Table 1.
Candidate mechanisms at different levels underlying visual (U) and cross-modal (CM) plasticity following early and late-onset ME and in comparison with binocular enucleation (BE) or dark exposure (DE) effects.
| Level | plasticity mechanism | uni (U)/cross-modal (CM) | early ME or visual deprivation (neonatal or short after birth) | late-onset ME or visual deprivation | reference |
|---|---|---|---|---|---|
| system | Reorientation of retinogeniculate or retinotectal axons from open eye | U | √ | / | Toldi et al. (1996) |
| system | Sprouting of retinogeniculate or retinotectal axons from open eye | U | √ | / | Toldi et al. (1996), Chandrasekaran et al. (2005) |
| system | Respecification of representations in subcortical nuclei | U + CM | √ | ? | Lund et al. (1973), Toldi et al. (1988, 1994b) |
| system | Sprouting of thalamocortical axons | U | √ | +/−; DE | Antonini et al. (1999), Montey and Quinlan (2011), Yu et al. (2012) |
| system | Proliferation of cortico-cortical connections | U + CM | √ | +/− | Valverde (1968), Laramée et al. (2011) |
| system | Rearrangements of cortico-cortical connections | U + CM | √ | √ | Van Brussel et al. (2011), Vasconcelos et al. (2011) |
| system | Rearrangements of callosaII connections | U + CM | √ | / | Laing et al. (2014), Olavarria et al. (2012) |
| system | Rearrangements of cortico-thalamo-cortical connections | U + CM | ME: ?, BE: √ | ? | Négyessy et al. (2000), Sherman and Guillery (2011) |
| system | Modulation of oscillatory activity patterns | U + CM | ME: ?, BE: √ | ? | Schepers et al. (2012) |
| synaptic | Changes in multisensory integration | U + CM | √ | √ | Dehner et al. (2004), Iurilli et al. (2012) |
| synaptic | Formation of new synapses; spines and axon boutons | U + CM | √ | √ | Valverde (1968), Kossut (1998) |
| synaptic/molecular | Strenghtening of synapses/ connections | ||||
| Plasticity of thalamocortical axons | U | ? | DE | Goel et al. (2006), Jitsuki et al. (2011), He et al. (2012) | |
| Plasticity of thalamocortical axons | CM | √ | √ | Yu et al. (2012), Petrus et al. (2014) | |
| synaptic | Unmasking of silent existing synapses | U + CM | √ | √ | Newton et al. (2002), Van Brussel et al. (2011) |
| molecular | Changes in neurotransmitter release | U + CM | √ | √ | Nakamura et al. (1984), Riback and Robertson (1986) |
| molecular | Epigenetic chromatin remodeling | U + CM | ME: ?, BE: √ | ? | Fetter-Pruneda et al. (2013) |
| molecular | Shift in the excitation- inhibition balance | U + CM | √ | √ | Desgent et al. (2010), Ni et al. (2010), Zhang et al. (2013) |