Morphology of Invertebrate Neurons and Synapses

The Oxford Handbook of Invertebrate Neurobiology ◽

10.1093/oxfordhb/9780190456757.013.9 ◽

2017 ◽

pp. 246-284 ◽

Cited By ~ 5

Author(s):

Ian A. Meinertzhagen

Keyword(s):

New Species ◽

Neurotransmitter Receptor ◽

Nervous Systems ◽

Synaptic Circuits ◽

Identified Neuron ◽

Functional Analyses

Despite their often small numbers, the neurons in invertebrate nervous systems can nevertheless constitute many classes, and the nervous systems of little studied or entirely new species still offer significant opportunities for discovery. Circuit analyses and connectomic data are of particular significance, as are the relationships of these to behavior, and the organization of simple larval brains. Functional analyses of synaptic circuits still require knowledge of the neurotransmitter and neurotransmitter receptor for each identified neuron. Synapse complexity ranges widely; undifferentiated pathways in basal species may have unpolarized synapses with presynaptic sites opposite each other, and specialized pathways may have polyadic synapses.

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OBSERVATIONS ON THE NERVOUS SYSTEM OF APORCELAIMUS AMPHIDYSIS N. SP. (NEMATODA: DORYLAIMOIDEA)

Canadian Journal of Zoology ◽

10.1139/z66-082 ◽

1966 ◽

Vol 44 (5) ◽

pp. 815-820 ◽

Cited By ~ 3

Author(s):

R. V. Anderson

Keyword(s):

Central Nervous System ◽

Nervous System ◽

New Species ◽

Nerve Ring ◽

Nervous Systems ◽

Diagnostic Characters ◽

The Central Nervous System ◽

Males And Females ◽

The Right ◽

First Time

Fifteen ganglia, associated with the nerve ring are reported. With the exception of the paired lateral cephalic papillary, postlateral papillary, and the amphidial ganglia, nine ganglia are linked by laterolateral commissures which are described for the first time. The laterolateral commissures appear to originate from paired internolateral ganglia located above and below the nerve ring. The longitudinal dorsal and paired ventral, amphidial, and lateral cephalic papillary nerves are traced from origin at their respective ganglia of the central nervous system to their termination. The paired ventral nerves pass to the right and left of the vagina, remaining double throughout most of their length. Portions of the rectosympathetic nervous systems are described in males and females. In the description of the new species based on males and females, the structure of the amphid is clarified, and the position of the plicated guiding ring and the dorsoventral width of the plicated guiding ring, expressed as percentage of spear length, are used as diagnostic characters. Illustrations and photomicrographs are provided.

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Organisms Without Nervous Systems

Brains as Engines of Association ◽

10.1093/oso/9780190880163.003.0002 ◽

2019 ◽

pp. 13-22

Author(s):

Dale Purves

Keyword(s):

New Species ◽

Great Majority ◽

Present Species ◽

Nervous Systems ◽

Extant Species ◽

Eukaryotic Species ◽

Prokaryotic Species ◽

Life On Earth

According to current estimates, the kingdoms of life on Earth comprise at least 8.7 million eukaryotic species (protists, fungi, plants, and animals) and many more prokaryotic species (eubacteria and archaebacteria). The fuzziness of these numbers is understandable: new species are being discovered daily, and extant species are going extinct, as they always have. Whatever the number may actually be, the great majority of past and present species don’t have nervous systems. Thus, before asking what function or functions nervous systems add to animal biology, an obvious question is how organisms without them get along so well. This chapter explores the answer.

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