A rare variations of the cephalic vein drainage: two cases report.

Throughout the years, anatomic studies have demonstrated numerous variations in the course of the cephalic vein (CV). There are, however, very rare cases of uncommon formation, course or termination of the vein to which our attention should be drawn. During a routine dissections conducted in the Department of Anatomy and Neurobiology, in two formalin-fixed cadavers, the very rare anatomical variants were found. In 80 year-old Caucasian female the right cephalic vein, after crossing the clavipectoral triangle, ascended anterior and superior to the clavicle and drained into the lateral branch of the right external jugular vein, which in turn opened to the right subclavian vein. In the second case, the dissection of 83 year-old Caucasian male cadaver revealed that after passing through the deltopectoral groove, the left cephalic vein run between clavicle and subclavius muscle to terminate in the left subclavian vein. Understanding of the topography, morphology and anatomical variations of the cephalic vein is important not only for the anatomists but for the clinicians and nurses as well. Such knowledge can prevent multiple complications during many invasive procedures including implantation of Cardiac Implantable Electronic Devices, central venous access, arteriovenous fistula creation or even iatrogenic injuries during clavicle or glenohumeral joint surgery.

Colocalization of neuropeptides with calcium-binding proteins in the claustral interneurons during postnatal development of the rat.

The claustrum is a relatively large telencephalic structure, situated close to the border of the neo- and allocortical regions. Its neuronal population consists of glutamatergic, projecting neurons and GABA-ergic interneurons, characterized by occurrence of numerous additional biochemical markers. The postnatal development of these latter neurons has not been extensively studied. Revealing the characteristic patterns of colocalizations between selected markers may shed some light on their function and origin. We investigated the colocalization patterns between three neuropeptides: neuropeptide Y, somatostatin, vasoactive intestinal polypeptide and three calcium-binding proteins: calbindin D28k, calretinin, parvalbumin in the interneurons of the rat claustrum during a four-month postnatal period (P0-P120; P: postnatal day). Our studies revealed the following types of colocalizations: neuropeptide Y with calbindin D28k, calretinin or parvalbumin; somatostatin with calbindin D28k; vasoactive intestinal polypeptide with calretinin. Only vasoactive intestinal polypeptide- and calretinin-containing, double-labeled neurons were present at the day of birth, whereas the other double-labeled neurons appeared at later stages of development. The ratios of colocalizing neurons to single-labeled neurons in each type of colocalization were differentiated and reached the highest value (51%) for vasoactive intestinal polypeptide- and calretinin-double-labeled neurons. In conclusion, the claustral interneurons represent differentiated population in respect to the occurrence of neuropeptides and calcium-binding proteins. The expression of studied substances is changing during the postnatal period.

Distribution of the parvalbumin, calbindin-D28K and calretinin immunoreactivity in globus pallidus of the Brazilian short-tailed opossum (Monodelphis domestica).

This study describes the topography, borders and divisions of the globus pallidus in the Brazilian short-tailed opossum (Monodelphis domestica) and distribution of the three calcium binding proteins, parvalbumin (PV), calbindin D-28k (CB) and calretinin (CR) in that nucleus. The globus pallidus of the opossum consists of medial and lateral parts that are visible with Nissl or Timm's staining and also in PV and CR immunostained sections. Neurons of the globus pallidus expressing these proteins were classified into three types on the basis of size and shape of their soma and dendritic tree. Type 1 neurons had medium-sized fusiform soma with dendrites sprouting from the opposite poles. Neurons of the type 2 had medium-to-large, multipolar soma with scarce, thin dendrites. Cell bodies of type 3 neurons were small and either ovoid or round. Immunostaining showed that the most numerous were neurons expressing PV that belonged to all three types. Density of the PV-immunopositive fibers and puncta correlated with the density of the PV-labeled neurons. Labeling for CB resulted mainly in the light staining of neuropil in both parts of the nucleus, while the CB-expressing cells (mainly of the type 2) were scarce and placed only along the border of the globus pallidus and putamen. Staining for calretinin resulted in labeling almost exclusively the immunoreactive puncta and fibers that were distributed with medium-to-high density throughout the nucleus. Close to the border of globus pallidus with the putamen these fibers (probably dendrites) were long, thin and varicous, while more medially bundles of thick, short and smooth fibers predominated. Single CR-ir neurons (all of the type 3) were scattered through the globus pallidus. Colocalization of two calcium binding proteins in one neuron was. never observed. The CB-ir puncta (probably terminals of axons projecting to the nucleus) frequently formed basket-like structures around the PV-ir neurons. Therefore, the globus pallidus in the opossum, much as that in the rat, consists of a heterogeneous population of neurons, probably playing diversified functions.

Projections from the amygdaloid complex to the piriform cortex: A PHA-L study in the rat.

Projections from the amygdala to the piriform cortex are proposed to provide a pathway via which the emotional system can modulate the processing of olfactory information as well as mediate the spread of seizure activity in epilepsy. To understand the details of the distribution and topography of these projections, we injected the anterograde tracer Phaseolus vulgaris-leucoagglutinin into different nuclear divisions of the amygdaloid complex in 101 rats and analyzed the distribution and density of projections in immunohistochemically processed preparations. The heaviest projections from the amygdala to the piriform cortex originated in the medial division of the lateral nucleus, the periamygdaloid and sulcal subfields of the periamygdaloid cortex, and the posterior cortical nucleus. The heaviest terminal labeling was observed in layers Ib and III of the medial aspect of the posterior piriform cortex. Lighter projections to the posterior piriform cortex originated in the dorsolateral division of the lateral nucleus, the magnocellular and parvicellular divisions of the basal and accessory basal nuclei, and the anterior cortical nucleus. The projections to the anterior piriform cortex were light and originated in the dorsolateral and medial divisions of the lateral nucleus, the magnocellular division of the basal and accessory basal nuclei, the anterior and posterior cortical nuclei, and the periamygdaloid subfield of the periamygdaloid cortex. The results indicate that only selective amygdaloid nuclei or their subdivisions project to the piriform cortex. In addition, substantial projections from several amygdaloid nuclei converge in the medial aspect of the posterior piriform cortex. Via these projections, the amygdaloid complex can modulate the processing of olfactory information in the piriform cortex. In pathologic conditions such as epilepsy, these connections might provide pathways for the spread of seizure activity from the amygdala to extra-amygdaloid regions.

Do seizures cause irreversible cognitive damage? Evidence from animal studies.

Data from experimental models provide evidence that both prolonged and brief seizures can cause irreversible impairment in spatial and emotional learning and memory. Factors related to the severity of the behavioral impairments include genetic background, age at the time of the epileptogenic insult, extent of brain lesion, location of seizure focus, seizure duration, seizure number, brain reserve, and environmental and social living conditions. Further, as in humans, the interval between the last seizure and behavioral testing as well as treatment with antiepileptic drugs can affect the test results.

Activation of the amygdalo-entorhinal pathway in fear-conditioning in rat.

Several studies implicate a role for the amygdala in processing of emotional memories that might partially occur in the connections between the amygdala and the hippocampal-parahippocampal areas. The present study was designed to determine if the pathway from the amygdala to the entorhinal cortex becomes activated during acquisition of fear-conditioning. First, the retrograde tracer Fluoro-Gold (FG) was iontophoresed into the entorhinal cortex in rats. Following habituation, animals were divided into five groups: (i) controls that received another habituation session; (ii) animals given a tone only; (iii) animals given a footshock only; (iv) animals given an unpaired presentation of a shock and a tone; and (v) conditioned animals that received a single tone-footshock pairing. Then double-immunohistochemistry against c-Fos and FG or glutamate decarboxylase (GAD67) was performed. The numbers and densities of labelled neurons were calculated in the lateral and basal nuclei of the amygdala. In conditioned animals the number and density of c-Fos-positive nuclei increased in dorsolateral and medial divisions of the lateral nucleus compared with the control group (P < 0.05). Additionally, in the medial division of the lateral nucleus, the percentage of c-Fos/FG double-labelled neurons was higher in the conditioned animals compared with the other groups (P < 0.05). Only a very few GAD67-positive interneurons expressed c-Fos. These data indicate that a part of the amygdalo-entorhinal pathway is activated during acquisition of fear-conditioning. These data support the idea that emotionally relevant sensory information in the lateral nucleus can influence information processing in the hippocampal and parahippocampal areas via the amygdalo-entorhinal pathway.

Projections from the periamygdaloid cortex to the amygdaloid complex, the hippocampal formation, and the parahippocampal region: a PHA-L study in the rat.

The periamygdaloid cortex, an amygdaloid region that processes olfactory information, projects to the hippocampal formation and parahippocampal region. To elucidate the topographic details of these projections, pathways were anterogradely traced using Phaseolus vulgaris leukoagglutinin (PHA-L) in 14 rats. First, we investigated the intradivisional, interdivisional, and intra-amygdaloid connections of various subfields [periamygdaloid subfield (PAC), medial subfield (PACm), sulcal subfield (PACs)] of the periamygdaloid cortex. Thereafter, we focused on projections to the hippocampal formation (dentate gyrus, hippocampus proper, subiculum) and to the parahippocampal region (presubiculum, parasubiculum, entorhinal, and perirhinal and postrhinal cortices). The PACm had the heaviest intradivisional projections and it also originated light interdivisional projections to other periamygdaloid subfields. Projections from the other subfields converged in the PACs. All subfields provided substantial intra-amygdaloid projections to the medial and posterior cortical nuclei. In addition, the PAC subfield projected to the ventrolateral and medial divisions of the lateral nucleus. The heaviest periamygdalohippocampal projections originated in the PACm and PACs, which projected moderately to the temporal end of the stratum lacunosum moleculare of the CA1 subfield and to the molecular layer of the ventral subiculum. The PACm also projected moderately to the temporal CA3 subfield. The heaviest projections to the entorhinal cortex originated in the PACs and terminated in the amygdalo-entorhinal, ventral intermediate, and medial subfields. Area 35 of the perirhinal cortex was lightly innervated by the PAC subfield. Thus, these connections might allow for olfactory information entering the amygdala to become associated with signals from other sensory modalities that enter the amygdala via other nuclei. Further, the periamygdalohippocampal pathways might form one route by which the amygdala modulates memory formation and retrieval in the medial temporal lobe memory system. These pathways can also facilitate the spread of seizure activity from the amygdala to the hippocampal and parahippocampal regions in temporal lobe epilepsy.

Projections from the amygdaloid complex to the claustrum and the endopiriform nucleus: a Phaseolus vulgaris leucoagglutinin study in the rat.

The claustrum and the endopiriform nucleus contribute to the spread of epileptiform activity from the amygdala to other brain areas. Data of the distribution of pathways underlying the information flow between these regions are, however, incomplete and controversial. To investigate the projections from the amygdala to the claustrum and the endopiriform nucleus, we injected the anterograde tracer Phaseolus vulgaris leucoagglutinin into various divisions of the amygdaloid complex, including the lateral, basal, accessory basal, central, anterior cortical and posterior cortical nuclei, the periamygdaloid cortex, and the amygdalohippocampal area in the rat. Analysis of immunohistochemically processed sections reveal that the heaviest projections to the claustrum originate in the magnocellular division of the basal nucleus. The projection is moderate in density and mainly terminates in the dorsal aspect of the anterior part of the claustrum. Light projections from the parvicellular and intermediate divisions of the basal nucleus terminate in the same region, whereas light projections from the accessory basal nucleus and the lateral division of the amygdalohippocampal area innervate the caudal part of the claustrum. The most substantial projections from the amygdala to the endopiriform nucleus originate in the lateral division of the amygdalohippocampal area. These projections terminate in the central and caudal parts of the endopiriform nucleus. Lighter projections originate in the anterior and posterior cortical nuclei, the periamygdaloid cortex, the medial division of the amygdalohippocampal area, and the accessory basal nucleus. These data provide an anatomic basis for recent functional studies demonstrating that the claustrum and the endopiriform nucleus are strategically located to synchronize and spread epileptiform activity from the amygdala to the other brain regions. These topographically organized pathways also provide a route by means of which the claustrum and the endopiriform nucleus have access to inputs from the amygdaloid networks that process emotionally significant information.