לוח שנה משולב

Neuro-plasticity is one of the key processes in our brain's physiology. This process allows our brain to change itself, functionally and structurally, following the acquisition of a new skill or experience. While functional aspects of neuro-plasticity can be studied using non-invasive techniques such as fMRI, EEF and MEG, investigation of the structural tissue characteristics of neuro-plasticity requires invasive histological approaches.
Long-term experience necessitates structural plasticity which, in the adult brain, is characterized by changes in the shape and number of the synapses (synaptogenesis) as well as other process (neurogenesis, gliogenesis and white matter plasticity).
Structural MRI studies of brain plasticity reveal significant volumetric changes via voxel-based morphometry of T1 weighted scans. Yet, the micro-structure correlates of these changes are not well understood.
Diffusion tensor imaging (DTI) became one of the most popular imaging techniques in neuroimaging and is regarded as a micro-structural probe. Recently, tract-based spatial statistics (TBSS) analysis of DTI scans before and after long-term motor coordination training (juggling) revealed regional fractional anisotropy (FA) increase in parietal pathways. In that study, FA changes were reported following few weeks of training.

An open question is what happens at shorter term learning and memory processes?

In a short term spatial navigation study performed both in humans and rodents, we found that diffusion MRI can detect structural changes in cell morphology induced by plasticity within mere hours. Both in humans and rodents, the micro-structural changes, as observed by MRI, were localized to the anticipated brain regions: hippocampus, para-hippocampus, visual cortex, cingulate cortex and insular cortex.
Our results indicate that significant structural occur in the tissue within mere hours - an interesting result by itself from the neurophysiological point of view. However, by investigating the induced structural changes both by histology and MRI it is possible to elucidate the relations between tissue micro-structure and the diffusion MRI signal. Preliminary results of such comparison indicate that in gray matter tissue one of cellular correlates of diffusion MRI indices is the density and shape of astrocyte. Indeed more studies should be directed

The problem of consciousness is sometimes divided into two parts: An "easy" part, which involves explaining how one can become aware of of something in the sense of being able to make use of it in one's rational behavior. This is called access consciousness. And a "hard" part, which involves explaining why sensations feel like something, or have a kind of sensory presence, rather than having no feel at all. This is called phenomenal consciousness. Phenomenal consciousness is considered hard because there seems logically no way physical mechanisms in the brain could explain such facts. For example why does red look red, rather than looking green, or rather than sounding like a bell. Indeed why does red have a feel at all? Why do pains hurt instead of just provoking avoidance reactions?
The sensorimotor approach provides a way of answering these questions by appealing to the idea that feels like red and pain should not be considered as things that happen to us, but rather as modes of ineraction with the environment. I shall show how the idea can be applied to color, touch, pain, and sensory substitution. In addition to helping understand human consciousness, the approach has applications in virtual reality and in robotics.

Droplets impacting on surfaces are common in our everyday life from raindrops splashing on car windows to inkjets printing on paper. Surprisingly, however, many aspects of the dynamics of droplet impact are not well understood; even the initial impact of the drop remains controversial. Here I discuss a new experimental approach and directly measure the interface between the drop and the surface. I show that the drop initially skates along a very thin film of air before contacting the surface, consistent with recent predictions. Moreover, the dynamics of the drop impact are governed by the ultimate rupture of this thin film of air which itself exhibits a fascinating range of instabilities; these dynamics can be directly observed by refining these new experimental techniques. In this talk I describe these experiments and report the results

We have strong evidence that about 95% of matter in our Universe is dark,
revealing
its presence only by its gravitational attraction. In hierarchical
structure formation, two macro-structures exist in the Milky Way: the dark
halo, and the dark disk. If the dark matter in these structures is made of
Weakly Interacting Massive Particles (WIMPs), it can be directly detected
via elastic scattering from nuclei in ultra-low background, deep underground
detectors. WIMPs arise naturally in many beyond standard model theories, a
popular example being the neutralino, or the lightest supersymmetric
particle. After an introduction to the direct detection method, I will review
the current techniques to search for these hypothetical particles. The focus
will be on recent results, and on the most promising techniques for the near
future.