COMPARISON OF DENDRITIC FIELDS OF LAYER-III PYRAMIDAL NEURONS IN STRIATE AND EXTRASTRIATE VISUAL AREAS OF THE MARMOSET - A LUCIFER YELLOW INTRACELLULAR INJECTION STUDY
Gn. Elston et al., COMPARISON OF DENDRITIC FIELDS OF LAYER-III PYRAMIDAL NEURONS IN STRIATE AND EXTRASTRIATE VISUAL AREAS OF THE MARMOSET - A LUCIFER YELLOW INTRACELLULAR INJECTION STUDY, Cerebral cortex, 6(6), 1996, pp. 807-813
Basal dendritic field areas of layer III pyramidal neurons were compar
ed between the first (V1), second (V2), dorsolateral (DL) and fundus o
f the superior temporal (FST) areas in marmoset monkey visual cortex.
These areas correspond to early stages of visual processing (V1, V2) a
nd to areas specialized for the analysis of shape (DL) and motion (FST
). Neurons in fixed tangential cortical slices (250 mu m) were injecte
d with Lucifer Yellow and immunohistochemically processed for a diamin
obenzidine reaction product. Dendritic field areas were calculated for
layer III pyramidal cells whose complete basal projection was judged
to be within the section (n = 189). Borders between different visual a
reas were established based on cytochrome oxidase immunohistochemistry
and myelin patterns in the experimental hemisphere, and electrophysio
logical recordings in the contralateral hemisphere. Pyramidal neurons
in V1 had a mean basal dendritic field area of 1.84 x 10(4) mu m(2) (S
EM = 2.04 x 10(3) mu m(2); n = 21). Layer III pyramidal cells in V2 ha
d a mean basal dendritic field 1.26 times larger (mean = 2.32 x 10(4)
+/- 1.78 x 10(3) mu m(2); n = 42) than that of V1 neurons. The mean de
ndritic field area of layer III pyramidal cells in DL in = 76) was 1.5
times larger than that in V1 (mean = 2.75 x 10(4) +/- 1.59 x 10(3) mu
m(2)). and that in FST (n = 50) was 2.3 times larger (mean = 4.26 x 1
0(4) +/- 2.79 x 10(3) mu m(2). Our results show that there is a correl
ation between tangential dendritic field area of basal dendrites of la
yer III pyramidal neurons and modality of visual processing. The incre
ase in basal dendritic field area of layer III pyramidal cells may all
ow more extensive sampling of inputs as required by higher-order proce
ssing of visual information.