Axial responses in visual cortical cells: Spatio-temporal mechanisms quantified by Fourier components of cortical tuning curves

1991 ◽  
Vol 83 (3) ◽  
Author(s):  
F. W�rg�tter ◽  
U.T. Eysel
Keyword(s):  
Cortical Cells ◽  
Tuning Curves ◽  
Spatio Temporal ◽  
Visual Cortical

scholarly journals Membrane properties and spike generation in rat visual cortical cells during reversible cooling

2000 ◽  
Vol 522 (1) ◽  
pp. 59-76 ◽  
Author(s):  
Maxim Volgushev ◽  
Trichur R. Vidyasagar ◽  
Marina Chistiakova ◽  
Tagrid Yousef ◽  
Ulf T. Eysel
Keyword(s):  
Membrane Properties ◽  
Spike Generation ◽  
Cortical Cells ◽  
Visual Cortical

Degradation of stimulus selectivity of visual cortical cells in senescent rhesus monkeys

10.1038/73957 ◽  
2000 ◽  
Vol 3 (4) ◽  
pp. 384-390 ◽  
Author(s):  
Matthew T. Schmolesky ◽  
Youngchang Wang ◽  
Mingliang Pu ◽  
Audie G. Leventhal
Keyword(s):  
Rhesus Monkeys ◽  
Cortical Cells ◽  
Visual Cortical

A model for the estimate of local image velocity by cells in the visual cortex

1990 ◽  
Vol 239 (1295) ◽  
pp. 129-161 ◽  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Frequency Tuning ◽  
Temporal Frequency ◽  
Spatial Integration ◽  
Temporal Area ◽  
Image Velocity ◽  
Tuning Curves ◽  
Spatio Temporal ◽  
Local Image

Some computational theories of motion perception assume that the first stage en route to this perception is the local estimate of image velocity. However, this assumption is not supported by data from the primary visual cortex. Its motion sensitive cells are not selective to velocity, but rather are directionally selective and tuned to spatio-temporal frequen­cies. Accordingly, physiologically based theories start with filters selec­tive to oriented spatio-temporal frequencies. This paper shows that computational and physiological theories do not necessarily conflict, because such filters may, as a population, compute velocity locally. To prove this point, we show how to combine the outputs of a class of frequency tuned filters to detect local image velocity. Furthermore, we show that the combination of filters may simulate ‘Pattern’ cells in the middle temporal area (MT), whereas each filter simulates primary visual cortex cells. These simulations include three properties of the primary cortex. First, the spatio-temporal frequency tuning curves of the in­dividual filters display approximate space-time separability. Secondly, their direction-of-motion tuning curves depend on the distribution of orientations of the components of the Fourier decomposition and speed of the stimulus. Thirdly, the filters show facilitation and suppression for responses to apparent motions in the preferred and null directions, respect­ively. It is suggested that the MT’s role is not to solve the aperture problem, but to estimate velocities from primary cortex information. The spatial integration that accounts for motion coherence may be postponed to a later cortical stage.

scholarly journals The angular selectivity of visual cortical cells to moving gratings

1968 ◽  
Vol 198 (1) ◽  
pp. 237-250 ◽  
Author(s):  
F. W. Campbell ◽  
B. G. Cleland ◽  
G. F. Cooper ◽  
Christina Enroth-Cugell
Keyword(s):  
Cortical Cells ◽  
Visual Cortical ◽  
Angular Selectivity

Postnatal development of functional properties of visual cortical cells in rats with excitotoxic lesions of basal forebrain cholinergic neurons

1997 ◽  
Vol 14 (1) ◽  
pp. 111-123 ◽  
Author(s):  
Rosita Siciliano ◽  
Gigliola Fontanesi ◽  
Fiorella Casamenti ◽  
Nicoletta Berardi ◽  
Paola Bagnoli ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Postnatal Development ◽  
Functional Properties ◽  
Basal Forebrain ◽  
Critical Period ◽  
Ocular Dominance ◽  
Cholinergic Neurons ◽  
Field Size ◽  
Cortical Cells ◽  
Visual Cortical

AbstractIn the rat, visual cortical cells develop their functional properties during a period termed as critical period, which is included between eye opening, i.e.˘postnatal day (PD) 15, and PD40. The present investigation was aimed at studying the influence of cortical cholinergic afferents from the basal forebrain (BF) on the development of functional properties of visual cortical neurons. At PD15, rats were unilaterally deprived of the cholinergic input to the visual cortex by stereotaxic injections of quisqualic acid in BF cholinergic nuclei projecting to the visual cortex. Cortical cell functional properties, such as ocular dominance, orientation selectivity, receptive-field size, and cell responsiveness were then assessed by extracellular recordings in the visual cortex ipsilateral to the lesioned BF both during the critical period (PD30) and after its end (PD45). After the recording session, the rats were sacrificed and the extent of both cholinergic lesion in BF and cholinergic depletion in the visual cortex was determined. Our results show that lesion of BF cholinergic nuclei transiently alters the ocular dominance of visual cortical cells while it does not affect the other functional properties tested. In particular, in lesioned animals recorded during the critical period, a higher percentage of visual cortical cells was driven by the contralateral eye with respect to normal animals. After the end of the critical period, the ocular dominance distribution of animals with cholinergic deafferentation was not significantly different from that of controls. Our results suggest the possibility that lesions of BF cholinergic neurons performed during postnatal development only transiently interfere with cortical competitive processes.

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