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Full-Text Articles in Medicine and Health Sciences

The Influence Of Competing Perceptual And Motor Priors In The Context Of The Size-Weight Illusion, Gavin Buckingham, Melvyn Goodale Jul 2010

The Influence Of Competing Perceptual And Motor Priors In The Context Of The Size-Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

When lifting objects of identical mass but different sizes, people perceive the smaller objects as weighing more than the larger ones (the 'size-weight' illusion, SWI). While individual's grip and load force rates are rapidly scaled to the objects' actual mass, the magnitude of the force used to lift these SWI-inducing objects is rarely discussed. Here, we show that participants continue to apply a greater loading force to a large SWI-inducing cube than to a small SWI cube, lift after lift. These differences in load force persisted long after initial errors in grip and load force rates had been corrected. Interestingly, …


Multiple Mechanisms Of Consciousness: The Neural Correlates Of Emotional Awareness., Jayna M Amting, Steven G Greening, Derek G V Mitchell Jul 2010

Multiple Mechanisms Of Consciousness: The Neural Correlates Of Emotional Awareness., Jayna M Amting, Steven G Greening, Derek G V Mitchell

Brain and Mind Institute Researchers' Publications

Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally, …


Gating Of Vibrotactile Detection During Visually Guided Bimanual Reaches, Gavin Buckingham, David Carey, Francisco Colino, John Degrosbois, Gordon Binsted Feb 2010

Gating Of Vibrotactile Detection During Visually Guided Bimanual Reaches, Gavin Buckingham, David Carey, Francisco Colino, John Degrosbois, Gordon Binsted

Gavin Buckingham

It is far more difficult to detect a small tactile stimulation on a finger that is moving compared to when it is static. This suppression of tactile information during motion, known as tactile gating, has been examined in some detail during single-joint movements. However, the existence and time course of this gating has yet to be examined during visually guided multi-joint reaches, where sensory feedback may be paramount. The current study demonstrated that neurologically intact humans are unable to detect a small vibratory stimulus on one of their index fingers during a bimanual reach toward visual targets. By parametrically altering …


Living In A Material World: How Visual Cues To Material Properties Affect The Way That We Lift Objects And Perceive Their Weight, Gavin Buckingham, Jonathan Cant, Melvyn Goodale Nov 2009

Living In A Material World: How Visual Cues To Material Properties Affect The Way That We Lift Objects And Perceive Their Weight, Gavin Buckingham, Jonathan Cant, Melvyn Goodale

Gavin Buckingham

The visual properties of an object provide many cues as to the tensile strength, compliance, and density of the material from which it is made. However, it is not well understood how these implicit associations affect our perceptions of these properties and how they determine the initial forces that are applied when an object is picked up. Here we examine the effects of these cues on such forces by using the classic "material-weight illusion" (MWI). Grip and load forces were measured in three experiments as participants lifted cubes made from metal, wood, and expanded polystyrene. These cubes were adjusted to …


Adapting To Dynamic Stimulus-Response Values: Differential Contributions Of Inferior Frontal, Dorsomedial, And Dorsolateral Regions Of Prefrontal Cortex To Decision Making., Derek G V Mitchell, Qian Luo, Shelley B Avny, Tomasz Kasprzycki, Karanvir Gupta, Gang Chen, Elizabeth C Finger, R James R Blair Sep 2009

Adapting To Dynamic Stimulus-Response Values: Differential Contributions Of Inferior Frontal, Dorsomedial, And Dorsolateral Regions Of Prefrontal Cortex To Decision Making., Derek G V Mitchell, Qian Luo, Shelley B Avny, Tomasz Kasprzycki, Karanvir Gupta, Gang Chen, Elizabeth C Finger, R James R Blair

Brain and Mind Institute Researchers' Publications

Dorsomedial prefrontal cortex (dmPFC), dorsolateral prefrontal cortex (dlPFC), and inferior frontal gyrus (IFG) have all been implicated in resolving decision conflict whether this conflict is generated by having to select between responses of similar value or by making selections following a reversal in reinforcement contingencies. However, work distinguishing their individual functional contributions remains preliminary. We used functional magnetic resonance imaging to delineate the functional role of these systems with regard to both forms of decision conflict. Within dmPFC and dlPFC, blood oxygen level-dependent responses increased in response to decision conflict regardless of whether the conflict occurred in the context of …


Perirhinal Cortex Contributes To Accuracy In Recognition Memory And Perceptual Discriminations., Edward B O'Neil, Anthony D Cate, Stefan Köhler Jul 2009

Perirhinal Cortex Contributes To Accuracy In Recognition Memory And Perceptual Discriminations., Edward B O'Neil, Anthony D Cate, Stefan Köhler

Brain and Mind Institute Researchers' Publications

The prevailing view of the medial temporal lobe (MTL) holds that its structures are dedicated to long-term declarative memory. Recent evidence challenges this position, suggesting that perirhinal cortex (PRc) in the MTL may also play a role in perceptual discriminations of stimuli with substantial visual feature overlap. Relevant neuropsychological findings in humans have been inconclusive, likely because studies have relied on patients with large and variable MTL lesions. Here, we conducted a functional magnetic resonance imaging study in healthy individuals to determine whether PRc shows a performance-related involvement in perceptual oddball judgments that is comparable to its established role in …


Rightward Biases During Bimanual Reaching, Gavin Buckingham, David Carey Mar 2009

Rightward Biases During Bimanual Reaching, Gavin Buckingham, David Carey

Gavin Buckingham

Two experiments were carried out to investigate whether attention is biased toward the right hand of right handers during bimanual coordination (Peters 1981). A novel discontinuous double-step reaching task was developed, where right-handed participants executed a bimanual reach followed by a left or right hand unimanual reach. Asymmetries in the downtime between the bimanual and unimanual reach portions (the refractory period) were used to infer the direction of attention. A shorter right hand refractory period was found in the first experiment, indicating a rightward bias in attention. In a second experiment, shifting the focus of attention during the bimanual portion …