ELECTROPHYSIOLOGICAL AND HISTOLOGICAL PROPERTIES OF THE OLFACTORY TRACT OF THE BURBOT (Lota lota L.)

Kb, Doeving; Gemne, G

doi:10.1152/jn.1965.28.1.139

Cited by 36 publications

(13 citation statements)

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“…Although much olfactory analysis occurs before the telencephalon, nevertheless there is an olfactory projection, whose terminations are detectable by physiological as well as anatomical means. For instance, Doving and Gemne (1965) have shown that there are three major components in the compound action potential of the burbot (Lota lota), corresponding to varying conduction rates, and it is possible that the slowest bundle of fibers may supply the hypophysis. Kandel (1964), using goldfish, found that the neurosecretory cells of the preoptic nucleus were driven by olfactory tract stimulation and that stimulation of the pituitary caused antidromic impulses to reach this nucleus.…”

Section: A Olfactionmentioning

confidence: 99%

The Fish Telencephalon and Its Relation to Learning

Savage

1980

Comparative Neurology of the Telencephalon

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Section: A Olfactionmentioning

confidence: 99%

The Fish Telencephalon and Its Relation to Learning

Savage

1980

Comparative Neurology of the Telencephalon

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“…However, the average number of axons in both species is greater than the number reported for the crucian carp (Carassius carassius) (73,246; Westerman and Wilson, 1968). In another freshwater fish, the burbot (Lota lota), Döving and Gemne (1965) found that the number of myelinated axons was around 10,000, although these authors did not estimate the number of unmyelinated axons in L. lota. Since Westerman and Wilson (1968) found that 89.5% of the olfactory tract axons in C. carassius are unmyelinated, if similar proportions are assumed for L. lota, the total number of olfactory tract axons in this species could be around 100,000.…”

Section: Comparison Of Olfactory Tract and Optic Nerve Axon Numbers Wmentioning

confidence: 77%

Ontogenetic Shifts in the Number of Axons in the Olfactory Tract and Optic Nerve in Two Species of Deep-Sea Grenadier Fish (Gadiformes: Macrouridae: Coryphaenoides)

2018

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Neuroanatomical studies of the peripheral sense organs and brains of deep-sea fishes are particularly useful for predicting their sensory capabilities and ultimately their behavior. Over the abyssal plane (between 2,000 and 6,000 m), communities of grenadiers (Gadiformes: Macrouridae) play an important ecological role as predator-scavengers. Previous studies suggest that these fishes rely heavily on chemosensation, especially olfaction. Furthermore, at least one species, Coryphaenoides armatus, undergoes an ontogenetic shift in the relative size of the optic tectum and the olfactory bulbs, suggesting. a shift from a reliance on vision to olfaction during ontogeny, apparently in association with a shift to a more scavenging lifestyle. Here, we compared the olfactory and visual sensory inputs to the brain in C. armatus, and in a second, closely-related species, Coryphaenoides profundicolus, by assessing the total number of axons (myelinated and unmyelinated) in the olfactory tract and optic nerve in a range of individuals from both species. In C. armatus, the numbers of axons in both tract and nerve increased with body size, with the total number of axons in the olfactory tract being far greater than the number of axons in the optic nerve. These differences became more pronounced in larger animals. In the two smaller C. profundicolus individuals (≤315 mm SL), there were more axons in the optic nerve than in the olfactory tract, but the opposite situation was found in larger individuals. As in C. armatus, the number of olfactory tract axons also increased with body size in C. profundicolus, but in contrast, the number of optic nerve axons decreased in this species. These results suggest that both C. armatus and C. profundicolus undergo an ontogenetic shift in sensory orientation, with olfaction becoming relatively more important than vision in larger animals. The differences in the ratio of olfactory tract to optic nerve axons in C. armatus indicate that olfaction is of Lisney et al. Olfactory and Visual Inputs in Deep-Sea Fish particular importance to larger individuals of this species. In both species, the percentage of myelinated axons in the olfactory tract was relatively low, but we found evidence for interspecific and ontogenetic variation in the percentages of myelinated axons in the optic nerve.

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“…The circumference of randomly selected axons was measured using ImageJ to provide axon diameter (n = 20 per location and per type) in all 6 individuals (right side only), using the formula diameter = circumference/π. For M axons, the inner membrane was used [Døving and Gemne, 1965] to measure the circumference. The myelin thickness was also measured and the number of myelin sheaths quantified (Fig.…”

Section: Axon Size and Myelin Thicknessmentioning

confidence: 99%

Convergence of Olfactory Inputs within the Central Nervous System of a Cartilaginous and a Bony Fish: An Anatomical Indicator of Olfactory Sensitivity

et al. 2020

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The volume of the olfactory bulbs (OBs) relative to the brain has been used previously as a proxy for olfactory capabilities in many vertebrate taxa, including fishes. Although this gross approach has predictive power, a more accurate assessment of the number of afferent olfactory inputs and the convergence of this information at the level of the telencephalon is critical to our understanding of the role of olfaction in the behaviour of fishes. In this study, we used transmission electron microscopy to assess the number of first-order axons within the olfactory nerve (ON) and the number of second-order axons in the olfactory peduncle (OP) in established model species within cartilaginous (brownbanded bamboo shark, Chiloscyllium punctatum [CP]) and bony (common goldfish, Carassius auratus [CA]) fishes. The total number of axons varied from a mean of 18.12 ± 7.50 million in the ON to a mean of 0.38 ± 0.21 million in the OP of CP, versus 0.48 ± 0.16 million in the ON and 0.09 ± 0.02 million in the OP of CA. This resulted in a convergence ratio of approximately 50:1 and 5:1, respectively, for these two species. Based on astroglial ensheathing, axon type (unmyelinated [UM] and myelinated [M]) and axon size, we found no differentiated tracts in the OP of CP, whereas a lateral and a medial tract (both of which could be subdivided into two bundles or areas) were identified for CA, as previously described. Linear regression analyses revealed significant differences not only in axon density between species and locations (nerves and peduncles), but also in axon type and axon diameter (p < 0.05). However, UM axon diameter was larger in the OPs than in the nerve in both species (p = 0.005), with no significant differences in UM axon diameter in the ON (p = 0.06) between species. This study provides an in-depth analysis of the neuroanatomical organisation of the ascending olfactory pathway in two fish taxa and a quantitative anatomical comparison of the summation of olfactory information. Our results support the assertion that relative OB volume is a good indicator of the level of olfactory input and thereby a proxy for olfactory capabilities.

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ELECTROPHYSIOLOGICAL AND HISTOLOGICAL PROPERTIES OF THE OLFACTORY TRACT OF THE BURBOT (Lota lota L.)

Cited by 36 publications

References 0 publications

The Fish Telencephalon and Its Relation to Learning

The Fish Telencephalon and Its Relation to Learning

Ontogenetic Shifts in the Number of Axons in the Olfactory Tract and Optic Nerve in Two Species of Deep-Sea Grenadier Fish (Gadiformes: Macrouridae: Coryphaenoides)

Convergence of Olfactory Inputs within the Central Nervous System of a Cartilaginous and a Bony Fish: An Anatomical Indicator of Olfactory Sensitivity

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