Specificity of Experiential Effects in Neurocognitive Development

Here, we report research on the neuroplasticity of different subsystems within vision, audition, sensory integration, language, and attention. In each section, we note different profiles of plasticity observed in different subsystems within the domain, situations in which enhancements versus deficits are observed, and likely mechanisms contributing to these different profiles of plasticity. A final section describes our studies that test the hypothesis, raised by this basic research on human neuroplasticity, that interventions that target the most plastic, and thus potentially vulnerable, neurocognitive systems can protect and enhance children with, or at risk for, developmental deficits. For several years we have employed psychophysics, electrophysiological (ERP), and magnetic resonance imaging (MRI) techniques to study the development and neuroplasticity of the human brain. We have studied deaf and blind individuals, people who learned their first or second spoken or signed language at different ages, and children of different ages and stages of cognitive development. Here, we review our research on the neuroplasticity of different brain systems and subsystems. As detailed in the sections that follow, in each of the domains examined in this research we observe the following characteristics: • Different brain systems and subsystems and related sensory and cognitive abilities display different degrees and time periods (“profiles”) of neuroplasticity. • Neuroplasticity within a system acts as a double-edged sword, conferring the possibility for either enhancement or deficit. • Multiple mechanisms both support and constrain the ability to modify different brain systems and subsystems, with the most malleable systems generally displaying longer developmental trajectories, higher levels of redundant connectivity, and a greater concentration of neurochemicals, including CAT301 and BDNF important in neuroplasticity. In the sections that follow, we describe our research on neuroplasticity within visual, auditory, sensory integration, language, and attention systems. In each section, we note different profiles of plasticity that are system and context dependent and in which enhancements versus deficits are observed. We also propose likely mechanisms contributing to these different profiles of plasticity. A final section describes our studies that test the hypothesis, raised by this basic research on human neuroplasticity, that interventions that target the most plastic, and thus potentially most vulnerable, neurocognitive systems can protect and enhance children with, or at risk for, developmental deficits. I. Vision The primate visual system contains multiple distinct visual areas, with a gross segregation of cortical visual processing into dorsal and ventral streams that project respectively from V1 toward posterior parietal cortex and ventrally toward the temporal cortex (Grill-Spector & Malach, 2004; Ungerleider & Haxby, 1994). In our research, we observe that aspects of vision