Neurological Question

Brown said:
1. Decreasing the longitudinal axonal resistance. As the axoplasm resistance is constant this improvement can only be achieved by increasing the diameter of the axon (in the way that a length of copper of large diameter is of lower resistance than one of small diameter). If you like equations, this means that conduction velocity is proportional to the square root of axonal diameter. Selection pressure for high conduction velocities has resulted in the appearance of giant axons.

Brown,

Thanks a lot! Actually, that does help quite a bit. My physiology class has moved past neurons and action potentials, but my instructor has encouraged me to gather more information on ceph neurology (he's a bat person). He thought that they (giant cephs) might solve the issue of conduction velocity by means of larger overall axonal radii.

Now to figure out why they are immune to serin! :)

Sushi and Sake,

Fujisawa... AKA John of the Great Pacific Northwest

P.S. Welcome to TONMO!
 
em youve explained the system perfectly acording to this gargantuin book ive got on my lap about marine biology and anatomy..but do they sense the world around them more like us or fish is what im still not clear on


:goldfish: :read: :|
 
mcatee123 said:
em but do they sense the world around them more like us or fish is what im still not clear on

mcatee,

Heh heh, you've hit the nail right on its proverbial noggin! A lot of my questions on this and other boards deal with how cephs look at the world around them. My guess (not yet being a marine biologist anyway) is that we have a lot of work to do and a lot of research to accomplish before we can truly answer these questions.

Maybe you should get into marine biology! :D I would love to work with a fellow TONMO'er someday in research!

John
 
em youve explained the system perfectly acording to this gargantuin book ive got on my lap about marine biology and anatomy..but do they sense the world around them more like us or fish is what im still not clear on


Good question.. ... there is no clear answer to this one as yet. The reason is that although they have acute visual and tactile senses (as good a ours), we have no idea how this is represented in the brain. So for example, in your CNS there is a representitive physical map of your sensory fields. This helps you to 'know' where you arm is positioned is space with your eyes shut. This does not seem to be the case for Octopus. For example from the recent the work of Hochner+ co on arm control it seems that the arm is 'cast ' (like a fly fisherman) towards an object and there seems to be no cns control other than a go signal. More work required though before a firm conclusion can be reached...
 
mcAtee,

Say, you mentioned the you have a large book on marine biology and anatomy... Could I have the title and author please? I would really appreciate it.

Brown,

I have a textbook Biopsychology: 5th Edition by Pinel, and Dr. Pinel makes reference to the type of CNS sensory mapping done by the brain. What I find interesting is the idea that an invertebrate has come up with similar adaptations due to convergent evolution of sorts.

I wonder if Hochner is right? Even then, there seems to be an overall reduction in number of arms over the evolutionary history of the cephalopoda. This has been addressed here, but if such a reduction has occured in the Class, maybe its due to the increasing complexity of the arms as sensory systems. It's "evolutionary streamlining", if you will, but I would think it would be less neurologically taxing to only control eight to ten appendages rather than a much larger number.

Do you know of any other spatial orientation or sensory tests done on cephs?

Thanks for your earlier information, btw

John
 
amazing really amazing but do they have the ability to copy? Beacuse on the discovery channel they say that only humans and great apes learn from copying or something along those lines . eh sorry to ask are you just very bright or are you in the medical/marine biology feild id love to know :madsci:
 
mcatee123 said:
amazing really amazing but do they have the ability to copy? Beacuse on the discovery channel they say that only humans and great apes learn from copying or something along those lines . eh sorry to ask are you just very bright or are you in the medical/marine biology feild id love to know :madsci:

mcatee,

No, I would have to say that copying is a learning process that exists in other animals as well. A lot of this is covered in Wilson's Sociobiology, but you also see evidence of mimicry in dolphins, and possibly in cephalopods as well.

Are you asking if I'm in the medical or marine biological field or did you pose the question to brown?

Have a great day!

John
 
write mate ive got it its "cephalopod neurobiology:neuroscience studies in squid,octopusand cuttlefish," by N.J Abbot its damn good fujisawas sake!!! if you are speacilizing in cephs like my brother and father runs in the family! it is a must have


samuel mcatee :grad:
 
So here's my attempt to George Romero this topic, mostly since neurology and behavior has recenly been discussed on other threads....

Brown said:
So for example, in your CNS there is a representitive physical map of your sensory fields. This helps you to 'know' where you arm is positioned is space with your eyes shut. This does not seem to be the case for Octopus. For example from the recent the work of Hochner+ co on arm control it seems that the arm is 'cast ' (like a fly fisherman) towards an object and there seems to be no cns control other than a go signal. More work required though before a firm conclusion can be reached...

So this is about proprioception, right? But isn't human movement not always completely regulated as well? I find it hard to believe that octos wouldn't have better control over their arms. It just doesn't seem to jive with selection; if you have eight arms, some not always in your feild of view, you would have to know where they were in three-dimensional space or risk losing them. Maybe their proprioception is percieved differenly?

Can anyone send me info on where I can find Hochner's paper?

John
 

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