Evolution of the forebrain — revisiting the pallium

doi:10.1002/cne.23444

Cited by 6 publications

(3 citation statements)

References 26 publications

(26 reference statements)

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“…Reflecting this rapidly changing concept of the organization of the telencephalon common to all vertebrates, Finger et al [19] have suggested a unified pattern of organization shown in figure 5, that attempts to reconcile the seemingly diverse telencephalic features of the different classes of vertebrates. Much research will still be required to flesh out this latest model and confirm its general validity, but the consequences of this unified model may have a profound influence on our concepts of the evolution of the vertebrate brain.…”

Section: A Unified Model Of Telencephalic Organization In Vertebratesmentioning

confidence: 99%

“…This resulted in a revision of terminologies of several of the divisions of the DVR, within the framework of the pathways and nuclear clusters discovered during the preceding 30 years. Several of the schematic diagrams displayed in this current publication were drawn from the series of publications consequent to the revised nomenclature and/or the works of [7,8,[17][18][19].…”

Section: What Are the Boundaries Of The Basal Ganglia In Birds?mentioning

confidence: 99%

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Vertebrate brains and evolutionary connectomics: on the origins of the mammalian ‘neocortex’

Karten¹

2015

Phil. Trans. R. Soc. B

114

105

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One contribution of 16 to a discussion meeting issue 'Origin and evolution of the nervous system'. The organization of the non-mammalian forebrain had long puzzled neurobiologists. Unlike typical mammalian brains, the telencephalon is not organized in a laminated 'cortical' manner, with distinct cortical areas dedicated to individual sensory modalities or motor functions. The two major regions of the telencephalon, the basal ventricular ridge (BVR) and the dorsal ventricular ridge (DVR), were loosely referred to as being akin to the mammalian basal ganglia. The telencephalon of non-mammalian vertebrates appears to consist of multiple 'subcortical' groups of cells. Analysis of the nuclear organization of the avian brain, its connections, molecular properties and physiology, and organization of its pattern of circuitry and function relative to that of mammals, collectively referred to as 'evolutionary connectomics', revealed that only a restricted portion of the BVR is homologous to the basal ganglia of mammals. The remaining dorsal regions of the DVR, wulst and arcopallium of the avian brain contain telencephalic inputs and outputs remarkably similar to those of the individual layers of the mammalian 'neocortex', hippocampus and amygdala, with instances of internuclear connections strikingly similar to those found between cortical layers and within radial 'columns' in the mammalian sensory and motor cortices. The molecular properties of these 'nuclei' in birds and reptiles are similar to those of the corresponding layers of the mammalian neocortex. The fundamental pathways and cell groups of the auditory, visual and somatosensory systems of the thalamus and telencephalon are homologous at the cellular, circuit, network and gene levels, and are of great antiquity. A proposed altered migration of these homologous neurons and circuits during development is offered as a mechanism that may account for the altered configuration of mammalian telencephalae.

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Section: A Unified Model Of Telencephalic Organization In Vertebratesmentioning

confidence: 99%

Section: What Are the Boundaries Of The Basal Ganglia In Birds?mentioning

confidence: 99%

Vertebrate brains and evolutionary connectomics: on the origins of the mammalian ‘neocortex’

Karten¹

2015

Phil. Trans. R. Soc. B

114

105

View full text Add to dashboard Cite

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“…Also, there is evidence that various fishes match mammals with respect to numerical competence (Agrillo et al, 2008(Agrillo et al, ,2009Bshary et al, 2014;Dadda et al, 2009;Feigenson et al, 2004;Messina et al, 2020;Piffer et al, 2012;Stancher et al, 2013). Thus, a presence/absence of these cognitive processes cannot explain the ten-fold difference in relative brain size and the even larger difference with respect to the pallial brain part (Finger et al, 2013;Karten, 2015) between endotherm and ectotherm vertebrate clades. The complete failure of cleaners in the object permanence task came as a surprise to us, as cleaners perform well in memory tasks, regarding both events that took place a few minutes ago (Salwiczek & Bshary, 2011) or almost a year ago .…”

Section: Discussionmentioning

confidence: 99%

No evidence for general intelligence in a fish

2022

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The average mammal or bird has a roughly ten times larger brain relative to body size than the average ectotherm vertebrate. It has been surprisingly challenging to determine how this translates into increased cognitive performance. In particular, it is unclear whether the brain size differences translate into qualitative differences in specific cognitive abilities. Here, we provide a first exploratory study to examine the possibility that the larger brains of endotherms support a different organisation of information processing, rather than specific differences in cognitive processes. In mammals, individual performance across domain‐general cognitive tasks is positively correlated, resulting in the psychometric factor g. The value of g is positively correlated with brain size. We tested wild‐caught female cleaner fish Labroides dimidiatus, known for its highly sophisticated social behaviour, in four ecologically nonrelevant cognitive tasks that have been used to varying degrees to assess g in mammals. Cleaner fish solved three of these four tasks, flexibility (reversal learning), self‐control (detour around an obstacle) and numerical competence (simultaneous two‐choice task), while also providing enough interindividual variation to test for g. They did not perform above chance levels in the fourth task, which tested for object permanence. For the three retained tasks, individual performance did not load positively on one principal component. Furthermore, all pairwise correlation coefficients were close to zero. These negative results contradict a frequent criticism of g studies, which proposes that g is a default result of how brains are designed. Rather, the results provide a first indication that endotherm and ectotherm vertebrates may process cognitive tasks in fundamentally different ways due to differences in brain organisation. Our relatively low number of experiments compared to mammalian studies enhances this hypothesis, as the probability of finding a g factor by chance would have been higher.

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A Bird’s Eye View of Sleep-Dependent Memory Consolidation

Brawn

Margoliash

2014

Sleep, Neuronal Plasticity and Brain Function

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How new experiences are solidified into long-lasting memories is a central question in the study of brain and behavior. One of the most intriguing discoveries in memory research is that brain activity during sleep helps to transform newly learned information and skills into robust memories. Though the first experimental work linking sleep and memory was conducted 90 years ago by Jenkins and Dallenbach, the case for sleep-dependent memory consolidation has only garnered strong support in the last decade. Recent studies in humans provide extensive behavioral, imaging, and polysomnographic data supporting sleep consolidation of a broad range of memory tasks. Likewise, studies in a few animal model systems have elucidated potential mechanisms contributing to sleep consolidation such as neural reactivation and synaptic homeostasis. Here, we present an overview of sleep-dependent memory consolidation, focusing on how investigations of sleep and learning in birds have complemented the progress made in mammalian systems by emphasizing a strong connection between behavior and physiology. We begin by describing the behavioral approach that has been utilized to demonstrate sleep consolidation in humans. We then address neural reactivation in the rodent hippocampal system as a putative mechanism of sleep consolidation. Next, we discuss the role of sleep in the learning and maintenance of song in zebra finches. We note that while both the rodent and zebra finch systems provide evidence for sleep-dependent memory changes in physiology and behavior, neither duplicates the pattern of changes most commonly observed in humans. Finally, we present a recently developed model of sleep consolidation involving auditory classification learning in European starlings , which has the potential to connect behavioral evidence of sleep consolidation as developed in humans with underlying neural mechanisms observable in animals.

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Evolution of the forebrain — revisiting the pallium

Cited by 6 publications

References 26 publications

Vertebrate brains and evolutionary connectomics: on the origins of the mammalian ‘neocortex’

Vertebrate brains and evolutionary connectomics: on the origins of the mammalian ‘neocortex’

No evidence for general intelligence in a fish

A Bird’s Eye View of Sleep-Dependent Memory Consolidation

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