Triple-task performance reveals common codes for spatial information

2009 ◽  
Author(s):  
Paul Atchley ◽  
David Marshall
2014 ◽  
Vol 26 (6) ◽  
pp. 1292-1299 ◽  
Author(s):  
Kelsey L. Clark ◽  
Behrad Noudoost ◽  
Tirin Moore

We previously reported the existence of a persistent spatial signal in the FEF during object-based STM. This persistent activity reflected the location at which the sample appeared, irrespective of the location of upcoming targets. We hypothesized that such a spatial signal could be used to maintain or enhance object-selective memory activity elsewhere in cortex, analogous to the role of a spatial signal during attention. Here, we inactivated a portion of the FEF with GABAa agonist muscimol to test whether the observed activity contributes to object memory performance. We found that, although RTs were slowed for saccades into the inactivated portion of retinotopic space, performance for samples appearing in that region was unimpaired. This contrasts with the devastating effects of the same FEF inactivation on purely spatial working memory, as assessed with the memory-guided saccade task. Thus, in a task in which a significant fraction of FEF neurons displayed persistent, sample location-based activity, disrupting this activity had no impact on task performance.


2019 ◽  
Vol 43 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Martin Remmele ◽  
Andreas Martens

Sculpting representations of human organs out of modeling clay is an acknowledged method of teaching anatomical structures. Because of its potential to provide detailed spatial information, stereoscopic imagery can be understood to function as a suitable template for such sculpting tasks. Currently, it is unknown whether the advantages of stereoscopic images for modeling structures result from enhanced depth impression alone, or whether task performance is impacted by factors such as situational intrinsic motivation and perceived competence while sculpting a human organ using stereoscopic imagery as template. To clarify these queries, 35 eighth-grade students constructed a representation of the nasal cavity consisting of modeling clay. After the working phase, their situational intrinsic motivation and their perceived competence were assessed by a paper-and-pencil test and then analyzed, as was the elaboration of the sculpted representations. A control group with 38 students working with nonstereoscopic visualizations functioned as a counterpart. Stereoscopic imagery outperformed nonstereoscopic imagery concerning the accuracy in elaborating structures within the representations. However, there was no difference between situational intrinsic motivation and perceived competence in the context of using the digital template for forming the representations. Within the cohort working with nonstereoscopic imagery, situational intrinsic motivation was correlated with task performance. In contrast, within the cohort working with stereoscopic imagery, there was no relation concerning this. The findings show that depth impression due to stereoscopic imagery can be utilized to construct template-close representations, independently of situational feelings. This independence from situational sensitivities indicates that low situational intrinsic motivation will not condemn students to poor task performance.


Author(s):  
Stephen M. Hess ◽  
Mark C. Detweiler ◽  
R. Darin Ellis

Information-display issues are described in the context of a complex memory-updating task similar to Yntema's (1963). Subjects performed the updating task with two types of graphic interfaces. In one condition, the interface provided invariant spatial information which could be used to support task performance; in the second condition, the same information was presented in a single spatial location. The results suggest that 1) the mapping effect (one-to-many vs. many-to-one) found by Yntema did not occur when the response sets being updated were composed of the same response alternatives; 2) the type of screen layout used to support the updating task had a large impact on both accuracy and time to respond; and 3) the type of screen layout used interacted with the task's cognitive demands, including length of lag between an update and a response, and the number of variables being monitored. These results suggest that the design of information displays requires consideration of the abstract representational requirements of the task being supported.


2010 ◽  
Vol 3 (5) ◽  
Author(s):  
Mauro Cherubini ◽  
Marc-Antoine Nüssli ◽  
Pierre Dillenbourg

Little is known of the interplay between deixis and eye movements in remote collaboration. This paper presents quantitative results from an experiment where participant pairs had to collaborate at a distance using chat tools that differed in the way messages could be enriched with spatial information from the map in the shared workspace. We studied how the availability of what we defined as an Explicit Referencing mechanism (ER) affected the coordination of the eye movements of the participants. The manipulation of the availability of ER did not produce any significant difference on the gaze coupling. However, we found a primary relation between the pairs recurrence of eye movements and their task performance. Implications for design are discussed.


Author(s):  
T. A. Welton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.


Author(s):  
Vijay Krishnamurthi ◽  
Brent Bailey ◽  
Frederick Lanni

Excitation field synthesis (EFS) refers to the use of an interference optical system in a direct-imaging microscope to improve 3D resolution by axially-selective excitation of fluorescence within a specimen. The excitation field can be thought of as a weighting factor for the point-spread function (PSF) of the microscope, so that the optical transfer function (OTF) gets expanded by convolution with the Fourier transform of the field intensity. The simplest EFS system is the standing-wave fluorescence microscope, in which an axially-periodic excitation field is set up through the specimen by interference of a pair of collimated, coherent, s-polarized beams that enter the specimen from opposite sides at matching angles. In this case, spatial information about the object is recovered in the central OTF passband, plus two symmetric, axially-shifted sidebands. Gaps between these bands represent "lost" information about the 3D structure of the object. Because the sideband shift is equal to the spatial frequency of the standing-wave (SW) field, more complete recovery of information is possible by superposition of fields having different periods. When all of the fields have an antinode at a common plane (set to be coincident with the in-focus plane), the "synthesized" field is peaked in a narrow infocus zone.


Author(s):  
John R. Porter

New ceramic fibers, currently in various stages of commercial development, have been consolidated in intermetallic matrices such as γ-TiAl and FeAl. Fiber types include SiC, TiB2 and polycrystalline and single crystal Al2O3. This work required the development of techniques to characterize the thermochemical stability of these fibers in different matrices.SEM/EDS elemental mapping was used for this work. To obtain qualitative compositional/spatial information, the best realistically achievable counting statistics were required. We established that 128 × 128 maps, acquired with a 20 KeV accelerating voltage, 3 sec. live time per pixel (total mapping time, 18 h) and with beam current adjusted to give 30% dead time, provided adequate image quality at a magnification of 800X. The maps were acquired, with backgrounds subtracted, using a Noran TN 5500 EDS system. The images and maps were transferred to a Macintosh and converted into TIFF files using either TIFF Maker, or TNtolMAGE, a Microsoft QuickBASIC program developed at the Science Center. From TIFF files, images and maps were opened in either NIH Image or Adobe Photoshop for processing and analysis and printed from Microsoft Powerpoint on a Kodak XL7700 dye transfer image printer.


Author(s):  
RAD Mackenzie ◽  
G D W Smith ◽  
A. Cerezo ◽  
J A Liddle ◽  
CRM Grovenor ◽  
...  

The position sensitive atom probe (POSAP), described briefly elsewhere in these proceedings, permits both chemical and spatial information in three dimensions to be recorded from a small volume of material. This technique is particularly applicable to situations where there are fine scale variations in composition present in the material under investigation. We report the application of the POSAP to the characterisation of semiconductor multiple quantum wells and metallic multilayers.The application of devices prepared from quantum well materials depends on the ability to accurately control both the quantum well composition and the quality of the interfaces between the well and barrier layers. A series of metal organic chemical vapour deposition (MOCVD) grown GaInAs-InP quantum wells were examined after being prepared under three different growth conditions. These samples were observed using the POSAP in order to study both the composition of the wells and the interface morphology. The first set of wells examined were prepared in a conventional reactor to which a quartz wool baffle had been added to promote gas intermixing. The effect of this was to hold a volume of gas within the chamber between growth stages, leading to a structure where the wells had a composition of GalnAsP lattice matched to the InP barriers, and where the interfaces were very indistinct. A POSAP image showing a well in this sample is shown in figure 1. The second set of wells were grown in the same reactor but with the quartz wool baffle removed. This set of wells were much better defined, as can be seen in figure 2, and the wells were much closer to the intended composition, but still with measurable levels of phosphorus. The final set of wells examined were prepared in a reactor where the design had the effect of minimizing the recirculating volume of gas. In this case there was again further improvement in the well quality. It also appears that the left hand side of the well in figure 2 is more abrupt than the right hand side, indicating that the switchover at this interface from barrier to well growth is more abrupt than the switchover at the other interface.


2019 ◽  
Vol 62 (7) ◽  
pp. 2099-2117 ◽  
Author(s):  
Jason A. Whitfield ◽  
Zoe Kriegel ◽  
Adam M. Fullenkamp ◽  
Daryush D. Mehta

Purpose Prior investigations suggest that simultaneous performance of more than 1 motor-oriented task may exacerbate speech motor deficits in individuals with Parkinson disease (PD). The purpose of the current investigation was to examine the extent to which performing a low-demand manual task affected the connected speech in individuals with and without PD. Method Individuals with PD and neurologically healthy controls performed speech tasks (reading and extemporaneous speech tasks) and an oscillatory manual task (a counterclockwise circle-drawing task) in isolation (single-task condition) and concurrently (dual-task condition). Results Relative to speech task performance, no changes in speech acoustics were observed for either group when the low-demand motor task was performed with the concurrent reading tasks. Speakers with PD exhibited a significant decrease in pause duration between the single-task (speech only) and dual-task conditions for the extemporaneous speech task, whereas control participants did not exhibit changes in any speech production variable between the single- and dual-task conditions. Conclusions Overall, there were little to no changes in speech production when a low-demand oscillatory motor task was performed with concurrent reading. For the extemporaneous task, however, individuals with PD exhibited significant changes when the speech and manual tasks were performed concurrently, a pattern that was not observed for control speakers. Supplemental Material https://doi.org/10.23641/asha.8637008


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