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Nature May 2023Sensory processing in the neocortex requires both feedforward and feedback information flow between cortical areas. In feedback processing, higher-level representations...
Sensory processing in the neocortex requires both feedforward and feedback information flow between cortical areas. In feedback processing, higher-level representations provide contextual information to lower levels, and facilitate perceptual functions such as contour integration and figure-ground segmentation. However, we have limited understanding of the circuit and cellular mechanisms that mediate feedback influence. Here we use long-range all-optical connectivity mapping in mice to show that feedback influence from the lateromedial higher visual area (LM) to the primary visual cortex (V1) is spatially organized. When the source and target of feedback represent the same area of visual space, feedback is relatively suppressive. By contrast, when the source is offset from the target in visual space, feedback is relatively facilitating. Two-photon calcium imaging data show that this facilitating feedback is nonlinearly integrated in the apical tuft dendrites of V1 pyramidal neurons: retinotopically offset (surround) visual stimuli drive local dendritic calcium signals indicative of regenerative events, and two-photon optogenetic activation of LM neurons projecting to identified feedback-recipient spines in V1 can drive similar branch-specific local calcium signals. Our results show how neocortical feedback connectivity and nonlinear dendritic integration can together form a substrate to support both predictive and cooperative contextual interactions.
Topics: Animals; Mice; Calcium; Dendrites; Visual Cortex; Visual Pathways; Feedback, Physiological; Primary Visual Cortex; Pyramidal Cells; Optogenetics; Calcium Signaling
PubMed: 37138089
DOI: 10.1038/s41586-023-06007-6 -
Neuron May 2022Light is a powerful modulator of non-visual functions. Although accumulating evidence suggests an antinociceptive effect of bright light treatment, the precise circuits...
Light is a powerful modulator of non-visual functions. Although accumulating evidence suggests an antinociceptive effect of bright light treatment, the precise circuits that mediate the effects of light on nocifensive behaviors remain unclear. Here, we show that bright light treatment suppresses mouse nocifensive behaviors through a visual circuit related to the lateral and ventral lateral parts of the periaqueductal gray area (l/vlPAG). Specifically, a subset of retinal ganglion cells (RGCs) innervates GABAergic neurons in the ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), which in turn inhibit GABAergic neurons in the l/vlPAG. The activation of vLGN/IGL-projecting RGCs, activation of l/vlPAG-projecting vLGN/IGL neurons, or inhibition of postsynaptic l/vlPAG neurons is sufficient to suppress nocifensive behaviors. Importantly, we demonstrate that the antinociceptive effects of bright light treatment are dependent on the activation of the retina-vLGN/IGL-l/vlPAG pathway. Together, our results delineate an l/vlPAG-related visual circuit underlying the antinociceptive effects of bright light treatment.
Topics: Analgesics; Animals; Geniculate Bodies; Mice; Periaqueductal Gray; Retinal Ganglion Cells; Visual Pathways
PubMed: 35263618
DOI: 10.1016/j.neuron.2022.02.009 -
Neuroimaging Clinics of North America May 2023Traumatic brain injury disrupts the complex anatomy of the afferent and efferent visual pathways. Injury to the afferent pathway can result in vision loss, visual field... (Review)
Review
Traumatic brain injury disrupts the complex anatomy of the afferent and efferent visual pathways. Injury to the afferent pathway can result in vision loss, visual field deficits, and photophobia. Injury to the efferent pathway primarily causes eye movement abnormalities resulting in ocular misalignment and double vision. Injury to both the afferent and efferent systems can result in significant visual disability.
Topics: Humans; Vision Disorders; Visual Pathways; Brain Injuries, Traumatic
PubMed: 36965949
DOI: 10.1016/j.nic.2023.01.007 -
Annual Review of Vision Science Sep 2020Area V4-the focus of this review-is a mid-level processing stage along the ventral visual pathway of the macaque monkey. V4 is extensively interconnected with other... (Review)
Review
Area V4-the focus of this review-is a mid-level processing stage along the ventral visual pathway of the macaque monkey. V4 is extensively interconnected with other visual cortical areas along the ventral and dorsal visual streams, with frontal cortical areas, and with several subcortical structures. Thus, it is well poised to play a broad and integrative role in visual perception and recognition-the functional domain of the ventral pathway. Neurophysiological studies in monkeys engaged in passive fixation and behavioral tasks suggest that V4 responses are dictated by tuning in a high-dimensional stimulus space defined by form, texture, color, depth, and other attributes of visual stimuli. This high-dimensional tuning may underlie the development of object-based representations in the visual cortex that are critical for tracking, recognizing, and interacting with objects. Neurophysiological and lesion studies also suggest that V4 responses are important for guiding perceptual decisions and higher-order behavior.
Topics: Animals; Form Perception; Humans; Macaca mulatta; Pattern Recognition, Visual; Visual Cortex; Visual Pathways; Visual Perception
PubMed: 32580663
DOI: 10.1146/annurev-vision-030320-041306 -
Journal of Neurotrauma Oct 2021Traumatic brain injury (TBI) causes structural and functional damage to the central nervous system including the visual pathway. Defects in the afferent visual pathways... (Review)
Review
Traumatic brain injury (TBI) causes structural and functional damage to the central nervous system including the visual pathway. Defects in the afferent visual pathways affect visual function and in severe cases cause complete visual loss. Visual dysfunction is detectable by structural and functional ophthalmic examinations that are routine in the eye clinic, including examination of the pupillary light reflex and optical coherence tomography (OCT). Assessment of pupillary light reflex is a non-invasive assessment combining afferent and efferent visual function. While a assessment using a flashlight is relatively insensitive, automated pupillometry has 95% specificity and 78.1% sensitivity in detecting TBI-related visual and cerebral dysfunction with an area under the curve of 0.69-0.78. OCT may also serve as a noninvasive biomarker of TBI severity, demonstrating changes in the retinal ganglion cell layer and nerve fiber layer throughout the range of TBI severity even in the absence of visual symptoms. This review discusses the impact of TBI on visual structure and function.
Topics: Animals; Biomarkers; Brain Injuries, Traumatic; Humans; Optic Nerve Injuries; Reflex, Pupillary; Tomography, Optical Coherence; Vision Disorders; Visual Pathways
PubMed: 34269619
DOI: 10.1089/neu.2021.0182 -
Continuum (Minneapolis, Minn.) Oct 2019This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes. (Review)
Review
PURPOSE OF REVIEW
This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes.
RECENT FINDINGS
Modern ophthalmic imaging can be used to monitor the effects of diseases of the optic chiasm and tract on the retinal ganglion cells. It can also be used to visualize transsynaptic degeneration of the anterior visual pathway in the setting of acquired retrogeniculate lesions. Visual prostheses that directly stimulate the occipital lobe are a potential strategy for rehabilitation that is in active clinical trials.
SUMMARY
Detecting and characterizing visual deficits due to optic chiasm and retrochiasmal disease are important for the diagnosis, localization, and monitoring of neurologic disease; identifying patient disability; and guiding rehabilitation.
Topics: Adult; Brain Diseases; Female; Humans; Middle Aged; Occipital Lobe; Optic Chiasm; Optic Nerve Diseases; Vision Disorders; Visual Pathways
PubMed: 31584539
DOI: 10.1212/CON.0000000000000785 -
Annual Review of Vision Science Sep 2021Coordination between different sensory systems is a necessary element of sensory processing. Where and how signals from different sense organs converge onto common... (Review)
Review
Coordination between different sensory systems is a necessary element of sensory processing. Where and how signals from different sense organs converge onto common neural circuitry have become topics of increasing interest in recent years. In this article, we focus specifically on visual-auditory interactions in areas of the mammalian brain that are commonly considered to be auditory in function. The auditory cortex and inferior colliculus are two key points of entry where visual signals reach the auditory pathway, and both contain visual- and/or eye movement-related signals in humans and other animals. The visual signals observed in these auditory structures reflect a mixture of visual modulation of auditory-evoked activity and visually driven responses that are selective for stimulus location or features. These key response attributes also appear in the classic visual pathway but may play a different role in the auditory pathway: to modify auditory rather than visual perception. Finally, while this review focuses on two particular areas of the auditory pathway where this question has been studied, robust descending as well as ascending connections within this pathway suggest that undiscovered visual signals may be present at other stages as well.
Topics: Animals; Auditory Cortex; Mammals; Sensation; Sense Organs; Visual Pathways; Visual Perception
PubMed: 34242053
DOI: 10.1146/annurev-vision-091517-034003 -
Zoological Research Jan 2023Strabismus and amblyopia are common ophthalmologic developmental diseases caused by abnormal visual experiences. However, the underlying pathogenesis and visual defects...
Strabismus and amblyopia are common ophthalmologic developmental diseases caused by abnormal visual experiences. However, the underlying pathogenesis and visual defects are still not fully understood. Most studies have used experimental interference to establish disease-associated animal models, while ignoring the natural pathophysiological mechanisms. This study was designed to investigate whether natural strabismus and amblyopia are associated with abnormal neurological defects. We screened one natural strabismic monkey ( ) and one natural amblyopic monkey from hundreds of monkeys, and retrospectively analyzed one human strabismus case. Neuroimaging, behavioral, neurophysiological, neurostructural, and genovariation features were systematically evaluated using magnetic resonance imaging (MRI), behavioral tasks, flash visual evoked potentials (FVEP), electroretinogram (ERG), optical coherence tomography (OCT), and whole-genome sequencing (WGS), respectively. Results showed that the strabismic patient and natural strabismic and amblyopic monkeys exhibited similar abnormal asymmetries in brain structure, i.e., ipsilateral impaired right hemisphere. Visual behavior, visual function, retinal structure, and fundus of the monkeys were impaired. Aberrant asymmetry in binocular visual function and structure between the strabismic and amblyopic monkeys was closely related, with greater impairment of the left visual pathway. Several similar known mutant genes for strabismus and amblyopia were also identified. In conclusion, natural strabismus and amblyopia are accompanied by abnormal asymmetries of the visual system, especially visual neurophysiological and neurostructural defects. Our results suggest that future therapeutic and mechanistic studies should consider defects and asymmetries throughout the entire visual system.
Topics: Animals; Humans; Visual Pathways; Evoked Potentials, Visual; Retrospective Studies; Haplorhini
PubMed: 36484227
DOI: 10.24272/j.issn.2095-8137.2022.254 -
Der Ophthalmologe : Zeitschrift Der... Nov 2020Humans receive information from their environment mainly via the visual system. Signals from the photoreceptors of the retina via bipolar and ganglion cells are... (Review)
Review
Humans receive information from their environment mainly via the visual system. Signals from the photoreceptors of the retina via bipolar and ganglion cells are projected onto specific neuronal subpopulations in the lateral geniculate body and from there are forwarded to appropriate layers of the primary visual cortex. The most important anatomical and functional features of the visual system are explained. For this purpose, a selective literature search was carried out in the databases PubMed (also in Europe PubMed Central), Psychline, Google Scholar, Cochrane Library and Web of Science as well as additional information in relevant books or websites in the fields of (neuro)anatomy, (neuro)physiology, (neuro)ophthalmology and (neuro)otology, among others with the search terms Sehbahn, visual system, visual pathway, receptors, spatial cognition and visual cognition.
Topics: Geniculate Bodies; Humans; Photoreceptor Cells; Retina; Visual Cortex; Visual Pathways
PubMed: 32152751
DOI: 10.1007/s00347-020-01069-7 -
Annual Review of Vision Science Sep 2019With modern neurophysiological methods able to record neural activity throughout the visual pathway in the context of arbitrarily complex visual stimulation, our... (Review)
Review
With modern neurophysiological methods able to record neural activity throughout the visual pathway in the context of arbitrarily complex visual stimulation, our understanding of visual system function is becoming limited by the available models of visual neurons that can be directly related to such data. Different forms of statistical models are now being used to probe the cellular and circuit mechanisms shaping neural activity, understand how neural selectivity to complex visual features is computed, and derive the ways in which neurons contribute to systems-level visual processing. However, models that are able to more accurately reproduce observed neural activity often defy simple interpretations. As a result, rather than being used solely to connect with existing theories of visual processing, statistical modeling will increasingly drive the evolution of more sophisticated theories.
Topics: Humans; Machine Learning; Models, Neurological; Nerve Net; Neurons; Visual Cortex; Visual Pathways
PubMed: 31386605
DOI: 10.1146/annurev-vision-091718-014731