nomenclature, or naming conventions, used here follow those
suggested by George Paxinos and his colleagues in the preparation
of their atlases of the rat, mouse, monkey and human, cited
below. To quote the authors of these magnificent brain atlases.:
There is a critical need for a stable neuroanatomical nomenclature
to accurately and intelligibly convey information between neuroscientists.
At the present time, many terms are used for the same structure,
and, in some cases, the same term is used for completely different
structures." "We have made an effort to establish homologies
and are using the same abbreviations for homologous structures
in the atlases of the rat ( Paxinos and Watson, 1986), mouse
(Franklin and Paxinos, 19 ), monkey (Paxinos et al., 1990; Mai
et al., 1987) and human brainstem ("Paxinos and Huang, 1995)
... "The abbreviations used in the present and our other work
were developed using the following principles". "
1. The abbreviations represent the order of words as spoken
in English (e.g., DLG=dorsal lateral geniculate nucleus).
2. Capital letters represent nuclei, and lower case letters
represent fiber tracts. Thus, the letter "N" has not been used
to denote nuclei, and the letter "t" has not been used to denote
3. The general principle used in the abbreviations of the names
of elements in the periodic table was followed: the capital
letter representing the first letter of a word in a nucleus
is followed by the lower case letter most characteristic of
that word ( not necessarily the second letter; e.g., Mg = Magnesium,
Rt = reticular thalamic nucleus).
4. Compound names of nuclei have a capital letter for each part
(e.g., LPGi = lateral paragigantocellular nucleus).
5. If a word occurs in the names of a number of structures,
it is usually given the same abbreviation (e.g., Rt = reticular
thalamic nucleus, RtTg = reticulotegmental nucleus of the pons).
Exceptions to this rule are made for well-established abbreviations
such as VTA (i.e., ventral tegmental area).
6. Abbreviations of brain regions are omitted where the identity
of the regions in question is clear from its position (CMn =
centromedian thalamic nucleus, not CMnTh).
7. Arabic numerals are used instead of Roman numerals in identifying
(a) cranial nerves and nuclei (as in the Berman atlas (1986)
and (b) layers of the spinal cord. While the spoken meaning
is the same, the detection threshold is lower, ambiguity is
reduced, and they are easier to position in small spaces available
"The delineations and descriptions of nuclei and fiber tracts
can be found in a number of different reviews."