Catherine M. Montagnese

Efferent Connections of Septal Nuclei of the Domestic Chick (Gallus domesticus): An Anterograde Pathway Tracing Study with a Bearing on Functional Circuits

Small iontophoretic injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin were placed in different subregions of the septum of domestic chicks. The main targets of septal projections comprised the ipsi‐ and contralateral septal nuclei, including the nucleus of the diagonal band, basal ganglia, including the ventral paleostriatum, lobus parolfactorius, nucleus accumbens, and olfactory tubercle, archistriatum, piriform cortex, and anterior neostriatum. Further diencephalic and mesencephalic septal projections were observed in the ipsilateral preoptic region, hypothalamus (the main regions of afferentation comprising the lateral hypothalamic nuclei, ventromedial, paraventricular and periventricular nuclei, and the mammillary region), dorsal thalamus, medial habenular and subhabenular nuclei, midbrain central gray, and ventral tegmental area. Contralateral projections were also encountered in the septal nuclei, ventral paleostriatum, periventricular and anteromedial hypothalamic nuclei, suprachiasmatic nucleus, and the lateral hypothalamic area. Avian septal efferents are largely similar to those of mammals, the main differences being a relatively modest hippocampal projection arising mainly from the nucleus of the diagonal band (as confirmed by a specific experiment with the retrograde pathway tracer True blue), the lack of interpeduncular projection, and a greater contingent of amygdalar efferents arising from the lateral septum rather than the nucleus of the diagonal band. This pattern of connectivity is likely to reflect an important role of the avian septal nuclei in the coordination of limbic circuits and the integration of a wide variety of information sources modulating the appropriate behavioral responses: attention and arousal level, memory formation, hormonally mediated behaviors, and their affective components (such as ingestive, reproductive, and parental behaviors), social interaction, locomotor modulation, and circadian rhythm. J. Comp. Neurol. 469:437–456, 2004.

Efferent connections of the dorsomedial thalamic nuclei of the domestic chick (Gallus domesticus)

Small iontophoretic injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin were placed in the thalamic anterior dorsomedial nucleus (DMA) of domestic chicks. The projections of the DMA covered the rostrobasal forebrain, ventral paleostriatum, nucleus accumbens, septal nuclei, Wulst, hyperstriatum ventrale, neostriatal areas, archistriatal subdivisions, dorsolateral corticoid area, numerous hypothalamic nuclei, and dorsal thalamic nuclei. The rostral DMA projects preferentially on the hypothalamus, whereas the caudal part is connected mainly to the dorsal thalamus. The DMA is also connected to the periaqueductal gray, deep tectum opticum, intercollicular nucleus, ventral tegmental area, substantia nigra, locus coeruleus, dorsal lateral mesencephalic nucleus, lateral reticular formation, nucleus papillioformis, and vestibular and cranial nerve nuclei. This pattern of connectivity is likely to reflect an important role of the avian DMA in the regulation of attention and arousal, memory formation, fear responses, affective components of pain, and hormonally mediated behaviors. J. Comp. Neurol. 459:301–326, 2003.

A subpopulation of large calbindin-like immunopositive neurones is present in the hippocampal formation in food-storing but not in non-storing species of bird

The avian hippocampal formation (HP) is thought to play a role in the processing of spatial memory related to food-storing behaviour. The HP of two food-storing species (marsh tit (Parus palustris) and magpie (Pica pica)) and two non-storing species (great tit (Parus major) and jackdaw (Corvus monedula)) were compared following calbindin-like immunostaining. In the dorsal hippocampal region, both species of food-storing birds had larger calbindin-immunoreactive cells than did the two non-storing species. The fact that this association between storing behaviour and cell morphology is seen in two unrelated families of birds, the Paridae (marsh tit versus great tit) and Corvidae (magpie versus jackdaw) suggests that there may be a direct link between food-storing behaviour and the dorsal hippocampal calbindin-immunoreactive cell population.

Histochemical distribution of zinc in the brain of the zebra finch (Taenopygia guttata)

The distribution of zinc was studied in the brain of the zebra finch (Taenopygia guttata) by means of the selenium histochemical method. A specifie pattern was seen, which usually correlated with the main known architectonic subdivisions. In addition, a few as yet unidentified structures were observed. In the telencephalon, the pallial components were stained with moderate to strong intensity. The only exceptions were the hyperstriatum intercalatus superior, a small medial area in the hyperstriatum accessorium and in the dorsolateral cortex, and the dorsomedial part of the hippocampal complex, which were virtually devoid of staining. Staining of the dorsal ventricular ridge components varied considerably. The archistriatum, the nucleus accumbens, the nucleus of the stria terminalis, the hyperstriatum ventrale and the lateral septum showed moderate to strong staining. The medial septum was weakly stained. The neostriatum showed a rather complex pattern of staining with unstained areas, such as the magnocellular nucleus of the anterior neostriatum, and other parts intensely stained, especially in its caudal region. Both paleostriatii primitivum and augmentatum showed a rostro-caudal gradient that was increasingly stained. We also observed an intensely stained area ventral to the fasciculus prosencephali lateralis and lateral to the tractus septomesencephalicus, a weakly to moderately stained band ventral to the lobus parolfactorius, an intensely stained zone along the lateral ventricle in the hyperstriatum ventrale, and an unstained almond-shaped nucleus in the lateral hyperstriatum ventrale. In the diencephalon, the hypothalamus showed a moderate to strong, rather uniform staining, whereas the thalamus was usually weakly to moderately stained, with the exception of a few unstained nuclei. Only the lateral nucleus of the habenula was stained, and with strong intensity. Most of the mesencephalon stained rather uniformly with a moderate to strong intensity. The most intense staining was seen in the substantia grisea centralis, the substantia grisea et fibrosa periventricularis, the torus semicircularis and the nucleus intercollicularis. The tectum opticum was virtually devoid of stain except for two light bands in the stratum griseum et fibrosum superficiale. The formatio reticularis was moderately stained. All the other structures were either weakly stained or unstained. Some staining was seen in the Purkinje and the granular layers of tha cerebellum, as well as around its internal nuclei. The pons and the medulla oblongata showed an overall moderate to intense staining, with the exception of a few unstained nuclei. When compared in three bird species belonging to different genera, zinc distribution shows remarkable similarities, despite species, age and methodological differences. The pattern of zinc staining suggests that this element may play an important role in integrative and autonomic functions.

Afferent connections of septal nuclei of the domestic chick (Gallus domesticus): A retrograde pathway tracing study

The afferents to the septum of the domestic chicken were studied using retrograde tracers, rhodamine conjugated latex bead or Fast Blue, placed in different septal subregions. The results were verified by anterograde tracer injections deposited to selected areas. The main telencephalic afferents to the septum arise ipsilaterally from the hippocampal formation, dorsolateral corticoid area, piriform cortex, amygdaloid pallium, and the ventral pallidum. Contralateral afferents originate from the lateral septum and the amygdaloid pallium. A massive bilateral projection arises from the lateral hypothalamus. Other hypothalamic afferents arise from the periventricular, paraventricular and anterior medial nuclei, and the premammillary and mammillary areas. The dorsal thalamic nuclei (dorsal medial anterior and posterior) and the reticular dorsal nuclei also contribute septal afferents. Brainstem afferents arise bilaterally from the ventral tegmental area, substantia nigra, central gray, A8, locus coeruleus, ventral subcoeruleus nucleus, and raphe nuclei. The main terminal fields for septal afferents lie in the lateral septal nucleus and the belt of medial septal nucleus. The core of the latter is invaded mainly by fibers from the brainstem, presumably belonging to the ascending activating system. The septal afferents of the chicken are largely similar to those of other avian and nonavian species. The most prominent differences with previous pigeon data were found in the subregional selectivity of the hippocampal formation, dorsolateral corticoid area, mammillary nuclei, some dorsal thalamic nuclei, substantia nigra, and subcoeruleus nuclei in their projections to defined septal nuclei. J. Comp. Neurol. 511:109–150, 2008.

Comparative distribution of NADPH-diaphorase activity and tyrosine hydroxylase immunoreactivity in the diencephalon and mesencephalon of the domestic chicken (Gallus domesticus)

We described the distribution of NADPH-diaphorase-containing neurons in relation to tyrosine hydroxylase immunoreactivity in the diencephalon and mesencephalon of the chicken. In the diencephalon, both markers were found in the lateral hypothalamus, dorsal hypothalamic area, hypothalamic periventricular nucleus, paraventricular nucleus and mamillary area. A close examination showed that the fine distribution of these markers differed slightly, so that they were never observed in the same neurons. In the mesencephalon, NADPH-diaphorase and tyrosine hydroxylase immunoreactivity were found in the ventral pedunculopontine area (nucleus tegmenti pedunculopontinus pars compacta, adjacent areas surrounding the quintofrontal tract and the nucleus mesencephalicus profundus ventralis), the coeruleus complex (locus coeruleus, ventral and dorsal subcoeruleus nuclei), the ventral tegmental area and the central gray. The majority of these neurons contained either diaphorase or tyrosine hydroxylase. Nevertheless, in a few cases both markers appeared to colocalize in the same neuron, typically in large perikarya of the ventral pedunculopontine area.

Distribution and morphological features of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in intrinsic neurons of the Oddi sphincter of the cat.

To clarify the role of nitric oxide (NO) in the sphincter of Oddi, we histochemically investigated the distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), a marker for NO synthase, in the cat. NADPH-diaphorase activity was localized in two neuronal subtypes: large neurons with many dendrites and smaller with one process. Most of the nerve cell bodies (99%) in the wall of the sphincter of Oddi showed strong activity for this enzyme. The nerve fibers with NADPH-d activity were observed in all layers, chiefly in the muscle layers. These results suggest that NO may play a very important role in the neuronal regulation of sphincter of Oddi.

Immunoreactivity Distribution of Vasotocin and Vasoactive Intestinal Peptide in Brain Nuclei of Two Songbird Species with Different Breeding Systems

Vasopressin influences social behaviour in mammals, in particular social recognition and bonding. However, much less is known about its avian analogue, vasotocin, although vasotocin appears to modulate singing behaviour and agonistic interactions together with vasoactive intestinal peptide (VIP) in some songbirds. The objectives of our study were to compare the expression of vasotocin and VIP in brain nuclei hypothetised to be part of the social behavioural network, i.e. septal areas, bed nucleus of the stria terminalis and medial preoptic nucleus (POM), in two songbird species in the wild: the blue tit (Cyanistes caeruleus) and European penduline tit (Remiz pendulinus). These two closely related passerine birds differ in their pair bonding and mating systems: blue tits are socially monogamous with extensive pair bond lasting for several months, whereas in the European penduline tit, pair bond is short and it dissolves during or after laying of the eggs. The two species did not differ in the distribution of vasotocin in the observed brain regions; however, VIP was more abundant in all three regions of penduline tits than in blue tits. We found a sex difference in favour of males in the distribution of vasotocin- and VIP-immunoreactive neurones, fibres and terminals in all three regions in penduline tits. In blue tits, such gender differences were only observed in the POM. The limited differences between the two species suggest that the levels of vasotocin and VIP in the socially relevant brain regions are likely influenced by many other social or environmental factors than just by differences in the duration of pair bonding.

Distribution of vasotocin- and vasoactive intestinal peptide-like immunoreactivity in the brain of blue tit (Cyanistes coeruleus)

Blue tits (Cyanistes coeruleus) are songbirds, used as model animals in numerous studies covering a wide field of research. Nevertheless, the distribution of neuropeptides in the brain of this avian species remains largely unknown. Here we present some of the first results on distribution of Vasotocine (AVT) and Vasoactive intestinal peptide (VIP) in the brain of males and females of this songbird species, using immunohistochemistry mapping. The bulk of AVT-like cells are found in the hypothalamic supraoptic, paraventricular and suprachiasmatic nuclei, bed nucleus of the stria terminalis, and along the lateral forebrain bundle. Most AVT-like fibers course toward the median eminence, some reaching the arcopallium, and lateral septum. Further terminal fields occur in the dorsal thalamus, ventral tegmental area and pretectal area. Most VIP-like cells are in the lateral septal organ and arcuate nucleus. VIP-like fibers are distributed extensively in the hypothalamus, preoptic area, lateral septum, diagonal band of Broca. They are also found in the bed nucleus of the stria terminalis, amygdaloid nucleus of taenia, robust nucleus of the arcopallium, caudo-ventral hyperpallium, nucleus accumbens and the brainstem. Taken together, these results suggest that both AVT and VIP immunoreactive structures show similar distribution to other avian species, emphasizing evolutionary conservatism in the history of vertebrates. The current study may enable future investigation into the localization of AVT and VIP, in relation to behavioral and ecological traits in the brain of tit species.