TY - JOUR
T1 - Different effects of cholinergic agents on responses recorded from the cat visual cortex and lateral geniculate nucleus dorsalis
AU - Arakawa, Kenji
AU - Tobimatsu, Shozo
AU - Kato, Motohiro
AU - Kobayashi, Takuro
PY - 1997/7
Y1 - 1997/7
N2 - We investigated the effect of cholinergic agents on the cat visual evoked potentials (VEPs) recorded from the primary visual cortex (V1) and lateral geniculate nucleus dorsalis (LGNd) to determine on which level of the visual pathway the cholinergic system acts. VEPs to the alternation of 0.1 cycles per degree sinusoidal gratings at 1 and 4 Hz were recorded from N2O- anesthetized cats directly from the surface of V1 and LGNd. The depth of recording in LGNd was determined by the site where the maximal response was obtained by 1 Hz stimulation. VEPs to 4 Hz stimulation, which showed sinusoidal waveforms and were analyzed by fast Fourier transforms, were used as indicators for modulation by cholinergic agents. Physostigmine, an acetylcholinesterase inhibitor, 0.7 mg/kg i.v., suppressed the amplitude of the responses more at V1 (suppression ratio: mean ± SD, 85.4 ± 9.3%) than at LGNd (32.4. ± 30.7%) (P < 0.05). Conversely, scopolamine, a muscarinic receptor blocker, 0.7 mg/kg i.v., increased the amplitude of the responses more at V1 (enhancement ratio: mean ± SD, 60.3 ± 22.3%) than at LGNd (- 22.2 ± 22.5%) (P < 0.05). These results indicate that the V1 changes reflect a direct cortical cholinergic effect, probably by modulating the cholinergic projection from the nucleus basalis of Meynert to V1.
AB - We investigated the effect of cholinergic agents on the cat visual evoked potentials (VEPs) recorded from the primary visual cortex (V1) and lateral geniculate nucleus dorsalis (LGNd) to determine on which level of the visual pathway the cholinergic system acts. VEPs to the alternation of 0.1 cycles per degree sinusoidal gratings at 1 and 4 Hz were recorded from N2O- anesthetized cats directly from the surface of V1 and LGNd. The depth of recording in LGNd was determined by the site where the maximal response was obtained by 1 Hz stimulation. VEPs to 4 Hz stimulation, which showed sinusoidal waveforms and were analyzed by fast Fourier transforms, were used as indicators for modulation by cholinergic agents. Physostigmine, an acetylcholinesterase inhibitor, 0.7 mg/kg i.v., suppressed the amplitude of the responses more at V1 (suppression ratio: mean ± SD, 85.4 ± 9.3%) than at LGNd (32.4. ± 30.7%) (P < 0.05). Conversely, scopolamine, a muscarinic receptor blocker, 0.7 mg/kg i.v., increased the amplitude of the responses more at V1 (enhancement ratio: mean ± SD, 60.3 ± 22.3%) than at LGNd (- 22.2 ± 22.5%) (P < 0.05). These results indicate that the V1 changes reflect a direct cortical cholinergic effect, probably by modulating the cholinergic projection from the nucleus basalis of Meynert to V1.
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U2 - 10.1016/S0168-5597(97)00025-7
DO - 10.1016/S0168-5597(97)00025-7
M3 - Article
C2 - 9246076
AN - SCOPUS:0031194223
SN - 0168-5597
VL - 104
SP - 375
EP - 380
JO - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
JF - Electroencephalography and Clinical Neurophysiology - Evoked Potentials
IS - 4
ER -