scholarly journals Hour-long adaptation in the awake early visual system

2015 ◽  
Vol 114 (2) ◽  
pp. 1172-1182 ◽  
Author(s):  
Carl R. Stoelzel ◽  
Joseph M. Huff ◽  
Yulia Bereshpolova ◽  
Jun Zhuang (庄骏) ◽  
Xiaojuan Hei (黑晓娟) ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Spontaneous Activity ◽  
Visual Stimulation ◽  
Sensory Stimulation ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Visual Signal ◽  
Induced Response ◽  
Sensory Adaptation ◽  
Layer 4 ◽  
Dorsal Lateral Geniculate

Sensory adaptation serves to adjust awake brains to changing environments on different time scales. However, adaptation has been studied traditionally under anesthesia and for short time periods. Here, we demonstrate in awake rabbits a novel type of sensory adaptation that persists for >1 h and acts on visual thalamocortical neurons and their synapses in the input layers of the visual cortex. Following prolonged visual stimulation (10–30 min), cells in the dorsal lateral geniculate nucleus (LGN) show a severe and prolonged reduction in spontaneous firing rate. This effect is bidirectional, and prolonged visually induced response suppression is followed by a prolonged increase in spontaneous activity. The reduction in thalamic spontaneous activity following prolonged visual activation is accompanied by increases in 1) response reliability, 2) signal detectability, and 3) the ratio of visual signal/spontaneous activity. In addition, following such prolonged activation of an LGN neuron, the monosynaptic currents generated by thalamic impulses in layer 4 of the primary visual cortex are enhanced. These results demonstrate that in awake brains, prolonged sensory stimulation can have a profound, long-lasting effect on the information conveyed by thalamocortical inputs to the visual cortex.

Evidence for the connections between a clutch cell and a corticotectal neuron in area 17 of the cat visual cortex

1988 ◽  
Vol 233 (1273) ◽  
pp. 385-391 ◽  
Keyword(s):  
Visual Cortex ◽  
Morphological Characteristics ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Synaptic Connectivity ◽  
Physiological Data ◽  
Gabaergic Interneuron ◽  
Area 17 ◽  
Cat Visual Cortex ◽  
Layer 4 ◽  
Dorsal Lateral Geniculate

Evidence is presented for the synaptic connectivity between a physiologically characterized and intracellularly filled GABAergic interneuron and a corticotectal pyramidal neuron in area 17 of the cat visual cortex. The interneuron was located in layer 4 and had the morphological characteristics of a clutch cell. The physiological data demonstrated that the clutch cell received direct X-type innervation from the dorsal lateral geniculate nucleus. These results indicate that a GABAergic neuron is directly involved during the first cortical stages of geniculocorticotectal interactions. Furthermore, the proximal location of the clutch-cell inputs to the labelled dendrite suggests a strategic siting of intracortical feedforward inhibition.

Effect of the Group II Metabotropic Glutamate Agonist, 2R,4R-APDC, Varies With Age, Layer, and Visual Experience in the Visual Cortex

1999 ◽  
Vol 82 (1) ◽  
pp. 86-93 ◽  
Author(s):  
C. J. Beaver ◽  
Q.-H. Ji ◽  
N. W. Daw
Keyword(s):  
Visual Cortex ◽  
Metabotropic Glutamate Receptors ◽  
Visual Stimulation ◽  
Ocular Dominance ◽  
Visual Response ◽  
Single Neurons ◽  
Metabotropic Glutamate ◽  
Layer 4 ◽  
Group Ii ◽  
Dark Rearing

Group II metabotropic glutamate receptors (mGluR 2/3) are distributed differentially across the layers of cat visual cortex, and this distribution varies with age. At 3–4 wk, mGluR 2/3 receptor immunoreactivity is present in all layers. By 6–8 wk of age, it is still present in extragranular layers (2, 3, 5, and 6) but has disappeared from layer 4, and dark-rearing postpones the disappearance of Group II receptors from layer 4. We examined the physiological effects of Group II activation, to see if these effects varied similarly. The responses of single neurons in cat primary visual cortex were recorded to visual stimulation, then the effect of iontophoresis of 2R,4R-4 aminopyrrolidine-2,4-decarboxylate (2R,4R-APDC), a Group II specific agonist, was observed in animals between 3 wk and adulthood. The effect of 2R,4R-APDC was generally suppressive, reducing both the visual response and spontaneous activity of single neurons. The developmental changes were in agreement with the immunohistochemical results: 2R,4R-APDC had effects on cells in all layers in animals of 3–4 wk but not in layer 4 of animals >6 wk old. Moreover, the effect of 2R,4R-APDC was reduced in the cortex of older animals (>22 wk). Dark-rearing animals to 47–54 days maintained the effects of 2R,4R-APDC in layer 4. The disappearance of Group II mGluRs from layer 4 between 3 and 6 wk of age is correlated with the segregation of ocular dominance columns in that layer, raising the possibility that mGluRs 2/3 are involved in this process.

Age dependent modification of cytochrome oxidase activity in the cat dorsal lateral geniculate nucleus following removal of primary visual cortex

1996 ◽  
Vol 13 (5) ◽  
pp. 805-816 ◽  
Author(s):  
Bertram R. Payne ◽  
Stephen G. Lomber
Keyword(s):  
Visual Cortex ◽  
Cytochrome Oxidase ◽  
Lateral Geniculate Nucleus ◽  
Oxidase Activity ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Cytochrome Oxidase Activity ◽  
Lateral Geniculate ◽  
Areas 17 And 18 ◽  
C Complex ◽  
Dorsal Lateral Geniculate

AbstractThe purpose of the present study was to assess changes in the levels of cytochrome oxidase (CO) activity in the dorsal lateral geniculate nucleus (dLGN) of the adult cat following removal of primary visual cortical areas 17 and 18 on the day of birth (P1), P28, or in adulthood (≫6 months). Cytochrome oxidase activity was measured in histological sections 9 or more months after the cortical ablation. Control measures obtained from intact cats show that CO activity is normally highest in the A-laminae of dLGN, and slightly lower in the C-complex. Following visual cortex ablations incurred at any age, CO activity levels are reduced in the A-laminae. This reduction is most profound following ablations incurred on P28 or in adulthood. In contrast, CO activity in the C-complex of dLGN is at nearly normal levels following ablations on P1 or P28, but not in adulthood. These findings contribute to our understanding of the role played by the dLGN in the transfer of visual signals along retino-geniculo-extrastriate pathways that expand following early removal of areas 17 and 18. Moreover, they have implications for our understanding of spared behavioral functions attributed to the extrastriate cortex in cats which incurred early damage of areas 17 and 18.

scholarly journals Peter Orlebar Bishop. 14 June 1917—3 June 2012

2018 ◽  
Vol 64 ◽  
pp. 51-68
Author(s):  
Jack D. Pettigrew ◽  
Bogdan Dreher
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Great Ability ◽  
Visual Research ◽  
Talented People ◽  
Relay Nucleus ◽  
Single Neurones ◽  
Schematic Eye ◽  
Dorsal Lateral Geniculate

Peter Orlebar Bishop was an Australian neurophysiologist renowned for his ingenious quantitative approach to the study of the mammalian visual system and his great ability to attract a large number of talented people to visual research. Peter’s research was based on specially designed, precise instrumentation and data quantification applied mainly to analysis of the response properties of single neurones in the principal dorsal thalamic visual relay nucleus, the dorsal lateral geniculate nucleus (LGNd) and the primary visual cortex. This quantitative bent was evident throughout Peter’s entire research career: starting with the design and construction of innovative DC amplifiers; to his quantitative analysis of optics, ‘schematic eye’ for the cat, which rivalled Gullstrand’s schematic eye for humans; to creating and demonstrating validity of the concept of ‘projection lines’ in the representation of contralateral visual field in different cellular layers of the LGNd of mammals with frontally positioned eyes and discovery of massive binocular input to single LGNd neurones. Peter’s engineering approach was probably at its heuristic peak when it revealed many details of binocular interactions at the level of single neurones in the primary visual cortex—the interactions which appear to underpin overall mechanisms underlying stereopsis, the high precision binocular depth sense.

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