Artículo de revista
Anatomical organization of the visual dorsal ventricular ridge in the chick (Gallus gallus): Layers and columns in the avian pallium
Fecha
2015Registro en:
The Journal of Comparative Neurology 523:2618–2636 (2015)
0021-9967
DOI: 10.1002/cne.23808
Autor
Ahumada Galleguillos, Patricio
Fernández, Máximo
Marín Game, Gonzalo
Letelier Parga, Juan
Mpodozis Marín, Jorge
Institución
Resumen
The dorsal ventricular ridge (DVR) is one of the main
components of the sauropsid pallium. In birds, the DVR
is formed by an inner region, the nidopallium, and a
more dorsal region, the mesopallium. The nidopallium
contains discrete areas that receive auditory, visual,
and multisensory collothalamic projections. These nidopallial
nuclei are known to sustain reciprocal, shortrange
projections with their overlying mesopallial areas.
Recent findings on the anatomical organization of the
auditory DVR have shown that these short-range projections
have a columnar organization that closely resembles
that of the mammalian neocortex. However, it is
unclear whether this columnar organization generalizes
to other areas within the DVR. Here we examine in
detail the organization of the visual DVR, performing
small, circumscribed deposits of neuronal tracers as
well as intracellular fillings in brain slices. We show that
the visual DVR is organized in three main laminae, the
thalamorecipient nucleus entopallium; a dorsally adjacent
nidopallial lamina, the intermediate nidopallium;
and a contiguous portion of the ventral mesopallium,
the mesopallium ventrale. As in the case of the auditory
DVR, we found a highly topographically organized system
of reciprocal interconnections among these layers,
which was formed by dorsoventrally oriented, discrete
columnar bundles of axons. We conclude that the
columnar organization previously demonstrated in the
auditory DVR is not a unique feature but a general
characteristic of the avian sensory pallium. We discuss
these results in the context of a comparison between
sauropsid and mammalian pallial organization.