The use of visual information in intercepting moving objects

In this thesis. we investigated the use of visual information in intercepting moving objects. We have tried to determine which sources of visual information are used in guiding different aspects of the intercepting action. There are many interception tasks that each have their own kind of action and their own potentially useful visual infonnation. For example. in catching balls you may have to run. whereas that is generally not necessary in hitting running spiders. The fact that the object that you want to intercept 'gets bigger' as it approaches you might be a useful source of information in catching balls. In contrast. this information is less useful in hitting spiders that run across a walL as their movement direction is not mainly towards your eyes. We thus looked at different tasks. which implied different kinds of action and different kinds of valuable information. An important aspect that all interception tasks have in common. is that one has to anticipate the movement of the target during one's own planning and moving. It is not possible to successfully intercept a moving target by determining the target's position and subsequently moving there. because by the time you arrive at the determined position. the target has already moved to somewhere else. It is poorly understood how this problem is solved

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness