Possibility of synthetic biological neural chips

If you look at a human, the amount of non nervous supporting tissue volume is vast, but this is not the case for all animals.  Some animals have vast nervous system volume with seemingly minimal supporting tissue volume.

"We discovered that the central nervous systems of the smallest spiders fill up almost 80 percent of their total body cavity, including about 25 percent of their legs."- sciencedaily news article

In theory such neural tissue could be hypothetically adapted to work in an artificial biochip, as it requires very little  volume of supporting tissue.   It would be an engineering challenge.  But one can imagine an interweaving of the minute support organ systems creating a large sheet of neural tissue. With some spacing and oxygenation and nutrient systems even volumetric systems are possible. 

 One of the problems observed in nature, including the human brain,  is that as neural communication length grows, natural systems change from analog neural transmission to digital action potential transmission which is less energy efficient, also long range transmission even with myelination is relatively slow.  But an artificial synthetic biology neural chip could make use of optimal optical interconnects that transmit at the speed of light between sections of the chip.

Insects depending on species can go for days without water or food, some can even withstand prolonged oxygen deprivation for tens of hours.   If metabolic suspension capabilities are brought into the equation the systems can hypothetically last for decades without food, water or oxygen.   So these are very resilient chips if designed appropriately.  Not fickle(On a side note: I'm not very fond of petri dishes, and growing things with special finicky settings, growth media, etc, I prefer full multicellular support structures that allow for biological cells to basically sit right there out on the open environment at room temperature and with minimal maintenance.)

Eventually a self contained gas exchange, and nutrient recycling with electric energy conversion(electrical to chemical to carry out recycling and power the molecular machinery) could make the entire computing system fully enclosed needing neither external water nor external food nor external oxygen.

Once the genetic regulation that regulates connectivity and learning is optimized such a system could be used for arbitrary applications.   In the unlikely event that it is true as some neuroscientists, seem to imply, that even a single biological neuron is basically supercomputer level maybe even as some hypothesize able to do quantum computations(very unlikely), well a biochip with billions of said neurons would vastly out compete any digital computer, if any of the implied performance hypotheses are true.   Even if the performance hypotheses aren't true, the energy efficiency durability and performance of such systems would be excellent.