Imaging Learning: The Search for a Memory Trace

Abstract

Learning is associated with structural changes in the human brain that can be seen and studied by MRI. These changes are observed in gray matter and surprisingly also in white matter tissue. Learning a wide range of skills, from sports, computer games, music, and reading, to abstract intellectual learning, including classroom study, is associated with structural changes in appropriate cortical regions or fiber tracts. The cellular changes underlying modifications of brain tissue during learning include changes in neuronal and glial morphology as well as vascular changes. Both alterations in axon morphology and myelination are thought to contribute to white matter plasticity during learning but to varying degrees depending on age. Structural changes in white matter could promote learning by improving the speed or synchrony of impulse transmission between cortical regions mediating the behavior. Action potentials can stimulate oligodendrocyte development and myelination by at least three known mechanisms that involve signaling molecules between axons and oligodendrocytes, which do not require neurotransmitter release from synapses. Integrating information from cellular/molecular and systems-level research on normal cognitive function, development, and learning is providing new insights into the biological mechanisms of learning and the structural changes produced in the brain.

Physics instruction induces changes in neural knowledge representation during successive stages of learning

“…At a more molar level, learning-based changes in grey and white matter have been observed in human participants (see Fields, 2011;Lövdén et al, 2013;Thomas and Baker, 2013;Zatorre et al, 2012 for reviews). For example, gray and white matter changes were observed when people were trained in juggling (Draganski et al, 2004).…”

Deformation-based brain morphometry in rats

“…Recent magnetic resonance imaging (MRI)-based morphometric studies in humans have shown that changes of the brain's morphology correlate with behavioral abilities, learning, diseases and age (for review see : Fields, 2011;Mietchen and Gaser, 2009;Raz and Rodrigue, 2006). Findings from this field of research have provided new and surprising insights into how the brain reorganizes under native and pathological conditions, and may be highly relevant for the improvement of therapeutic interventions for aging-or disease-induced disabilities.…”

White Matter Dementia: Origin, Development, Progress, and Prospects

“…35 Long considered an exclusive capacity of the gray matter, where synaptic changes are widely thought to underlie learning and memory, 36 plasticity can also be observed in white matter. This idea was actually first proposed by 19th-century neuroanatomists who could see white matter but had no electrophysiology with which to study synapses, and white matter plasticity is now being observed with modern investigative techniques.…”