The modelling organismCaenorhabditis elegansdoesn’t have anything we would regard as a brain . In fact , the nematode nematode has just 302 neurons with which to work information , so efficiency is essential . Using just two of these , C. eleganshas evolved a method of tracking the odour of nutrient to its source that is remarkably effective , not just in genius major power but in clock time and energy . The freshly revealed account of how this is done could have software for miniature robots with modified processing capacity .
Our eyes can deceive us , but not nearly as often as our noses . To use smell to find food , animal follow a gradient of scent chemical concentrations in their environment . commit the potential for confusing factors , however , they will often start off on a path that direct them past their goal , rather than take them directly to it .
Single - celled organisms’solution to this problemis what mathematicians call the biased - random walk strategy . They will punctuate a journey by change state arbitrarily to see if the scent is unassailable in a particular direction , adjust the rate of work base on the chemical absorption .
Dr Alon Zaslaverof the Hebrew University of Jerusalem and his postgraduate educatee notice inNature Communicationsthat multicellular creature have devise more advanced methods . True to its name , they foundC. elegans’solution is in particular refined .
C. elegansisknown tosquirm in the direction of a probable nutrient source before either “ pirouetting ” or making gradual curvature correction to its motion . However , before Zaslaver ’s work no one understood how the dirt ball knew when to change course .
Zaslaver evidence that one ofC. elegans ' precious neurons senses the amount of food scent , driving the worm towards its goal . However , when its direction is imperfect , a second neuron , which Zaslaver likened to the recalculating function on a navigation app , hire over .
The second nerve cell react not to the strength of the smell , but to the extent at which it is changing . In mathematical terms , it valuate the order of magnitude of derivatives , or the precipitousness of slope of a graph of smell intensity . If the first derivative is damaging , the odour is weaken , indicating a probable ill-timed direction . The more confirming the first derivative , the more likely it is this is the direction the insect should go .
When the squad run simulations compare the two strategies , the louse ’s approach always beat the biased - random walk strategy . Zaslaver found that without either nerve cell , the worm could still find food but they take less direct routes .
Useful as the discovery could be for design ego - lead machines , one might ask why , with our 100 billion neurons , man are too stubborn to change course when we are clearly on the wrong path .
[ H / T : Haaretz ]
