Projection to the inferior colliculus from the basal nucleus of the amygdala.
Animals; Acoustic Stimulation/methods; Species Specificity; Action Potentials/physiology; Amygdala/*cytology/physiology; Dextrans; Rhodamines; Fluorescent Dyes; *Stilbamidines; Auditory Cortex/cytology; Auditory Pathways/*cytology/physiology; Axonal Transport/physiology; Brain Stem/cytology; Chiroptera/*anatomy & histology/physiology; Cholera Toxin/pharmacokinetics; Inferior Colliculi/*cytology/physiology; Neurons/cytology/physiology; Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; Electrodes; Implanted
This report describes a projection from the amygdala, a forebrain center mediating emotional expression, to the inferior colliculus (IC), the midbrain integration center of the ascending auditory system. In the IC of mustached bats (Pteronotus parnellii) and pallid bats (Antrozous pallidus), we placed deposits of retrograde tracers at physiologically defined sites and then searched for retrogradely labeled somata in the forebrain. Labeling was most sensitive in experiments using cholera toxin B-subunit as tracer. We consistently observed retrograde labeling in a single amygdalar subdivision, the magnocellular subdivision of the basal nucleus (Bmg). The Bmg is distinctive across mammals, containing the largest cells in the amygdala and the most intense acetylcholinesterase staining. Labeled amygdalar cells occurred ipsilateral and contralateral to IC deposits, but ipsilateral labeling was greater, averaging 72%. Amygdalar labeling was observed after tracer deposits throughout the IC, including its central nucleus (ICC). In comparison, labeling in the auditory cortex (layer V) was heavily ipsilateral (averaging 92%). Cortical labeling depended on the location of IC deposits: dorsomedial deposits resulted in the most labeled cells, whereas ventrolateral deposits labeled few or no cortical cells. Cortical labeling occurred after several deposits in the ICC. Across experiments, the average number of labeled cells in the amygdala was similar to that in the auditory cortex, indicating that the amygdalocollicular projection is significant. The results demonstrate a direct, widespread projection from the basal amygdala to the IC. They also suggest the presence of a rapid thalamoamygdalocollicular feedback circuit that may impose emotional content onto processing of sensory stimuli at a relatively low level of an ascending sensory pathway.
Marsh Robert A; Fuzessery Zoltan M; Grose Carol D; Wenstrup Jeffrey J
The Journal of neuroscience : the official journal of the Society for Neuroscience
2002
2002-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1523/jneurosci.22-23-10449.2002" target="_blank" rel="noreferrer noopener">10.1523/jneurosci.22-23-10449.2002</a>
Immunohistochemical distribution of enkephalin, substance P, and somatostatin in the brainstem of the leopard frog, Rana pipiens.
*Stilbamidines; Animals; Brain Stem/*chemistry/cytology; Enkephalins/*analysis; Fluorescent Dyes; Immunohistochemistry; Male; Rana pipiens/*metabolism; Somatostatin/*analysis; Spinal Cord/chemistry/cytology; Substance P/*analysis
The brainstems of frogs contain many of the neurochemicals that are found in mammals. However, the clustering of nuclei near the ventricles makes it difficult to distinguish individual cell groups. We addressed this problem by combining immunohistochemistry with tract tracing and an analysis of cell morphology to localize neuropeptides within the brainstem of Rana pipiens. We injected a retrograde tracer, Fluoro-Gold, into the spinal cord, and, in the same frog, processed adjacent sections for immunohistochemical location of antibodies to the neuropeptides enkephalin (ENK), substance P (SP), and somatostatin (SOM). SOM+ cells were more widespread than cells containing immunoreactivity (ir) to the other substances. Most reticular nuclei in frog brainstem contained ir to at least one of these chemicals. Cells with SOM ir were found in nucleus (n.) reticularis pontis oralis, n. reticularis magnocellularis, n. reticularis paragigantocellularis, n. reticularis dorsalis, the optic tectum, n. interpeduncularis, and n. solitarius. ENK-containing cell bodies were found in n. reticularis pontis oralis, n. reticularis dorsalis, the nucleus of the solitary tract, and the tectum. The midbrain contained most of the SP+ cells. Six nonreticular nuclei (griseum centrale rhombencephali, n. isthmi, n. profundus mesencephali, n. interpeduncularis, torus semicircularis laminaris, and the tectum) contained ir to one or more of the substances but did not project to the spinal cord. The descending tract of V, and the rubrospinal, reticulospinal, and solitary tracts contained all three peptides as did the n. profundus mesencephali, n. isthmi, and specific tectal layers. Because the distribution of neurochemicals within the frog brainstem is similar to that of amniotes, our results emphasize the large amount of conservation of structure, biochemistry, and possibly function that has occurred in the brainstem, and especially in the phylogenetically old reticular formation.
Stuesse S L; Adli D S; Cruce W L
Microscopy research and technique
2001
2001-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1002/jemt.1135" target="_blank" rel="noreferrer noopener">10.1002/jemt.1135</a>
Brainstem neurons with descending projections to the spinal cord of two elasmobranch fishes: thornback guitarfish, Platyrhinoidis triseriata, and horn shark, Heterodontus francisci.
*Stilbamidines; Animals; Axonal Transport; Brain Stem/*anatomy & histology/physiology; Diencephalon/anatomy & histology/physiology; Fishes/*anatomy & histology; Fluorescent Dyes; Horseradish Peroxidase; Mesencephalon/anatomy & histology/physiology; Neural Pathways/anatomy & histology/physiology; Neurons/*cytology/physiology; Pons/anatomy & histology/physiology; Reticular Formation/anatomy & histology/physiology; Species Specificity; Spinal Cord/*anatomy & histology/physiology
We studied two cartilaginous fishes and described their brainstem supraspinal projections because most nuclei in the reticular formation can be identified that way. A retrogradely transported tracer, horseradish peroxidase or Fluoro-Gold, was injected into the spinal cord of Platyrhinoidis triseriata (thornback guitarfish) or Heterodontus fransisci (horn shark). We described labeled reticular cells by their position, morpohology, somatic orientation, dendritic processes, and laterality of spinal projections. Nineteen reticular nuclei have spinal projections: reticularis (r.) dorsalis, r. ventralis pars alpha and beta, r. gigantocellularis, r. magnocellularis, r. parvocellularis, r. paragigantocellularis lateralis and dorsalis, r. pontis caudalis pars alpha and beta, r. pontis oralis pars medialis and lateralis, r. subcuneiformis, r. peduncularis pars compacta, r. subcoeruleus pars alpha, raphe obscurus, raphe pallidus, raphe magnus, and locus coeruleus. Twenty nonreticular nuclei have spinal projections: descending trigeminal, retroambiguus, solitarius, posterior octaval, descending octaval, magnocellular octaval, ruber, Edinger-Westphal, nucleus of the medial longitudinal fasciculus, interstitial nucleus of Cajal, latral mesencephalic complex, periventricularis pretectalis pars dorsalis, central pretectal, ventromedial thalamic, posterior central thalamic, posterior dorsal thalamic, the posterior tuberculum, and nuclei B, F, and J. The large number of distinct reticular nuclei with spinal projections corroborates the hypothesis that the reticular formation of elasmobranches is complexly organized into many of the same nuclei that are found in frogs, reptiles, birds, and mammals.
Cruce W L; Stuesse S L; Northcutt R G
The Journal of comparative neurology
1999
1999-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1002/(sici)1096-9861(19990125)403:4%3C534::aid-cne8%3E3.0.co;2-8" target="_blank" rel="noreferrer noopener">10.1002/(sici)1096-9861(19990125)403:4%3C534::aid-cne8%3E3.0.co;2-8</a>