On Mon, Jan 10, 2011 at 6:01 PM, Maryann Martone <mary...@ncmir.ucsd.edu> wrote:
> Thanks Jyl.  Definitions that I have been able to glean from various
> textbooks etc suggest that tracts are distinguished by having a common
> origin and common destination and are named accordingly, e.g., cortical
> spinal tract.

> Lemniscus according to one definition is used to describe flattened (i.e.,
> "ribbon") macroscopic white matter associated with ascending sensory
> systems.

> Decussation is the crossing of fibers not connecting the same structures on
> both sides of the brain, as opposed to a commissure which connects the same
> structures on both sides.  The decussation is certainly a site, i.e., the
> place where fibers cross, but the decussation also refers to the crossing
> fibers themselves.

> Pathways need not be macroscopically visible nor represent a bundle of
> axons, e.g., the perforant pathway.

> I'm all for simplifying the current mess according to Onard's suggestions.
>  The idea is to make it computable.  The preferred label can reflect the
> historic name, e.g., fasciculus, lemniscus.

> On Jan 10, 2011, at 2:37 PM, Jyl Boline wrote:

>> Hello All and welcome back from the holidays,

>> I haven't come up with any consensus definitions for nerve, nerve
>> fiber bundle, tract and pathway, because it seems this discussion
>> isn't finished yet.  Clif has pointed out that nerves are considered
>> part of the PNS, while tracts and pathways are considered part of the
>> CNS (although these are not synonymous).

>> However, Onard brought up an interesting suggestion, which I hoped
>> people might weigh in on before we move forward.  While some of the
>> names are a little different than the ones we're discussing, perhaps
>> we can create synonyms and also use this this structure to help us
>> organize.  I've pasted Onard's suggestion below and all comments and
>> suggestions would be greatly appreciated.  Thanks much!

>> Neural fiber bundle (aggregate or collection of axons in cord-like
>> configuration)
>>       - CNS fiber bundle -
>>             ( Here we need to resolve what is the difference or what
>> are the similarities between, TRACT, FASCICULUS, LEMNISCUS, STRIA,
>> ANSA, FUNICULUS, DECUSSATION, RADIATION and PATHWAY. Which ones are
>> subtypes of another and which one are parts of another? E.g.
>> corticospinal TRACT has a part " pyramidal DECUSSATION segment of
>> corticospinal tract". Are they defined based on structural or
>> functional properties or both?)
>>       - PNS fiber bundle
>>               - Nerve trunk
>>                      -Cranial nerve trunk
>>                      -Spinal nerve trunk
>>                -Nerve root
>>                -Nerve rootlet
>>                -Nerve cord (e.g. lateral cord of brachial plexus)

>> Nerve in the FMA is a neural tree which consists of root, trunk and
>> branches (each branch consists of its own trunk and its own set of
>> branches).

>> Best,
>> Jyl

>> On Thu, Dec 16, 2010 at 2:56 PM, Mihail Bota <mbot...@gmail.com> wrote:

>>> Thank you for correction Dr. Saper.

>>> So, the criterion to dissociate a nerve from a tract is actually a
>>> structural one, not only a positional one - it is the type of the cell
>>> that
>>> produces myelin.

>>> Can I ask for references regarding the myelinization of cranial nerves?
>>> If
>>> we get this, then we can better answer the questions of Chris Mungall.

>>> Mihai
>>> On Thu, Dec 16, 2010 at 4:27 AM, <csa...@bidmc.harvard.edu> wrote:

>>>> Mihail, the optic nerve is not a nerve.  It is a misnomer, because it is
>>>> a
>>>> CNS tract (it has central myelin).  Nerves are PNS structures and have
>>>> peripheral myelin.

>>>> As for the olfactory nerve, this is a misnomer as well, but of a
>>>> different
>>>> kind, because there really is no olfactory nerve.  There are olfactor
>>>> nerve
>>>> rootlets, which run from the olfactory epithelium, through the cribiform
>>>> plate, into the olfactory bulb, but then never form a distinct nerve
>>>> bundle.
>>>>  The thing that most neuroanatomy teachers point to when they teach the
>>>> cranial nerves is actually the olfactory tract, from the olfactory bulb
>>>> (which is already part of the CNS) to the basal forebrain.

>>>> Clif

>>>> Clifford B. Saper, MD, PhD

>>>> James Jackson Putnam Professor of Neurology and Neuroscience, Harvard
>>>> Medical School

>>>> Chairman, Department of Neurology

>>>> Beth Israel Deaconess Medical Center

>>>> 330 Brookline Avenue, Boston, MA 02215 USA

>>>> Phone: 617-667-2622; Fax: 617-975-5161

>>>> Email: csa...@bidmc.harvard.edu

>>>> Note: This message is confidential and may be legally privileged. It is
>>>> intended solely for the addressee. If you receive it in error, please
>>>> delete
>>>> this message and notify the sender immediately. Any use by an unintended
>>>> recipient is prohibited.

>>>> ________________________________

>>>> From: Mihail Bota [mailto:mbot...@gmail.com]
>>>> Sent: Wednesday, December 15, 2010 8:52 PM
>>>> To: Chris Mungall
>>>> Cc: Jyl Boline; Maryann Martone; Saper,Clifford (Chief, BIDMC
>>>> Neurology);
>>>> structurallexicontf@googlegroups.com;
>>>> pons-representation-and-deployment@googlegroups.com;
>>>> neurolex@googlegroups.com
>>>> Subject: Re: nucleus and ganglion

>>>> Very good questions!
>>>> Please see below some of my answers.

>>>> On Wed, Dec 15, 2010 at 5:25 PM, Chris Mungall <cjmung...@lbl.gov>
>>>> wrote:

>>>> No answers, only questions and some exercises to help improve these

>>>> * can we list examples of each of these? E.g the cranial nerves.

>>>>  --the list:
>>>> http://brancusi.usc.edu/bkms/brain/ontology-details.php?id=852

>>>> Also, FMC definition for nerves:

>>>> http://brancusi1.usc.edu/thesaurus/definition/nerves/

>>>> and for tracts

>>>> http://brancusi1.usc.edu/thesaurus/definition/white-matter-tract/ --
>>>> this
>>>> one answers, at least partially, to some of your questions.

>>>> See also the definitions of the vomeronasal nerve:
>>>> http://brancusi.usc.edu/bkms/brain/ontology-details.php?id=855

>>>> of the optic nerve:

>>>> http://brancusi.usc.edu/bkms/brain/ontology-details.php?id=859

>>>> As you'll see, some subparts of them have "tract" in their names.

>>>> Optic nerve and olfactory nerve are in CNS.

>>>> I'll think at the remaining questions.

>>>> Mihai

>>>> * what are the relationships between these classes? Is NFB a superclass
>>>> of
>>>> both nerve and tract? If not, are they all mutually disjoint classes? I
>>>> presume not, but it's good to make all assumptions explicit

>>>> * are tract and nerve disjoint classes? I presume so based on the
>>>> CNS/PNS
>>>> distinction. Again, it's good to make this explicit

>>>> * can we avoid weasel-words like "largely"? Is there a tract that does
>>>> not
>>>> go from one CNS location to another? If so, mention it. If not, remove
>>>> "largely"

>>>> * Are nerves always part_of the nervous system, or can they overlap with
>>>> the CNS? Is there a name for the structure that is a continuous
>>>> nerve+tract?

>>>> * Many AOs have a class "peripheral nerve" but treatment is
>>>> inconsistent.
>>>> Can we come up with a good shared definition for this?

>>>> * FMA divides things into neural tree organs and segments of neural tree
>>>> organs. For example, cranial nerve II is not a subclass of cranial nerve
>>>> -
>>>> it's a subclass of nerve trunk, which is a subclass of segment of neural
>>>> tree organ. Do we want to adopt their definitions?

>>>> On Dec 15, 2010, at 10:27 AM, Jyl Boline wrote:

>>>>> Hello again All,

>>>>> So far we haven't had any feedback on our set of definitions having to
>>>>> do with nerves/tracts etc.  This is what we have so far, but we're
>>>>> probably missing terms, and some of these may be synonyms.  Please let
>>>>> me know your thoughts on these.

>>>>> Nerve:
>>>>> 1)      Bundles of axons located in the peripheral nervous system
>>>>> 2)      Segment of neural tree organ which has as its direct proper
>>>>> parts a nerve trunk and its branches; together with other nerves of
>>>>> the same tree it constitutes a neural tree.

>>>>> Nerve fiber bundle:
>>>>> A fasciculated bundle of neuron projections largely or completely
>>>>> lacking synapses.

>>>>> Tract:
>>>>> A collection of axons that largely arises from one central nervous
>>>>> system part and terminates in another.  Tracts are generally named by
>>>>> their region or origin followed by their region of primary
>>>>> termination, e.g., mammillothalamic tract contains axons that arise
>>>>> from neurons in the mammillary bodies and terminate in the thalamus.

>>>>> Pathway:
>>>>> A collection of nerve fibers

>>>>> Thanks much!

>>>>> Best,
>>>>> Jyl

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> Maryann Martone
> Professor-In-Residence
> Dept of Neurosciences
> University of California, San Diego
> San Diego, CA  92093-0446
> Tel:  858 822 0745
> Fax:  858 246 0644

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