DocToxyn said:
Another source for some interesting rodent brain info is the
Mouse Brain Library (have you seen this Moonbear?).
No, I wasn't aware of that. I've never been far from an atlas, so never considered looking online for a mouse brain atlas. I know Larry Swanson has been pushing for sometime now to get some sort of data base set up and available along the lines of what GenBank is for genes but for the brain. But, he doesn't just want a crude atlas, but something that's searchable by cellular phenotype. I think he just wanted to start with rat brain because that's where we have the most data. So, the idea would be you could type in, for example, arcuate nucleus, and get a list of cellular phenotypes present there, or you could then search a specific phenotype, say dynorphin neurons in the arcuate, and get a list of all the cells and regions that are known to be efferent and afferent to that dynorphin population.
saltydog said:
Would you kindly explain what CSF is?
A reference too wouldn't hurt.
CSF is cerebrospinal fluid. There has been a slowly[/size] growing body of literature indicating that CSF may not just be providing a nutrient support for neurons, but actually carry neurotransmitter signals throughout the brain. So far, the data in support of this includes detection of neurotransmitters and neurohormones in CSF of the cerebral ventricles and anatomical evidence of neurons with axon terminals projecting to the cerebral ventricles (anatomically positioned so they could release directly to CSF) and dendrites projecting out into the periventricular regions (anatomically positioned so they can detect signals from CSF). Direct evidence that this is a functional method of communication between neurons within the brain is far more limited. The best direct evidence is work done with suprachiasmatic nucleus (SCN) transplants. This is a small nucleus located just ventral to the third ventricle that function in circadian timing. You can dissect it out of an animal with a mutation that shortens their circadian rhythm to 20 hours rather than 24 hours, encase it in a membrane that allows diffusion of proteins, but does not permit axon re-growth past the membrane, transplant it into another animal (wild type rhythm of 24 hours) with the SCN lesion, and in the recipient, you get restoration of circadian rhythms, but with the short cycle of the donor animal. Silver R, LeSauter J, Tresco PA, Lehman MN. 1996 A diffusible coupling signal from the transplanted suprachiasmatic nucleus controlling circadian locomotor rhythms. Nature 382:810-3.
And then a review article on the system I'm currently studying:
Skinner DC, Caraty A. 2002 Measurement and possible function of GnRH in cerebrospinal fluid in ewes. Reprod Suppl. 59:25-39.
Okay, so for now, don't really worry about CSF, because we don't have clear functional data yet, just growing evidence pointing that way. My current work focuses more on the neuroanatomical side of the issue because there is no easy way to do a direct test of function just yet. Though, I'll be starting pilot studies this fall in an attempt to develop a method to test it directly, but don't yet know if it will really work. Now that I have a bit of the anatomical work done, I have a reasonable chance, but still no guarantees. Mostly, I just happen to have the right animal model to even consider it being feasible.