationary stimulus. Results provide further evidence for a neuroanatomical convergence of tactile-motion processing and visual-motion processing in humans. The sites of this convergence are found to lie in the middle temporal complex (hMT+V5), an area with known specialization for visual-motion processing, and in the intraparietal area of the posterior parietal cortex. In an advance on previous studies, the present study includes separate delineation of activations for moving tactile stimuli and activations for moving visual stimuli. Results suggest that the two sets of activations are not entirely collocated. Compared to the visual-motion activations, the tactile-motion activations are found to lie nearer the midline of the brain and further superior.
Abstract Although sensory problems, including unusual tactile sensitivity, are heavily associated... more Abstract Although sensory problems, including unusual tactile sensitivity, are heavily associated with autism, there is a dearth of rigorous psychophysical research. We compared tactile sensation in adults with autism to controls on the palm and forearm, the latter innervated by low-threshold unmyelinated afferents subserving a social/affiliative submodality of somatosensation.
ABSTRACT CT (C tactile) afferents are a distinct type of unmyelinated, low-threshold mechanorecep... more ABSTRACT CT (C tactile) afferents are a distinct type of unmyelinated, low-threshold mechanoreceptive units existing in the hairy but not glabrous skin of humans and other mammals. Evidence from patients lacking myelinated tactile afferents indicates that signaling in these fibers activate the insular cortex.
Facial expressions of emotion elicit increased activity in the human amygdala. Such increases are... more Facial expressions of emotion elicit increased activity in the human amygdala. Such increases are particularly evident for expressions that convey potential threat to the observer, and arise even when the face is masked from awareness. We used functional magnetic resonance imaging (fMRI) to examine whether the amygdala responds differentially to threatening (fearful) versus nonthreatening (happy) facial expressions depending on whether the face is attended or actively ignored.
Summary There is growing evidence for cognitive impairments in Parkinson's disease (PD), includin... more Summary There is growing evidence for cognitive impairments in Parkinson's disease (PD), including in the orienting of attention and inhibition of return (IOR). IOR refers to the slowing of a response to a target stimulus presented in the same location as a previous stimulus. While some researchers have reported normal levels of visual IOR in PD patients using cue‐target tasks, others have reported significant reductions in IOR in this patient group.
Abstract We show that the affective experience of touch and the sight of touch can be modulated b... more Abstract We show that the affective experience of touch and the sight of touch can be modulated by cognition, and investigate in an fMRI study where top-down cognitive modulations of bottom-up somatosensory and visual processing of touch and its affective value occur in the human brain. The cognitive modulation was produced by word labels,'Rich moisturizing cream'or 'Basic cream', while cream was being applied to the forearm, or was seen being applied to a forearm.
Abstract The neural mechanisms underlying variability in human sensory perception remain incomple... more Abstract The neural mechanisms underlying variability in human sensory perception remain incompletely understood. In particular, few studies have attempted to investigate the relationship between in vivo measurements of neurochemistry and individuals' behavioral performance. Our previous work found a relationship between GABA concentration in the visual cortex and orientation discrimination thresholds (Edden et al., 2009).
The technique of intraneural microneurography/microstimulation has been used extensively to study... more The technique of intraneural microneurography/microstimulation has been used extensively to study contributions of single, physiologically characterized mechanoreceptive afferents (MRAs) to properties of somatosensory experience in awake human subjects. Its power as a tool for sensory neurophysiology can be greatly enhanced, however, by combining it with functional neuroimaging techniques that permit simultaneous measurement of the associated CNS responses.
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Papers by Francis McGlone