Effects of early monocular enucleation on cortical spreading depression in well-nourished and malnourished adult rats.

Sensory development is a complex process that can influence physiological and pathological factors. In laterally-eyed mammals, monocular enucleation (ME) during development and the subsequent lack of external sensory stimuli can result in permanent morphological and physiological changes. Malnutrition, especially in early life, also can cause permanent morphofunctional changes due to inadequate nutrient intake in both hemispheres. This study investigated the effects of early (postnatal day 7) ME and malnutrition during the suckling period on cortical excitability in adulthood (110-140 days of life). For this, we compared the speed propagation of cortical spreading depression in the occipital and parietal cortex of malnourished and well-nourished adult rats, previously suckled small-sized litters with three pups (L3/dam) medium-sized litters with six pups (L6/dam), and large-sized litters with twelve pups (L12/dam). The CSD velocity was augmented by the ME in the contralateral side of the removed eye in the parietal and occipital cortex. These findings suggest that visual sensory input deprivation is associated with permanent functional changes in the visual pathways, which can alter cortical excitability and lead to modifications in CSD propagation.

Intrinsic projections of cebus-monkey area 17: cell morphology and axon terminals

Metric features of the axon terminals and cell morphology of intrinsic projections of area 17 were studied in the Cebus apella. Anterograde and retrograde labeled cell appendages were obtained using saturated pellets and iontophoretic injections of biocytin in the operculum. Details of the histological and histochemical procedures have been described elsewhere (Amorim and Picanço-Diniz, 1996). We distinguished three labeled cell types: pyramidal, star pyramidal and stellate cells and three distinct morphologies of axon terminals were found: Ia, Ib and II, located at supragranular layers. Axon terminals of the group I innervate larger extent of striate cortex through longer intermediate segments, and acute branching angles compared to group II. Group II present on average similar characteristics of the smooth neurons axon terminals. The results taken together with the occurrence of only two types of synapses (I and II) from Gray's ultrastructural studies, seem to give an additional support to extend to the Cebus apella the major subdivision of neocortical neuronal morphology that classified them as smooth and spine neurons.