Background:A few hours of monocular deprivation with a diffuser eye patch temporarily strengthens the contribution of the deprived eye to binocular vision.This shift in favour of the deprived eye is characterized as a...Background:A few hours of monocular deprivation with a diffuser eye patch temporarily strengthens the contribution of the deprived eye to binocular vision.This shift in favour of the deprived eye is characterized as a form of adult visual plasticity.Studies in animal and human models suggest that neuromodulators can enhance adult brain plasticity in general.Specifically,acetylcholine has been shown to improve certain aspects of visual function and plasticity in adulthood.We investigated whether a single administration of donepezil(a cholinesterase inhibitor)could further augment the temporary shift in perceptual eye dominance that occurs after two hours of monocular patching.Methods:We conducted three experiments to investigate whether donepezil enhances the shift in perceptual eye dominance induced by monocular patching.In each experiment,healthy adults completed two experimental sessions while taking either donepezil(5 mg,oral)or a placebo(lactose)pill.In experiment 1 we patched the non-dominant eye for 2 hours and measured ocular balance with a binocular phase combination task.In experiment 2 we patched for one hour to investigate whether donepezil shortens the amount of time necessary to observe a shift in ocular dominance.In experiment 3 we patched for 2 hours and measured ocular balance with a binocular rivalry task to see if the effect of donepezil was comparable across the two tasks.We calculated AUCs for the shift in perceptual eye dominance across five time points after removing the patch to compare our treatment conditions in each experiment.Results:Donepezil significantly reduces the magnitude and duration of the shift in perceptual eye dominance produced by both 2(P<0.01)and 1 hours(P<0.05)of monocular patching when measuring ocular balance with a binocular phase combination task.Donepezil also reduces the magnitude of the shift in ocular dominance when measuring balance with a binocular rivalry task.Conclusions:Previous studies have demonstrated that cholinergic potentiation enhances adult brain plasticity.Because of this,we hypothesized donepezil would further augment the strength of the deprived eye after patching.Our study demonstrates that enhanced cholinergic potentiation actually interferes with the consolidation of the perceptual eye dominance plasticity induced by several hours of monocular deprivation.These results contribute to the growing evidence that cholinergic potentiation enhances certain forms of adult brain plasticity at the expense of others.展开更多
Previous research has shown that ocular dominance can be biased by prolonged attention to one eye.The ocular-opponency-neuron model of binocular rivalry has been proposed as a candidate account for this phenomenon.Yet...Previous research has shown that ocular dominance can be biased by prolonged attention to one eye.The ocular-opponency-neuron model of binocular rivalry has been proposed as a candidate account for this phenomenon.Yet direct neural evidence is still lacking.By manipulating the contrast of dichoptic testing gratings,here we measured the steady-state visually evoked potentials(SSVEPs)at the intermodulation frequencies to selectively track the activities of ocular-opponency-neurons before and after the“dichoptic-backward-movie”adaptation.One hour of adaptation caused a shift of perceptual and neural ocular dominance towards the unattended eye.More importantly,we found a decrease in the intermodulation SSVEP response after adaptation,which was significantly greater when high-contrast gratings were presented to the attended eye than when they were presented to the unattended eye.These results strongly support the view that the adaptation of ocular-opponency-neurons contributes to the ocular dominance plasticity induced by prolonged eye-based attention.展开更多
Background:Short-term monocular deprivation has been recently shown to temporarily increase the sensitivity of the patched eye.Many studies have patched subjects for an arbitrary period of 2.5 hours,but for no princip...Background:Short-term monocular deprivation has been recently shown to temporarily increase the sensitivity of the patched eye.Many studies have patched subjects for an arbitrary period of 2.5 hours,but for no principled reason.Our goal is to show a relationship,if any,between the length of patching duration and the strength of its effect.Methods:We tested nine subjects with three different patching durations:1-,2-,3-hour.Four of the nine subjects were patched for 5-hour.Monocular deprivation was achieved by the use of a translucent eyepatch.A session included two rounds of baseline testing of interocular eye balance,patching,and post-patching tests.Each post-patching test occurred at 0,3,6,12,24,48,60 and 96 minutes after patching to track the patching effect over time.Every subject performed two sessions per condition.Results:One-hour patching produced a small shift in ocular dominance.A larger shift occurred from 2-hour patching,but 3-hour patching produced a comparable effect to the one measured after 2-hour patching.Conclusions:These results show a saturation of the patching effect beyond 2-hour patching.Hence,we believe that 2-hour patching duration is the optimal duration for eye dominance changes induced by monocular deprivation.展开更多
Background:Aim of the study is to provide an operational definition of“visual dyslexia”referred to a particular subgroup of dyslexics characterized by x,y anisotropic perception of the visual space,or unstable ocula...Background:Aim of the study is to provide an operational definition of“visual dyslexia”referred to a particular subgroup of dyslexics characterized by x,y anisotropic perception of the visual space,or unstable ocular dominance,or abnormal binocular interaction,and who benefit from increased interletter spacing.The working hypothesis of this investigation is that in dyslexic children who show the abovementioned alterations the correlation between reading rate and interletter spacing is a marker of visual involvement,and supports a causal role of these visual-perceptive alterations in their reading problems.Methods:Based on the results obtained by three psychophysical tests devised on purpose,a group of 193 school-age disabled readers with normal visual acuity and no significant co-morbidities has been classified into four different classes:non-visual-perceptive sample,anisotropic sample(AS),abnormal binocular interaction sample and unstable dominance sample(UDS).To test for the working hypothesis,the absence of the visual marker has been verified in the non-visual-perceptive sample,and its presence has then been investigated in the remaining classes.Results:The non-visual-perceptive class was negative to the visual marker.In the other classes the average reading rate of words and non-words improved as a function of the distance between characters(AS:R2:0.51 and 0.43,P=0.01 and 0.02 respectively;abnormal binocular interaction sample:R2:0.47 and R2:0.57,P=0.02 and 0.007 respectively;unstable dominance:R2:0.43,P=0.02 at non-words).Yet,individual analysis revealed that the marker was present in no more than 23%of subjects with increased anisotropy,in 50%of unstable dominants,and in only 12%of patients with abnormal interocular inhibition.Conclusions:Even if on a population scale this line of investigation seems able to provide an operational definition of“visual dyslexia”,the individual detection of the“visual dyslexics”requires methodological improvement.展开更多
文摘Background:A few hours of monocular deprivation with a diffuser eye patch temporarily strengthens the contribution of the deprived eye to binocular vision.This shift in favour of the deprived eye is characterized as a form of adult visual plasticity.Studies in animal and human models suggest that neuromodulators can enhance adult brain plasticity in general.Specifically,acetylcholine has been shown to improve certain aspects of visual function and plasticity in adulthood.We investigated whether a single administration of donepezil(a cholinesterase inhibitor)could further augment the temporary shift in perceptual eye dominance that occurs after two hours of monocular patching.Methods:We conducted three experiments to investigate whether donepezil enhances the shift in perceptual eye dominance induced by monocular patching.In each experiment,healthy adults completed two experimental sessions while taking either donepezil(5 mg,oral)or a placebo(lactose)pill.In experiment 1 we patched the non-dominant eye for 2 hours and measured ocular balance with a binocular phase combination task.In experiment 2 we patched for one hour to investigate whether donepezil shortens the amount of time necessary to observe a shift in ocular dominance.In experiment 3 we patched for 2 hours and measured ocular balance with a binocular rivalry task to see if the effect of donepezil was comparable across the two tasks.We calculated AUCs for the shift in perceptual eye dominance across five time points after removing the patch to compare our treatment conditions in each experiment.Results:Donepezil significantly reduces the magnitude and duration of the shift in perceptual eye dominance produced by both 2(P<0.01)and 1 hours(P<0.05)of monocular patching when measuring ocular balance with a binocular phase combination task.Donepezil also reduces the magnitude of the shift in ocular dominance when measuring balance with a binocular rivalry task.Conclusions:Previous studies have demonstrated that cholinergic potentiation enhances adult brain plasticity.Because of this,we hypothesized donepezil would further augment the strength of the deprived eye after patching.Our study demonstrates that enhanced cholinergic potentiation actually interferes with the consolidation of the perceptual eye dominance plasticity induced by several hours of monocular deprivation.These results contribute to the growing evidence that cholinergic potentiation enhances certain forms of adult brain plasticity at the expense of others.
基金supported by the Ministry of Science and Technology of China(2021ZD0203800)the National Natural Science Foundation of China(31871104 and 31830037).
文摘Previous research has shown that ocular dominance can be biased by prolonged attention to one eye.The ocular-opponency-neuron model of binocular rivalry has been proposed as a candidate account for this phenomenon.Yet direct neural evidence is still lacking.By manipulating the contrast of dichoptic testing gratings,here we measured the steady-state visually evoked potentials(SSVEPs)at the intermodulation frequencies to selectively track the activities of ocular-opponency-neurons before and after the“dichoptic-backward-movie”adaptation.One hour of adaptation caused a shift of perceptual and neural ocular dominance towards the unattended eye.More importantly,we found a decrease in the intermodulation SSVEP response after adaptation,which was significantly greater when high-contrast gratings were presented to the attended eye than when they were presented to the unattended eye.These results strongly support the view that the adaptation of ocular-opponency-neurons contributes to the ocular dominance plasticity induced by prolonged eye-based attention.
文摘Background:Short-term monocular deprivation has been recently shown to temporarily increase the sensitivity of the patched eye.Many studies have patched subjects for an arbitrary period of 2.5 hours,but for no principled reason.Our goal is to show a relationship,if any,between the length of patching duration and the strength of its effect.Methods:We tested nine subjects with three different patching durations:1-,2-,3-hour.Four of the nine subjects were patched for 5-hour.Monocular deprivation was achieved by the use of a translucent eyepatch.A session included two rounds of baseline testing of interocular eye balance,patching,and post-patching tests.Each post-patching test occurred at 0,3,6,12,24,48,60 and 96 minutes after patching to track the patching effect over time.Every subject performed two sessions per condition.Results:One-hour patching produced a small shift in ocular dominance.A larger shift occurred from 2-hour patching,but 3-hour patching produced a comparable effect to the one measured after 2-hour patching.Conclusions:These results show a saturation of the patching effect beyond 2-hour patching.Hence,we believe that 2-hour patching duration is the optimal duration for eye dominance changes induced by monocular deprivation.
文摘Background:Aim of the study is to provide an operational definition of“visual dyslexia”referred to a particular subgroup of dyslexics characterized by x,y anisotropic perception of the visual space,or unstable ocular dominance,or abnormal binocular interaction,and who benefit from increased interletter spacing.The working hypothesis of this investigation is that in dyslexic children who show the abovementioned alterations the correlation between reading rate and interletter spacing is a marker of visual involvement,and supports a causal role of these visual-perceptive alterations in their reading problems.Methods:Based on the results obtained by three psychophysical tests devised on purpose,a group of 193 school-age disabled readers with normal visual acuity and no significant co-morbidities has been classified into four different classes:non-visual-perceptive sample,anisotropic sample(AS),abnormal binocular interaction sample and unstable dominance sample(UDS).To test for the working hypothesis,the absence of the visual marker has been verified in the non-visual-perceptive sample,and its presence has then been investigated in the remaining classes.Results:The non-visual-perceptive class was negative to the visual marker.In the other classes the average reading rate of words and non-words improved as a function of the distance between characters(AS:R2:0.51 and 0.43,P=0.01 and 0.02 respectively;abnormal binocular interaction sample:R2:0.47 and R2:0.57,P=0.02 and 0.007 respectively;unstable dominance:R2:0.43,P=0.02 at non-words).Yet,individual analysis revealed that the marker was present in no more than 23%of subjects with increased anisotropy,in 50%of unstable dominants,and in only 12%of patients with abnormal interocular inhibition.Conclusions:Even if on a population scale this line of investigation seems able to provide an operational definition of“visual dyslexia”,the individual detection of the“visual dyslexics”requires methodological improvement.
