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Current Biology : CB Aug 2009In both insect and vertebrate olfactory systems only two synapses separate the sensory periphery from brain areas required for memory formation and the organisation of... (Review)
Review
In both insect and vertebrate olfactory systems only two synapses separate the sensory periphery from brain areas required for memory formation and the organisation of behaviour. In the Drosophila olfactory system, which is anatomically very similar to its vertebrate counterpart, there has been substantial recent progress in understanding the flow of information from experiments using molecular genetic, electrophysiological and optical imaging techniques. In this review, we shall focus on how olfactory information is processed and transformed in order to extract behaviourally relevant information. We follow the progress from olfactory receptor neurons, through the first processing area, the antennal lobe, to higher olfactory centres. We address both the underlying anatomy and mechanisms that govern the transformation of neural activity. We emphasise our emerging understanding of how different elementary computations, including signal averaging, gain control, decorrelation and integration, may be mapped onto different circuit elements.
Topics: Animal Structures; Animals; Brain; Drosophila melanogaster; Feeding Behavior; Grasshoppers; Larva; Learning; Mushroom Bodies; Neurotransmitter Agents; Odorants; Olfactory Pathways; Olfactory Receptor Neurons; Receptors, Odorant; Sense Organs; Smell; Spatial Behavior
PubMed: 19706282
DOI: 10.1016/j.cub.2009.06.026 -
Journal of Neurogenetics 2020From Sydney Brenner's backyard to hundreds of labs across the globe, inspiring six Nobel Prize winners along the way, research has come far in the past half century.... (Review)
Review
From Sydney Brenner's backyard to hundreds of labs across the globe, inspiring six Nobel Prize winners along the way, research has come far in the past half century. The journey is not over. The virtues of research are numerous and have been recounted extensively. Here, we focus on the remarkable progress made in sensory neurobiology research in . This nematode continues to amaze researchers as we are still adding new discoveries to the already rich repertoire of sensory capabilities of this deceptively simple animal. Worms possess the sense of taste, smell, touch, light, temperature and proprioception, each of which is being studied in genetic, molecular, cellular and systems-level detail. This impressive organism can even detect less commonly recognized sensory cues such as magnetic fields and humidity.
Topics: Animals; Behavior, Animal; Caenorhabditis elegans; Interneurons; Models, Animal; Neurobiology; Sensation; Sense Organs; Sensory Receptor Cells
PubMed: 33191820
DOI: 10.1080/01677063.2020.1823386 -
The International Journal of... 2009The inner ear is a complex structure responsible for the senses of audition and balance in vertebrates. The ear is organised into different sense organs that are... (Review)
Review
The inner ear is a complex structure responsible for the senses of audition and balance in vertebrates. The ear is organised into different sense organs that are specialised to detect specific stimuli such as sound and linear or angular accelerations. The elementary sensory unit of the ear consists of hair cells, supporting cells, neurons and Schwann cells. Hair cells are the mechano-electrical transducing elements, and otic neurons convey information coded in electrical impulses to the brain. With the exception of the Schwann cells, all cellular elements of the inner ear derive from the otic placode. This is an ectodermal thickening that is specified in the head ectoderm adjacent to the caudal hindbrain. The complex organisation of the ear requires precise coupling of regional specification and cell fate decisions during development, i.e. specificity in defining particular spatial domains containing particular cell types. Those decisions are taken early in development and are the subject of this article. We review here recent work on: i) early patterning of the otic placode, ii) the role of neural tube signals in the patterning of the otic vesicle, and iii) the genes underlying cell fate determination of neurons and sensory hair cells.
Topics: Animals; Body Patterning; Cell Differentiation; Chickens; Ear, Inner; Gene Expression Regulation, Developmental; Hair Cells, Auditory; Mice; Models, Biological; Rhombencephalon
PubMed: 19247974
DOI: 10.1387/ijdb.072422ba -
International Journal of Molecular... Oct 2022The contribution of choroidal vasculature to the pathogenesis of age-related macular degeneration (AMD) has been long debated. The present narrative review aims to... (Review)
Review
The contribution of choroidal vasculature to the pathogenesis of age-related macular degeneration (AMD) has been long debated. The present narrative review aims to discuss the primary molecular and choroidal structural changes occurring with aging and AMD with a brief overview of the principal multimodal imaging modalities and techniques that enable the optimal in vivo visualization of choroidal modifications. The molecular aspects that target the choroid in AMD mainly involve human leukocyte antigen (HLA) expression, complement dysregulation, leukocyte interaction at Bruch's membrane, and mast cell infiltration of the choroid. A mechanistic link between high-risk genetic loci for AMD and mast cell recruitment has also been recently demonstrated. Recent advances in multimodal imaging allow more detailed visualization of choroidal structure, identifying alterations that may expand our comprehension of aging and AMD development.
Topics: Aging; Bruch Membrane; Choroid; Humans; Macular Degeneration
PubMed: 36233311
DOI: 10.3390/ijms231912010 -
Tumour Biology : the Journal of the... 2022Exosomes are a subgroup of membrane-bound extracellular vesicles secreted by all cell types and present virtually in all biological fluids. The composition of exosomes...
Exosomes are a subgroup of membrane-bound extracellular vesicles secreted by all cell types and present virtually in all biological fluids. The composition of exosomes in the same cell type varies in healthy and disease conditions. Hence, exosomes research is a prime focus area for clinical research in cancer and numerous age-related metabolic syndromes. Functions of exosomes include crucial cell-to-cell communication that mediates complex cellular processes, such as antigen presentation, stem cell differentiation, and angiogenesis. However, very few studies reported the presence and role of exosomes in normal physiological and pathological conditions of specialized ocular tissues of the eye and ocular cancers. The eye being a protected sense organ with unique connectivity with the rest of the body through the blood and natural passages, we believe that the role of exosomes in ocular tissues will significantly improve our understanding of ocular diseases and their interactions with the rest of the body. We present a review that highlights the existence and function of exosomes in various ocular tissues, their role in the progression of some of the neoplastic and non-neoplastic conditions of the eyes.
Topics: Cell Communication; Exosomes; Eye; Face; Humans; Sense Organs
PubMed: 35964221
DOI: 10.3233/TUB-211543 -
Physiological Reviews Oct 2018Calcium influx through voltage-gated Ca (Ca) channels is the first step in synaptic transmission. This review concerns Ca channels at ribbon synapses in primary sense... (Review)
Review
Calcium influx through voltage-gated Ca (Ca) channels is the first step in synaptic transmission. This review concerns Ca channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the Ca channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of Ca channels at presynaptic, ribbon-type active zones, because the spatial relationship between Ca channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, Ca1.3, and Ca1.4 channels or their protein modulatory elements.
Topics: Animals; Calcium Channels; Ear, Inner; Humans; Retina; Sensory Receptor Cells; Synapses; Synaptic Transmission
PubMed: 30067155
DOI: 10.1152/physrev.00030.2017 -
International Journal of Molecular... Aug 2017The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the... (Review)
Review
The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the tear film determines the dry eye (DE) syndrome. Despite having a multifactorial origin, the main risk factors are female gender and advanced age. Likewise, morphological changes in several glands and in the chemical composition of their secretions, such as proteins, mucins, lipidics, aqueous tears, and salinity, are highly relevant factors that maintain a steady ocular surface. Another key factor of recurrence and onset of the disease is the presence of local and/or systemic inflammation that involves the ocular surface. DE syndrome is one of the most commonly encountered diseases in clinical practice, and many other causes related to daily life and the increase in average life expectancy will contribute to its onset. This review will consider the disorders of the ocular surface that give rise to such a widespread pathology. At the end, the most recent therapeutic options for the management of DE will be briefly discussed according to the specific underlying pathology.
Topics: Aging; Animals; Disease Management; Dry Eye Syndromes; Humans; Lacrimal Apparatus; Meibomian Glands
PubMed: 28805710
DOI: 10.3390/ijms18081764 -
Biology Letters Apr 2022The Hemiptera, with approximately 98 000 species, is one of the largest insect orders. Most species feed by sucking sap from plant tissues and are thus often vectors for...
The Hemiptera, with approximately 98 000 species, is one of the largest insect orders. Most species feed by sucking sap from plant tissues and are thus often vectors for economically important phytopathogens. Well known within this group are the large cicadas (Cicadomorpha: Cicadoidea: Cicadidae) because they produce extremely loud airborne sounds. Less well known are their mostly tiny relatives, the leafhoppers, spittlebugs, treehoppers and planthoppers that communicate by silent vibrational signals. While the generation of these signals has been extensively investigated, the mechanisms of their perception are poorly understood. This study provides a complete description and three-dimensional reconstruction of a large and complex array of mechanoreceptors in the first abdominal segments of the Rhododendron leafhopper (Cicadomorpha: Membracoidea: Cicadellidae). Further, we identify homologous organs in the spittlebug (Cicadomorpha: Cercopoidea: Aphrophoridae) and the planthopper (Fulgoromorpha: Fulgoroidea: Issidae). Such large abdominal sensory arrays have not been found in any other insect orders studied so far. This indicates that these sense organs, together with the signal-producing tymbal organ, constitute a synapomorphy of the Tymbalia (Hemiptera excl. Sternorrhyncha). Our results contribute to the understanding of the evolution from substrate-borne to airborne communication in insects.
Topics: Animals; Hemiptera; Sense Organs
PubMed: 35414220
DOI: 10.1098/rsbl.2022.0078 -
TheScientificWorldJournal Apr 2006The vertebrate cranial sensory placodes are ectodermal embryonic patches that give rise to sensory receptor cells of the peripheral paired sense organs and to neurons in... (Review)
Review
The vertebrate cranial sensory placodes are ectodermal embryonic patches that give rise to sensory receptor cells of the peripheral paired sense organs and to neurons in the cranial sensory ganglia. Their differentiation and the genetic pathways that underlay their development are now well understood. Their evolutionary history, however, has remained obscure. Recent molecular work, performed on close relatives of the vertebrates, demonstrated that some sensory placodes (namely the adenohypophysis, the olfactory, and accoustico-lateralis placodes) first evolved at the base of the chordate lineage, while others might be specific to vertebrates. Combined with morphological and cellular fate data, these results also suggest that the sensory placodes of the ancestor of all chordates differentiated into a wide range of structures, most likely to fit the lifestyle and environment of each species.
Topics: Animals; Cranial Nerves; Evolution, Molecular; Gene Expression Regulation, Developmental; Humans; Models, Biological; Neural Crest; Sense Organs
PubMed: 17205191
DOI: 10.1100/tsw.2006.314 -
Developmental Dynamics : An Official... Aug 2000The Drosophila Distal-less (Dll) gene was identified in the early 1980s by means of dominant and recessive mutations that caused both striking antenna-to-leg... (Review)
Review
The Drosophila Distal-less (Dll) gene was identified in the early 1980s by means of dominant and recessive mutations that caused both striking antenna-to-leg transformations and leg truncations. The gene initially was named "Bristle on arista" or "Brista" because one aspect of the phenotype is the formation of leg bristles on the antenna (Sato [1984] Drosophila Information Service 60:180-182; Sunkel and Whittle [1987] Wilhelm Roux's. Arch. Dev. Biol. 196:124-132). Subsequent studies have revealed that Dll encodes a homeodomain transcription factor (Cohen et al. [1989] Nature 338:432-434) that is expressed throughout limb development from embryogenesis on (Cohen [1990] Nature 343:173-177; Weigmann and Cohen [1999] Development 126:3823-3830). Dll is required for the elaboration of distal pattern elements in the antenna, the legs, the limb-derived gnathal structures (Cohen and Jurgens [1989] Nature 482-485), and the anal plate (Gorfinkiel et al. [1999] Mech. Dev. 868:113-123) and can initiate proximodistal axis formation when expressed ectopically (Gorfinkiel et al. [1997] Genes Dev. 11:2259-2271). Dll homologs are expressed in developing appendages in at least six coelomate phyla, including chordates (Akimenko et al. [1994] J. Neurosci. 14:3475-3486; Beauchemin and Savard [1992] Dev. Biol. 154:55-65; Bulfone et al. [1993] Mech. Dev. 40:129-140; Dolle et al. [1992] Differentiation 49:93-99; Ferrari et al. [1995] Mech. Dev. 52:257-264; Panganiban et al. [1997] Proc. Natl. Acad. Sci. USA 94:5162-5166; Simeone et al. [1994] Proc. Natl. Acad. Sci. USA 91:2250-2254), consistent with requirements for Dlx function in normal limb development across the animal kingdom. Distal-less also has been implicated in various aspects of vertebrate neurogenesis (see reviews by Kraus and Lufkin [1999] J. Cell. Biochem. 32-33:133-140 and the accompanying review by Beanan and Sargent [2000] Dev. Dyn. 218:000-000). Here, I outline what is known about Dll function and regulation in Drosophila.
Topics: Animals; Drosophila; Extremities; Gene Expression Regulation, Developmental; Homeodomain Proteins; Models, Genetic; Sense Organs; Time Factors; Transcription Factors; Wings, Animal
PubMed: 10906775
DOI: 10.1002/1097-0177(200008)218:4<554::AID-DVDY1023>3.0.CO;2-#