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Centrifugal telencephalic afferent connections to the main and accessory olfactory bulbs.

Mohedano-Moriano A, de la Rosa-Prieto C, Saiz-Sanchez D, Ubeda-Bañon I, Pro-Sistiaga P, de Moya-Pinilla M, Martinez-Marcos A - Front Neuroanat (2012)

Bottom Line: Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic structures.The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively.Interestingly, olfactory (e.g., piriform cortex), vomeronasal (e.g., posteromedial cortical amygdala), mixed (e.g., the anterior medial amygdaloid nucleus), and non-chemosensory-recipient (e.g., the nucleus of the diagonal band) structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Medicina de Albacete, Laboratorio de Neuroanatomía Humana, Departamento de Ciencias Médicas, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha Albacete, Spain.

ABSTRACT
Parallel to the olfactory system, most mammals possess an accessory olfactory or vomeronasal system. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs, which in turn project to adjacent areas of the telencephalon, respectively. New data indicate that projections arising from the main and accessory olfactory bulbs partially converge in the rostral telencephalon and are non-overlapping at caudal telencephalic levels. Therefore, the basal telencephalon should be reclassified in olfactory, vomeronasal, and mixed areas. On the other hand, it has been demonstrated that virtually all olfactory- and vomeronasal-recipient structures send reciprocal projections to the main and accessory olfactory bulbs, respectively. Further, non-chemosensory recipient structures also projects centrifugally to the olfactory bulbs. These feed-back projections appear to be essential modulating processing of chemosensory information. The present work aims at characterizing centrifugal projections to the main and accessory olfactory bulbs arising from olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic areas. This issue has been addressed by using tracer injections in the rat and mouse brain. Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic structures. The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively. Interestingly, olfactory (e.g., piriform cortex), vomeronasal (e.g., posteromedial cortical amygdala), mixed (e.g., the anterior medial amygdaloid nucleus), and non-chemosensory-recipient (e.g., the nucleus of the diagonal band) structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing.

No MeSH data available.


Sagittal (A) and coronal sections (B–H) from rostral to caudal levels of the telencephalic hemisphere showing the resulting labeling (B–H) after a dextran-amine labeled tetramethylrhodamine injection in the rat main olfactory bulb (A). Abbreviations: AA, anterior amygdala; ACO, anterior cortical amygdala; AON, anterior olfactory nucleus; CXA, cortex-amygdala transition zone; DB, nucleus of the diagonal band; LE, lateral entorhinal cortex; LOT, nucleus of the lateral olfactory tract; ME, medial amygdala; MOB, main olfactory bulb; PIR, piriform cortex; PLCO, posterolateral cortical amygdala. Scale bar for A: 800 μm, B–H: 400 μm.
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Figure 2: Sagittal (A) and coronal sections (B–H) from rostral to caudal levels of the telencephalic hemisphere showing the resulting labeling (B–H) after a dextran-amine labeled tetramethylrhodamine injection in the rat main olfactory bulb (A). Abbreviations: AA, anterior amygdala; ACO, anterior cortical amygdala; AON, anterior olfactory nucleus; CXA, cortex-amygdala transition zone; DB, nucleus of the diagonal band; LE, lateral entorhinal cortex; LOT, nucleus of the lateral olfactory tract; ME, medial amygdala; MOB, main olfactory bulb; PIR, piriform cortex; PLCO, posterolateral cortical amygdala. Scale bar for A: 800 μm, B–H: 400 μm.

Mentions: Injections of dextran amine-labeled RDA into the granule cell layer of the main olfactory bulb of rats gave rise a similar pattern of labeling, but a considerably reduced injection site (as example see case R4505, 6.6 mm from Bregma, Figure 2A, 7.5 mm from Bregma) and consequently to a scarcer retrograde labeling as compared to FG injections. As in the previous case, labeled cells could be observed in the anterior olfactory nucleus (not shown), nucleus of the diagonal band (Figure 2B), rostral piriform cortex (Figure 2C), olfactory tubercle (not shown), anterior amygdaloid area, nucleus of the lateral olfactory tract, anterior cortical amygdaloid nucleus, cortex-amygdala transition zone (Figures 2D,E), caudal piriform cortex (Figure 2F), anterodorsal medial amygdaloid nucleus (−2.0 mm from Bregma, Figure 2G), posterolateral cortical amygdaloid nucleus (not show) and lateral entorhinal cortex (Figure 2H).


Centrifugal telencephalic afferent connections to the main and accessory olfactory bulbs.

Mohedano-Moriano A, de la Rosa-Prieto C, Saiz-Sanchez D, Ubeda-Bañon I, Pro-Sistiaga P, de Moya-Pinilla M, Martinez-Marcos A - Front Neuroanat (2012)

Sagittal (A) and coronal sections (B–H) from rostral to caudal levels of the telencephalic hemisphere showing the resulting labeling (B–H) after a dextran-amine labeled tetramethylrhodamine injection in the rat main olfactory bulb (A). Abbreviations: AA, anterior amygdala; ACO, anterior cortical amygdala; AON, anterior olfactory nucleus; CXA, cortex-amygdala transition zone; DB, nucleus of the diagonal band; LE, lateral entorhinal cortex; LOT, nucleus of the lateral olfactory tract; ME, medial amygdala; MOB, main olfactory bulb; PIR, piriform cortex; PLCO, posterolateral cortical amygdala. Scale bar for A: 800 μm, B–H: 400 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3362118&req=5

Figure 2: Sagittal (A) and coronal sections (B–H) from rostral to caudal levels of the telencephalic hemisphere showing the resulting labeling (B–H) after a dextran-amine labeled tetramethylrhodamine injection in the rat main olfactory bulb (A). Abbreviations: AA, anterior amygdala; ACO, anterior cortical amygdala; AON, anterior olfactory nucleus; CXA, cortex-amygdala transition zone; DB, nucleus of the diagonal band; LE, lateral entorhinal cortex; LOT, nucleus of the lateral olfactory tract; ME, medial amygdala; MOB, main olfactory bulb; PIR, piriform cortex; PLCO, posterolateral cortical amygdala. Scale bar for A: 800 μm, B–H: 400 μm.
Mentions: Injections of dextran amine-labeled RDA into the granule cell layer of the main olfactory bulb of rats gave rise a similar pattern of labeling, but a considerably reduced injection site (as example see case R4505, 6.6 mm from Bregma, Figure 2A, 7.5 mm from Bregma) and consequently to a scarcer retrograde labeling as compared to FG injections. As in the previous case, labeled cells could be observed in the anterior olfactory nucleus (not shown), nucleus of the diagonal band (Figure 2B), rostral piriform cortex (Figure 2C), olfactory tubercle (not shown), anterior amygdaloid area, nucleus of the lateral olfactory tract, anterior cortical amygdaloid nucleus, cortex-amygdala transition zone (Figures 2D,E), caudal piriform cortex (Figure 2F), anterodorsal medial amygdaloid nucleus (−2.0 mm from Bregma, Figure 2G), posterolateral cortical amygdaloid nucleus (not show) and lateral entorhinal cortex (Figure 2H).

Bottom Line: Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic structures.The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively.Interestingly, olfactory (e.g., piriform cortex), vomeronasal (e.g., posteromedial cortical amygdala), mixed (e.g., the anterior medial amygdaloid nucleus), and non-chemosensory-recipient (e.g., the nucleus of the diagonal band) structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Medicina de Albacete, Laboratorio de Neuroanatomía Humana, Departamento de Ciencias Médicas, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha Albacete, Spain.

ABSTRACT
Parallel to the olfactory system, most mammals possess an accessory olfactory or vomeronasal system. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs, which in turn project to adjacent areas of the telencephalon, respectively. New data indicate that projections arising from the main and accessory olfactory bulbs partially converge in the rostral telencephalon and are non-overlapping at caudal telencephalic levels. Therefore, the basal telencephalon should be reclassified in olfactory, vomeronasal, and mixed areas. On the other hand, it has been demonstrated that virtually all olfactory- and vomeronasal-recipient structures send reciprocal projections to the main and accessory olfactory bulbs, respectively. Further, non-chemosensory recipient structures also projects centrifugally to the olfactory bulbs. These feed-back projections appear to be essential modulating processing of chemosensory information. The present work aims at characterizing centrifugal projections to the main and accessory olfactory bulbs arising from olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic areas. This issue has been addressed by using tracer injections in the rat and mouse brain. Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic structures. The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively. Interestingly, olfactory (e.g., piriform cortex), vomeronasal (e.g., posteromedial cortical amygdala), mixed (e.g., the anterior medial amygdaloid nucleus), and non-chemosensory-recipient (e.g., the nucleus of the diagonal band) structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing.

No MeSH data available.