לוח שנה משולב

When faced with complex visual scene, observers inspect different parts of a scene sequentially, storing corresponding features in working memory for subsequent integration into a holistic perception. Yet models of perception rarely consider working memory explicitly. We probed processing hierarchy by comparing absolute judgements of single orientations and relative/ordinal judgements between two sequentially presented orientations. We found that lower-level, absolute judgements failed to account for higher-level, relative/ordinal judgements. However, when ordinal judgement was used to retrospectively decode memory representations of absolute orientations, striking aspects of absolute judgements, including their correlation and forward/backward aftereffects, were explained. We suggest that the brain prioritizes decoding of more useful, higher-level features, which are more invariant and categorical and thus easier to specify and maintain in noisy working memory, and that more-reliable higher-level decoding.

Today’s MRI receive coil arrays provide increased signal-to-noise-ratio (SNR) over standard single receivers. This excess SNR is often traded for either higher resolution or faster acquisitions. However, poor fit to patients can negate the array’s SNR gains. In fact, it is common, in clinical settings, to see coil elements offset from the anatomy to the point that the coils have poor fill-factor. This fit problem is exacerbated in pediatric imaging where patients come in different sizes.

In this work we present a new approach for designing and manufacturing MRI coils. We print coils using screen printing onto flexible plastic substrates. The resulting devices are extremely thin, light and flexible. In the first part of the presentation we will discuss the process and tradeoffs in using printing for making MRI coils as well as detailed analysis and characterization of the devices followed by demonstrating their use for pediatric MRI. In the second part, we will discuss a new application of these devices for minimally invasive interventional applications. Because our devices are extremely thin and made of plastic material and conductive inks, they are nearly transparent to ultrasound. This makes them ideal for use in MR Guided High Intensity Focused Ultrasound where the ultrasound transducers must have a clear acoustic path to the body, and therefore traditional coils are often displaced away from the body. We demonstrate feasibility for both head and body applications. This is a joint work with Prof. Ana Claudia Arias, Joseph Corea and Balthazar Lechene with collaborations with Stanford Radiology and GE Healthcare.

A combination of ideas originating from Condensed Matter physics, Supersymmetric Field Theory, and AdS/CFT has led to a detailed web of conjectured dualities. These relate the long distance behavior of different short distance theories. These dualities clarify a large number of confusing and controversial issues in Condensed Matter physics and in the study of 2+1 dimensional quantum field theory.

The mammalian gut microbiota is essential in shaping many of its host's functional attributes. Relationships between gut bacterial communities and their mammalian hosts have been shown in recent years to play an important role in the well-being and proper function of their hosts. A classic example of these relationships is found in the bovine digestive tract in a compartment termed the rumen. The rumen microbiota is necessary for the proper physiological development of the rumen and for the animal’s ability to digest and convert plant mass into basic food products, making it highly significant to humans and a perfect model system for the study of host-microbes interactions.
In my lecture I will discuss some of our recent findings regarding this ecosystem's development, interaction with the host and gene mobility via plasmids.

The hundreds of sex differences found in the brain beg the question as to how they develop and what is their function. Factors that cause sex differences in the brain are sex chromosomal gene expression, gonadal hormones, and environmental interactions. Parsimony dictates that these factors act directly on the brain. In fact, available literature on sexual differentiation of the mammalian brain by and large considers just two organs: the gonads and the brain. This perspective, which leaves out all other body parts, misleads us in several ways. First, there is accumulating evidence that all organs are sexually differentiated, and that sex differences in peripheral organs affect the brain. For example, there are sex differences in muscles, adipose tissue, the liver, immune system, gut, kidneys, bladder, and placenta that directly affect the nervous system and behavior. Sex differences may therefore develop in part because brains reside in fundamentally different bodies. This has consequences for brain function as well. Brains may generate different output autonomously, but if they are wired up to different bodies, similar output will have different consequences. To generate similar behaviors, the nervous system may have to compensate by giving different commands. This interaction between body and brain has to be taken into account for a full understanding of the development as well as function of sex differences in the brain. Considering the consequences of this interaction also provides possible explanations for the often remarkable sex differences in neurological and behavioral disorders. These principles will be demonstrated by discussing the development and function of sex differences in vasopressin signaling in brain and body.