Chronic ocular hypertension induces dendrite pathology in the lateral geniculate nucleus of the brain

2007 ◽  
Vol 84 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Neeru Gupta ◽  
Tina Ly ◽  
Qiang Zhang ◽  
Paul L. Kaufman ◽  
Robert N. Weinreb ◽  
...  
Keyword(s):  
Ocular Hypertension ◽  
Lateral Geniculate Nucleus ◽  
Lateral Geniculate ◽  
The Brain

Circuitry of the Lateral Geniculate Nucleus

2017 ◽  
pp. 87-98
Author(s):  
S. Murray Sherman
Keyword(s):  
Functional Connectivity ◽  
Lateral Geniculate Nucleus ◽  
Excellent Model ◽  
Brain Circuits ◽  
Lateral Geniculate ◽  
Retinal Input ◽  
The Brain

The circuitry of the thalamus is among the most thoroughly studied and best understood exemplars of functional connectivity in the brain. This chapter shall focus on the A laminae of the cat’s lateral geniculate nucleus (LGN), which represents the relay of retinal input to the cortex, because this has proved to be an excellent model for the thalamus. There are two major payoffs for understanding this circuit: the basic plan revealed by LGN circuitry seems to be applied throughout the thalamus, with some relatively minor modifications, so this provides general insights into overall thalamic functioning; and many circuit principles first appreciated in the LGN apply to other brain circuits.

Review Lecture - Behavioural analysis of the monkey’s visual nervous system

1972 ◽  
Vol 182 (1069) ◽  
pp. 427-455 ◽  
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Visual Space ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Anterior Portion ◽  
Lateral Geniculate ◽  
Early Results ◽  
Negative Effect ◽  
Occipital Lobes ◽  
The Brain

1. Introduction Of the three million or so nerve fibres that stream into the primate brain, about two million originate in the eyes. Of these fibres, about one-and-a-half million are in the geniculo-striate system, so named because it connects the eyes with a region of the thalamus known as the dorsal lateral geniculate nucleus and that nucleus with the striate cortex (also known as area 17 or area OC, figure 1) in the occipital lobes. About half, therefore, of all the inputs to the brain are fibres of retinal origin having relatively direct and concentrated access to the cerebral cortex. One may be allowed some surprise, therefore, to find that David Ferrier claimed in 1886 that monkeys subjected to large occipital lobectomies (figures 2, 3) were unaffected by this drastic interruption of such a massive afferent channel. He said 'I removed the greater portion of both occipital lobes at the same time without causing the slightest appreciable impairment of vision. One of these animals within 2 h of the operation was able to run about freely, avoiding obstacles, to pick up such a minute object as a raisin without the slightest hesitation or want of precision, and to act in accordance with its visual experience in a perfectly normal manner’ (Ferrier 1886, p. 273). Ferrier went on to say that ‘Horseley and Schäfer inform me that their results of removal of the occipital lobes entirely harmonize with mine as to the completely negative effect of this operation’ (p. 276), which is a curious claim because two years later Schäfer was locked in a most bitter dispute with Ferrier over just this point, and their argument is merely the most extreme example of the lack of agreement about the functions of the visual cortex in animals that has persisted over the years. We now know, with the benefit of hindsight, that there may have been an uninteresting explanation of these early results of Ferrier’s, because not all of the fibres from the lateral geniculate nucleus project to the lateral surface of the brain. Some of the striate cortex ─ that part which responds to stimulation of the most peripheral parts of the retinae ─ is buried in the calcarine fissure on the medial aspect of the brain, and the most anterior portion of this may be spared even after a complete occipital lobectomy (figure 1). Were Ferrier’s animals using an intact part of their visual space?

Effects of brain stem parabrachial activation on receptive field properties of cells in the cat's lateral geniculate nucleus

1995 ◽  
Vol 73 (6) ◽  
pp. 2428-2447 ◽  
Author(s):  
D. J. Uhlrich ◽  
N. Tamamaki ◽  
P. C. Murphy ◽  
S. M. Sherman
Keyword(s):  
Receptive Field ◽  
Brain Stem ◽  
Spontaneous Activity ◽  
Lateral Geniculate Nucleus ◽  
Visual Stimuli ◽  
Visual Responses ◽  
Burst Stimulation ◽  
Lateral Geniculate ◽  
Almost All ◽  
The Brain

1. The lateral geniculate nucleus is the primary thalamic relay for the transfer of retinal signals to the visual cortex. Geniculate cells are heavily innervated from nonretinal sources, and these modify retinogeniculate transmission. A major ascending projection to the lateral geniculate nucleus arises from cholinergic cells in the parabrachial region of the brain stem. This is an important pathway in the ascending control of arousal. In an in vivo preparation, we used extracellular recordings to study the effects of electrical activation of the parabrachial region on the spontaneous activity and visual responses of X and Y cells in the lateral geniculate nucleus of the cat. 2. We studied the effects of two patterns of parabrachial activation on the spontaneous activity of geniculate cells. Burst stimulation consisted of a short pulse at high frequency (16 ms at 250 Hz). Train stimulation was of longer duration at lower frequency (e.g., 1 s at 50 Hz). The firing rate of almost all geniculate cells was enhanced by either pattern of stimulation. However, the burst pattern of stimulation elicited a short, modulated response with excitatory and inhibitory epochs. We found that the different epochs could differentially modulate the visual responses to drifting gratings. Thus the temporal alignment of the brain stem and visual stimuli was critical with burst stimulation, and varied alignments could dramatically confound the results. In comparison, the train pattern of stimulation consistently produced a relatively flat plateau of increased firing, after a short initial period of more variable effects. We used the less confounding pattern of train stimuli to study the effects of parabrachial activation on visual responses. 3. Our main emphasis was to examine the parabrachial effects on the visual responses of geniculate cells. For most visual stimuli, we used drifting sine wave gratings that varied in spatial frequency; these evoked modulated responses from the geniculate cells. Parabrachial activation enhanced the visual responses of almost all geniculate cells, and this enhancement included both increased depth of modulation and greater response rates. 4. Our results were incorporated quantitatively into a difference-of-Gaussians model of visual receptive fields in order to study the parabrachial effects on the spatial structure of the receptive field. This model fit our data well and provided measures of the response amplitude and radius of the receptive field center (Kc and Rc, respectively) and the response amplitude and radius of the receptive field surround (Ks and Rs, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Organization of brain stem afferents to the ventral lateral geniculate nucleus of rats

2000 ◽  
Vol 17 (2) ◽  
pp. 313-318 ◽  
Author(s):  
CHRISTIAN KOLMAC ◽  
JOHN MITROFANIS
Keyword(s):  
Brain Stem ◽  
Lateral Geniculate Nucleus ◽  
Visual Processing ◽  
Pedunculopontine Tegmental Nucleus ◽  
Reticular Nucleus ◽  
Sprague Dawley ◽  
Tegmental Nucleus ◽  
Lateral Geniculate ◽  
To Receive ◽  
The Brain

We have examined the patterns of projections from different nuclei of the brain stem to the ventral lateral geniculate nucleus (vLGN) of the thalamus. Injections of biotinylated dextran were made into different nuclei of the brainstem (i.e., midbrain reticular nucleus, pontine reticular nucleus, deep layers of superior colliculus, periaqueductal grey matter [ventrolateral, dorsolateral, and lateral columns], pedunculopontine tegmental nucleus, parabrachial nucleus, lateral dorsal tegmental nucleus, substantia nigra [pars reticulata], locus coeruleus, and dorsal raphe) of Sprague-Dawley rats using stereotaxic coordinates. Our results show that all of the abovementioned brain-stem nuclei have overlapping projections to the medial regions of the vLGN, within the parvocellular lamina of the nucleus. This if the first instance of the parvocellular lamina being shown to receive a major set of projections. Very few labelled terminals from the brain stem were ever seen within the larger more lateral magnocellular lamina, which has been shown by previous studies to receive heavy inputs from visually associated structures, such as the retina and occipital cortex. Since many of the brain-stem nuclei injected in this study have little to do with visual processing, our results suggest that one can perhaps package the vLGN into distinct visual (magnocellular) and nonvisual (parvocellular) components.

scholarly journals Structural Changes and Astrocyte Response of the Lateral Geniculate Nucleus in a Ferret Model of Ocular Hypertension

2020 ◽  
Vol 21 (4) ◽  
pp. 1339
Author(s):  
Takashi Fujishiro ◽  
Megumi Honjo ◽  
Hiroshi Kawasaki ◽  
Ryo Asaoka ◽  
Reiko Yamagishi ◽  
...  
Keyword(s):  
Ocular Hypertension ◽  
Lateral Geniculate Nucleus ◽  
Structural Changes ◽  
Neuronal Damage ◽  
Immunohistochemical Analysis ◽  
Toxin B ◽  
Lateral Geniculate ◽  
Conjunctival Cells ◽  
The Right ◽  
First Time

We investigated structural changes and astrocyte responses of the lateral geniculate nucleus (LGN) in a ferret model of ocular hypertension (OH). In 10 ferrets, OH was induced via the injection of cultured conjunctival cells into the anterior chamber of the right eye; six normal ferrets were used as controls. Anterograde axonal tracing with cholera toxin B revealed that atrophic damage was evident in the LGN layers receiving projections from OH eyes. Immunohistochemical analysis with antibodies against NeuN, glial fibrillary acidic protein (GFAP), and Iba-1 was performed to specifically label neurons, astrocytes, and microglia in the LGN. Significantly decreased NeuN immunoreactivity and increased GFAP and Iba-1 immunoreactivities were observed in the LGN layers receiving projections from OH eyes. Interestingly, the changes in the immunoreactivities were significantly different among the LGN layers. The C layers showed more severe damage than the A and A1 layers. Secondary degenerative changes in the LGN were also observed, including neuronal damage and astrocyte reactions in each LGN layer. These results suggest that our ferret model of OH is valuable for investigating damages during the retina–brain transmission of the visual pathway in glaucoma. The vulnerability of the C layers was revealed for the first time.

Brain-stem modulation of the response properties of cells in the cat's perigeniculate nucleus

1994 ◽  
Vol 11 (4) ◽  
pp. 781-791 ◽  
Author(s):  
P. C. Murphy ◽  
D. J. Uhlrich ◽  
N. Tamamaki ◽  
S. Murray Sherman
Keyword(s):  
Brain Stem ◽  
Lateral Geniculate Nucleus ◽  
Visual Stimulation ◽  
Temporal Frequency ◽  
Visual Responses ◽  
Mixed Effect ◽  
Tuning Curves ◽  
Perigeniculate Nucleus ◽  
Lateral Geniculate ◽  
The Brain

AbstractTransmission through the lateral geniculate nucleus is facilitated following activation of the cholinergic input from the brain stem, which is thought to reflect activity patterns seen during arousal. One of the underlying mechanisms is the suppression of inhibitory circuits local to the lateral geniculate nucleus. However, evidence exists that some visually driven inhibitory inputs to geniculate relay cells may be preserved or even enhanced under conditions of arousal, and during electrical activation of the parabrachial region of the brain stem. We have therefore reexamined the effect of brain-stem activation on the visual responses of one group of local inhibitory inputs to geniculate relay cells, those emanating from the adjacent perigeniculate nucleus. We recorded single perigeniculate cells in anesthetized, paralyzed cats. Axons innervating the lateral geniculate and perigeniculate nuclei from the parabrachial region of the brain stem were electrically activated, and the effect of this activation was assessed on both spontaneous and visually evoked responses. Visual stimulation consisted of sinusoidally modulated sine–wave gratings of varying spatial and temporal frequency. For the great majority of perigeniculate cells (32 of 40), brain-stem activation inhibited spontaneous activity, while one cell was excited, three showed a mixed effect and four were unaffected. Nevertheless, the responses of most cells (30 of 40) were facilitated when brain-stem activation was paired with certain spatio-temporal patterns of visual stimulation. Spatial tuning curves were constructed for 17 cells and temporal tuning curves for 14, before and during parabrachial activation. The responses of any one cell could be facilitated, unchanged, or suppressed, depending on the visual stimulus used. In some cases, this substantially modified the cell’s spatial and temporal tuning properties. We conclude that activation of the brain stem disinhibits geniculate relay cells in the absence of visual stimulation, but it has the potential to enhance either the magnitude or specificity of visually driven inhibition arising from the perigeniculate nucleus.

Developmental changes in the pattern of NADPH-diaphorase staining in the cat's lateral geniculate nucleus

1997 ◽  
Vol 14 (6) ◽  
pp. 1167-1173 ◽  
Author(s):  
William Guido ◽  
Christopher A. Scheiner ◽  
R. Ranney Mize ◽  
Kenneth E. Kratz
Keyword(s):  
Nitric Oxide ◽  
Brain Stem ◽  
Lateral Geniculate Nucleus ◽  
Cholinergic Neurons ◽  
Nadph Diaphorase ◽  
Thalamic Nuclei ◽  
Dorsal Thalamus ◽  
Cell Staining ◽  
Lateral Geniculate ◽  
The Brain

AbstractWe examined the pattern of NADPH-diaphorase (NADPH-d) staining in the lateral geniculate nucleus (LGN) of dorsal thalamus in fetal and newborn kittens, and adult cats. This staining visualizes the synthesizing enzyme of nitric oxide (NO), a neuromodulator associated with central nervous system (CNS) development and synaptic plasticity. In the adult, very few LGN cells stained for NADPH-d, and these were restricted to interlaminar zones and ventral C layers. NADPH-d labeled a dense network of fibers and axon terminals throughout the LGN and adjacent thalamic nuclei. The source of such labelling has been reported to be cholinergic neurons from the parabrachial region of the brain stem (Bickford et al., 1993). A very different pattern of staining was observed in prenatal and early postnatal kittens. Between embryonic (E) day 46–57, lightly stained cells appeared throughout the LGN. From this age, through about the first month of life, the number of stained cells in the LGN rose rapidly. The density (cells/ mm2) of labeled cells peaked at postnatal day (P) 28 (P28), and was about 150 times greater than the level measured in the adult LGN. After P28, cell staining declined rapidly, and fell to adult levels at P41. The reduction in cell staining that occurred between P35–41 was accompanied by the appearance of fine-caliber fiber staining, similar to that observed in the adult LGN. NADPH-d staining, which reveals the presence of nitric oxide synthase (NOS), and thus NO activity, may reflect two processes. In the adult LGN, the labeling of cholinergic axons arising from the brain-stem parabrachial region coupled with a paucity of the LGN cellular staining suggests that NO operates in an orthograde manner, being co-released with ACh to influence the gain and efficacy of retinogeniculate transmission. By contrast, in developing kitten, NADPH-d staining of LGN cells suggests that NO acts in a retrograde fashion, perhaps playing a role in maintaining associative processes underlying activity-dependent refinement of retinogeniculate connections.

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