On 24 feb, 23:57, Kalman Rubinson <k... from earthlink.net> wrote:
> On Wed, 24 Feb 2010 09:33:28 -0800 (PST), "Peter H."
>>>>>> <pjwh... from yahoo.es> wrote:
> >On 24 feb, 00:15, Kalman Rubinson <k... from earthlink.net> wrote:
> >> >*2: See Macaca Mulatta, Nissl, horizontal, histo, whole-brain,
> >> >section 0205 hemisphere at bottom inhttp://brainmaps.org>> >> I do not see what you are describing. This section looks perfectly
> >> normal to me and comparable to standard descriptions.
>> >> Kal
>> >Wish there were coordinates I could point to, but being things as they
> >are I will just have to describe the situation:
>> > Magnify section 0205 until the scale bar measures at most 184
> >micrometers. Below the Vermis on this section, the posterior margin of
> >the molecular layer of the bottom hemisphere forms a "U" leaning to
> >the right, the right arm of which points to the plexus choroideus on
> >the top right of it and is fatter than the left one. The inside of
> >this U, which represents the outside of the molecular layer, you will
> >see lined with Purkinje cells. And on the right side of this right arm
> >you will see fairly large cells (diam. ca. 23 microns), which due to
> >their size I interpret to be neurons and not Glia, nearly touching the
> >molecular layer.
>> >Alternatively, in section 0254 of this series you can see what
> >doubtlessly are the deep nuclei approaching the molecular layer on its
> >inside to a distance of about 400 microns.
>> I do see those large cells in both 205 and 254 but these seem to be in
> the white matter adjacent to the granular layer while the normal
> pattern of the molecular/Purkinje/granular layers remains intact and
> external.
>> Kal- Ocultar texto de la cita -
>> - Mostrar texto de la cita -
The granular layer is supposed to be on the same side of the molecular
layer as are the Purkinje cells. But those large neurons in 205 to
which I was referring myself are on the opposite side of the molecular
layer from where the Purkinje cells are. And besides that, only in
205, but not in 254, can these neurons opposite to the Purkinje side
really be seen to be adjacent to the molecular layer. So it seems like
we are talking about different cells here. I wish there were
coordinates.
Furthermore, what you should have written is that " the normal pattern
of the molecular/Purkinje/granular layers remains intact *but is*
external". Because according to Niewenhuys and apparently everybody
else "These layers are, passing from superficial to deep, the cell-
poor molecular layer, the monolayered Purkinje layer and the granular
layer." (see my first article). I repeat: The molecular layer
supposedly is on the outside (towards the surface), below it
supposedly comes the thin Purkinje layer, and below that supposedly
comes the granular layer. And that would mean that the Purkinje cells
were on the internal side of the molecular layer - and not on its
external side, where they really appear to be. Or not?
And this is really the crucial point here: If the Purkinje and
granular layers were on the inside of the molecular layer, then there
would be no problem of understanding how the Purkinje cell axons reach
the deep nuclei and how the Mossy Fibers reach the Granule cells. But
these layers appears to be (?are!) on the outside (or external side)
of the molecular layer, and thus the molecular layer is situated in
between the Purkinje layer and the deep nuclei. Hence my problem.
Hope I have made myself clear this time.
Peter
