Re: Communication between cells...

Howard, this is an interesting situation...

I read the two paragraphs here, and I see "time" all over them:

HP:

In other words, the information capacity of electrical signals is small. It is entirely temporal (i.e., one dimensional) while binding sites in molecules can carry large amounts of information in one shape and they are not so crucially dependent on timing.

Roughly speaking, electrical signals are important for rate-dependent coordination movements of muscles (sensorimotor controls) and for decoding temporal inputs in the brain (e.g. speech and music). Chemical signals work better for metabolic and reproductive coordination that are not so dependent on rates. Of course, at the molecular level, the electrical forces always coexist right along with all the other forces.

I don't know why you refer to temporal aspects as "one dimensional", though. Could you elaborate on that?

In any case, there are aspects of this which fascinate me. Like; just because the "information capacity" of electrical signals is small, why would that be any reflection on how important this aspect is in the overall organization? What if there's far more information being transmitted than what we define as information? Or perhaps the role of electrical communication is more along the lines of "a synergist"? Something doesn't need to be big to be potent.

Another aspect I find intriguing is you said "electrical signals are important for rate-dependent coordinations" and for activity regarding time in the brain... Molecular/chemical activity is dependent on sequencing, isn't it? Rate, sequence, duration... all of these are time-related aspects. So these two modes are both dealing with different aspects of time.

Electrical charge is one of the known aspects of atomic organization/behavior as well (is it an ingredient or an effect?)... Hmmmmm.......

Plus, I still would keep looking for other communication modes besides these two in intracellular/intercellular communications that are also in use and interacting with the ones we know about. The combined interaction of all modes is going to have different effects than any single mode in-and-of itself.

Judith

----- Original Message -----

From: Howard Pattee

To: ***

Sent: Thursday, January 20, 2005 6:05 PM

Subject: Re: [ROSEN] Communication between cells...

At 01:31 PM 1/20/05 -0500, Judith asks:

Why do they assume that there are only chemical signals? Medical science has demonstrated, for instance, that there are also electrical signals (which is how heart cells are able to beat in unison with each other). So if there are two modes of communication between cells, there's a good possibility that there are more.

Yes, as you say there there are electrical signals like action potentials that travel along axons in the muscles and brain. However, electrical signals are not nearly as specific as chemical shapes, so they are almost always mediated by complex molecular structures. In other words, the information capacity of electrical signals is small. It is entirely temporal (i.e., one dimensional) while binding sites in molecules can carry large amounts of information in one shape and they are not so crucially dependent on timing.

Roughly speaking, electrical signals are important for rate-dependent coordination movements of muscles (sensorimotor controls) and for decoding temporal inputs in the brain (e.g. speech and music). Chemical signals work better for metabolic and reproductive coordination that are not so dependent on rates. Of course, at the molecular level, the electrical forces always coexist right along with all the other forces.

It is not considered likely that more forces will be found except possibly at the fundamental particle level, and they would not apply at the energies required by life as we know it. But one should never say never.

Howard