I am generalizing "thinking" to be just the process of "adding meaningful changes to an input before delivering the output."

I am reading a lot of information about "receptors" (inputs) and about "chemotaxis" (outputs) but not a lot about what happens in between. I do see a lot of research results of the "in between" part immediately at one side or the other (ie, details of how the receptors work or details about the mechanisms that a cell uses to move), but I don’t see much joining the inputs to the outputs, especially for higher organisms like white blood cells.

The best I have found are comments like "In more advanced systems, such as the active movement of a eukaryotic cell towards a particular chemical agent, this response certainly must be a result of a series of complex biological steps." (http://www.ncbi.nlm.nih.gov/pmc/article … 66/?page=6)

It seems to me that life often finds one way or another to manage itself in its environment – via receptors, information-processing and then responses and that evolution has developed these same functions in more than one way. Complex multi-cellular organisms do it via a nervous system whereas single cells have an entirely unique method that we have yet to fully identify.

My main objective in asking this question is to simply find out if there is a missing link there that we are still trying to find an answer for. I would like to know if this mystery still exists (which includes the mystery of how a cell knows whether it is to become a toe nail cell or a liver cell).

Thank you, Kolean.

You have provided exactly what I was looking for. "Signalling" led me to "Systems Biology" and ideas about emerging properties, etc, which was exactly what I was after. I have now verified a theory on this related to evolution and can proceed with my paper.

Thanks!

Len

Hi Mith,

Thanks for the link to http://www.pnas.org/content/97/9/4649.full.

I had a good look at this document and putting in terms of your analogy, this document only focuses on the thermostat itself, not the furnace. The ‘feedback’ they are discussing is within the thermostat itself to make it more sensitive to ‘changing’ temperature. So the analogy doesn’t really apply either because thermostats only care about the static temperature.

A better analogy would be if we needed to know if the temperature was rising steadily (pretend that could mean some sort of danger). The "feedback" that the refer to allows the thermometer to "detect that the temperature has risen" – then reset itself so that the current temperature is "now the norm and forget that it had previously risen" so that it is ready to again detect a further increase. The ‘feedback’ refers to the part where the thermostat adapts/desensitizes (ie, in psych referred to has habituation) to the existing ‘change’ so that it is ready to detect another change.

So, we still do not have much on the topic of what connects this thermometer to the furnace. My analogy of this is when using a ‘beacon’ to search for a lost person in the snow where the beacon can only tell you if you’re (sort of) getting closer. My brain still connects the readings of the receptor (beacon/eyes) to my legs.