The Comparative Neurology of Neocortical Gyration and the Quest for Functional Specialization

Triarhou, Lazaros C.

doi:10.3389/fnsys.2017.00096

Cited by 4 publications

(4 citation statements)

References 61 publications

(68 reference statements)

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“…However, it is currently still difficult to compare the brain function in different species. Animals might share brain areas, circuits, and pathways that mediate perceptual, visual, auditory, somatosensory, and other processes or, reversely, they could share homologous behaviours, possibly managed by different cytoarchitectonic areas [35]. Because subjective experiences are generated and processed by the brain, activity in the relevant cerebral areas might represent emotions more accurately than any other physiological and behavioural indicators [15].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Sheep Anticipatory Response to a Food Reward by Means of Functional Near-Infrared Spectroscopy

Chincarini

Qiu

Spinelli

et al. 2018

Animals

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Simple SummaryAnticipatory behaviour to an oncoming food reward can be triggered via classical conditioning, implies the activation of neural networks, and may serve to study the emotional state of animals. This work aimed to investigate how the anticipatory response affects cerebral cortex activity in sheep. Eight ewes were conditioned to associate a neutral auditory stimulus (water bubble) to a food reward (maize grains). Then, sheep were trained to wait 15 s before accessing the food (anticipatory phase). Behavioural reaction and changes in cortical oxy-haemoglobin ([ΔO2Hb]) and deoxy-haemoglobin ([ΔHHb]) concentration were recorded by functional near infrared spectroscopy (fNIRS). During the anticipatory phase, sheep increased their active behaviour together with a cortical activation (increase of [ΔO2Hb] and a decrease of [ΔHHb]) compared to baseline. Sheep showed a greater response of the right hemisphere compared to the left hemisphere, possibly indicating frustration. Behavioural and cortical changes observed during anticipation of a food reward reflect a learnt association and an increased arousal, but no clear emotional valence of the sheep subjective experience.AbstractAnticipatory behaviour to an oncoming food reward can be triggered via classical conditioning, implies the activation of neural networks, and may serve to study the emotional state of animals. The aim of this study was to investigate how the anticipatory response to a food reward affects the cerebral cortex activity in sheep. Eight ewes from the same flock were trained to associate a neutral auditory stimulus (water bubble) to the presence of a food reward (maize grains). Once conditioned, sheep were trained to wait 15 s behind a gate before accessing a bucket with food (anticipation phase). For 6 days, sheep were submitted to two sessions of six consecutive trials each. Behavioural reaction was filmed and changes in cortical oxy- and deoxy-hemoglobin concentration ([ΔO2Hb] and [ΔHHb] respectively) following neuronal activation were recorded by functional near infrared spectroscopy (fNIRS). Compared to baseline, during the anticipation phase sheep increased their active behaviour, kept the head oriented to the gate (Wilcoxon’s signed rank test; p ≤ 0.001), and showed more asymmetric ear posture (Wilcoxon’s signed rank test; p ≤ 0.01), most likely reflecting a learnt association and an increased arousal. Results of trial-averaged [ΔO2Hb] and [ΔHHb] within individual sheep showed in almost every sheep a cortical activation during the anticipation phase (Student T-test; p ≤ 0.05). The sheep showed a greater response of the right hemisphere compared to the left hemisphere, possibly indicating a negative affective state, such as frustration. Behavioural and cortical changes observed during anticipation of a food reward reflect a learnt association and an increased arousal, but no clear emotional valence of the sheep subjective experience. Future work should take into consideration possible factors affecting the accurateness of measures, such a...

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Section: Discussionmentioning

confidence: 99%

Evaluation of Sheep Anticipatory Response to a Food Reward by Means of Functional Near-Infrared Spectroscopy

Chincarini

Qiu

Spinelli

et al. 2018

Animals

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“…A lissencephalic brain is normally found in small mammals, particularly in small rodents such as mice and rats. Conversely, convolutedness in gyrencephalic brains is highly variable and increases in large mammals with an increasing brain mass [Pillay and Manger, 2007;Kelava et al, 2013, Zilles et al, 2013Triarhou, 2017]. Despite being confined by the skull, cortical folding has enabled brain growth during evolution, increasing cortical surface in direct relation to the degree of gyrification.…”

Section: Introductionmentioning

confidence: 99%

“…To understand the variation of the anatomical structure of the brain in phyletic lineages, the use of quantitative parameters such as the encephalization quotient (EQ) [Jerison, 1973[Jerison, , 1977, the gyrification index (GI) [Zilles et al, 2013], and the cortical thickness are invaluable tools. In particular, the use of exotic species with highly gyrated brains for comparative quantitative studies may help to test hypotheses on brain anatomical variation [Triarhou, 2017]. Most of our understanding of brain morphological variability has been founded on studies from a few mammalian species, especially in the so-called laboratory models and scattered species of primates, ungulates, carnivores, and cetaceans [Triarhou, 2017].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the use of exotic species with highly gyrated brains for comparative quantitative studies may help to test hypotheses on brain anatomical variation [Triarhou, 2017]. Most of our understanding of brain morphological variability has been founded on studies from a few mammalian species, especially in the so-called laboratory models and scattered species of primates, ungulates, carnivores, and cetaceans [Triarhou, 2017]. In the order Rodentia, which encompasses more than 2,270 living species [Wilson and Reeder, 2006], brain morphology has been extensively studied in mice and rats, and just a few anatomical descriptions are found for other species.…”

Section: Introductionmentioning

confidence: 99%

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Neocortical Anatomy in the South American Plains Vizcacha, Lagostomus maximus, Reveals Different Strategies in Encephalic Development among Hystricomorpha and Myomorpha Rodents

et al. 2020

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Depending on the presence or absence of sulci and convolutions, the brains of mammals are classified as gyrencephalic or lissencephalic. We analyzed the encephalic anatomy of the hystricomorph rodent Lagostomus maximus in comparison with other evolutionarily related species. The encephalization quotient (EQ), gyrencephaly index (GI), and minimum cortical thickness (MCT) were calculated for the plains vizcacha as well as for other myomorph and hystricomorph rodents. The vizcacha showed a gyrencephalic brain with a sagittal longitudinal fissure that divides both hemispheres, and 3 pairs of sulci with bilateral symmetry; that is, lateral-rostral, intraparietal, and transverse sulci. The EQ had one of the lowest values among Hystricomorpha, while GI was one of the highest. Besides, the MCT was close to the mean value for the suborder. The comparison of EQ, GI, and MCT values between hystricomorph and myomorph species allowed the detection of significant variations. Both EQ and GI showed a significant increase in Hystricomorpha compared to Myomorpha, whereas a Pearson’s analysis between EQ and GI depicted an inverse correlation pattern for Hystricomorpha. Furthermore, the ratio between MCT and GI also showed a negative correlation for Hystricomorpha and Myomorpha. Our phylogenetic analyses showed that Hystricomorpha and Myomorpha do not differ in their allometric patterning between the brain and body mass, GI and brain mass, and MCT and GI. In conclusion, gyrencephalic neuroanatomy in the vizcacha could have developed from the balance between the brain size, the presence of invaginations, and the cortical thickness, which resulted in a mixed encephalization strategy for the species. Gyrencephaly in the vizcacha, as well as in other Hystricomorpha, advocates in favor of the proposal that in the more recently evolved Myomorpha lissencephaly would have arisen from a phenotype reversal process.

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Neuroanatomy and Brain Histological Atlas of the South American Plains Vizcacha

Schmidt,

Vitullo,

Dorfman

2024

Plains Vizcachas

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The Comparative Neurology of Neocortical Gyration and the Quest for Functional Specialization

Cited by 4 publications

References 61 publications

Evaluation of Sheep Anticipatory Response to a Food Reward by Means of Functional Near-Infrared Spectroscopy

Evaluation of Sheep Anticipatory Response to a Food Reward by Means of Functional Near-Infrared Spectroscopy

Neocortical Anatomy in the South American Plains Vizcacha, <b><i>Lagostomus maximus</i></b>, Reveals Different Strategies in Encephalic Development among Hystricomorpha and Myomorpha Rodents

Neuroanatomy and Brain Histological Atlas of the South American Plains Vizcacha

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