Interlacing roles of bottom-up, top-down, endogenous, and anthropogenic factors in population oscillations

Top-down and bottom-up modulation of pain-induced oscillations

Attention is an important factor that is able to strongly modulate the experience of pain. In order to differentiate cortical mechanisms underlying subject-driven (i.e., top-down) and stimulus-driven (bottom-up) modes of attentional pain modulation, we recorded electric brain activity in healthy volunteers during painful laser stimulation while spatial attention and stimulus intensity were syst...

Bottom-up, top-down

Event-Related Potentials of Bottom-Up and Top-Down Processing of Emotional Faces

Introduction: Emotional stimulus is processed automatically in a bottom-up way or can be processed voluntarily in a top-down way. Imaging studies have indicated that bottom-up and top-down processing are mediated through different neural systems. However, temporal differentiation of top-down versus bottom-up processing of facial emotional expressions has remained to be clarified. The present st...

Bottom-Up Beats Top-Down

In PEPA, the calculation of the transitions enabled by a process accounts for a large part of the time for the state space exploration of the underlying Markov chain. Unlike other approaches based on recursion, we present a new technique that is iterative—it traverses the process’ binary tree from the sequential components at the leaves up to the root. Empirical results shows that this algorith...

Population Regulation in Insect Herbivores - Top-down or Bottom-up?

Recent evidence points to the plant's being a much more limited resource than previously expected. In addition to the restraints on feeding and population growth imposed by such factors as leaf toughness, the physical environment, plant nutrition, etc., recent work points to the role of feeding-induced chemical changes in the leaves in reducing herbivore 'fitness'. This suggests that population...