No abstract

Under appropriate conditions, with good depth cues, the perception of the bar width or spatial frequency of a pattern of black and white stripes (a grating) shows excellent size constancy. Two gratings at different distances look similar in spatial frequency when the actual width, not the angular width, of their stripes is the same. Adaptation to a high-contrast grating causes a rise in the threshold contrast for detecting gratings of similar orientation and spatial frequency. This aftereffect transfers from one eye to the other, so it probably depends on binocular orientation-selective neurones in the visual cortex. With the adapting grating at three times the distance of the test grating the maximum elevation of threshold occurs for exactly the same angular spatial frequency as that of the adapting pattern. Therefore the neural mechanism for size-constancy scaling probably occurs after the visual cortex, perhaps in the inferotemporal cortex.

The US Air Force, Navy and Marine Corps use the direction orientation task (DOT) to assess spatial ability of potential pilots. However, recent research has shown limitations with the current implementation of the DOT, as well as an earlier candidate replacement the DOT 2. Specifically, there is evidence to suggest that the use of a math strategy and math ability may be related to performance on both tasks. The focus of the current paper is on the evaluation of a revised version of the DOT task (DOT 2.5) designed to encourage the use of spatial solutions by removing the numerical values from the task. We compared the performance of DOT 2.5 with previously validated measures of spatial ability, namely the paper folding and block rotation tasks. We also asked participants how often they employed different strategies on the task (e.g., a spatial strategy or mathematical one). Our results show the DOT 2.5 is significantly related to spatial ability as measured with block rotation. However, while participants were three times more likely to use a spatial strategy on the task, only the use of a math strategy was related to improved performance.

AimThe aim of this case study was to describe the cognitive profile of a gentleman who was assessed at an NHS Memory Service with a complex presentation of transient global amnesia, dementia worry and a preoccupation with his health.CaseA 63 year old intelligent gentleman was referred to the Memory Service following two episodes of transient global amnesia resulting in residual mild cognitive symptoms which resolved after six months. A clinical interview and neuropsychological assessment battery were conducted via video conferencing due to Covid-19 restrictions.ResultsThere was no clear pattern of objective cognitive impairments to indicate that Mr X was suffering from a neurodegenerative disease.ConclusionDiscussions were held regarding managing Mr X’s preoccupation with his health whilst following NICE guidelines of further investigating the potential causes for the episodes of transient global amnesia.ConsentMr X was provided with an information sheet detailing the purpose for his participation in this case study. He kindly provided informed written consent for the case study to be published within an academic journal. Some demographic details have been amended to protect his identity.