This title is part of UC Press's Voices Revived program, which commemorates University of California Press's mission to seek out and cultivate the brightest minds and give them voice, reach, and ...impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1970.
Recent research has identified individual differences in interoceptive sensitivity as a key source of variation in action, cognition, and emotion. This research has relied heavily on a single method ...for assessing interoceptive sensitivity: the accuracy of counting heartbeats while at rest. The validity of this method was assessed here by comparing the heartbeat counting (HBC) performance of 48 individuals with their heartbeat detection (HBD) performance. The HBC task required participants to report the numbers of heartbeats counted during brief signaled periods and indexed cardioceptive accuracy by the difference between the numbers of reported and actual heartbeats. In the HBD task, participants indicated the temporal location of heartbeat sensations relative to the onset of ventricular contraction. On each trial, they judged whether heartbeat sensations were or were not simultaneous with brief tones presented at one of six fixed delays following R waves of the ECG. In this method, cardioceptive accuracy or precision was indexed by variability in the temporal locations, relative to the R wave, of tones judged to be simultaneous with heartbeat sensations. Although intratask correlations indicated that each method yielded reliable scores, intertask correlations showed that HBC scores were unrelated to HBD scores. These results, which indicate that heartbeat detection and heartbeat counting are distinct processes, raise important questions about the assessment of interoceptive sensitivity and the involvement of this attribute in the psychological processes that have been associated with it on the basis of their correlations with HBC performance.
The purpose of this study was to investigate the functional effects of peripheral refractive errors on mobility performance through a stair negotiation task.PurposeThe purpose of this study was to ...investigate the functional effects of peripheral refractive errors on mobility performance through a stair negotiation task.Twenty-one young, normal sighted subjects navigated through an obstacle with steps, wearing spectacles that altered only their peripheral refraction. Lenses were used to induce positive defocus (+2 diopters D and +4 D), negative defocus (-2 D and -4 D), or astigmatism (+1.75 D and -3.75 D, axis 45 degrees) in the periphery. Feet trajectories were analyzed, and several gait assessment parameters were obtained. Statistical tests were conducted to determine significant performance differences between the lenses. Peripheral refraction in each subject was measured using a scanning Hartmann-Shack wavefront sensor to assess the impact of intrinsic peripheral refraction on the experiment.MethodsTwenty-one young, normal sighted subjects navigated through an obstacle with steps, wearing spectacles that altered only their peripheral refraction. Lenses were used to induce positive defocus (+2 diopters D and +4 D), negative defocus (-2 D and -4 D), or astigmatism (+1.75 D and -3.75 D, axis 45 degrees) in the periphery. Feet trajectories were analyzed, and several gait assessment parameters were obtained. Statistical tests were conducted to determine significant performance differences between the lenses. Peripheral refraction in each subject was measured using a scanning Hartmann-Shack wavefront sensor to assess the impact of intrinsic peripheral refraction on the experiment.Statistically significant differences in performance appeared when peripheral errors were superimposed. Crossing time with respect to plano lenses increased by 6.2%, 7.6%, 19.2%, and 29.6% for the -2 D, +2 D, -4 D, and +4 D lenses, respectively (P < 0.05 in the last 3 cases). Subjects exhibited slower walking speeds, increased step count, and adopted precautionary measures. High-power positive defocus lenses had the biggest impact on performance, and differences were observed in distance to steps between induced positive and negative defocus.ResultsStatistically significant differences in performance appeared when peripheral errors were superimposed. Crossing time with respect to plano lenses increased by 6.2%, 7.6%, 19.2%, and 29.6% for the -2 D, +2 D, -4 D, and +4 D lenses, respectively (P < 0.05 in the last 3 cases). Subjects exhibited slower walking speeds, increased step count, and adopted precautionary measures. High-power positive defocus lenses had the biggest impact on performance, and differences were observed in distance to steps between induced positive and negative defocus.In this laboratory-based study without an adaptation period, peripheral refractive errors affected stair negotiation, causing cautious behavior in subjects. Performance differences among types of peripheral defocus may result from magnification effects and intrinsic peripheral refraction. These results highlight the importance of understanding the effects of induced peripheral errors by myopia control and intraocular lenses.ConclusionsIn this laboratory-based study without an adaptation period, peripheral refractive errors affected stair negotiation, causing cautious behavior in subjects. Performance differences among types of peripheral defocus may result from magnification effects and intrinsic peripheral refraction. These results highlight the importance of understanding the effects of induced peripheral errors by myopia control and intraocular lenses.
The vast majority of studies into visual processing are conducted using computer display technology. The current paper describes a new free suite of software tools designed to make this task easier, ...using the latest advances in hardware and software. PsychoPy is a platform-independent experimental control system written in the Python interpreted language using entirely free libraries. PsychoPy scripts are designed to be extremely easy to read and write, while retaining complete power for the user to customize the stimuli and environment.
Tools are provided within the package to allow everything from stimulus presentation and response collection (from a wide range of devices) to simple data analysis such as psychometric function fitting. Most importantly, PsychoPy is highly extensible and the whole system can evolve via user contributions. If a user wants to add support for a particular stimulus, analysis or hardware device they can look at the code for existing examples, modify them and submit the modifications back into the package so that the whole community benefits.
First principles of perimetry Redmond, Tony
Acta ophthalmologica (Oxford, England),
December 2022, 2022-12-00, 20221201, Volume:
100, Issue:
S275
Journal Article
Peer reviewed
Clinical visual field tests are adaptations of classic psychophysical approaches to measuring the minimum value of a stimulus that can be seen (threshold or sensitivity). Although the classic ...approaches can be highly accurate and precise, they are also lengthy and unsuitable for clinical practice. Therefore, the design of a clinical visual field test must strike a balance between accuracy, precision, speed, and ease of understanding. Such a compromise brings both advantages and pitfalls. In this course, we will discuss the psychophysical underpinnings of conventional visual field tests and their standard parameters, why they were chosen, and how they might influence interpretation of clinical findings.
The study of perceptual decision-making offers insight into how the brain uses complex, sometimes ambiguous information to guide actions. Understanding the underlying processes and their neural bases ...requires that one pair recordings and manipulations of neural activity with rigorous psychophysics. Though this research has been traditionally performed in primates, it seems increasingly promising to pursue it at least partly in mice and rats. However, rigorous psychophysical methods are not yet as developed for these rodents as they are for primates. Here we give a brief overview of the sensory capabilities of rodents and of their cortical areas devoted to sensation and decision. We then review methods of psychophysics, focusing on the technical issues that arise in their implementation in rodents. These methods represent a rich set of challenges and opportunities.
It is difficult to collect objective evidence of interoception. Unlike exteroception, the effective stimuli for interoception are often unknown, and even when identifiable, they are difficult to ...control experimentally. Furthermore, direct stimulation of the interoceptors is seldom appropriate in human experimentation. Hence, non-invasive behavioural measures of accuracy in heartbeat detection have frequently been adopted to index interoceptive sensitivity. However, there has been little standardization and the two most popular methods for assessing heartbeat detection, heartbeat tracking and two alternative forced choice methods, appear to be biased and of questionable validity. These issues do not arise with other methods that are based on classical psychophysics and that enable subjects to indicate when during the cardiac cycle their heartbeat sensations occur. Not only are these classical methods highly reliable, but they also provide continuous unbiased measures of the temporal locations of heartbeat sensations and the precision with which these sensations are detected.
This article is part of the themed issue ‘Interoception beyond homeostasis: affect, cognition and mental health’.
•Free software for behavioral control and data acquisition on the latest 64-bit MATLAB.•New scripting framework to handle dynamic visual stimuli and complex behavior.•Real-time behavior monitoring ...with improved temporal resolution, using only one data acquisition device.•Support for more input devices and more stimulus types to control a wide range of experiments.
Computerized control of behavioral paradigms is an essential element of neurobehavioral studies, especially physiological recording studies that require sub-millisecond precision. Few software solutions provide a simple, flexible environment to create and run these applications. MonkeyLogic, a MATLAB-based package, was developed to meet these needs, but faces a performance crisis and obsolescence due to changes in MATLAB itself.
Here we report a complete redesign and rewrite of MonkeyLogic, now NIMH MonkeyLogic, that natively supports the latest 64-bit MATLAB on the Windows platform. Major layers of the underlying real-time hardware control were removed and replaced by custom toolboxes: NIMH DAQ Toolbox and MonkeyLogic Graphics Library. The redesign resolves undesirable delays in data transfers and limitations in graphics capabilities.
NIMH MonkeyLogic is essentially a new product. It provides a powerful new scripting framework, has dramatic speed enhancements and provides major new graphics abilities.
NIMH MonkeyLogic is fully backward compatible with earlier task scripts, but with better temporal precision. It provides more input device options, superior graphics and a new real-time closed-loop programming model. Because NIMH MonkeyLogic requires no commercial toolbox and has a reduced hardware requirement, implementation costs are substantially reduced.
NIMH MonkeyLogic is a versatile, powerful, up-to-date tool for controlling a wide range of experiments. It is freely available from https://monkeylogic.nimh.nih.gov/.
PDF
