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Published in Philip Winn, Dictionary of Biological Psychology, 2003
Masking refers to the occlusion of one STIMULUS by another: it is a term usually qualified by a sensory domain—auditory masking or visual masking for instance. Backward masking is said to occur when the mask appears after the target stimulus; forward masking occurs when the mask is presented before. Brightness masking involves presentation of a bright light which makes perception of the target difficult; pattern masking involves presentation of a complex pattern (in whatever sensory modality). Metacontrast masking involves the brief presentation of a target followed by a mask which occupies the space around where the target was (it follows the target's contours). Paracontrast masking is the same as metacontrast masking except that the mask is presented before the target.
Neural Correlates of Visual Attention and Short-Term Memory in Children with Reading Difficulty
Published in Developmental Neuropsychology, 2023
Alexis F. Koffman, Erica Flaten, Amy S. Desroches, Richard S. Kruk
We examined ERP modulations in attention alerting, SVA, and VSTM to examine how reading-ability and developmental differences are manifested in ERP patterns using an object substitution masking (OSM) task. OSM is useful to investigate visual attention and visual memory, as the three ERP components described above have been documented in adults over the time course of OSM task trials, particularly for correct trials (Forest, Kruk, & Desroches, 2021; Prime et al., 2011; Salahub & Emrich, 2018). Visual masking in OSM occurs when a non-overlapping visual mask is presented simultaneously with a stimulus array in close spatial proximity to a target. Perception of the target is impaired when the mask offset is delayed after stimulus offset (Woodman & Luck, 2003). The mechanism for this effect involves modification and updating of the features of the target object representation in working memory by features of the delayed mask (Salahub & Emrich, 2018). Our OSM task, derived from Prime et al (2011), included two potential target locations: one in the left and one in the right visual field. This initial ambiguity about target location increases demands on attention alerting and was expected to reduce N1 negativity in children with reading difficulty compared to typical readers. An SVA pattern consistent with diffuse attention was expected in attenuated N2pc amplitudes. Finally, reduced SPCN amplitudes in children with reading difficulty with delayed mask offset would indicate lower capacity to store lingering delayed-mask representations in VSTM.
Error Feedback Frequency Affects Automaticity But Not Accuracy and Consistency After Extensive Motor Skill Practice
Published in Journal of Motor Behavior, 2018
Daniel Krause, Manfred Agethen, Christina Zobe
The apparatus was an underarm lever device, which allows movement in the horizontal plane. A visual masking occluded online movement control (Figure 1). The lever arm was adjustable in length to adapt to individual underarm lengths. A potentiometer was attached to the vertical axis functioning as a goniometer. The measurement chain consisted of a Novotech 6500 P6501 (Novotechnik, Ostfildern, Germany) linear potentiometer (resolution: 0.007% Linearity: ± 0.05%, manipulating speed: 10,000 rpm), an Advantech USB 4716 (Advantech Co., Ltd., Germany) analog-to-digital converter (16 bit, 1000 Hz), a Voltkraft PS 1152A (Conrad Electronic AG, Emmenbrücke, Switzerland) regulated power supply at 4.00 V with galvanic separation and a computer with Dasylab 10.0 (National Instruments, Austin, TX) plus Java-based software for data collection (movement time, movement reversals). Further experimental setup components were a monitor (17”; 4:3) installed above the lever device for the secondary task and feedback presentation; an adjustable chair for replicable positioning of the participants in vertical, horizontal, and sagittal planes; and a keyboard on the left side of the lever as the input device for the secondary task response.
Posterior cortical atrophy: clinical, neuroimaging, and neuropathological features
Published in Expert Review of Neurotherapeutics, 2023
John Best, Marianne Chapleau, Gil D. Rabinovici
Alexia slowly progresses over a few years [2,28]. Reading difficulties include difficulty scanning from line to line, difficulty tracking text across the page, or a sensation that the words move around the page. They may also describe trouble with visual crowding, a type of visual masking where an object or word is more difficult to perceive when surrounded by adjacent object, letters, or patterns [29]. Another common complaint is seeing individual letters but reported difficulty seeing whole word form. This crowding phenomenon can extend beyond reading to other visual scanning tasks.