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PubMed1995

Projections from the lateral mammillary nucleus to the anterodorsal thalamic nucleus in the rat.

There has been an abundance of research on the connections of the mammillary bodies but the projections from the lateral mammillary nucleus to the anterodorsal thalamic nucleus has remained a gray area due to a dearth of material which directly addresses the details of this pathway. This study seeks to further define the nature of this particular nerve connection within the mammillothalmic tract. The technique employed is fluorescent nerve tract tracing using two fluorescent tracers implanted separately into each anterodorsal thalamic nucleus then followed retrogradely to the soma of the neurons in the lateral mammillary nucleus. Fluorescent photomicrography allowed us to document the single and double labeled cells of the lateral mammillary nucleus. The single labeled cells can be categorized into ipsilaterally projecting neurons and contralaterally projecting neurons. About half of all labeled cells were bilaterally projecting double-labeled, a third was ipsilaterally projecting single-labeled and the remainder were contralaterally projecting single labeled-cells. There were no labeled cells traced to the medial mamillary nucleus. The mammillary bodies play an important role in the limbic circuitry and a part of the so-called "Papez Circuit". The pathway by which the mammillary body projects to the other structures of the limbic system and the way it connects the limbic system to other parts of the brain like the tegmentum is not fully understood. This clarification of the connection between the lateral mammilary nucleus and the anterodorsal thalamic nucleus is but one of the contemplated pathways.

Animals↗
PubMed1997

Synaptic connections between identified neuron types in the antennal lobe glomeruli of the cockroach, Periplaneta americana: I. Uniglomerular projection neurons.

A combination of three different labels was used to demonstrate synapses between three types of neurons within the glomeruli: 1) antennal receptor cells, 2) gamma-aminobutyric acid (GABA)-immunoreactive neurons, and 3) uniglomerular projection neurons. Receptor cell axons were experimentally severed and caused to degenerate; uniglomerular projection neurons, a subgroup of glomerular output neurons, were labeled by intracellular horseradish peroxidase (HRP) injection and GABA-containing neurons by postembedding immunogold staining. The following synaptic connections were identified: 1) Receptor cell axons form monosynaptic contacts in a dyadic fashion onto a dendritic process of a uniglomerular projection neuron and in addition onto a GABA-immunoreactive neuron. 2) Receptor cell axons form polysynaptic connections with dendrites of uniglomerular projection neurons via GABA-immunoreactive neurons. 3) GABA-immunoreactive neurons form dyadic output synapses onto receptor cell axons and in addition onto projection neuron dendrites. These findings provide further evidence that signal transfer from receptor cells onto uniglomerular projection neurons is mediated by two different paths: first, a monosynaptic and presumably excitatory route and, second, an inhibitory polysynaptic route via GABAergic, most likely multiglomerular interneurons. The output synapses of GABA-immunoreactive neurons onto both receptor cells and uniglomerular projection neurons are assumed to exert control functions in regulating the neuronal activity within the glomeruli.

Animals↗
PubMed1997

Topographical organisation within the lateral reticular nucleus mossy fibre projection to the c1 and c2 zones in the rostral paramedian lobule of the cat cerebellum.

The organisation of the projection from the principal lateral reticular nucleus (LRN) to the electrophysiologically defined cerebellar cortical c1 and c2 zones within apical folia of the forelimb-receiving area of the rostral paramedian lobule was investigated in cats. In individual experiments, small injections of either of two retrograde tracers, wheat germ agglutinin-horseradish peroxidase or fluorescent-tagged beads, were made into one or the other of the two zones. The mossy fibre projection from the LRN was found to arise almost entirely from the ipsilateral nucleus, primarily from its magnocellular region. In the pars anterior (folia 1-3) of the paramedian lobule, the projection to the c1 zone arose from cells located throughout most of the rostrocaudal extent of the magnocellular LRN, whereas the projection to the c2 zone was from cells in the rostral half of this region. There was also a small projection from cells in the dorsolateral parvicellular LRN to the c2 zone, but there was none to the c1 zone. Double-label experiments showed that, in territories within LRN where overlap occurred, cells that target either zone were intermingled, and, at most, about 9% of cells had axons that branched to innervate both zones. In the pars posterior (folia 4-6), cells targeting the two zones arose from largely overlapping areas throughout both the magnocellular and the dorsolateral parvicellular LRN, although cells targeting the c2 zone appeared to be more restricted in distribution. In addition to these interzonal differences, it was found that the projection to the pars posterior from cells in the parvicellular LRN was stronger than that to the pars anterior, irrespective of the cortical zone injected. Overall, the present study provides evidence that there is at least some topographical organisation within the LRN mossy fibre projection to certain cerebellar cortical zones.

Afferent Pathways↗
PubMed1997

Comparison of nipple projection with the modified double-opposing tab and star flaps.

This study compared nipple projection after nipple reconstruction (following breast mound reconstruction) with either the modified double-opposing tab flap or the star flap. Areolar reconstruction and pigmentation of the nipple were achieved with tattooing. Nipple projection for 153 nipples was measured at least 6 months after the reconstruction, when projection was believed to have become stable. Mean follow-up was 2.27 years. In the 106 nipples reconstructed with modified double-opposing tab flaps, the mean projection was 2.4292 mm, while in the 47 nipples reconstructed with star flaps, the mean projection was 1.9681 mm (p = 0.021). We conclude that although both methods are effective, the modified double-opposing tab flap has slightly more projection after approximately 2 years. It is not known, however, whether this is because of reduced flap atrophy or longer initial projection by the modified double-opposing tab flap; further studies are ongoing.

Female↗
PubMed1997

GABAergic and other noncholinergic basal forebrain neurons, together with cholinergic neurons, project to the mesocortex and isocortex in the rat.

The extrathalamic relay from the brainstem reticular formation to the cerebral cortex in the basal forebrain has been thought to be constituted predominantly, if not exclusively, by cholinergic neurons. In contrast, the septohippocampal projection has been shown to contain an important contingent of gamma-aminobutyric acid (GABA)ergic neurons. In the present study, we investigated whether GABAergic neurons also contribute to the projection from the basal forebrain to neocortical regions, including the mesocortex (limbic) and the isocortex in the rat. For this purpose, retrograde transport of cholera toxin (CT) was examined from the medial prefrontal cortex for the mesocortex and from the parietal cortex for the isocortex and was combined with dual-immunohistochemical staining for either choline acetyltransferase (ChAT) or glutamic acid decarboxylase (GAD) in adjacent series of sections. Retrogradely labelled GAD+ neurons were codistributed with retrogradely labelled ChAT+ neurons through the basal forebrain from both the prefrontal and the parietal cortex, suggesting parallel, widespread cortical projections. The GAD+ cortically projecting cells were similar in size to the ChAT+ cells, thereby indicating that they comprise a contingent of the magnocellular basal cell complex. The proportions of retrogradely labelled neurons that were GAD+ (approximately one-third) were equal to or greater than those that were ChAT+ from both the prefrontal cortex and the parietal cortex. In addition, the total of GAD+ and ChAT+ neurons did not account for the total number of cortically projecting cells, indicating that another equivalent proportion of chemically unidentified noncholinergic neurons also contributes to the basalocortical projection. Accordingly, as in the allocortex, GABAergic, cholinergic, and other unidentified noncholinergic neurons may have the capacity to modulate activity in the mesocortex (limbic) and the isocortex through parallel, widespread projections.

Animals↗
PubMed1997

Organization of the descending projections from the parabrachial nucleus to the trigeminal sensory nuclear complex and spinal dorsal horn in the rat.

To clarify direct descending projections from the parabrachial nucleus (PB) to the trigeminal sensory nuclear complex (TSNC) and spinal dorsal horn (SpDH), the origin and termination of descending tract cells were examined by the anterograde and retrograde transport methods. Phaseolus vulgaris leucoagglutinin (PHA-L) and Fluorogold (FG) or dextran-tetramethylrhodamine (Rho) were used as neuronal tracers for the anterograde and retrograde transport, respectively. The ventrolateral PB, including Kölliker-Fuse nucleus (KF), sent axons terminating mainly in the ventrolateral parts of rostral trigeminal nuclei of the principalis (Vp), oralis (Vo), and interpolaris (Vi) as well as in the inner lamina II of the medullary (nucleus caudalis, Vc) and SpDH. Although the descending projections were bilateral with an ipsilateral dominance, TSNC received a more dominant ipsilateral projection than SpDH. The cells of origin of the descending tracts were located mainly in KF, but TSNC received fewer projections from the KF than SpDH. Namely, TSNC received a considerable projection from the medial subnucleus of PB and the ventral parts of lateral subnuclei of PB, such as the central lateral subnucleus and lateral crescent area. The other difference noted between TSNC and SpDH was that the former received projections mainly from the caudal two thirds of KF and the latter from the rostral two thirds of KF. These results demonstrate the existence of direct parabrachial projections to TSNC and SpDH that are organized in a distinct manner and suggest that both pathways are involved in the control of nociception.

Animals↗
PubMed1997

Organization of corticostriatal and corticoamygdalar projections arising from the anterior inferotemporal area TE of the macaque monkey: a Phaseolus vulgaris leucoagglutinin study.

Corticostriatal and corticoamygdalar projections arising from area TE of the macaque monkey were studied by focal injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into the dorsolateral and ventromedial subdivisions of the anterior TE (TEad and TEav, respectively). This approach yielded several new results. First, the global distributions of labeled terminals revealed that both TEad and TEav projected to the ventrocaudal striatum, including the tail of the caudate nucleus and the adjacent ventral putamen, and the dorsolateral aspect of the deep amygdaloid nuclei. TEav also projected to the medial basal nucleus of the amygdala and the ventral striatum. Second, the reconstructed single axons (n = 18) demonstrated that some axons originating from TEav or TEad projected simultaneously to the ventrocaudal striatum and the dorsolateral aspect of the deep amygdaloid nuclei by giving off collaterals. TEav axons projected to the medial basal nucleus of the amygdala also had collaterals projecting to the perirhinal cortex or area TG. And third, it was revealed that the axons originating from a focal TEav or TEad projected to a restricted territory (3.4-3.6 mm rostrocaudally) in the ventrocaudal striatum with four to six dispersed, rostrocaudally elongated, rod-like modules. Individual axons with multiple arbors innervated many of these modules. These findings add the evidence that the anterior part of TE is anatomically heterogeneous and suggest that the deep amygdaloid nuclei may be functionally dissociated, with the dorsolateral aspect more closely related to the ventrocaudal striatum and the medial basal nucleus more closely related to the perirhinal cortex.

Amygdala↗
PubMed1997

Combating tuberculosis--lessons learnt from a rural community project in the Klein Drakenstein area of the Western Cape.

OBJECTIVE: To describe and evaluate a lay worker project designed to enhance the effective control of tuberculosis in a rural/farm setting. DESIGN: A descriptive cohort study using both qualitative and quantitative research methodology. SETTING AND PARTICIPANTS: Farming community in the Klein Drakenstein area of Paarl, Western Cape, with health services provided by the Cape Metropolitan Council. The adherence of patients receiving tuberculosis treatment from 1 January 1993 to 31 December 1995 was analysed. The acceptability of the project was assessed using indepth interviews with key stakeholders. RESULTS: A cohort of 402 tuberculosis patients was included in the study. This cohort was divided into the patients from farms that had participated in the project (intervention group) and those that had not (non-intervention group). The adherence data for children and adults were analysed separately. The adherence rates for children in both groups were the same (RR = 1.00, 95% Cl 0.88-1.14), whereas the adherence rate for the adult intervention group was significantly better than that of the non-intervention group (RR = 1.19, 95% Cl 1.08-1.31). The qualitative component of the investigation indicated a high level of commitment to the intervention from the members of the implementation team, the farm health workers and their employers. The farm health workers described how their role had assisted their communities and had improved their own perceptions of self-efficacy. The close bond that they had developed with the formal health sector had improved the access of the labourers on the farm to primary health care. Although the project had commenced as a tuberculosis initiative, the farm health workers were dealing with a variety of health issues. Their ongoing training was designed to facilitate this development. The formal health sector found their activities facilitated by the easy access that they had with a representative from each farm. The employers were satisfied that the project had increased the cost-effectiveness of their economic endeavours. CONCLUSION: This farm worker project appears to be a model of a well-designed and expertly managed community-based project for tuberculosis control in rural/farm areas.

Adolescent↗
PubMed1997

Anterograde projections of the cortical tongue area of the tree shrew (Tupaia belangeri).

In altogether seven tree shrews, Tupaia belangeri, the anterograde projections of the motorcortical tongue area were investigated as part of a larger comparative study. Identification of the tongue area was carried out by electrical brain stimulation. Three different tracers were used: biotin-conjugated dextranamine (BDA), Phaseolus vulgaris leucoagglutinin (PHA-L) and 3H-leucine. Intracortical projections were found to the motor cortex around the injection site, the premotor cortex, supplementary motor area, the homologues of the primate frontoparietal operculum and insula, the anterior cingulate and agrannular retrosplenial cortex, the somatosensory and bordering inferior parietal cortex as well as to the perirhinal cortex. Except the very weak projections into the retrosplenial, posterior parietal and perirhinal region which were ipsilateral, all other projections were bilateral. Subcortically, there was a projection into the ventral putamen, rostrodorsal claustrum and, very sparsely, into the caudate nucleus. In the thalamus, terminal labeling was found in the nuclei reticularis, anteroventralis, anteromedialis, ventralis lateralis, ventralis posterior medialis, ventralis posterior inferior, medialis dorsalis, in the intralaminar nuclei paracentralis, centralis lateralis, centrum medianum and parafascicularis, in the midline thalamus and in the nuclei posterior and pulvinaris. Further diencephalic projections, however all of them wak, could be traced into the zona incerta, dorsolateral subthalamus, dorsomedial, lateral and supraoptic hypothalamus. In the midbrain, labeling was found in the deep layers of the lateral superior colliculus, in the bordering reticular formation and, very sparsely, in the periaqueductal grey. In the lower brain-stem, fibres ended in the griseum pontis, dorsolateral reticular formation, principal and spinal trigeminal nucleus and, sparsely, in the lateral parabrachial region, solitary tract nucleus, inferior olive and magnocellular reticular formation. No terminals were found in the hypoglossal nucleus. The projection system revealed with PHA-L was less extensive than that demonstrated with BDA and 3H-leucine, both of which were similar.

Animals↗
PubMed1998

Numerical aspects of pontine, lateral reticular, and inferior olivary projections to two paravermal cortical zones of the cat cerebellum.

Two different olivo-cortico-nuclear zones in the cat cerebellum have been compared quantitatively as regards the numbers of cells projecting to them from within several sources of mossy fibres (MFs), namely the basal pontine nuclei (BPN), nucleus reticularis tegmenti pontis (NRTP), and the ipsilateral lateral reticular nucleus (LRN). The zones chosen were the C3 zone in lobule V of the anterior lobe and the C1 zone in pars copularis of the paramedian lobule (PMLpc), localised by recording climbing fibre-mediated potentials evoked on their surface as a result of volleys set up in their spino-olivocerebellar paths. The zones were injected with fluorescent-labelled latex microspheres and cell bodies, retrogradely labelled in the MF source nuclei and in the contralateral inferior olive, were counted and mapped. Evidence was obtained that tracer efficiency was very high in both the MF projections and the olivo-cerebellar projection and that each olivocerebellar axon may provide only one climbing fibre to the upper part of a lobule V folium but an average of nearly two to the same part of a PML folium. When the numbers of labelled cells in each MF source nucleus were expressed as a percentage of the total number of labelled pontine cells, the biggest source for lobule V was the contralateral BPN, followed by LRN, contralateral NRTP, ipsilateral BPN, and ipsilateral NRTP. For PMLpc, the order was similar except that ipsilateral BPNs exceeded contralateral NRTPs, but the dominance of contralateral BPN as a source was much greater. Cell totals were converted into projection densities (i.e., numbers of cells labelled per square millimetre of cortical sheet involved in the injection site); densities for PMLpc were found to be almost three times greater than those for lobule V for contralateral BPN but the two densities were not significantly different for ipsilateral BPN. The three other MF sources projected at higher densities to lobule V than to PML. These findings indicate that two cortical zones, both of which receive climbing fibres from the rostral part of the dorsal accessory olive and project to nucleus interpositus anterior, nevertheless differ markedly in regard to both the relative and the absolute sizes of the projections they receive from several of their most important sources of MFs.

Animals↗
PubMed1997

The relationship between cervical enamel projection and class II furcation defects in humans.

The purposes of the present study were to examine the frequency of cervical enamel projection in mandibular molars with class II furcation defects and to examine the response of these teeth to guided tissue regeneration procedures. Probing depth and vertical and horizontal periodontal attachment levels were recorded with a constant-force electronic periodontal probe. Following surgical exposure of the bifurcation and prior to membrane placement, the cervical enamel projection was examined and then graded clinically; photographs were taken to allow further examination of the bifurcation. An overall improvement in clinical parameters was observed in most sites. Cervical enamel projection was present in 82.1% of all molars examined. Grade II was the most prevalent (34.8%). Patients with any degree of cervical enamel projection demonstrated significantly higher mean probing depths at baseline than did patients without cervical enamel projection. Likewise, pretreatment probing attachment levels were higher in patients with some degree of cervical enamel projection. However, greater posttreatment horizontal and vertical attachment gains were observed in sites with a baseline cervical enamel projection.

Analysis of Variance↗
PubMed1997

Development of the olivocerebellar projection.

The establishment of orderly axonal projections is one of the essential steps in the formation of central networks. In this review, we discuss several of the current hypotheses on the mechanisms and molecules which govern this developmental process, using the olivocerebellar system as a model. During the formation of the olivocerebellar projection, there is a simultaneous and independent process of parcellation of the inferior olive and of the cerebellum. During embryogenesis, Purkinje cells in the cerebellar cortex and inferior olivary neurons are subdivided into small subsets of biochemically distinct compartments. We propose that this parcellation is involved in matching groups of olivary neurons to their corresponding subsets of target Purkinje cells. In vitro, the rotation of the anteroposterior axis of the cerebellum is followed by an equivalent inversion of the olivocerebellar projection. Olivary axons still project to the same Purkinje cells, suggesting that the formation of the olivocerebellar projection is regulated by positional information shared between pre- and postsynaptic neurons. We suggest that, in the chick embryo, the cell adhesion molecule BEN/SC1/DM-GRASP could be one of the target recognition molecules controlling the development of the olivocerebellar projection. These results also emphasize that coarse grained projection maps can form through chemoaffinity mechanisms, independent of the activity of the interacting neurons.

Animals↗
PubMed1997

Some claustral neurons projecting to various neocortical areas show morphological differences.

The morphology of claustral neurons projecting to the motor, somatosensory, auditory and visual cortical areas in the rat was analyzed by means of combination of axonal retrograde transport and morphometric analysis. Fluoro-Gold (FG) injections placed into various cortical fields resulted in labeling in the claustrum four neuronal types: pyramidal with thick main dendrite, oval with a few thin dendrites spreading out in various directions, fusiform possessing two main dendrites arising from opposite poles of the cell body and polygonal. Pyramidal neurons prevailed in populations of neurons projecting to the motor cortex of the contralateral hemisphere. Oval neurons outnumbered other types in populations projecting to the somatosensory, auditory and visual cortical fields. The number of fusiform and polygonal neurons did not exceed at 12.5% together in any populations. Neurons projecting to the contralateral hemisphere were the largest claustral neurons (mean cross-section are 167.19 +/- 2.9 micron 2) whereas neurons projecting to the motor cortex where the largest claustral neurons projecting ipsilaterally (141.89 +/- 2.22 micron 2). There was no significant difference between neurons projecting to the somatosensory (113.46 +/- 1.9 micron 2) cortex and to the visual (111.8 +/- 1.4 micron 2) cortex whereas neurons related to the auditory are (95.98 +/- 1.75 micron 2) were the smallest claustral neurons. These observations pointed out that the morphology of claustral neurons is closely related to a cortical area to which they send axons.

Animals↗
PubMed1998

Projection of HIV infection in Calcutta.

Starting with the base year of 1991, the HIV infection projection for 1992-99 for the total, as well as various high-risk sub-populations of Calcutta, the first of its kind is provided. These projections are based on statistical methodology developed in this paper. Our methodology for spread of HIV infection takes into account various social interactions and practices and also uses available data. Rates of these interactions and practices and estimates of demographic parameters used in making projections were obtained primarily from surveys and census data. Since one of these estimated rates, that of HIV transmission rate through heterosexual encounters between an infected and an uninfected had a large range, we have provided two sets of projections based on the largest of these rates (worst-case scenario) and another that is consistent with the available data. The total projection of the number of HIV infected cases in Calcutta for 1999 is between 49,000 and 1,26,000. Separate projections are also provided for high-risk sub-groups. Among these, the sex workers expectedly will continue to manifest the highest numbers of newly infected cases. The temporal rate of increase in prevalence is projected to be alarmingly higher in the general population than even among sex workers, although the actual prevalence will continue to be the lowest in the general population compared to all other sub-groups of the population.

Female↗
PubMed1998

Projections from substantia nigra and zona incerta to the cat's nucleus of Darkschewitsch.

The goal of the present experiments was to examine the relationships of the nucleus of Darkschewitsch (ND) with the substantia nigra pars reticulata (SNr), the zona incerta (ZI), and the oculomotor nuclei by using wheat germ agglutinin-horseradish peroxidase (WGA-HRP) as a retrograde and anterograde neuronal tracer injected into various sites of the cat's brain. To eliminate the possibility that fibres of passage from the motor cortex passing through the SNr and ZI were responsible for the ND label, WGA-HRP also was injected into the SNr or the ZI after a large area of the frontal cortex, including the motor area, was destroyed. Retrograde axonal transport demonstrated that many cells of the rostromedial part of the ZI project to the ND, with the ipsilateral projections being dominant. Some cells of the caudomedial part of the SNr project to the ND, again, with the ipsilateral projection being dominant. A few small cells in the ND project bilaterally to the oculomotor nucleus. Anterograde tracer demonstrated that the SNr-ND terminal fields are less dense than the ZI-ND terminal fields. A few fine terminal fibres were observed bilaterally in the oculomotor, trochlear, and abducens nuclei. Electron microscopic examination demonstrated that these fine, labelled terminals contain pleomorphic vesicles and have symmetrical synaptic contacts with dendrites. These results indicate that the ND, a structure that is known to be important for the control of axial muscles (i.e., eye, head, and body muscles), is the target of projections from restricted areas of the SNr and ZI: areas that, during saccadic eye movement, may lead to disinhibition of the ND-oculomotor projection. Accordingly, the ND may function to inhibit the activity of extraocular muscles during saccades.

Animals↗
PubMed1998

Duodenal sensory neurons project to sphincter of Oddi ganglia in guinea pig.

Retrograde labeling of duodenum-sphincter of Oddi (SO) preparations in vitro with the carbocyanine dye DiI revealed that duodenal neurons project to the SO. The duodenum-SO-projecting neurons were immunoreactive (IR) for choline acetyltransferase but not nitric oxide synthase or calretinin, indicating that this is a cholinergic projection and that this pathway is distinct from the circuitry involved in the ascending limb of the peristaltic reflex. Approximately 20% of the duodenum-SO projection neurons were IR for calbindin. Calbindin-IR nerves within SO ganglia degenerated when the SO was maintained in organ culture alone, but persisted when the SO was cultured with the duodenum intact. Therefore, SO ganglia are a target of the calbindin-positive duodenum-SO projection. Because calbindin is a marker of intrinsic sensory neurons that have processes that pass to the mucosa, these neurons are in position to detect the release of a compound from the mucosa and signal its release to SO ganglia. When applied to retrogradely labeled neurons, cholecystokinin (CCK) elicited a prolonged depolarization, indicating that duodenum-SO-projecting neurons could be capable of detecting CCK released from the mucosa. It is proposed that the role of the intrinsic sensory neurons that project to the SO may be to signal the postprandial release of CCK, thus providing an instruction to decrease SO resistance and facilitate the flow of bile into the duodenum.

Animals↗
PubMed1998

Project management skills.

1. Project management skills are important to develop because occupational and environmental health nurses are increasingly asked to implement and manage health related projects and programs. 2. Project management is the process of planning and managing project tasks and resources, and communicating the progress and results. This requires the coordination of time, tasks, equipment, people, and budget. 3. Three main critical skill areas are needed to be an effective project manager: behavioral skills such as negotiation, conflict resolution, and interpersonal problem solving; use of project management tools to manage project tasks and resources; and effective communication skills.

Communication↗
PubMed1998

Prefrontal cortical projections to the hypothalamus in macaque monkeys.

The organization of projections from the macaque orbital and medial prefrontal cortex (OMPFC) to the hypothalamus and related regions of the diencephalon and midbrain was studied with retrograde and anterograde tracing techniques. Almost all of the prefrontal cortical projections to the hypothalamus arise from areas within the "medial prefrontal network," as defined previously by Carmichael and Price ([1996] J. Comp. Neurol. 371:179-207). Outside of the OMPFC, only a few neurons in the temporal pole, anterior cingulate and insular cortex project to the hypothalamus. Axons from the OMPFC also innervate the basal forebrain, zona incerta, and ventral midbrain. Within the medial prefrontal network, different regions project to distinct parts of the hypothalamus. The medial wall areas 25 and 32 send the heaviest projections to the hypothalamus; axons from these areas are especially concentrated in the anterior hypothalamic area and the ventromedial hypothalamic nucleus. Orbital areas 13a, 12o, and Iai, which are related to the medial prefrontal network, selectively innervate the lateral hypothalamic area, especially its posterior part. The cellular regions of the paraventricular, supraoptic, suprachiasmatic, arcuate, and mammillary nuclei are conspicuously devoid of cortical axons, but many axons abut the borders of these nuclei and may contact dendrites that extend from them. Areas within the orbital prefrontal network on the posterior orbital surface and agranular insula send only weak projections to the posterior lateral hypothalamic area. The rostral orbital surface does not contribute to the cortico-hypothalamic projection.

Amidines↗