Biomaterial Database

Intra-amygdaloid projections of the basolateral and basomedial nuclei in the cat: Phaseolus vulgaris-leucoagglutinin anterograde tracing at the light and electron microscopic level. 1995

D Paré, and Y Smith, and J F Paré

Département de Physiologie, Faculté de Médecine, Université Laval, Québec, Canada.

The amygdaloid complex plays an essential role in auditory fear conditioning of the Pavlovian type. The available evidence suggests that the lateral nucleus is the input station of the amygdala for auditory conditioned stimuli, whereas the central medial nucleus is the output for conditioned fear responses. However, the intrinsic pathway transmitting auditory information about the conditioned stimulus from the lateral to the central medial nuclei is unknown as there are no direct projections between these nuclei. The present study was undertaken to determine if the main intra-amygdaloid targets of the lateral nucleus, namely the basomedial and basolateral nuclei, project to the central medial nucleus. To this end, iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin were performed in these nuclei. To rule out the possibility that the anterograde labeling reflected passing fibers merging with the major fiber bundles that course in and around the central medial nucleus, labeled terminals and varicosities were observed in the electron microscope. It was determined that the basolateral and basomedial nuclei have partially overlapping intraamygdaloid targets. They both project to the central medial nucleus, nucleus of the lateral olfactory tract and peri-amygdaloid cortex, but have limited projections to each other. Small Phaseolus vulgaris-leucoagglutinin injections in both nuclei gave rise to prominent intranuclear projections but only the basomedial nucleus was found to project to the lateral and anterior cortical nuclei. At the electron microscopic level, all labeled axon terminals and varicosities formed asymmetric synapses (n = 245) with dendritic spines (83%) or with dendritic shafts (17%). This is the first unambiguous demonstration that the basolateral and basomedial nuclei project to the central medial nucleus. Since these nuclei constitute the main intra-amygdaloid targets of the lateral nucleus, they represent likely candidates for the transmission of auditory conditioned stimuli to the central medial nucleus in auditory fear conditioning.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D010835	Phytohemagglutinins	Mucoproteins isolated from the kidney bean (Phaseolus vulgaris); some of them are mitogenic to lymphocytes, others agglutinate all or certain types of erythrocytes or lymphocytes. They are used mainly in the study of immune mechanisms and in cell culture.	Kidney Bean Lectin,Kidney Bean Lectins,Lectins, Kidney Bean,Phaseolus vulgaris Lectin,Phaseolus vulgaris Lectins,Phytohemagglutinin,Hemagglutinins, Plant,Lectin, Kidney Bean,Lectin, Phaseolus vulgaris,Lectins, Phaseolus vulgaris,Plant Hemagglutinins
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D000679	Amygdala	Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.	Amygdaloid Body,Amygdaloid Nuclear Complex,Amygdaloid Nucleus,Archistriatum,Corpus Amygdaloideum,Intercalated Amygdaloid Nuclei,Massa Intercalata,Nucleus Amygdalae,Amygdalae, Nucleus,Amygdaloid Bodies,Amygdaloid Nuclear Complices,Amygdaloid Nuclei, Intercalated,Amygdaloid Nucleus, Intercalated,Amygdaloideum, Corpus,Amygdaloideums, Corpus,Archistriatums,Complex, Amygdaloid Nuclear,Complices, Amygdaloid Nuclear,Corpus Amygdaloideums,Intercalata, Massa,Intercalatas, Massa,Intercalated Amygdaloid Nucleus,Massa Intercalatas,Nuclear Complex, Amygdaloid,Nuclear Complices, Amygdaloid,Nuclei, Intercalated Amygdaloid,Nucleus, Amygdaloid,Nucleus, Intercalated Amygdaloid
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon
D017729	Presynaptic Terminals	The distal terminations of axons which are specialized for the release of neurotransmitters. Also included are varicosities along the course of axons which have similar specializations and also release transmitters. Presynaptic terminals in both the central and peripheral nervous systems are included.	Axon Terminals,Nerve Endings, Presynaptic,Synaptic Boutons,Synaptic Terminals,Axon Terminal,Bouton, Synaptic,Boutons, Synaptic,Ending, Presynaptic Nerve,Endings, Presynaptic Nerve,Nerve Ending, Presynaptic,Presynaptic Nerve Ending,Presynaptic Nerve Endings,Presynaptic Terminal,Synaptic Bouton,Synaptic Terminal,Terminal, Axon,Terminal, Presynaptic,Terminal, Synaptic,Terminals, Axon,Terminals, Presynaptic,Terminals, Synaptic