LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 270

Search options

  1. Article ; Online: Stimulus-Driven Retinal Intrinsic Signal Optical Imaging in Mouse Demonstrates a Dominant Rod-Driven Component.

    Begum, Momotaz / Joiner, Dorothy P / Ts'o, Daniel Y

    Investigative ophthalmology & visual science

    2020  Volume 61, Issue 8, Page(s) 37

    Abstract: Purpose: The primary hypotheses tested are that (1) there exist stimulus-driven intrinsic optical signals in the mouse retina similar to those previously observed in other species, and (2) these optical signals require an intact rod photoreceptor ... ...

    Abstract Purpose: The primary hypotheses tested are that (1) there exist stimulus-driven intrinsic optical signals in the mouse retina similar to those previously observed in other species, and (2) these optical signals require an intact rod photoreceptor phototransduction cascade.
    Methods: We used 38 wild-type C57BL6J mice and 18 genetic knockout Gnat1-/- mice to study the light-evoked retinal intrinsic response. A custom mouse fundus camera delivered visual stimuli and collected mouse retinal imaging data of changes in retinal reflectance for further analysis. The retina was stimulated in the high-mesopic range with a 505-nm light-emitting diode while also being illuminated with 780-nm near-infrared light.
    Results: Wild-type C57BL6J mice yielded retinal imaging signals that typically showed a stimulus-driven decrease in retinal reflectance of ∼0.1%, with a time course of several seconds. The signals exhibit spatial specificity in the retina. Overall, the mouse imaging signals are similar in sign and time course to those reported in other mammalian species but are of lower amplitude. In contrast, functional retinal imaging of Gnat1-/- mice that lack a functional rod transducin yielded no such stimulus-driven signals.
    Conclusions: Previous studies have not shown which pathway component is essential for the generation of these imaged signals. The absence of the intrinsic signal responses in Gnat1-/- knockout mice indicates that a functional rod transducin is likely to be necessary for generating the retinal intrinsic signals. These studies, to the best of our knowledge, demonstrate for the first time in vivo mouse retinal functional imaging signals similar to those previously shown in other mammalian species.
    MeSH term(s) Animals ; Evoked Potentials, Visual ; Light Signal Transduction/physiology ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Optical Imaging/methods ; Photic Stimulation/instrumentation ; Photic Stimulation/methods ; Retina/physiopathology ; Retinal Rod Photoreceptor Cells/physiology ; Transducin/genetics ; Vision, Ocular/physiology
    Chemical Substances Gnat1 protein, mouse ; Transducin (EC 3.6.5.1)
    Language English
    Publishing date 2020-07-25
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 391794-0
    ISSN 1552-5783 ; 0146-0404
    ISSN (online) 1552-5783
    ISSN 0146-0404
    DOI 10.1167/iovs.61.8.37
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: Integration of color, orientation, and size functional domains in the ventral pathway.

    Ghose, Geoffrey M / Ts'o, Daniel Y

    Neurophotonics

    2017  Volume 4, Issue 3, Page(s) 31216

    Abstract: Functional specialization within the extrastriate areas of the ventral pathway associated with visual form analysis is poorly understood. Studies comparing the functional selectivities of neurons within the early visual areas have found that there are ... ...

    Abstract Functional specialization within the extrastriate areas of the ventral pathway associated with visual form analysis is poorly understood. Studies comparing the functional selectivities of neurons within the early visual areas have found that there are more similar than different between the areas. We simultaneously imaged visually evoked activation over regions of V2 and V4 and parametrically varied three visual attributes for which selectivity exists in both areas: color, orientation, and size. We found that color selective regions were observed in both areas and were of similar size and spatial distribution. However, two major areal distinctions were observed: V4 contained a greater number and diversity of color-specific regions than V2 and exhibited a higher degree of overlap between domains for different functional attributes. In V2, size and color regions were largely segregated from orientation domains, whereas in V4 both color and size regions overlapped considerably with orientation regions. Our results suggest that higher-order composite selectivities in the extrastriate cortex may arise organically from the interactions afforded by an overlap of functional domains for lower order selectivities.
    Language English
    Publishing date 2017-05-27
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2781943-7
    ISSN 2329-4248 ; 2329-423X
    ISSN (online) 2329-4248
    ISSN 2329-423X
    DOI 10.1117/1.NPh.4.3.031216
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: Contextual modulation revealed by optical imaging exhibits figural asymmetry in macaque V1 and V2.

    Zarella, Mark D / Ts'o, Daniel Y

    Eye and brain

    2017  Volume 9, Page(s) 1–12

    Abstract: Neurons in early visual cortical areas are influenced by stimuli presented well beyond the confines of their classical receptive fields, endowing them with the ability to encode fine-scale features while also having access to the global context of the ... ...

    Abstract Neurons in early visual cortical areas are influenced by stimuli presented well beyond the confines of their classical receptive fields, endowing them with the ability to encode fine-scale features while also having access to the global context of the visual scene. This property can potentially define a role for the early visual cortex to contribute to a number of important visual functions, such as surface segmentation and figure-ground segregation. It is unknown how extraclassical response properties conform to the functional architecture of the visual cortex, given the high degree of functional specialization in areas V1 and V2. We examined the spatial relationships of contextual activations in macaque V1 and V2 with intrinsic signal optical imaging. Using figure-ground stimulus configurations defined by orientation or motion, we found that extraclassical modulation is restricted to the cortical representations of the figural component of the stimulus. These modulations were positive in sign, suggesting a relative enhancement in neuronal activity that may reflect an excitatory influence. Orientation and motion cues produced similar patterns of activation that traversed the functional subdivisions of V2. The asymmetrical nature of the enhancement demonstrated the capacity for visual cortical areas as early as V1 to contribute to figure-ground segregation, and the results suggest that this information can be extracted from the population activity constrained only by retinotopy, and not the underlying functional organization.
    Language English
    Publishing date 2017-04-11
    Publishing country New Zealand
    Document type Journal Article
    ZDB-ID 2587460-3
    ISSN 1179-2744
    ISSN 1179-2744
    DOI 10.2147/EB.S105609
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article: Cue combination encoding via contextual modulation of V1 and V2 neurons.

    Zarella, Mark D / Ts'o, Daniel Y

    Eye and brain

    2016  Volume 8, Page(s) 177–193

    Abstract: Neurons in early visual cortical areas encode the local properties of a stimulus in a number of different feature dimensions such as color, orientation, and motion. It has been shown, however, that stimuli presented well beyond the confines of the ... ...

    Abstract Neurons in early visual cortical areas encode the local properties of a stimulus in a number of different feature dimensions such as color, orientation, and motion. It has been shown, however, that stimuli presented well beyond the confines of the classical receptive field can augment these responses in a way that emphasizes these local attributes within the greater context of the visual scene. This mechanism imparts global information to cells that are otherwise considered local feature detectors and can potentially serve as an important foundation for surface segmentation, texture representation, and figure-ground segregation. The role of early visual cortex toward these functions remains somewhat of an enigma, as it is unclear how surface segmentation cues are integrated from multiple feature dimensions. We examined the impact of orientation- and motion-defined surface segmentation cues in V1 and V2 neurons using a stimulus in which the two features are completely separable. We find that, although some cells are modulated in a cue-invariant manner, many cells are influenced by only one cue or the other. Furthermore, cells that are modulated by both cues tend to be more strongly affected when both cues are presented together than when presented individually. These results demonstrate two mechanisms by which cue combinations can enhance salience. We find that feature-specific populations are more frequently encountered in V1, while cue additivity is more prominent in V2. These results highlight how two strongly interconnected areas at different stages in the cortical hierarchy can potentially contribute to scene segmentation.
    Language English
    Publishing date 2016-10-21
    Publishing country New Zealand
    Document type Journal Article
    ZDB-ID 2587460-3
    ISSN 1179-2744
    ISSN 1179-2744
    DOI 10.2147/EB.S105616
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Specificity of V1-V2 orientation networks in the primate visual cortex.

    Roe, Anna W / Ts'o, Daniel Y

    Cortex; a journal devoted to the study of the nervous system and behavior

    2015  Volume 72, Page(s) 168–178

    Abstract: The computation of texture and shape involves integration of features of various orientations. Orientation networks within V1 tend to involve cells which share similar orientation selectivity. However, emergent properties in V2 require the integration of ...

    Abstract The computation of texture and shape involves integration of features of various orientations. Orientation networks within V1 tend to involve cells which share similar orientation selectivity. However, emergent properties in V2 require the integration of multiple orientations. We now show that, unlike interactions within V1, V1-V2 orientation interactions are much less synchronized and are not necessarily orientation dependent. We find V1-V2 orientation networks are of two types: a more tightly synchronized, orientation-preserving network and a less synchronized orientation-diverse network. We suggest that such diversity of V1-V2 interactions underlies the spatial and functional integration required for computation of higher order contour and shape in V2.
    MeSH term(s) Animals ; Brain Mapping ; Macaca fascicularis ; Nerve Net/physiology ; Neurons/physiology ; Orientation/physiology ; Photic Stimulation ; Visual Cortex/physiology ; Visual Pathways/physiology ; Visual Perception/physiology
    Language English
    Publishing date 2015-07-22
    Publishing country Italy
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 280622-8
    ISSN 1973-8102 ; 0010-9452
    ISSN (online) 1973-8102
    ISSN 0010-9452
    DOI 10.1016/j.cortex.2015.07.007
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Whither the hypercolumn?

    Ts'o, Daniel Y / Zarella, Mark / Burkitt, Guy

    The Journal of physiology

    2009  Volume 587, Issue Pt 12, Page(s) 2791–2805

    Abstract: Among the crowning achievements of Hubel and Wiesel's highly influential studies on primary visual cortex is the description of the cortical hypercolumn, a set of cortical columns with functional properties spanning a particular parameter space. This ... ...

    Abstract Among the crowning achievements of Hubel and Wiesel's highly influential studies on primary visual cortex is the description of the cortical hypercolumn, a set of cortical columns with functional properties spanning a particular parameter space. This fundamental concept laid the groundwork for the notion of a modular sensory cortex, canonical cortical circuits and an understanding of visual field coverage beyond simple retinotopy. Surprisingly, the search for and description of analogous hypercolumnar organizations in other cortical areas to date has been limited. In the present work, we have applied the hypercolumn concept to the functional organization of the second visual area, V2. We found it important to separate out the original definition of the hypercolumn from other associated observations and concepts, not all of which are applicable to V2. We present results indicating that, as in V1, the V2 hypercolumns for orientation and binocular interaction (disparity) run roughly orthogonal to each other. We quantified the 'nearest neighbour' periodicities for the hypercolumns for ocular dominance, orientation, colour and disparity, and found a marked similarity in the periodicities of all of these hypercolumns, both across hypercolumn type and across visual areas V1 and V2. The results support an underlying common mechanism that constrains the anatomical extent of hypercolumn systems, and highlight the original definition of the cortical hypercolumn.
    MeSH term(s) Algorithms ; Animals ; Brain Mapping ; Electrophysiology ; Models, Anatomic ; Retina/physiology ; Vision Disparity/physiology ; Visual Cortex/anatomy & histology ; Visual Cortex/physiology ; Visual Pathways/anatomy & histology ; Visual Pathways/physiology
    Language English
    Publishing date 2009-06-13
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/jphysiol.2009.171082
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Retinal intrinsic optical signals in a cat model of primary congenital glaucoma.

    Schallek, Jesse B / McLellan, Gillian J / Viswanathan, Suresh / Ts'o, Daniel Y

    Investigative ophthalmology & visual science

    2012  Volume 53, Issue 4, Page(s) 1971–1981

    Abstract: Purpose: To examine the impact of reduced inner retinal function and breed on intrinsic optical signals in cats.: Methods: Retinal intrinsic optical signals were recorded from anesthetized cats with a modified fundus camera. Near infrared light (NIR, ...

    Abstract Purpose: To examine the impact of reduced inner retinal function and breed on intrinsic optical signals in cats.
    Methods: Retinal intrinsic optical signals were recorded from anesthetized cats with a modified fundus camera. Near infrared light (NIR, 700-900 nm) was used to illuminate the retina while a charge-coupled device (CCD) camera captured the NIR reflectance of the retina. Visible stimuli (540 nm) evoked patterned changes in NIR retinal reflectance. NIR intrinsic signals were compared across three subject groups: two Siamese cats with primary congenital glaucoma (PCG), a control Siamese cat without glaucoma, and a control group of seven normally pigmented cats. Intraocular pressure (IOP), pattern electroretinogram, and optical coherence tomography measurements were evaluated to confirm the inner retinal deficit in PCG cats.
    Results: Stimulus-evoked, NIR retinal reflectance signals were observed in PCG cats despite severe degeneration of the nerve fiber layer and inner retinal function. The time course, spectral dependence, and spatial profile of signals imaged in PCG cats were similar to signals measured from normal and Siamese control cats.
    Conclusions: Despite increased IOP, reduced nerve fiber layer thickness and ganglion cell function, intrinsic optical signals persist in cats affected with PCG. The mechanisms giving rise to intrinsic signals remain despite inner retinal damage. Signal strength was reduced in all Siamese cats compared to controls, suggesting that reduced intrinsic signals in PCG cats represent a difference between breeds rather than loss of ganglion cells. These results corroborated previous findings that retinal ganglion cells are not the dominant source of intrinsic optical signals of the retina.
    MeSH term(s) Animals ; Cats ; Disease Models, Animal ; Electroretinography ; Female ; Fluorescein Angiography ; Fundus Oculi ; Glaucoma/congenital ; Glaucoma/diagnosis ; Glaucoma/physiopathology ; Intraocular Pressure ; Photic Stimulation ; Retina/pathology ; Retina/physiopathology ; Tomography, Optical Coherence
    Language English
    Publishing date 2012-04-18
    Publishing country United States
    Document type Comparative Study ; Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 391794-0
    ISSN 1552-5783 ; 0146-0404
    ISSN (online) 1552-5783
    ISSN 0146-0404
    DOI 10.1167/iovs.11-8299
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article: Color processing in macaque striate cortex: electrophysiological properties.

    Landisman, Carole E / Ts'o, Daniel Y

    Journal of neurophysiology

    2002  Volume 87, Issue 6, Page(s) 3138–3151

    Abstract: We have shown in the accompanying paper that optical imaging of macaque striate cortex reveals patches that are preferentially activated by equiluminant chromatic gratings compared with luminance gratings. These imaged color patches are highly correlated, ...

    Abstract We have shown in the accompanying paper that optical imaging of macaque striate cortex reveals patches that are preferentially activated by equiluminant chromatic gratings compared with luminance gratings. These imaged color patches are highly correlated, although not always in one-to-one correspondence, with the cytochrome-oxidase (CO) blobs. In the present study, we have investigated the electrophysiological properties of neurons in the imaged color patches and the CO blobs. Our results indicate that individual blobs tend to contain cells of only one type of color opponency: either red/green or blue/yellow. Individual imaged color patches, however, can bridge blobs of similar opponency or differing opponency. When imaged color patches contain two blobs of differing opponency, the cells in the bridge region exhibit mixed color properties that are not opponent along the two cardinal color axes (either red/green or blue/yellow). Two blobs within a single imaged color patch receive input from the same eye or from different eyes. In the latter case, the bridge region between blobs contains binocular cells that are color selective. Because the cells recorded in imaged color patches were more color selective and unoriented than cells outside of color patches, color properties appear to be organized in a clustered and segregated fashion in primate V1.
    MeSH term(s) Animals ; Brain Mapping ; Color Perception/physiology ; Electron Transport Complex IV/analysis ; Electron Transport Complex IV/physiology ; Electrophysiology ; Macaca fascicularis ; Neurons/enzymology ; Photic Stimulation ; Visual Cortex/physiology ; Visual Fields/physiology
    Chemical Substances Electron Transport Complex IV (EC 1.9.3.1)
    Language English
    Publishing date 2002-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 80161-6
    ISSN 1522-1598 ; 0022-3077
    ISSN (online) 1522-1598
    ISSN 0022-3077
    DOI 10.1152/jn.00957.1999
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article: Color processing in macaque striate cortex: relationships to ocular dominance, cytochrome oxidase, and orientation.

    Landisman, Carole E / Ts'o, Daniel Y

    Journal of neurophysiology

    2002  Volume 87, Issue 6, Page(s) 3126–3137

    Abstract: We located clusters of color-selective neurons in macaque striate cortex, as mapped with optical imaging and confirmed with electrophysiological recordings. By comparing responses to an equiluminant red/green stimulus versus a high-contrast luminance ... ...

    Abstract We located clusters of color-selective neurons in macaque striate cortex, as mapped with optical imaging and confirmed with electrophysiological recordings. By comparing responses to an equiluminant red/green stimulus versus a high-contrast luminance stimulus, we were able to reveal a patchy distribution of color selectivity. Other color imaging protocols, when compared with electrophysiological data, did not reliably indicate the location of functional structures. The imaged color patches were compared with other known functional subdivisions of striate cortex. There was a high degree of overlap of the color patches with the cytochrome-oxidase (CO) blobs. The patches were often larger than a single blob in size, however, and in some instances spanned two neighboring blobs. More than one-half (56%) of the color-selective patches seen in optical imaging were not confined to one ocular dominance (OD) column. Almost one-quarter of color patches (23%) extended across OD columns to encompass two blobs of different eye preference. We also compared optical images of orientation selectivity to maps of color selectivity. Results indicate that the layout of orientation and color selectivity are not directly related. Specifically, despite having similar scales and distributions, the maps of orientation and color selectivity were not in consistent alignment or registration. Further, we find that the maps of color selectivity and of orientation are each only loosely related to maps of OD. This description stands in contrast to a common depiction of color-selective regions as identical to CO blobs, appearing as pegs in the centers of OD columns in the classical "ice cube" model. These results concerning the pattern of color selectivity in V1 support the view (put forth in previous imaging studies of the organization of orientation and ocular dominance) that there is not a fundamental registration of functional hypercolumns in V1.
    MeSH term(s) Animals ; Brain Mapping ; Color Perception/physiology ; Electron Transport Complex IV/analysis ; Electron Transport Complex IV/physiology ; Electrophysiology ; Macaca fascicularis ; Neurons/enzymology ; Orientation/physiology ; Photic Stimulation ; Visual Cortex/physiology
    Chemical Substances Electron Transport Complex IV (EC 1.9.3.1)
    Language English
    Publishing date 2002-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 80161-6
    ISSN 1522-1598 ; 0022-3077
    ISSN (online) 1522-1598
    ISSN 0022-3077
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases.

    Sullivan, Kevin M / Jiang, Xiuyun / Guha, Prajna / Lausted, Christopher / Carter, Jason A / Hsu, Cynthia / Labadie, Kevin P / Kohli, Karan / Kenerson, Heidi L / Daniel, Sara K / Yan, Xiaowei / Meng, Changting / Abbasi, Arezou / Chan, Marina / Seo, Y David / Park, James O / Crispe, Ian Nicholas / Yeung, Raymond S / Kim, Teresa S /
    Gujral, Taranjit S / Tian, Qiang / Katz, Steven C / Pillarisetty, Venu G

    Gut

    2022  Volume 72, Issue 2, Page(s) 325–337

    Abstract: Objective: Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of ... ...

    Abstract Objective: Programmed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate the effect of interleukin 10 (IL-10) blockade on endogenous T cell and chimeric antigen receptor T (CAR-T) cell antitumour function in CRLM slice cultures.
    Design: We created organotypic slice cultures from human CRLM (n=38 patients' tumours) and tested the antitumour effects of a neutralising antibody against IL-10 (αIL-10) both alone as treatment and in combination with exogenously administered carcinoembryonic antigen (CEA)-specific CAR-T cells. We evaluated slice cultures with single and multiplex immunohistochemistry, in situ hybridisation, single-cell RNA sequencing, reverse-phase protein arrays and time-lapse fluorescent microscopy.
    Results: αIL-10 generated a 1.8-fold increase in T cell-mediated carcinoma cell death in human CRLM slice cultures. αIL-10 significantly increased proportions of CD8
    Conclusion: Neutralising the effects of IL-10 in human CRLM has therapeutic potential as a stand-alone treatment and to augment the function of adoptively transferred CAR-T cells.
    MeSH term(s) Animals ; Humans ; Mice ; Carcinoembryonic Antigen/immunology ; Carcinoma/immunology ; Carcinoma/secondary ; CD8-Positive T-Lymphocytes/immunology ; Colorectal Neoplasms/pathology ; Immunotherapy, Adoptive ; Interleukin-10/antagonists & inhibitors ; Liver Neoplasms/immunology ; Liver Neoplasms/secondary ; Lymphocyte Activation ; Receptors, Antigen, T-Cell/metabolism ; Receptors, Chimeric Antigen/genetics ; Receptors, Chimeric Antigen/metabolism ; Receptors, Interleukin-10/antagonists & inhibitors ; Antibodies, Blocking/immunology
    Chemical Substances Carcinoembryonic Antigen ; Interleukin-10 (130068-27-8) ; Receptors, Antigen, T-Cell ; Receptors, Chimeric Antigen ; Receptors, Interleukin-10 ; Antibodies, Blocking
    Language English
    Publishing date 2022-06-15
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 80128-8
    ISSN 1468-3288 ; 0017-5749
    ISSN (online) 1468-3288
    ISSN 0017-5749
    DOI 10.1136/gutjnl-2021-325808
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top