The Origin of Vertebrates

2019 ◽  
pp. 58-124
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Lateral Line ◽  
Olfactory System ◽  
Brain Regions ◽  
Early Cambrian ◽  
Vestibular Apparatus ◽  
Vertebrate Lineage ◽  
Embryonic Tissues ◽  
Pharyngeal Muscles ◽  
Evolutionary Success ◽  
Early Vertebrates

Some time in the Ediacaran or early Cambrian period, the first vertebrates emerged. Compared to the invertebrate chordates, early vertebrates were active predators, rather than suspension feeders. This change in behavior was facilitated by several major morphological innovations, including pharyngeal muscles that pump water through the pharynx, vascularized gills, paired image-forming eyes, a complex vestibular apparatus, lateral line receptors, taste buds, and a well-developed olfactory system. Early vertebrates also evolved several new brain regions, notably the telencephalon and the midbrain. Developmentally, most of these innovations were linked to the emergence of two novel embryonic tissues, namely placodes and neural crest. Although these tissues and their adult derivatives did not evolve “out of nothing,” they represent genuine innovations that contributed substantially to the evolutionary success of the vertebrate lineage.

The Origin of Jaws and Paired Fins

2019 ◽  
pp. 125-195
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Olfactory Receptor ◽  
Mass Extinction ◽  
Sensory Information ◽  
Brain Regions ◽  
Vestibular Apparatus ◽  
Olfactory Information ◽  
Vomeronasal Receptors ◽  
Early Vertebrates ◽  
Cartilaginous Fishes ◽  
Olfactory Receptor Genes

Between 450 and 500 million years ago, some vertebrates evolved paired fins and jaws, which made them more efficient swimmers and fiercer predators. These jawed vertebrates (i.e., gnathostomes) diversified in the Devonian period, but most died out during the end-Devonian mass extinction. The surviving gnathostomes had a more complex vestibular apparatus than their jawless ancestors, an expanded set of olfactory receptor genes, and vomeronasal receptors. A major innovation in the brains of gnathostomes was the emergence of a cerebellum that is distinct from the cerebellum-like areas found in all vertebrates. The telencephalon of early vertebrates processed primarily olfactory information, but this olfactory dominance was independently reduced in three later lineages, namely in cartilaginous fishes, ray-finned fishes, and tetrapods. In concert with the reduction in olfactory dominance, these lineages enlarged their telencephalon, relative to other brain regions, and evolved a telencephalic “dorsal pallium” that receives non-olfactory sensory information from the diencephalon.

scholarly journals Dynamics of Structural Barriers and Innate Immune Components during Incubation of the Avian Egg: Critical Interplay between Autonomous Embryonic Development and Maternal Anticipation

2018 ◽  
Vol 11 (2) ◽  
pp. 111-124 ◽  
Author(s):  
Maxwell T. Hincke ◽  
Mylène Da Silva ◽  
Nicolas Guyot ◽  
Joël Gautron ◽  
Marc D. McKee ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Innate Immune ◽  
Vitelline Membrane ◽  
Structural Barriers ◽  
Embryonic Tissues ◽  
Egg Incubation ◽  
Evolutionary Success ◽  
Protective Structures ◽  
Amniotic Membranes ◽  
Autonomous Development

The integrated innate immune features of the calcareous egg and its contents are a critical underpinning of the remarkable evolutionary success of the Aves clade. Beginning at the time of laying, the initial protective structures of the egg, i.e., the biomineralized eggshell, egg-white antimicrobial peptides, and vitelline membrane, are rapidly and dramatically altered during embryonic development. The embryo-generated extra-embryonic tissues (chorioallantoic/amniotic membranes, yolk sac, and associated chambers) are all critical to counteract degradation of primary egg defenses during development. With a focus on the chick embryo (Gallus gallus domesticus), this review describes the progressive transformation of egg innate immunity by embryo-generated structures and mechanisms over the 21-day course of egg incubation, and also discusses the critical interplay between autonomous development and maternal anticipation.

scholarly journals Brain-wide mapping of water flow perception in zebrafish

2020 ◽  
Author(s):  
Gilles Vanwalleghem ◽  
Kevin Schuster ◽  
Michael A. Taylor ◽  
Itia A. Favre-Bulle ◽  
Ethan K. Scott
Keyword(s):  
Water Flow ◽  
Lateral Line ◽  
Reverse Flow ◽  
Forward Direction ◽  
Brain Regions ◽  
Reverse Direction ◽  
Departure Point ◽  
Forward Flow ◽  
Larval Zebrafish ◽  
The Brain

AbstractInformation about water flow, detected by lateral line organs, is critical to the behavior and survival of fish and amphibians. While certain specific aspects of water flow processing have been revealed through electrophysiology, we lack a comprehensive description of the neurons that respond to water flow and the network that they form. Here, we use brain-wide calcium imaging in combination with microfluidic stimulation to map out, at cellular resolution, all neurons involved in perceiving and processing water flow information in larval zebrafish. We find a diverse array of neurons responding to forward flow, reverse flow, or both. Early in this pathway, in the lateral line ganglia, these are almost exclusively neurons responding to the simple presence of forward or reverse flow, but later processing includes neurons responding specifically to flow onset, representing the accumulated volume of flow during a stimulus, or encoding the speed of the flow. The neurons reporting on these more nuanced details are located across numerous brain regions, including some not previously implicated in water flow processing. A graph theory-based analysis of the brain-wide water flow network shows that a majority of this processing is dedicated to forward flow detection, and this is reinforced by our finding that details like flow velocity and the total volume of accumulated flow are only encoded for the simulated forward direction. The results represent the first brain-wide description of processing for this important modality, and provide a departure point for more detailed studies of the flow of information through this network.Significance statementIn aquatic animals, the lateral line is important for detecting water flow stimuli, but the brain networks that interpret this information remain mysterious. Here, we have imaged the activity of individual neurons across the entire brains of larval zebrafish, revealing all response types and their brain locations as water flow processing occurs. We find some neurons that respond to the simple presence of water flow, and others that are attuned to the flow’s direction, speed, duration, or the accumulated volume of water that has passed during the stimulus. With this information, we modeled the underlying network, describing a system that is nuanced in its processing of water flow simulating forward motion but rudimentary in processing flow in the reverse direction.

scholarly journals Olfactory Stimulation Effect of Aldehydes, Nonanal, and Decanal on the Human Electroencephalographic Activity, According to Nostril Variation

Biomedicines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 57 ◽  
Author(s):  
Minju Kim ◽  
Kandhasamy Sowndhararajan ◽  
Hae Jin Choi ◽  
Se Jin Park ◽  
Songmun Kim
Keyword(s):  
Olfactory System ◽  
Power Spectra ◽  
Brain Regions ◽  
Eeg Power Spectra ◽  
Beta Power ◽  
Eeg Changes ◽  
Electroencephalographic Activity ◽  
Healthy Participants ◽  
Human Nose ◽  
Better Than

Fragrances play a pivotal role in humans’ psychological and physiological functions through the olfactory system. Aldehydes are important organic compounds with a variety of fragrance notes. Particularly, nonanal (C9) and decanal (C10) aldehydes are important natural fragrant components used to enhance floral, as well as citrus notes in perfumery products. In general, each nostril of the human nose is tuned to smell certain odor molecules better than others due to slight turbinate swelling between the nostrils. Hence, the objective of the present investigation was aimed to evaluate the influence of binasal and uninasal inhalations of C9 and C10 aldehydes on human electroencephalographic (EEG) activity. Twenty healthy participants (10 males and 10 females) participated in this study. The EEG readings were recorded from 8 electrodes (QEEG-8 system) according to the International 10-20 System. The results revealed that C10 exposure exhibited significantly different EEG changes, during binasal and uninasal inhalations. In different brain regions, C10 odor markedly decreased the absolute alpha and absolute beta power spectra. In regards to C9 odor, significant changes of EEG power spectra were noticed only during binasal inhalation. In addition, C10 mainly produced changes at the left parietal site (P3) than other brain sites. In conclusion, the variations in EEG activities of C9 and C10 aldehydes might be owing to their characteristic fragrance quality, as well as the influence of nostril differences.

scholarly journals Regulatory evolution of Tbx5 and the origin of paired appendages

2016 ◽  
Vol 113 (36) ◽  
pp. 10115-10120 ◽  
Author(s):  
Noritaka Adachi ◽  
Molly Robinson ◽  
Aden Goolsbee ◽  
Neil H. Shubin
Keyword(s):  
Phylogenetic Footprinting ◽  
Regulatory Evolution ◽  
Expression Domain ◽  
Vertebrate Lineage ◽  
Enhancer Activity ◽  
T Box ◽  
Evolutionarily Conserved ◽  
Evolutionary Radiation ◽  
Early Vertebrates ◽  
Chromatin Profiling

The diversification of paired appendages has been a major factor in the evolutionary radiation of vertebrates. Despite its importance, an understanding of the origin of paired appendages has remained elusive. To address this problem, we focused on T-box transcription factor 5 (Tbx5), a gene indispensable for pectoral appendage initiation and development. Comparison of gene expression in jawless and jawed vertebrates reveals that the Tbx5 expression in jawed vertebrates is derived in having an expression domain that extends caudal to the heart and gills. Chromatin profiling, phylogenetic footprinting, and functional assays enabled the identification of a Tbx5 fin enhancer associated with this apomorphic pattern of expression. Comparative functional analysis of reporter constructs reveals that this enhancer activity is evolutionarily conserved among jawed vertebrates and is able to rescue the finless phenotype of tbx5a mutant zebrafish. Taking paleontological evidence of early vertebrates into account, our results suggest that the gain of apomorphic patterns of Tbx5 expression and regulation likely contributed to the morphological transition from a finless to finned condition at the base of the vertebrate lineage.

scholarly journals Dopamine Modulation of Motor and Sensory Cortical Plasticity among Vertebrates

2021 ◽  
Author(s):  
Matheus Macedo-Lima ◽  
Luke Remage-Healey
Keyword(s):  
Mammalian Species ◽  
Brain Structures ◽  
Brain Regions ◽  
Research Progress ◽  
Vertebrate Lineage ◽  
Broad Perspective ◽  
Anatomical Basis ◽  
Dopamine Signaling ◽  
Cortical Regions ◽  
Sensory Adaptations

Synopsis Goal-directed learning is a key contributor to evolutionary fitness in animals. The neural mechanisms that mediate learning often involve the neuromodulator dopamine. In higher order cortical regions, most of what is known about dopamine’s role is derived from brain regions involved in motivation and decision-making, while significantly less is known about dopamine’s potential role in motor and/or sensory brain regions to guide performance. Research on rodents and primates represents over 95% of publications in the field, while little beyond basic anatomy is known in other vertebrate groups. This significantly limits our general understanding of how dopamine signaling systems have evolved as organisms adapt to their environments. This review takes a pan-vertebrate view of the literature on the role of dopamine in motor/sensory cortical regions, highlighting, when available, research on non-mammalian vertebrates. We provide a broad perspective on dopamine function and emphasize that dopamine-induced plasticity mechanisms are widespread across all cortical systems and associated with motor and sensory adaptations. The available evidence illustrates that there is a strong anatomical basis—dopamine fibers and receptor distributions—to hypothesize that pallial dopamine effects are widespread among vertebrates. Continued research progress in non-mammalian species will be crucial to further our understanding of how the dopamine system evolved to shape the diverse array of brain structures and behaviors among the vertebrate lineage.

scholarly journals ODOR IDENTITY CAN BE EXTRACTED FROM THE RECIPROCAL CONNECTIVITY BETWEEN OLFACTORY BULB AND PIRIFORM CORTEX IN HUMANS

2021 ◽  
Author(s):  
Behzad Iravani ◽  
Artin Arshamian ◽  
Mikael Lundqvist ◽  
Leslie M Kay ◽  
Donald A Wilson ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Information Flow ◽  
Information Exchange ◽  
Olfactory System ◽  
Critical Role ◽  
Piriform Cortex ◽  
Brain Regions ◽  
Oscillatory Circuit ◽  
Healthy Human ◽  
Gamma Frequency

Neuronal oscillations route external and internal information across brain regions. In the olfactory system, the two central nodes-the olfactory bulb (OB) and the piriform cortex (PC)-communicate with each other via neural oscillations to shape the olfactory percept. Communication between these nodes have been well characterized in non-human animals but less is known about their role in the human olfactory system. Using a recently developed and validated EEG-based method to extract signals from the OB and PC sources, we show in healthy human participants that there is a bottom-up information flow from the OB to the PC in the beta and gamma frequency bands, while top-down information from the PC to the OB is facilitated by delta and theta oscillations. Importantly, we demonstrate that there was enough in-formation to decipher odor identity above chance from the low gamma in the OB-PC oscillatory circuit as early as 100ms after odor onset. These data further our understanding of the critical role of bidirectional information flow in human sensory systems to produce perception. However, future studies are needed to determine what specific odor information is extracted and communicated in the information exchange.

The Invasion of Land

2019 ◽  
pp. 196-260
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
High Resolution ◽  
Lateral Line ◽  
Musculoskeletal System ◽  
Water Surface ◽  
Brain Regions ◽  
Main Function ◽  
Oxygen Levels ◽  
Early Tetrapods

Basal stem tetrapods were fully aquatic but spent time at the water surface breathing air, which was useful at the end of the Devonian, when aquatic oxygen levels were low. After the Devonian, early tetrapods became fully terrestrial, at least as adults. This transition involved major changes in the musculoskeletal system for locomotion and the evolution of new modes of feeding. Aerial vision required changes in the eye but then allowed for high-resolution vision over long distances. In contrast, the lateral line systems are useless in air and were lost in fully terrestrial tetrapods. The brains of early tetrapods were relatively simple, possibly simplified through a process called paedomorphosis. The telencephalon’s main function in early tetrapods was to inhibit or disinhibit the lower brain regions. Later tetrapods diverged into extant amphibians and amniotes. Within the amphibian lineage, anurans evolved a tympanic ear, which increased their ability to hear airborne sounds.

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