Abstract
The amplitude and the phase of the simultaneously recorded steady-state pattern electroretinogram (PERG) and visual evoked potential (VEP) were evaluated in humans as a function of the vertical diameter (D) of unidimensional Gabor stimuli. In the other dimension, parallel to the horizontal gratings, the patterns all had constant diameter (see Methods and Materials). Spatial frequencies (SFs) of 1 cycle per degree (cpd) and 5.3 cpd were counterphase modulated at a rate of 6.8 Hz. After off-line artifact rejection, the response was subject to Fast Fourier Transformation (FFT). Amplitude and phase of the first and second harmonics of both ERG and VEP were displayed for each SF and stimulus diameter. Both ERG and VEP amplitude were found to increase as a function of D. Using trend analysis we found that ERG amplitude increased linearly as a function of D. VEP amplitude was found to be both linear and cubic, as a function of D. We calculated the ratio of VEP amplitude and ERG amplitude at each D and termed it retinocortical gain (G). G normalized to stimulus area was high for small D and decreased with D independently of SE Unity gain occurred at stimulus sizes of 6° to 7°. ERG phase was found to be more negative at 5.3 cpd than at 1 cpd. Although no significant difference was found between VEP phases at the two SFs tested, neither ERG nor VEP phase changed as a function of D. The results suggest that retinocortical gain is highest for the foveally centered low spatial frequency small patch Gabors. The results provide support for the notion of the "foveal window" in human vision.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 67-74 |
| Number of pages | 8 |
| Journal | Clinical EEG Electroencephalography |
| Volume | 32 |
| Issue number | 2 |
| State | Published - Apr 2001 |
| Externally published | Yes |
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Keywords
- Foveal Vision
- Pattern Electroretinogram
- Retinocortical Gain
- Spatial Summation
- Visual Evoked Potential
ASJC Scopus subject areas
- Clinical Neurology
Cite this
Retinocortical gain in the foveal pathway : The effect of spatial frequency and stimulus size. / Mari, Z.; Sagliocco, L.; Bodis-Wollner, Ivan.
In: Clinical EEG Electroencephalography, Vol. 32, No. 2, 04.2001, p. 67-74.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Retinocortical gain in the foveal pathway
T2 - The effect of spatial frequency and stimulus size
AU - Mari, Z.
AU - Sagliocco, L.
AU - Bodis-Wollner, Ivan
PY - 2001/4
Y1 - 2001/4
N2 - The amplitude and the phase of the simultaneously recorded steady-state pattern electroretinogram (PERG) and visual evoked potential (VEP) were evaluated in humans as a function of the vertical diameter (D) of unidimensional Gabor stimuli. In the other dimension, parallel to the horizontal gratings, the patterns all had constant diameter (see Methods and Materials). Spatial frequencies (SFs) of 1 cycle per degree (cpd) and 5.3 cpd were counterphase modulated at a rate of 6.8 Hz. After off-line artifact rejection, the response was subject to Fast Fourier Transformation (FFT). Amplitude and phase of the first and second harmonics of both ERG and VEP were displayed for each SF and stimulus diameter. Both ERG and VEP amplitude were found to increase as a function of D. Using trend analysis we found that ERG amplitude increased linearly as a function of D. VEP amplitude was found to be both linear and cubic, as a function of D. We calculated the ratio of VEP amplitude and ERG amplitude at each D and termed it retinocortical gain (G). G normalized to stimulus area was high for small D and decreased with D independently of SE Unity gain occurred at stimulus sizes of 6° to 7°. ERG phase was found to be more negative at 5.3 cpd than at 1 cpd. Although no significant difference was found between VEP phases at the two SFs tested, neither ERG nor VEP phase changed as a function of D. The results suggest that retinocortical gain is highest for the foveally centered low spatial frequency small patch Gabors. The results provide support for the notion of the "foveal window" in human vision.
AB - The amplitude and the phase of the simultaneously recorded steady-state pattern electroretinogram (PERG) and visual evoked potential (VEP) were evaluated in humans as a function of the vertical diameter (D) of unidimensional Gabor stimuli. In the other dimension, parallel to the horizontal gratings, the patterns all had constant diameter (see Methods and Materials). Spatial frequencies (SFs) of 1 cycle per degree (cpd) and 5.3 cpd were counterphase modulated at a rate of 6.8 Hz. After off-line artifact rejection, the response was subject to Fast Fourier Transformation (FFT). Amplitude and phase of the first and second harmonics of both ERG and VEP were displayed for each SF and stimulus diameter. Both ERG and VEP amplitude were found to increase as a function of D. Using trend analysis we found that ERG amplitude increased linearly as a function of D. VEP amplitude was found to be both linear and cubic, as a function of D. We calculated the ratio of VEP amplitude and ERG amplitude at each D and termed it retinocortical gain (G). G normalized to stimulus area was high for small D and decreased with D independently of SE Unity gain occurred at stimulus sizes of 6° to 7°. ERG phase was found to be more negative at 5.3 cpd than at 1 cpd. Although no significant difference was found between VEP phases at the two SFs tested, neither ERG nor VEP phase changed as a function of D. The results suggest that retinocortical gain is highest for the foveally centered low spatial frequency small patch Gabors. The results provide support for the notion of the "foveal window" in human vision.
KW - Foveal Vision
KW - Pattern Electroretinogram
KW - Retinocortical Gain
KW - Spatial Summation
KW - Visual Evoked Potential
UR - http://www.scopus.com/inward/record.url?scp=0035008842&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035008842&partnerID=8YFLogxK
M3 - Article
C2 - 11360723
AN - SCOPUS:0035008842
VL - 32
SP - 67
EP - 74
JO - Clinical EEG and Neuroscience
JF - Clinical EEG and Neuroscience
SN - 0009-9155
IS - 2
ER -