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PubMed1998

Dopaminergic growth patterns induced by striatal and cortical grafts show differences in sensitivity to increased striatal trophic activity induced by haloperidol.

During development, dopaminergic neurons innervate the developing striatal target, forming two different growth patterns: a patchy growth and a diffuse growth. Chronic treatment with the dopamine antagonist haloperidol increase the neurotrophic activity in striatum, but it is not known how this trophic activity influences different patterns of dopaminergic growth. In this paper we have studied dopaminergic growth patterns by evaluating tyrosine hydroxylase (TH)-positive growth from mature midbrain dopaminergic neurons innervating grafted fetal lateral ganglionic eminence (LGE) or fetal cortical tissue implanted into the dorsal striatum. Host dopaminergic neurons innervated LGE grafts with a patchy growth pattern, leaving large portions of the striatal graft noninnervated, and cortical grafts with diffuse, nonpatchy growth, evenly distributed over the total volume of the graft. Both types of growth patterns were enhanced over time, albeit the most pronounced change was found in the nonpatchy pattern in the cortical grafts. When fetal LGE or cortical tissues were transplanted into the dorsal striatum of chronically haloperidol-treated animals, the nonpatchy growth into fetal cortical grafts was enhanced while the patchy growth into fetal striatal tissue was not. Taken together, the results suggest that both the patchy and diffuse growth patterns may be induced from adult midbrain dopaminergic neurons depending on the target of innervation, and that increased striatal trophic activity due to blockade of the dopaminergic input stimulates growth from a subpopulation of dopaminergic neurons that produce the nonpatchy growth.

Animals↗
PubMed1996

Expression patterns of bone-related proteins during osteoblastic differentiation in MC3T3-E1 cells.

Bone formation involves several tightly regulated gene expression patterns of bone-related proteins. To determine the expression patterns of bone-related proteins during the MC3T3-E1 osteoblast-like cell differentiation, we used Northern blotting, enzymatic assay, and histochemistry. We found that the expression patterns of bone-related proteins were regulated in a temporal manner during the successive developmental stages including proliferation (days 4-10), bone matrix formation/maturation (days 10-16), and mineralization stages (days 16-30). During the proliferation period (days 4-10), the expression of cell-cycle related genes such as histone H3 and H4, and ribosomal protein S6 was high. During the bone matrix formation/maturation period (days 10-16), type I collagen expression and biosynthesis, fibronectin, TGF-beta 1 and osteonectin expressions were high and maximal around day 16. During this maturation period, we found that the expression patterns of bone matrix proteins were two types: one is the expression pattern of type I collagen and TGF-beta 1, which was higher in the maturation period than that in both the proliferation and mineralization periods. The other is the expression pattern of fibronectin and osteonectin, which was higher in the maturation and mineralization periods than in the proliferation period. Alkaline phosphatase activity was high during the early matrix formation/maturation period (day 10) and was followed by a decrease to a level still significantly above the baseline level seen at day 4. During the mineralization period (days 16-30), the number of nodules and the expression of osteocalcin were high. Osteocalcin gene expression was increased up to 28 days. Our results show that the expression patterns of bone-related proteins are temporally regulated during the MC3T3-E1 cell differentiation and their regulations are unique compared with other systems. Thus, this cell line provides a useful in vitro system to study the developmental regulation of bone-related proteins in relation to the different stages during the osteoblast differentiation.

Alkaline Phosphatase↗
PubMed1998

Experimental analysis of character coupling across a complex life cycle: pigment pattern metamorphosis in the tiger salamander, Ambystoma tigrinum tigrinum.

Developmental relationships among characters are expected to bias patterns of morphological variation at the population level. Studies of character development thus can provide insights into processes of adaptation and the evolutionary diversification of morphologies. Here I use experimental manipulations to test whether larval and adult pigment patterns are coupled across metamorphosis in the tiger salamander, Ambystoma tigrinum tigrinum (Ambystomatidae). Previous investigations showed that the early larval pigment pattern depends on interactions between pigment cells and the lateral line sensory system. In contrast, the results of this study demonstrate that the major features of the adult pigment pattern develop largely independently of both the early larval pattern and the lateral lines. These results suggest that ontogenetic changes that occur across metamorphosis decouple larval and adult pigment patterns and could thereby facilitate independent evolutionary modifications to the patterns during different stages of the life cycle.

Ambystoma↗
PubMed2001

Evidence for two distinct mechanisms of neurogenesis and cellular pattern formation in regenerated goldfish retinas.

After its destruction by intraocular injection of ouabain, the goldfish retina regenerates, but little is known about the histogenesis of the new tissue, including the structure and formation of regenerated cell mosaic patterns. In an effort to determine how retinal cells are generated and spatially organized within retina regenerated after ouabain injection, in situ hybridization and immunocytochemical techniques were combined with computational analyses of two-dimensional spatial patterns of identified neurons. Labeling with specific opsin riboprobes revealed two distinct cone patterns in the ouabain-injected eyes, each of which was different from the relatively orderly cone patterns of native retina. Central, regenerated regions had sparse aggregates of cones, and a relatively lower density of each cone type. Peripheral regions of experimental retina, likely derived from the circumferential germinal zone, had high densities of all cone types, each of which tended to be distributed randomly. The spatial patterns of inner retinal neurons in experimental eyes were also disorganized with respect to native retina. These results indicate that although some aspects of retinal regeneration resemble normal retinal development and growth, ouabain-induced regeneration does not produce well-organized mosaics of neurons, indicating a failure of the developmental interactions needed for proper pattern formation, which in turn could compromise visual recovery. Furthermore, the distinct cone patterns in different regions of experimental retina support the hypothesis that new goldfish retina arises via two spatially and cellularly distinct mechanisms after exposure to ouabain.

Animals↗
PubMed1983

Carcinoids: the association of histologic growth pattern and survival.

There are five generally accepted carcinoid histologic growth patterns, i.e., insular, trabecular, glandular, undifferentiated, and mixed. To determine their possible prognostic significance, a panel of pathologists studied the growth patterns of 138 carcinoids collected from an Eastern Cooperative Oncology Group carcinoid advanced stage disease chemotherapy investigation. Survival times were measured from date of initial pathologic diagnosis of carcinoid disease to date of either death or last follow-up. Significant differences were observed in survival times between the five major growth patterns (P less than 0.001). Within the mixed growth pattern group, significant differences in survival time were also observed (P approximately 0.05). In decreasing order of median survival time in years, the growth patterns ranked as follows: mixed insular plus glandular, 4.4; insular, 2.9; trabecular, 2.5; mixed insular plus trabecular, 2.3; three pooled low incidence rate mixed growth patterns, 1.4; glandular, 0.9; and undifferentiated, 0.5. Histologic growth patterns are recommended as a stratification factor in future studies of this disease.

Aged↗
PubMed1979

Three patterns of brain damage of the WAIS.

Compared four groups of matched Ss (40 each) in order to examine different subtest patterns of brain damage on the WAIS, using F-tests and age mean profiles. The groups were: Normals, diffuse cortical degeneration, right and left hemisphere damage. The results indicated three patterns: (1) a normal pattern; (2) a diffuse degenerative and right hemisphere pattern; and (3) a left hemisphere pattern. The diffuse degenerative results were not significantly different from the right hemisphere results. The left hemisphere pattern had no large verbal vs. performance differences. These patterns appear to be produced by the interaction of three brain damage effects: (1) a general effect; (2) a right hemisphere effect; and (3) a left hemisphere effect. Verbal tests are both "hold" and left hemisphere tests, while three Performance Tests are "don't hold" and right hemisphere tests. The WAIS requires other specific tests of brain damage for an adequate assessment of brain damage.

Brain Damage, Chronic↗
PubMed2005

Social influences on the acquisition of sex-typical foraging patterns by juveniles in a group of wild tufted capuchin monkeys (Cebus nigritus).

Foraging traditions in primates are becoming the subject of increasing debate. Recent evidence for such a phenomenon was recently provided for wild Cebus capucinus [Fragaszy & Perry, 2003]. To better understand the bases of animal traditions, one should examine intrapopulation behavioral variability and the influence of social context on within-group transmission of specific foraging patterns. We studied the variability of foraging patterns across age and sex classes, and the proximity patterns of juveniles to adults of both sexes in a group of wild tufted capuchin monkeys (Cebus nigritus) living in the Iguazu National Park, Argentina. Foraging activity was examined for a period of 9 months in terms of proportions of focal samples devoted to foraging on certain food targets, microhabitats, and supports, and using specific foraging patterns. Proximity analyses were performed to reveal patterns of association between juveniles and adults. Sex differences in foraging behavior were present and overrode age differences. Overall, males ate more animal foods, foraged more for invertebrates on woody microhabitats (especially large branches), palms, and epiphytes, and used lower and larger supports than females. Females ate more fruits, foraged more on leaves and bamboo microhabitats, and used smaller supports than males. Juveniles were similar to adults of the same sex in terms of food targets, foraging substrates, and choice of supports, but were less efficient than adults. Proximity patterns indicated that juvenile males stayed in close spatial association with adult males and preferentially focused their "food interest" on them. This phenomenon was less evident in juvenile females. The degree to which juveniles, especially males, showed some of the sex-typical foraging patterns correlated positively with their proximity to adults of the same sex. These findings suggest that the acquisition of foraging behaviors by juvenile males is socially biased by their closeness to adults of the same sex.

Age Factors↗
PubMed1979

A multivariate analysis of fatness and relative fat patterning.

Skinfold measurements (triceps, subscapular, suprailiac and medial calf) in four samples (376 boys, 352 girs, 338 men and 380 women from rural Colombia) were subjected to principal components analysis to identify components of obesity and relative fat patterning. Three components emerged which were similar in the four samples: a first component of fatness explaining 70-80% of the variance and two fat pattern components each explaining 10-15% of the variance: trunk-extremity and upper-lower body. Fatness and the trunk-extremity pattern components changed with age in children (7-12 years), but none of the components changed with age in adults (25-60+). The fatter tended to be more patterned in both age groups. Canonical correlation analysis revealed that socioeconomic status was more related to fatness than to patterning. With the exception of brothers, all first degree relatives (sib, parent-off-spring) and spouses were correlated in fatness. Some of the correlations between relatives--usually sibs, but not spouses--were also significant for the pattern components, suggesting a genetic basis for the known stability of this characteristic (Garn, '55a). Principal components analysis is a useful multivariate alternative for quantitative studies of anthropometric patterning.

Adipose Tissue↗
PubMed1987

Fat patterning in Papua New Guineans: effects of age, sex and acculturation.

For the renewed interest in fat patterning to be fruitful, more information on the biology of fat patterning, particularly normative data are required. Nine skinfold thicknesses were measured in 2312 coastal and highland Papua New Guineans of all ages undergoing acculturation. Principal component analysis of the skinfold data revealed components of fatness and fat patterning. First component scores were typical of the changes in fatness with age and the sex differences expected in these populations. Second component scores of limb-trunk fat patterning showed marked changes with age in both sexes but they stabilised in adulthood. This pattern seemed more affected by maturity although it is usually thought to be a sex-specific pattern. The third component, upper-lower body patterning, was more sexually dimorphic in adults. Marked differences were not observed between the two communities but over a 15-year period fatness levels increased slightly and subcutaneous fat tended to be deposited more centrally.

Acculturation↗
PubMed2006

Patterns of craniofacial integration in extant Homo, Pan, and Gorilla.

Brain size increased greatly during Pleistocene human evolution, while overall facial and dentognathic size decreased markedly. This mosaic pattern is due to either selective forces that acted uniquely on each functional unit in a modularized, developmentally uncoupled craniofacial complex, or alternatively, selection that acted primarily on one unit, with the other responding passively as part of a coevolved set of ontogenetically and evolutionarily integrated structures. Using conditional independence modeling on homologous linear measurements of the height, breadth, and depth of the cranium in Pan (n = 95), Gorilla (n = 102), and recent Homo (n = 120), we reject the null hypothesis of equal levels of overall cranial integration. While all three groups share the pattern of greater neurocranial integration with distinct separation between the face and neurocranium (modularization), family differences do exist. The apes are more integrated in their entire crania, but display a particularly strong pattern of integration within the facial complex related to prognathism. Modern humans display virtually no facial integration, a pattern which is likely related to their markedly decreased facial projection. Modern humans also differ from their great ape counterparts in being more integrated within the breadth dimension of the cranial vault, likely tied to the increase in brain size and eventual globularity seen in human evolution. That the modern human integration pattern differs from the ancestral African great ape pattern along the inverse neurocranial-facial trend seen in human evolution indicates that this shift in the pattern of integration is evolutionarily significant, and may help to clarify aspects of the current debate over defining modern humans.

Animals↗
PubMed1994

Vascular branching pattern and zonation of gene expression in the mammalian liver. A comparative study in rat, mouse, cynomolgus monkey, and pig.

BACKGROUND: A significant part of the liver volume consists of regions in which hepatocytes are in close contact with large branches of the afferent (portal vein) or efferent (hepatic vein) vessels. As most studies have addressed zonation of gene expression around the parenchymal branches of the portal and hepatic vein only, the patterns of gene expression in hepatocytes surrounding larger vessels are largely unknown. METHODS: For that reason, we studied the patterns of expression of the mRNAs and proteins of the pericentral marker enzymes glutamine synthase, ornithine aminotransferase, and glutamate dehydrogenase and the periportal marker enzymes phosphoenolpyruvate carboxykinase and carbamoylphosphate synthase in the rat liver, in relation to the branching pattern of the afferent and efferent hepatic veins with immuno and hybridocytochemical techniques. These patterns of expression were compared with those seen in mouse, monkey, and pig liver. RESULTS: The distribution patterns of the genes studied appear to reflect the "intensity" of the pericentral and periportal environment, glutamine synthase and phosphoenolypyruvate carboxykinase requiring the most pronounced environment, respectively. The patterns of gene expression around the large branches of the portal and hepatic vein were found to be related to the parenchymal branches in the neighbourhood of these large blood vessels. Only the cells of the limiting plate retain their periportal and pericentral phenotype for those marker enzymes that do not require a pronounced periportal or pericentral environment to be expressed. GS-negative areas in the pericentral limiting plate appear to correlate with a local absence of draining central veins, and become more frequent and extensive around the larger branches of the hepatic vein. CONCLUSIONS: The similarity of the observed patterns of gene expression of the genes studied in mouse, rat, monkey, pig, and man suggests that they reflect a general feature of gene expression in the mammalian liver. A comparison of mouse, rat, pig, and human liver suggests that the presence of glutamine synthase-negative areas reflects the branching order of the efferent hepatic blood vessel.

Animals↗
PubMed1988

DNA ploidy pattern and tumour spread in gastric cancer.

The DNA ploidy pattern of gastric cancer was studied in 58 patients to investigate the heterogeneity between primary tumour and metastases. In both primary tumours and lymph node metastases, diploid patterns accounted for 33 per cent, whereas all liver metastases were aneuploid. The percentage of polyploid cells was higher in the liver metastases than in primary tumours and lymph node metastases. When the heterogeneity of DNA ploidy pattern between primary tumour and metastasis was evaluated, diploid tumours had a significantly lower rate of lymph node metastasis heterogeneity than aneuploid tumours. When the DNA ploidy pattern and survival were evaluated, the patients who had a diploid pattern in both primary tumour and metastasis had a significantly higher survival rate than the patients who had an aneuploid pattern in the primary tumour and metastasis (57 per cent versus 26 per cent at 5 years). These data suggest that cell heterogeneity is a common phenomenon in gastric cancer, and this may be important in the evolution of the disease. Furthermore, the role of the DNA ploidy pattern as a prognostic factor is emphasized.

DNA, Neoplasm↗
PubMed1996

Prognostic significance of the initial electrocardiographic pattern in patients with inferior wall acute myocardial infarction.

The purpose of the study was to determine whether the initial electrocardiographic pattern is predictive of in-hospital mortality in inferior wall acute myocardial infarction. It is commonly perceived that patients with acute myocardial infarction presenting with greater ST elevation have a worse prognosis. The initial electrocardiogram of patients (n = 213) with inferior wall myocardial infarction was categorized based on the pattern of ST-segment elevation in inferior leads: (A) ST <1 mm with tall T waves, (B) ST > or = 1 mm with normal terminal QRS, and (C) ST > or = 1 mm with distortion of terminal QRS. ST deviation from baseline was calculated for all leads. Patients with maximal precordial ST depression in V4-V6 and pattern A had an in-hospital mortality rate of 68.8% compared with 16.9% for the entire study group. By univariate analysis, only pattern A was significantly predictive of in-hospital mortality [odds ratio = 2.91, 95% confidence interval (CI) 1.22-6.93], but by multivariate analysis adjusted for (1) age, (2) diabetes mellitus, (3) previous myocardial infarction, (4) thrombolytic therapy, (5) precordial ST-depression pattern, and (6) patterns of ST elevation, maximal ST depression in V4-V6 was significantly predictive (odds ratio = 4.93, 95% CI 1.79-13.56), whereas pattern A was not (odds ratio = 1.12, 95% CI 0.36-3.52). Contrary to popular perception, patients with inferior wall myocardial infarction presenting with minimal ST-segment elevation are at highest risk for in-hospital mortality, especially if accompanied by maximal precordial ST depression in V4-V6.

Adult↗
PubMed1997

Circadian patterns in the onset of cardiogenic acute pulmonary edema.

BACKGROUND: Circadian patterns of onset favoring the morning hours have been demonstrated for many cardiovascular disorders. Although much is known about cardiogenic acute pulmonary edema (CAPE), the relationship between time of day and CAPE episode onset has not been previously studied. METHODS: We examined 154 consecutive episodes of CAPE treated at an urban community hospital to determine whether circadian patterns existed in the time these episodes began. RESULTS: For all episodes, a significant circadian pattern existed, with peak onset between 6:00 and 11:59 A.M. (p < 0.01). When CAPE episodes were analyzed by the most probable precipitant of pulmonary edema, only the pattern for patients with progressive symptoms, showing a peak in the 6:00 and 11:59 A.M. interval, was statistically significant (p < 0.01). Although a similar trend existed for CAPE occurring in association with acute myocardial infarction, the pattern fell short of statistical significance (p = 0.09). CONCLUSIONS: These data suggest that circadian patterns favoring the morning hours exist for episodes of CAPE, and that patterns may vary depending on the precipitant of the episode.

Acute Disease↗
PubMed1985

Bending patterns of Chlamydomonas flagella: II. Calcium effects on reactivated Chlamydomonas flagella.

Ca2+ has profound effects on the movement of cilia and eukaryotic flagella, including those of Chlamydomonas. Two clear changes seen in Chlamydomonas flagella with changes in Ca2+ are beat frequency and symmetry. Photographic and computer assisted analysis of flagellar bending patterns on a uniflagellate mutant of Chlamydomonas have been used to examine details of the effects of Ca2+ on the movement of ATP-reactivated, demembranated flagella. In addition to the forward mode bending pattern seen at low Ca2+ concentrations (10(-9)M), which has a frequency of about 50 Hz and the reverse mode bending pattern seen at high Ca2+ concentrations (10(-4)M) with a frequency around 70 Hz, we carefully examined bending patterns in the intermediate Ca2+ concentration range of 1-6.5 X 10(-6)M. In this intermediate range, the bending patterns have significantly reduced asymmetry and slightly increased frequency, compared to the motility observed at low Ca2+ concentrations. These observations indicate that changes in these two parameters of motion do not occur in parallel and suggest that the effects of Ca2+ may be a multicomponent process. Physiologically, these changes in the beat pattern at intermediate Ca2+ may signal either 1) the beginning stages of transition to the symmetrical, high-frequency beating seen at high Ca2+, or 2) a more normal forward mode motility for the trans flagellum as suggested by Kamiya and Witman [1984]. No large amplitude bending patterns associated with transitions between forward and reverse mode beating in intact cells were seen at the intermediate Ca2+ concentrations.

Calcium↗
PubMed1980

Ontogeny of the retina and optic nerve in Xenopus laevis. II. Ontogeny of the optic fiber pattern in the retina.

The ontogeny of optic fiber patterns within the Xenopus laevis retina has been studied in silver-stained serial sections and whole mounts. Ganglion cell axons ("pioneers") appear much earlier than previously recognized, at Nieuwkoop-Faber ('56) Stage 28. Fibers fasciculate into bundles as they arise in the retina and reach the chiasma by NF Stage 32. Because the retina grows in rings at its margins, ganglion cell axons differentiate at the periphery and join the nearest fiber bundles (fascicles) to reach the optical disc. A radial fascicle pattern develops by Stage X (Grant et al., '80) within the optic fiber layer of the retina and acts as a template of pathways that lead all later appearing fibers out of the retina. Since the retina grows asymmetrically along its dorso-ventral axis, the fascicle pattern develops asymmetrically, with dorsal quadrant fascicles forming an arcuate pattern in contrast to shorter, thicker ventral quadrant fascicles. The growth pattern of the retina and the "principle" of fiber following suggest that "positional information" is acquired by ganglion cells according to a system of polar coordinates (MacDonald, '77). A radial distance "r" from the center is determined temporarily by ganglion cell birthday and an angular value "theta" is given by the angular position of the fascicle followed by its axons to the optical disc. Wedges of ganglion cells send their axons into a common fascicle which retains its integrity as it leaves the retina at the optic disc. This pattern of optic fiber development suggests a model for retino-topic ordering of the optic fiber projection in Xenopus, with the fascicle acting as the "pattern-forming unit of connectivity."

Animals↗
PubMed1990

Transient patterns of GAP-43 expression during the formation of barrels in the rat somatosensory cortex.

The development of the rat barrel field cortex was investigated with an antibody to the axonal membrane-specific phosphoprotein GAP-43 in order to examine the developmental pattern of afferent projections, and with cytochrome oxidase histochemistry and Nissl stains to reveal the morphogenesis of cortical barrels. On the first two days after birth, GAP-43 immunostaining in the cortical plate was light and diffuse, then became intense in the presumptive layer IV of the parietal cortex on PND3 (day of birth = PND0). Immunoreactive densities were visible as small, focal patches within the centers of prospective barrels. These densities increased in size and intensity over the next few days and then diminished abruptly. On PND7, the distribution of GAP-43 was coextensive with barrels, as defined by cytochrome oxidase histochemistry and Nissl staining. GAP-43 virtually disappeared from the barrels after PND7. From the second postnatal week, GAP-43 immunostaining was evident in the septa between barrels and in the dysgranular regions of SI cortex. This pattern of GAP-43 distribution was complementary to the pattern of cytochrome oxidase activity, and persisted into maturity. In an attempt to identify possible source(s) of GAP-43 positive afferents in the developing barrels, we examined the effects of altering the sensory periphery on the distribution of GAP-43 immunostaining in the cortex. Rat pups had row C whiskers cauterized on PND0 and were sacrificed on PND3 or PND5. Whereas immunopositive densities corresponding to intact whiskers developed in a normal, punctate pattern, cortical representation of the lesioned whiskers formed a continuous band of labeling that was evident as early as PND3. We argue that the disjunctive expression of GAP-43 in the barrel field reflects the pattern of distribution of afferents (most likely from the ventro-basal thalamic nucleus) to the barrel field cortex, and that this pattern may be instructive in the formation of barrels as cytoarchitectonic units. The rapid alteration in patterns of immunostaining following whisker lesions lends further support to the conclusion that the "barrel template" is conveyed to the neocortex by incoming afferents. The possible significance of the transient expression of GAP-43 in the maturing barrel field is discussed.

Aging↗
PubMed1991

Effects of cortical and thalamic lesions upon primary afferent terminations, distributions of projection neurons, and the cytochrome oxidase pattern in the trigeminal brainstem complex.

Early postnatal lesions of the primary somatosensory cortex alter the vibrissa-related cytochrome oxidase (CO) pattern in nucleus principalis (PrV) of the rat's trigeminal (V) brainstem complex (Erzurumlu and Ebner, '88: Dev. Brain Res. 44:302-308). At present, the reason for this change is not clear. It may be that the corticotrigeminal projection is necessary for the maintenance of vibrissa-related patterns in PrV. However, it is also possible that the loss of the normal pattern of CO activity reflects a change in the organization of brainstem cells resulting from transneuronal retrograde degeneration. In order to address this question, we made lesions of either the primary somatosensory cortex (S-I) or ventrobasal thalamus (VB) in newborn rats and directly assayed distribution of V primary afferents by transganglionic transport of horseradish peroxidase and V-thalamic neurons by retrograde transport of either fluorogold or true blue. Neonatal cortical and thalamic lesions produced no qualitative change in the distribution of primary afferent terminals in either PrV or V subnucleus interpolaris (SpI) beyond that which could be attributed to shrinkage of the brainstem resulting from retrograde degeneration. Most importantly, the "patchy" pattern of terminations observed in normal rats remained apparent in the brain-damaged animals. The normal distribution of V-thalamic neurons in PrV was disrupted by both cortical and thalamic lesions. These cells are normally patterned in a way that matches the distribution of primary afferent terminals and thus that of the mystacial vibrissae. This was not the case in the neonatally brain-damaged rats. Taken together, these results are consistent with the conclusion that neonatal cortical and thalamic lesions disrupt the normal CO pattern in PrV primarily because of their effects upon the patterning of brainstem cells. The present findings demonstrate further that clustering of primary afferents does not require a normal complement of postsynaptic neurons.

Afferent Pathways↗