Sensitive periods and experience-dependent plasticity have become core issues in visual system development. Converging evidence indicates that visual experience is an indispensable factor in establishing mature visual system circuitry during sensitive periods and the visual system exhibits substantial plasticity while facing deprivation. The mechanisms that underlie the environmental regulation of visual system development and plasticity are of great interest but need further exploration. Here, we investigated a unique sample of human infants who experienced initial stage blindness (beginning at birth and lasting for 2–8 months) before the removal of bilateral cataracts. Retinal thickness (RT), axial length (AL), refractive status, visual grating acuity and genetic integrity were recorded during the preoperative period or at surgery and then during follow-up. The results showed that the development of the retina is malleable and associated with external environmental influences. Our work supported that the retina might play critical roles in the development of the experience-dependent visual system and its malleability might partly contribute to the sensitive period plasticity.

There has recently been a significant change in the way we think about organ regeneration. In the adult, organ formation and regeneration was thought to occur through the action of organ-or tissue-restricted stem cells (i.e. haematopoietic stem cells making blood; gut stem cells making gut, etc.). However, there is a large body of recent work that has extended this model. Thanks to lineage tracking techniques, we now believe that stem cells from one organ system, for example the haematopoietic compartment, can develop into the differentiated cells within another organ system, such as liver, brain or kidney. This cellular plasticity not only occurs under experimental conditions, but has also been shown to take place in humans following bone marrow and organ transplants. This trafficking is potentially bi-directional, and even differentiated cells from different organ systems can interchange, with pancreatic cells able to form hepatocytes, for example. In this review we will detail some of these findings and attempt to explain their biological significance.

Swallowing problems can affect as many as one in three patients in the period immediately after a stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing usually recovers to a safe level in the majority of patients within weeks. This propensity for recovery is likely to relate to how the swallowing motor cortex is organized and then reorganized after cerebral injury. In this review, we examine present knowledge on the cortical control of swallowing in humans, and examine the aspects of its organization that are important for compensating for recovery after damage. In addition, we examine approaches which may be useful in speeding up the process of recovery. Swallowing may turn out to be a useful model for studying central nervous system plasticity.