Question

A three dimensional map indicates

Answer 1

Explanation:

A topographic map shows a three-dimensional representation of a flat surface. It has contour lines joining points of equal elevation; the closer the lines are the steeper the elevation is. ... This is an example from a U.S. Geological Survey topographic map of Bisbee, Arizona. Gray areas indicate trees.

Answer 2

Answer:

Real-time mapping and manipulation of electrophysiology in three-dimensional (3D) tissues could impact broadly fundamental scientific and clinical studies, yet realization lacks effective methods. Here we introduce tissue-scaffold-mimicking 3D nanoelectronic arrays consisting of 64 addressable devices with subcellular dimensions and sub-millisecond time-resolution. Real-time extracellular action potential (AP) recordings reveal quantitative maps of AP propagation in 3D cardiac tissues, enable in situ tracing of the evolving topology of 3D conducting pathways in developing cardiac tissues, and probe the dynamics of AP conduction characteristics in a transient arrhythmia disease model and subsequent tissue self-adaptation. We further demonstrate simultaneous multi-site stimulation and mapping to manipulate actively the frequency and direction of AP propagation. These results establish new methodologies for 3D spatiotemporal tissue recording and control, and demonstrate the potential to impact regenerative medicine, pharmacology and electronic therapeutics.

Developments in cardiac tissue engineering over the past two decades1–5 have substantially advanced in vitro models for drug-screening6–8 and disease studies9, as well as in vivo implants to replace diseased or damaged tissues10, 11, for example, resulting from myocardial infarction11. However, effective methodologies for real-time 3D mapping and manipulation of electrical activity in studies of tissue development, drug modulation and implantation have thus far been missing. Optical imaging using exogenous or genetically-encoded voltage-sensitive dyes12–14 has allowed high spatial-resolution mapping of AP propagation but can be limited by a relatively slow time-resolution in 3D scanning13–15 and light scattering in tissues13, 15. On the other hand, multiplexed electrical recordings with planar microelectrodes8, 16 or field-effect transistor (FET)17, 18 arrays can map APs with a sub-millisecond temporal resolution, but have been limited to studies of 2D cultured cells17 or the surfaces of 3D tissue samples18.