A late component of flash-evoked potentials in the cat's optic chiasma and superior colliculus: its appearance due to background illumination

1975 ◽  
Vol 98 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Isao Uramoto
Keyword(s):  
Evoked Potentials ◽  
Superior Colliculus ◽  
Late Component ◽  
Background Illumination ◽  
Optic Chiasma

Visual thresholds in albino and pigmented rats

1992 ◽  
Vol 9 (3-4) ◽  
pp. 409-414 ◽  
Author(s):  
Pilar Herreros De Tejada ◽  
Daniel G. Green ◽  
Carmen Muñoz Tedó
Keyword(s):  
Evoked Potentials ◽  
Superior Colliculus ◽  
Absolute Threshold ◽  
Albino Rats ◽  
Response Curves ◽  
Albino Rat ◽  
A Value ◽  
Visual Evoked Cortical Potential ◽  
Single Unit Recordings ◽  
Visual Evoked

AbstractAlbino rats have recently been reported to have increment thresholds against dim backgrounds that are two log units higher than those of pigmented rats. We, on the other hand, have failed to confirm these differences using electroretinogram b waves and pupillary light reflexes. This paper reports on experiments using evoked potentials from cortex and colliculus and single-unit recordings from colliculus.We recorded visual-evoked potentials from cortex and superior colliculus in the strains of albino (CD) and pigmented (Long-Evans) rats used in the earlier studies. Thresholds were determined on eight fully dark-adapted animals by extrapolating intensity-response curves to the point at which there was zero evoked potential. The average dark-adapted threshold for the visual-evoked cortical potential was —5.26 log cd/m2in pigmented and —5.80 log cd/m2 in albino animals. The average dark-adapted threshold for the superior colliculus evoked response was —5.54 log cd/m2 in pigmented and —5.84 log cd/m2 in albinos. The differences were not statistically significant. On the same apparatus, the average absolute threshold for three human observers was —5.3 log cd/m2, a value close to the rat dark-adapted thresholds. Thus, visual-evoked cortical potentials and superior collicular evoked potentials failed to confirm the report of higher dark-adapted thresholds for albinos. In addition, we find that single units in superior colliculus in the albino rat respond to very dim flashes.

scholarly journals Slow Late Component in Conditioned Stimulus-Evoked Potentials From the Amygdala After Fear Conditioning in the Rat

2002 ◽  
Vol 9 (4) ◽  
pp. 261-272 ◽  
Author(s):  
J. M. J. Knippenberg ◽  
E. L. J. M. van Luijtelaar ◽  
J. H. R. Maes
Keyword(s):  
Evoked Potentials ◽  
Fear Conditioning ◽  
Slow Component ◽  
Pavlovian Fear Conditioning ◽  
Late Component ◽  
Conditioning Procedure ◽  
Experimental Conditions ◽  
Before And After ◽  
Male Wistar Rats ◽  
Lateral Nucleus

Male Wistar rats were subjected to a differential Pavlovian fear conditioning procedure in which one of two tones (6 or 10 kHz) was followed by an electric shock (CS+) and the other was not (CS-). Before and after fear conditioning, we recorded the evoked potentials elicited byCS+andCS-from electrodes aimed at the lateral nucleus of the amygdala. Before conditioning, a slow, negative component with peak amplitude around 150 ms was present in the evoked potentials. This component was sensitive to habituation. After fear conditioning, bothCS+andCS-elicited the same late component, albeit with a larger amplitude. This enhancement was temporary: decreasing amplitude was observed in the course of CS test presentations under extinction. Prior research revealed a comparable slow component in the amygdala of the cat under similar experimental conditions. The collective results indicate that the large late component in the amygdala is enhanced by fear conditioning, suggesting that such enhancement reflects the anticipation of a biologically significant event.

Acute effects of alcohol on evoked potentials in visual cortex and superior colliculus of the rat

1981 ◽  
Vol 51 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Bruce E Hetzler ◽  
Robert L Heilbronner ◽  
Judith Griffin ◽  
Gregory Griffin
Keyword(s):  
Visual Cortex ◽  
Evoked Potentials ◽  
Superior Colliculus ◽  
Acute Effects

Functional aspects of plasticity in the visual system of adult cats after early monocular deprivation

1977 ◽  
Vol 278 (961) ◽  
pp. 411-424 ◽  
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Lateral Geniculate Nucleus ◽  
Visual Stimuli ◽  
Monocular Deprivation ◽  
Early Deprivation ◽  
Optic Chiasma ◽  
Lateral Geniculate ◽  
Eyes Open ◽  
Y Cells

Responses to visual stimuli and to electrical stimulation of the optic chiasma were analysed in neurons of the lateral geniculate nucleus, visual cortex and superior colliculus in monocularly deprived cats with different post-deprivation periods. If the cats had both eyes open in their post-deprivation period (1 year) no recovery from the effects of early deprivation was found in the responses of neurones in all 3 visual structures. In cats with a post-deprivation reverse closure we found an increase in the proportion of Y-cells recorded in the early deprived layer of LGN when compared to the Y-cell proportion found in the same layers immediately after the deprived eye was opened. In neurons of the visual cortex and superior colliculus the functional abnormalities remained unaltered. The late closure of the non-deprived eye for up to 3 years did not effect neurons normally activated through that eye. Removal of the non-deprived eye unmasked connections of the deprived eye’s pathway onto neurons in the visual cortex and the superior colliculus. The neurons showed no specificity for the direction of movement or the orientation of visual stimuli. This recovery from deprivation was greater after enucleating the cats at the age of 6 months than at 18 months after birth. In the lateral geniculate nucleus of these cats the proportion of Y-cells in the recorded sample driven by the deprived eye had recovered to the value of normal cats. The difficulties in relating these physiological findings to results from morphological or behavioural studies are discussed.

Acute effects of alcohol on photic evoked potentials of Albino rats: Visual cortex and superior colliculus

1982 ◽  
Vol 17 (6) ◽  
pp. 1313-1316 ◽  
Author(s):  
Bruce E. Hetzler ◽  
Karen E. Oaklay ◽  
Robert L. Heilbronner ◽  
Todd Vestal
Keyword(s):  
Visual Cortex ◽  
Evoked Potentials ◽  
Superior Colliculus ◽  
Albino Rats ◽  
Acute Effects

Use of an extraretinal signal by monkey superior colliculus neurons to distinguish real from self-induced stimulus movement

1976 ◽  
Vol 39 (4) ◽  
pp. 852-870 ◽  
Author(s):  
D. L. Robinson ◽  
R. H. Wurtz
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Eye Movement ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Saccadic Eye Movement ◽  
Background Illumination ◽  
Stimulus Movement ◽  
Stationary Stimulus ◽  
Extraretinal Signal

1. In order to see whether cells in the superficial layers of the monkey superior colliculus can differentiate between real stimulus movement and self-induced stimulus movement we compared the discharge of these cells to stimulus movement in front of the stationary eye with stimulus movement generated by eye movements across a stationary stimulus. 2. Most of the cells recorded (65% of 231 cells) responded to stimulus velocities in front of the stationary eye as fast as those occurring during the peak velocity of a saccadic eye movement. Those cells that do respond usually have weak inhibitory regions and tend to have receptive fields further from fovea. 3. Move (61% of 105 cells) of the cells that did respond to rapid stimulus movement did not respond when an eye movement swept the receptive field over a stationary stimulus. 4. About half of these cells differentiated between these stimulus conditions when we used stimuli at least 1 log unit above background illumination; the remaining cells differentiated for stimuli 2 and 3 log units above background. Many cells differentiated between the two stimulus conditions over a wide range of directions of movement and the effect appears with about equal frequency in receptive fields at all distances from the fovea. 5. The differentiation is present for most cells even when the background illumination is reduced, indicating that visual factors are not the cause of the effect on these cells but may modify the response of other cells. 6. The suppression of background activity accompanying eye movements in the light is present following eye movements made in total darkness; the suppression, therefore, must result from an extraretinal signal. 4. The failure of these cells to respond to visual stimulation during eye movements is due to the same extraretinal signal that produces the suppression since a) the cells that show this suppression tend to be those that fail to respond to stimuli during eye movements, b) the time course of the suppression matches the time at which the effects of visual stimulation during an eye movement would reach the colliculus, and c) the cells which differentiate also show a decreased responsiveness to visual stimulation during the time of background suppression. While this extraretinal signal has the characteristics one would expect of a corollary discharge, proprioception as a source of the signal cannot be excluded. 8. Cells which differentiate between the two stimulus conditions usually also show an enhanced response to a visual stimulus in their receptive field when it is to be the target for a saccadic eye movement. These cells in the superior colliculus receive an extraretinal input which permits them to differentiate betweent real stimulus movements and stimulus movements resulting from the monkey's own eye movements. This differentiation would provide an uncontaminated visual movement signal and facilitate the detection of real movement in the environment...

The long-latency component of cerebral evoked potentials in anesthetized cats

1986 ◽  
Vol 65 (3) ◽  
pp. 392-397 ◽  
Author(s):  
Kyu Ho Lee ◽  
Jun Kim ◽  
Jin Mo Chung
Keyword(s):  
Evoked Potentials ◽  
Sural Nerve ◽  
Evoked Potential ◽  
Afferent Input ◽  
Late Component ◽  
Content Type ◽  
C Fibers ◽  
Long Latency ◽  
Fine Print ◽  
Stimulation Of

✓ A late component of the cortical evoked potential elicited by somatosensory afferent input was studied in cats anesthetized with α-chloralose. Cortical evoked potentials were recorded from the somatosensory-motor cortex during stimulation of the sural nerve with graded intensities. The stimulus intensity was adjusted to activate Aαβ fibers only, then both Aαβ and Aδ fibers, and both A and C fibers, as judged by afferent volleys monitored from the sural nerve proximal to the stimulating site. In addition to early components reported previously, a very late component was identified at a latency of 400 to 600 msec following stimulation of the sural nerve with intensities above threshold for Aδ fibers. A further increase in stimulation intensity to include activation of C fibers did not reveal any more components. This late component was depressed by a systemic intravenous injection of morphine (2 mg/kg), and intravenous naloxone (0.1 mg/kg) reversed the effect of morphine. The late component of the evoked potential could also be recorded from subcortical tissue after decortication of the sensorimotor cortex. From these results, it appears that a very late component of the cortical evoked potential can be recorded from cats anesthetized with α-chloralose. The late component is evoked by activation of peripheral Aδ fibers. Furthermore, its morphine sensitivity suggests that this component may be elicited by nociceptive afferent fibers. If further investigations prove this, the late component, which is analogous to human long-latency potentials, could be used in an experimental model for pain research.

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