FIGURE 1 - uploaded by Andrew N Iwaniuk
Content may be subject to copyright.
Source publication
In this paper, we review the connections and physiology of visual pathways to the cerebellum in birds and consider their role in flight. We emphasize that there are two visual pathways to the cerebellum. One is to the vestibulocerebellum (folia IXcd and X) that originates from two retinal-recipient nuclei that process optic flow: the nucleus of the...
Similar publications
Flight through cluttered environments, such as forests, poses great challenges for animals and machines alike because even small changes in flight path may lead to collisions with nearby obstacles. When flying along narrow corridors, insects use the magnitude of visual motion experienced in each eye to control their position, height, and speed but...
In this paper, we analyse two deep learning methods to predict sperm motility and sperm morphology from sperm videos. We use two different inputs: stacked pure frames of videos and dense optical flows of video frames. To solve this regression task of predicting motility and morphology, stacked dense optical flows and extracted original frames from...
There is considerable support for the hypothesis that heading perception is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a novel method, termed "phase motion," for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended p...
In this paper, we analyse two deep learning methods to predict sperm motility and sperm morphology from sperm videos. We use two different inputs: stacked pure frames of videos and dense optical flows of video frames. To solve this regression task of predicting motility and morphology, stacked dense optical flows and extracted original frames from...
Citations
... With respect to the content of potential dreams, however, a very preliminary hypothesis could be formulated. When organisms move forward, they experience optic flow as a visual expansion in the direction of self-motion 48 , while local motion signals code for obstacles that should be avoided in flight through visually cluttered environments 49 . Such optic flow and local motion signals are integrated in the oculomotor cerebellum of which folia VI is a part 50 . ...
Mammalian sleep has been implicated in maintaining a healthy extracellular environment in the brain. During wakefulness, neuronal activity leads to the accumulation of toxic proteins, which the glymphatic system is thought to clear by flushing cerebral spinal fluid (CSF) through the brain. In mice, this process occurs during non-rapid eye movement (NREM) sleep. In humans, ventricular CSF flow has also been shown to increase during NREM sleep, as visualized using functional magnetic resonance imaging (fMRI). The link between sleep and CSF flow has not been studied in birds before. Using fMRI of naturally sleeping pigeons, we show that REM sleep, a paradoxical state with wake-like brain activity, is accompanied by the activation of brain regions involved in processing visual information, including optic flow during flight. We further demonstrate that ventricular CSF flow increases during NREM sleep, relative to wakefulness, but drops sharply during REM sleep. Consequently, functions linked to brain activation during REM sleep might come at the expense of waste clearance during NREM sleep.
... The nLM is homologous to the nucleus of the optic tract and highly conserved across all vertebrates (Fite, 1985;McKenna and Wallman, 1985). The majority of nLM neurons prefer slow velocity and become excited by visual motion in the temporal-to-nasal direction, while other neurons are predominantly sensitive to the nasal-to-temporal, or vertical motion (Winterson and Brauth, 1985;Wylie and Frost, 1996;Fu et al., 1998;Wylie and Crowder, 2000;Cao et al., 2004;Wylie et al., 2018). Reversible inactivation or electrolytic lesions of the nLM impair generating horizontal OKN (Fite et al., 1979;Gioanni et al., 1983;Yang et al., 2008a;Yang et al., 2008b). ...
... Regarding connectivity, the nLM relays visual information from the retina directly or indirectly to the vestibular cerebellum, the oculomotor cerebellum, the thalamus, the brainstem, and other brain areas ( Figure 1D). These connections are integral to the nLM's role in eye and head movements, and many other behaviors, including postural and steering control (Cao et al., 2006;Yang et al., 2008b;Wylie, 2013;Ibbotson, 2017;Wylie et al., 2018). This established circuitry and decades of work documenting these specific sensorimotor transformations the nLM performs make it an ideal candidate to study the effects of MIRS on behavioral and neuronal responses. ...
Neuromodulation serves as a cornerstone for brain sciences and clinical applications. Recent reports suggest that mid-infrared stimulation (MIRS) causes non-thermal modulation of brain functions. Current understanding of its mechanism hampers the routine application of MIRS. Here, we examine how MIRS influences the sensorimotor transformation in awaking-behaving pigeons, from neuronal signals to behavior. We applied MIRS and electrical stimulation (ES) to the pretectal nucleus lentiformis mesencephali (nLM), an essential retinorecipient structure in the pretectum, and examined their influences on the optokinetic nystagmus, a visually guided eye movement. We found MIRS altered eye movements by modulating a specific gain depending on the strength of visual inputs, in a manner different than the effect of ES. Simultaneous extracellular recordings and stimulation showed that MIRS could either excite and inhibit the neuronal activity in the same pretectal neuron depending on its ongoing sensory responsiveness levels in awake-behaving animals. Computational simulations suggest that MIRS modulates the resonance of a carbonyl group of the potassium channel, critical to the action potential generation, altering neuronal responses to sensory inputs and as a consequence, guiding behavior. Our findings suggest that MIRS could be a promising approach toward modulating neuronal functions for brain research and treating neurological diseases.
... It is noteworthy that the retina of diurnal vertebrates, including chickens, offers a useful complement to nocturnal models (rats and mice) in addition to having a number of differential characteristics and advantages in terms of cone-dominant retinas and cone-rich photoreceptor mosaics and resilience to neuronal injury in response to bright or continuous light exposure (reviewed in [175,176]. In birds, higher processing requirements within the retina are associated with higher visual acuity [177] and the inner nuclear layer (INL) is significantly larger in size and cell number than in nocturnal rodents, where most visual processing takes place in the visual cortex. Moreover, given its large ocular size and ease of handling, the chicken further offers the possibility of rapid retinal dissection and separation into different retinal cell layers allowing differential metabolic studies [178][179][180] and axonal transport of labeled GPLs to the contralateral optic tectum in the brain [178,181]. ...
Along evolution, living organisms developed a precise timekeeping system, circadian clocks, to adapt life to the 24-h light/dark cycle and temporally regulate physiology and behavior. The transcriptional molecular circadian clock and metabolic/redox oscillator conforming these clocks are present in organs, tissues, and even in individual cells, where they exert circadian control over cellular metabolism. Disruption of the molecular clock may cause metabolic disorders and higher cancer risk. The synthesis and degradation of glycerophospholipids (GPLs) is one of the most highly regulated metabolisms across the 24-h cycle in terms of total lipid content and enzyme expression and activity in the nervous system and individual cells. Lipids play a plethora of roles (membrane biogenesis, energy sourcing, signaling, and the regulation of protein-chromatin interaction, among others), making control of their metabolism a vital checkpoint in the cellular organization of physiology. An increasing body of evidence clearly demonstrates an orchestrated and sequential series of events occurring in GPL metabolism across the 24-h day in diverse retinal cell layers, immortalized fibroblasts, and glioma cells. Moreover, the clock gene Per1 and other circadian-related genes are tightly involved in the regulation of GPL synthesis in quiescent cells. However, under proliferation, the metabolic oscillator continues to control GPL metabolism of brain cancer cells even after molecular circadian clock disruption, reflecting the crucial role of the temporal metabolism organization in cell preservation. The aim of this review is to examine the control exerted by circadian clocks over GPL metabolism, their synthesizing enzyme expression and activities in normal and tumorous cells of the nervous system and in immortalized fibroblasts.
Graphical abstract
... The idea that sensory systems encode the salient features of the physical environment would support this hypothesis. In birds, higher processing requirements could be associated with flying and migration as well as visual acuity (Wylie et al. 2018). Strikingly, the INL containing the horizontal cells population is significantly larger in birds and other diurnal vertebrates in terms of size and cell number than in some mammals, mainly nocturnal rodents where most visual processing takes place in the visual cortex. ...
In recent decades, a number of novel non-visual opsin photopigments belonging to the family of G protein- coupled receptors, likely involved in a number of non-image-forming processes, have been identified and characterized in cells of the inner retina of vertebrates. It is now known that the vertebrate retina is composed of visual photoreceptor cones and rods responsible for diurnal/color and nocturnal/black and white vision, and cells like the intrinsically photosensitive retinal ganglion cells (ipRGCs) and photosensitive horizontal cells in the inner retina, both detecting blue light and expressing the photopigment melanopsin (Opn4). Remarkably, these non-visual photopigments can continue to operate even in the absence of vision under retinal degeneration. Moreover, inner retinal neurons and Müller glial cells have been shown to express other photopigments such as the photoisomerase retinal G protein-coupled receptor (RGR), encephalopsin (Opn3), and neuropsin (Opn5), all able to detect blue/violet light and implicated in chromophore recycling, retinal clock synchronization, neuron-to-glia communication, and other activities. The discovery of these new photopigments in the inner retina of vertebrates is strong evidence of novel light-regulated activities. This review focuses on the features, localization, photocascade, and putative functions of these novel non-visual opsins in an attempt to shed light on their role in the inner retina of vertebrates and in the physiology of the whole organism.
... Anterior 682 lobules (I-V) contain the somatotopic representation of the tail, leg and wings (Whitlock, 1952) and 683 are more pronounced in avian species with strong hind limbs (Iwaniuk et al., 2007). Cerebellar 684 lobules VII and VIII are part of the oculomotor cerebellum (VI-VIII) and receive visual input (Clarke, 685 1977), input from the pretecto-ponto-cerebellar system involved in flight (Wylie et al., 2018) and 686 have a somatotopic representation of the cochlea and retina (Whitlock, 1952). can affect cerebellar Purkinje firing related to locomotor activity (Dean and McCarthy, 2008;Smith, 711 1995). ...
Traditionally, research unraveling seasonal neuroplasticity in songbirds has focused on the male song control system and testosterone. We longitudinally monitored the song behavior and neuroplasticity in male and female starlings during multiple photoperiods using Diffusion Tensor and Fixel-Based techniques. These exploratory data-driven whole-brain methods resulted in a population-based tractogram confirming microstructural sexual dimorphisms in the song control system. Furthermore, male brains showed hemispheric asymmetries in the pallium, whereas females had higher interhemispheric connectivity, which could not be attributed to brain size differences. Only females with large brains sing but differ from males in their song behavior by showing involvement of the hippocampus. Both sexes experienced multisensory neuroplasticity in the song control, auditory and visual system, and cerebellum, mainly during the photosensitive period. This period with low gonadal hormone levels might represent a 'sensitive window' during which different sensory and motor systems in the cerebrum and cerebellum can be seasonally re-shaped in both sexes.
... 395) characterised the optic lobe as a "relay station" for transmitting ascending visual output to the forebrain (see Section 4.4.2.1 above), projecting descending output to the premotor regions of the hindbrain (see Section 4.4.2.4 below), and comprise multiple "retinotopically organised, and functionally specific" cell types. So called "optic flow" (sensu [159]), are retinal stimuli generated by self-motion through stationary environments (see [150,160] and references therein). Optic flow stimuli are analysed by recipient nuclei in the accessory optic system and pretectum, wherein the lentiformis mesencephali, or pretectal nucleus, responds to "moving large-field" visual stimuli and generates optokinetic response for the control of posture, eye movement stabilisation, and compensatory movement during locomotion ( [117,150,[160][161][162][163][164] and references therein), facilitated by processes within the cerebellum [87,165]. ...
... So called "optic flow" (sensu [159]), are retinal stimuli generated by self-motion through stationary environments (see [150,160] and references therein). Optic flow stimuli are analysed by recipient nuclei in the accessory optic system and pretectum, wherein the lentiformis mesencephali, or pretectal nucleus, responds to "moving large-field" visual stimuli and generates optokinetic response for the control of posture, eye movement stabilisation, and compensatory movement during locomotion ( [117,150,[160][161][162][163][164] and references therein), facilitated by processes within the cerebellum [87,165]. ...
Dromornithids are an extinct group of large flightless birds from the Cenozoic of Australia. Their record extends from the Eocene to the late Pleistocene. Four genera and eight species are currently recognised, with diversity highest in the Miocene. Dromornithids were once considered ratites, but since the discovery of cranial elements, phylogenetic analyses have placed them near the base of the anseriforms or, most recently, resolved them as stem galliforms. In this study, we use morphometric methods to comprehensively describe dromornithid endocranial morphology for the first time, comparing Ilbandornis woodburnei and three species of Dromornis to one another and to four species of extant basal galloanseres. We reveal that major endocranial reconfiguration was associated with cranial foreshortening in a temporal series along the Dromornis lineage. Five key differences are evident between the brain morphology of Ilbandornis and Dromornis, relating to the medial wulst, the ventral eminence of the caudoventral telencephalon, and morphology of the metencephalon (cerebellum + pons). Additionally, dromornithid brains display distinctive dorsal (rostral position of the wulst), and ventral morphology (form of the maxillomandibular [V2+V3], glossopharyngeal [IX], and vagus [X] cranial nerves), supporting hypotheses that dromornithids are more closely related to basal galliforms than anseriforms. Functional interpretations suggest that dromornithids were specialised herbivores that likely possessed well-developed stereoscopic depth perception, were diurnal and targeted a soft browse trophic niche.
... The cerebellum can be subdivided into individual folia, which receive different combinations of somatosensory input from different parts of the body. Enlargement of the number of cerebellar foliations has been associated with major density of cerebellar neural circuitry, which allows an improvement of the processing capacity and motor abilities, specifically manipulative skills (Butler & Hoods, 2005;Hall et al., 2013;Iwaniuk et al., 2009;Wylie et al., 2018). There is a positive correlation between cerebellar foliation and tool use in birds and between the enlargement of the cerebellum and beak control (Sultan & Glickstein, 2007). ...
... Optic lobes ratio relative to the telencephalic hemispheres was the only index that yielded a high phylogenetic signal (K > 1, it has not been studied in much detail, the size of specific folia is reportedly associated with flight behavior (Iwaniuk et al., 2007b;Wylie et al., 2018) and cognitive ability (Sultan, 2005) in birds. ...
We used three‐dimensional digital models to investigate the brain and endosseous labyrinth morphology of selected Neotropical Piciformes (Picidae, Ramphastidae, Galbulidae and Bucconidae). Remarkably, the brain morphology of Galbulidae clearly separates from species of other families. The eminentiae sagittales of Galbulidae and Bucconidae (insectivorous with high aerial maneuverability abilities) are smaller than those of the toucans (scansorial frugivores). Galbula showed the proportionally largest cerebellum, and Ramphastidae showed the least foliated one. Optic lobes ratio relative to the telencephalic hemispheres showed a strong phylogenetic signal. Three hypotheses were tested: (a) insectivorous taxa that need precise and fast movements to catch their prey, have well developed eminentiae sagittales compared to fruit eaters, (b) species that require high beak control would show larger cerebellum compared to other brain regions and higher number of visible folia and (c) there are marked differences between the brain shape of the four families studied here that bring valuable information of this interesting bird group. Hypotheses H1 and H2 are rejected, meanwhile H3 is accepted. We use 3D digital models of the brain cavity and inner ear of species of Picidae, Ramphastidae, Galbulidae and Bucconidae to better understand functional and ecological implications. We found marked differences among the brains of the four families, being G. ruficauda the most different one. Fruit eaters (Ramphastidae) had the biggest eminenta sagittales ratio. The cerebellum showed variable sizes and variable visible foliation among species. Only the optic lobe ratio has a phylogenetic signal.
... Anterior lobules (I-634 V) contain the somatotopic representation of the tail, leg and wings (Whitlock, 1952) and are more 635 pronounced in avian species with strong hind limbs (Iwaniuk et al., 2007). Cerebellar lobules VII and 636 VIII are part of the oculomotor cerebellum (VI-VIII) and receive visual input (Clarke, 1977), input from 637 the pretecto-ponto-cerebellar system involved in flight (Wylie et al., 2018) and have a somatotopic 638 representation of the cochlea and retina (Whitlock, 1952). The pronouncement of the oculomotor 639 cerebellum in males versus females could reflect the integration of visual and auditory sensory input, 640 ...
Traditionally, research unraveling seasonal neuroplasticity in songbirds has focused on the male song control system and testosterone. We longitudinally monitored the song and neuroplasticity in male and female starlings during multiple photoperiods using Diffusion Tensor and Fixel-Based techniques. These exploratory data-driven whole-brain methods resulted in a population-based tractogram uncovering microstructural sexual dimorphisms in the song control system and beyond. Male brains showed microstructural hemispheric asymmetries, whereas females had higher interhemispheric connectivity, which could not be attributed to brain size differences. Only females with large brains sing but differ from males in their song behavior by showing involvement of the hippocampus. Both sexes experienced multisensory neuroplasticity in the song control, auditory and visual system, and the cerebellum, mainly during the photosensitive period. This period with low gonadal hormones might represent a sensitive window during which different sensory and motor systems in telencephalon and cerebellum can be seasonally re-shaped in both sexes.
... Several studies of experimental MeHg exposure in adult game birds have also reported lesions of the cerebellum (Finley and Stendell 1978, Borg et al. 1970, Pass et al. 1975), but little is known about the effect of MeHg on the cerebellum of songbirds, especially when exposure is during development. A fully functioning cerebellum is essential for movement through a complex environment, for example much of the processing of visual inputs during flight occurs in the cerebellum (Wylie et al. 2018). Because most of the world's bird species are altricial songbirds, and there is much focus on the role of pollutants in their conservation, a better understanding of the effects of mercury on the songbird cerebellum is needed. ...
Mercury exposure can disrupt development of the cerebellum, part of the brain essential for coordination of movement through a complex environment, including flight. In precocial birds, such as fowl, the cerebellum develops embryonically, and the chick is capable of leaving the nest within hours of hatching. However, most birds, including all songbirds, are altricial, and spend weeks in the nest between hatching and fledging. The objective of this study was to describe the normal development of the cerebellum in a model altricial songbird so as to determine the effect of exposure to mercury on cerebellar maturation. Adult zebra finch (Taeniopygia guttata) pairs were fed either a control diet, or a diet augmented with one of four treatment-levels of methylmercury (0.3–2.4 μg/g wet weight), and their offspring, the subjects of this study, were fed the same diet by parents. We documented, for the first time, the schedule of cerebellar development in an altricial bird, and compared stages of development among methylmercury-exposed groups. For all treatments of methylmercury, the age of completion of cellular migration was later than for control zebra finches, indicating a delay in cerebellar maturation. Displaced (heterotopic) Purkinje neurons, a pathology typical of methylmercury exposure in developing vertebrate brains, were more numerous in methylmercury-exposed birds, and persisted at least until the age of independence. Delays in maturation of the cerebellum could delay fledging in altricial bird species, with potential serious implications for the fitness of exposed individuals, as predation rates in the nest are often very high.
... We identified one significant cluster of 21 voxels (1.107 mm 3 ) that showed a rearing condition-related developmental difference in FC to the left NCM cluster seed (CDT: p-uncorrected = 0.001, cluster-extent threshold: pFWE < 0.05; Fig 1C-D). 19 voxels (90.5% of cluster volume) overlapped the left dorsal cerebellum, positioned over folium VI (Wylie et al., 2018), whereas two voxels (9.5% of cluster volume) overlapped the adjacent left auditory forebrain region, as labeled in our previously published zebra finch brain atlas (Layden et al., 2019). The cerebellar cluster was largely posterior to the NCM cluster detected in ICC analyses, with its most posterior portion 8 voxels (1.6 mm) posterior to the most posterior extent of the NCM cluster. ...
One of the central questions of neuroethology is how specialized brain areas communicate to form dynamic networks that support complex cognitive and behavioral processes. Developmental song learning in the male zebra finch songbird (Taeniopygia guttata) provides a unique window into the complex interplay among sensory, sensorimotor, and motor network nodes. The foundation of a young male's song structure is the sensory memory he forms during interactions with an adult "tutor." However, even in the absence of tutoring, juveniles produce a song-like behavior. Thus, by controlling a juvenile male's tutor exposure, we can examine how tutor experience affects distributed neural networks and how network properties predict behavior. Here, we used longitudinal, resting-state fMRI (rs-fMRI) functional connectivity (FC) and song analyses to examine known nodes of the song network, and to allow discovery of additional areas functionally related to song learning. We present three major novel findings. First, tutor deprivation significantly reduced the global FC strength of the caudomedial nidopallium (NCM) subregion of the auditory forebrain required for sensory song learning. Second, tutor deprivation resulted in reduced FC between NCM and cerebellar lobule VI, a region analogous to areas that regulate limbic, social, and language functions in humans. Third, NCM FC strength predicted song stereotypy and mediated the relationship between tutoring and stereotypy, thus completing the link between experience, neural network properties, and complex learned behavior.
