The projection of the visual field to the lateral geniculate and medial interlaminar nuclei in the cat

Sanderson, K. J.

doi:10.1002/cne.901430107

Cited by 487 publications

(199 citation statements)

References 23 publications

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“…In the current study, we take advantage of the precise retinotopic organization of the LGN (Sanderson, 1971) and the ability to control the pattern of neural activity with respect to our specialized electrode. We have measured monophasic negative and positive oxygen responses and associated neural activity to visual stimuli at different durations and contrast levels.…”

Section: Discussionmentioning

confidence: 99%

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

Li¹,

Freeman²

2007

J. Neurosci.

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The relationships between neural and metabolic processes in activated brain regions are central to the interpretation of noninvasive imaging. To examine this relationship, we have used a specialized sensor to measure simultaneously tissue oxygen changes and neural activity in colocalized regions of the cat's lateral geniculate nucleus (LGN). Previous work with this sensor has shown that a decrease or increase in tissue oxygen can be elicited by selective control of the location and extent of neural activation in the LGN. In the current study, to evaluate the temporal integration and homogeneity of neurometabolic coupling, we have determined the relationship between multiunit extracellular neural activity and tissue oxygen responses to visual stimuli of various durations and contrasts. Our results show that the negative but not the positive oxygen response changes in an approximately linear manner with stimulus duration. The relationship between the negative oxygen response and neural activity is relatively constant with stimulus duration. Moreover, both negative and positive oxygen responses saturate at high stimulus contrast levels. Coupling between neural activity and negative oxygen responses is well described by a power law function. These results help elucidate differences between the initial negative and subsequent positive metabolic responses and may be directly relevant to questions concerning brain mapping with functional magnetic resonance imaging.

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Section: Discussionmentioning

confidence: 99%

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

Li¹,

Freeman²

2007

J. Neurosci.

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“…Investigations of the receptive field properties of perigeniculate neurons in the anesthetized cat indicate that they typically are binocular, although dominated by one eye, have large receptive fields in comparison to thalamocortical cells, and exhibit both ON and OFF visual responses (Sanderson, 1971;So and Shapley, 1981;Xue et al, 1988;Uhlrich et al, 1991). Presumably these properties allow PGN neurons to contribute to binocular and long-range inhibition in the LGNd (Eysel et al, 1986).…”

Section: Functional Consequences Of Intra-pgn Inhibitionmentioning

confidence: 99%

Inhibitory Interactions between Perigeniculate GABAergic Neurons

Bal²,

1997

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Perigeniculate neurons form an interactive sheet of cells that inhibit one another as well as thalamocortical neurons in the dorsal lateral geniculate nucleus (LGNd). The inhibitory influence of the GABAergic neurons of the perigeniculate nucleus (PGN) onto other PGN neurons was examined with intracellular recordings in vitro. Intracellular recordings from PGN neurons during the generation of spindle waves revealed barrages of EPSPs and IPSPs. The excitation of local regions of the PGN with the local application of glutamate resulted in activation of IPSPs in neighboring PGN neurons. These IPSPs displayed an average reversal potential of Ϫ77 mV and were blocked by application of bicuculline methiodide or picrotoxin, indicating that they are mediated by GABA A receptors. In the presence of GABA A receptor blockade, the activation of PGN neurons with glutamate could result in slow IPSPs that were mediated by GABA B receptors in a subset (40%) of cells. Similarly, application of specific agonists muscimol and baclofen demonstrated that PGN neurons possess both functional GABA A and GABA B receptors. Examination of the axon arbors of biocytin-filled PGN neurons often revealed the presence of beaded axon collaterals within the PGN, suggesting that this may be an anatomical substrate for PGN to PGN inhibition.Functionally, activation of inhibition between PGN neurons could result in a shortening or a complete abolition of the low threshold Ca 2ϩ spike or an inhibition of tonic discharge. We suggest that the mutual inhibition between PGN neurons forms a mechanism by which the excitability of these cells is tightly controlled. The activation of a point within the PGN may result in the inhibition of neighboring PGN neurons. This may be reflected in the LGNd as a center of inhibition surrounded by an annulus of disinhibition, thus forming a "center-surround" mechanism for thalamic function.

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“…The LGN is a visual area of the thalamus with precise retinotopic organization and small receptive fields (RFs). Magnification factors in the LGN range between 0.1 and 0.5 mm of tissue per degree of visual angle (Sanderson, 1971). In the current study, we take advantage of these properties of the LGN to vary the pattern of neural activity with respect to our sensor.…”

Section: Introductionmentioning

confidence: 99%

Separate Spatial Scales Determine Neural Activity-Dependent Changes in Tissue Oxygen within Central Visual Pathways

Thompson

Peterson²,

Freeman³

2005

J. Neurosci.

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The relationship between oxygen levels and neural activity in the brain is fundamental to functional neuroimaging techniques. We have examined this relationship on a fine spatial scale in the lateral geniculate nucleus (LGN) and visual cortex of the cat using a microelectrode sensor that provides simultaneous colocalized measurements of oxygen partial pressure in tissue (tissue oxygen) and multiunit neural activity. In previous work with this sensor, we found that changes in tissue oxygen depend strongly on the location and spatial extent of neural activation. Specifically, focal neural activity near the microelectrode elicited decreases in tissue oxygen, whereas spatially extended activation, outside the field of view of our sensor, yielded mainly increases. In the current study, we report an expanded set of measurements to quantify the spatiotemporal relationship between neural responses and changes in tissue oxygen. For the purpose of data analysis, we develop a quantitative model that assumes that changes in tissue oxygen are composed of two response components (one positive and one negative) with magnitudes determined by neural activity on separate spatial scales. Our measurements from visual cortex and the LGN are consistent with this model and suggest that the positive response spreads over a distance of 1-2 mm, whereas the negative component is confined to a few hundred micrometers. These results are directly relevant to the mechanisms that generate functional brain imaging signals and place limits on their spatial properties.

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The projection of the visual field to the lateral geniculate and medial interlaminar nuclei in the cat

Cited by 487 publications

References 23 publications

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

High-Resolution Neurometabolic Coupling in the Lateral Geniculate Nucleus

Inhibitory Interactions between Perigeniculate GABAergic Neurons

Separate Spatial Scales Determine Neural Activity-Dependent Changes in Tissue Oxygen within Central Visual Pathways

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