Biomedical subjects

Mikhail Y Frenkel

Publications and source records attributed to Mikhail Y Frenkel.

3 recordsLinked to original sources

PubMed2006

Instructive effect of visual experience in mouse visual cortex.

We describe a form of experience-dependent response enhancement in the visual cortex of awake mice. Repeated presentations of grating stimuli of a single orientation result in a persistent enhancement of responses evoked by the test stimulus. Response potentiation is specific to the orientation of the test stimulus, develops gradually over the course of several training sessions, and occurs in both juvenile and adult mice. The stimulus-selective response potentiation (SRP) can mask deprivation-induced response depression in adult mice. SRP requires NMDA receptor activation and is prevented by viral delivery of a peptide that interferes with AMPA receptor trafficking. SRP may reveal the mechanisms involved in certain forms of perceptual learning.

Animals↗

PubMed2004

How monocular deprivation shifts ocular dominance in visual cortex of young mice.

We used a chronic recording method to document the kinetics of ocular dominance (OD) plasticity induced by temporary lid closure in young mice. We find that monocular deprivation (MD) induces two separate modifications: (1) rapid, deprivation-induced response depression and (2) delayed, deprivation-enabled, experience-dependent response potentiation. To gain insight into how altering retinal activity triggers these cortical responses, we compared the effects of MD by lid closure with monocular inactivation (MI) by intravitreal injection of tetrodotoxin. We find that MI fails to induce deprived-eye response depression but promotes potentiation of responses driven by the normal eye. These effects of MI in juvenile mice closely resemble the effects of MD in adult mice. Understanding how MI and MD differentially affect activity in the visual system of young mice may provide key insight into how the critical period ends.

Age Factors↗

PubMed2003

NMDA receptor-dependent ocular dominance plasticity in adult visual cortex.

The binocular region of mouse visual cortex is strongly dominated by inputs from the contralateral eye. Here we show in adult mice that depriving the dominant contralateral eye of vision leads to a persistent, NMDA receptor-dependent enhancement of the weak ipsilateral-eye inputs. These data provide in vivo evidence for metaplasticity as a mechanism for binocular competition and demonstrate that an ocular dominance shift can occur solely by the mechanisms of response enhancement. They also show that adult mouse visual cortex has a far greater potential for experience-dependent plasticity than previously appreciated. These insights may force a revision in how data on ocular dominance plasticity in mutant mice have been interpreted.

Aging↗