Commentary: Cortical Plasticity and Olfactory Function in Early Blindness.

Abstract

Humans beings are visual creatures, which means that they preferentially map the world guided largely by sight (Aglioti and Pazzaglia, 2010). However, multiple senses contribute to the creation of an integrated experience of the real world (Aglioti and Pazzaglia, 2011). Among these, the olfactory sense is undoubtedly the most neglected. One of the reasons for this is that odors do not always prevail at a conscious level (Sobel et al., 1999), even though olfactory receptors are continuously active in order to acquire sensory, motor and affective information (Pazzaglia, 2015). A second reason is the fact that sight occasionally prevails over, or even hides, the information provided by other senses. In a recent stimulating and timely article, Araneda and colleagues presented an important view of the pathophysiological mechanisms of plasticity that occur in the visual brain of early blind patients (Araneda et al., 2016). The authors produced a behavioral and anatomo-physiological perspective on the guiding role of olfactory information when sight is lacking. Behaviorally, early blind subjects perform better than sighted individuals when it comes to odor detection and awareness, indicating that the sense of smell is highly plastic and suggesting the possibility of incremental odor processing by way of learning and experience. Neurally, active olfactory processing occurs within the occipital cortex, suggesting the privileged access of odor to other, seemingly unrelated, sensory systems and neural regions.