Embryonic interneurons from the medial, but not the caudal ganglionic eminence trigger ocular dominance plasticity in adult mice

Abstract

The maturation of cortical inhibition provided by parvalbumin-containing basket cells derived from the medial ganglionic eminence (MGE) is a key event in starting the enhanced visual cortical plasticity during the critical period. Although it is generally assumed that a further increase in inhibition closes the critical period again, it was recently shown that embryonic interneurons derived from the MGE can induce an additional, artificial critical period when injected into the visual cortex of young mice. It has, however, remained open whether this effect was indeed specific for MGE-derived cells, and whether critical period-like plasticity could also be induced in fully adult animals. To clarify these issues, we injected explants from either the MGE or the caudal ganglionic eminence (CGE) into the visual cortices of fully adult mice, and performed monocular deprivation 33 days later for 4 days. Animals implanted with MGE cells, but not with CGE cells, showed marked ocular dominance plasticity. Immunohistochemistry confirmed that the injected cells from both sources migrated far in the host cortex, that most developed into neurons producing GABA, and that only cells from the MGE expressed parvalbumin. Thus, our results confirm that the plasticity-inducing effect of embryonic interneurons is specific for cells from the MGE, and is independent of the host animal's age.

Homeostatic plasticity and synaptic scaling in the adult mouse auditory cortex

“…As a first step we designed an auditory stimulus that enabled us to generate reliable tonotopic maps of the auditory cortex in mice using Fourier intrinsic optical imaging. This technique allows non-invasive measurements of stimulus evoked cortical responses in the visual 10,[25][26][27][28] and auditory cortex 29,30 and its reliability has been validated by electrophysiological recordings 10,31 . Because intrinsic optical imaging is based on temporally periodic stimulus presentation 25 , we used tone sweeps linearly ascending or descending in frequency (1-15 kHz) with 70 dB sound pressure level (SPL), which were repeated with a period of 8 s for 5 min.…”

Amblyopia: New molecular/pharmacological and environmental approaches

“…These neuromodulatory systems can be activated by pharmacological treatments such as cholinesterase (AChE) inhibitors (Morishita et al, 2010) or selective serotonin reuptake inhibitors (SSRIs; Maya Vetencourt et al, 2008; Thompson et al, 2014) or behavioral therapies such as exercise (Fu et al, 2015; Lunghi & Sale, 2015) and video game training (Bavelier et al, 2010). Transplantation of embryonic inhibitory neurons into the postnatal visual cortex induces a second critical period of OD plasticity after the normal one (Southwell et al, 2010; Tang et al, 2014; Isstas et al, 2017). Plasticity is also enhanced in the adult visual cortex by decreasing perineuronal nets that predominantly enwrap the PV cells by pharmacological (Pizzorusso et al, 2002) or behavioral interventions, such as environmental enrichment (Sale et al, 2007) or dark exposure (Stodieck et al, 2014).…”

Transplantation of GABAergic interneurons for cell-based therapy

“…As the CGE is a caudal extension of both LGE and MGE, using the most rostral aspect of the CGE for transplantation may give rise to grafts enriched in LGE-derived cells that exhibit poor dispersal (Wichterle et al, 1999). However, in line with genetic fate mapping studies (Miyoshi et al, 2010; Rudy et al, 2011), CGE transplant-derived interneurons were more likely to localize to cortical layer I (Larimer et al, 2016) and express VIP, CR, and RLN (Hunt and Baraban, 2015; Isstas et al, 2016; Larimer et al, 2016) (Fig. 2).…”

“…Not surprisingly, CGE transplant-derived cells were found to migrate extensively following heterochronic transplantation in the neonatal brain, with a dispersal similar to that of MGE cells (Hunt and Baraban, 2015; Larimer et al, 2016), thus suggesting that tangential migration of ventral forebrain inter-neuron precursors is a determinant factor for their dispersal upon transplantation. However, conflicting results were found following transplantation in the adult brain, with one report describing the failure of CGE cells to disperse in the mature cortex (Davis et al, 2015) and another study showing accentuated dispersal of CGE cells compared to that of MGE cells (Isstas et al, 2016). Such inconsistencies may be due to the lack of a clear anatomical distinction between MGE/LGE and CGE (Fig.…”

“…3) (Davis et al, 2015; Isstas et al, 2016; Larimer et al, 2016; Southwell et al, 2010; Tang et al, 2014). This line of work has reinforced the importance of the intrinsic programs that govern interneuron development and their integration upon transplantation.…”