Differential development of high-level visual cortex correlates with category-specific recognition memory

296

231

Brain development is characterized by maturational processes that span the period from childhood through adolescence to adulthood, but little is known whether and how developmental processes differ during these phases. We analyzed the development of functional networks by measuring neural synchrony in EEG recordings during a Gestalt perception task in 68 participants ranging in age from 6 to 21 years. Until early adolescence, developmental improvements in cognitive performance were accompanied by increases in neural synchrony. This developmental phase was followed by an unexpected decrease in neural synchrony that occurred during late adolescence and was associated with reduced performance. After this period of destabilization, we observed a reorganization of synchronization patterns that was accompanied by pronounced increases in gammaband power and in theta and beta phase synchrony. These findings provide evidence for the relationship between neural synchrony and late brain development that has important implications for the understanding of adolescence as a critical period of brain maturation.oscillations ͉ synchrony ͉ adolescence ͉ electroencephalography ͉ Gestalt perception D evelopmental psychology and brain research has focused mainly on the early pre-and postnatal periods as critical windows for the organization and functional adjustment of neural circuitry. These studies revealed the important role of early experience in shaping cortical networks and emphasized the decline of neuronal plasticity with age. However, more recent evidence suggests that brain development and its susceptibility to epigenetic influences extends far beyond the early postnatal stages and in humans comes to an end only around age 20.Emerging evidence from anatomy and physiology suggests that later developmental periods, such as adolescence, may have a crucial impact on the organization of cortical circuitry. Anatomically, the volume and organization of white matter increases continuously (1-3), whereas the volume of cortical gray matter increases only until the onset of adolescence and then decreases again (4-6). Physiologically, there is evidence that dopamine-NMDA receptor interactions in prefrontal cortex (7) mature only after adolescence, and there are data suggesting late maturation of GABAergic neurotransmission (8).These findings indicate important changes in anatomical and physiological parameters during late developmental periods, but the functional implications of these changes are poorly understood. The putative relevance of these changes is highlighted by the fact that the onset of brain disorders, such as schizophrenia, that cause lasting emotional and cognitive dysfunctions often occurs during the transition from adolescence to adulthood (9). Thus, not only the early but also the late maturational processes are likely to be critical, especially for the development of higher cognitive functions.We investigated the development of functional networks by examining age-dependent changes in task-related neural oscillation...

Section: Discussionsupporting

confidence: 90%

The development of neural synchrony reflects late maturation and restructuring of functional networks in humans

Uhlhaas

Roux

Singer

et al. 2009

296

231

“…Second, although our findings demonstrate the role of experience in shaping the selectivity of the cLSSR, they leave unanswered the question of why this region lands in a very similar location across subjects and why it apparently cannot ''move over'' to adjacent cortex when damaged in adulthood (54,55). Finally, what is the time course of the development of the cLSSR (56), what does this region do before children learn to read, and (how) does it differ in dyslexic versus normal children (26)(27)(28)(29)?…”

Section: Discussionmentioning

confidence: 69%

Visual word processing and experiential origins of functional selectivity in human extrastriate cortex

Baker

Liu

Wald

et al. 2007

336

300

How do category-selective regions arise in human extrastriate cortex? Visually presented words provide an ideal test of the role of experience: Although individuals have extensive experience with visual words, our species has only been reading for a few thousand years, a period not thought to be long enough for natural selection to produce a genetically specified mechanism dedicated to visual word recognition per se. Using relatively high-resolution functional magnetic resonance imaging (1.4 ؋ 1.4 ؋ 2-mm voxels), we identified a small region of extrastriate cortex in most participants that responds selectively to both visually presented words and consonant strings, compared with line drawings, digit strings, and Chinese characters. Critically, we show that this pattern of selectivity is dependent on experience with specific orthographies: The same region responds more strongly to Hebrew words in Hebrew readers than in nonreaders of Hebrew. These results indicate that extensive experience with a given visual category can produce strong selectivity for that category in discrete cortical regions.learning ͉ vision ͉ fMRI ͉ experience ͉ ventral visual pathway

“…Consistent with this view, several imaging papers (89,90) have argued that the FFA increases in size through and even beyond adolescence. Some have suggested that this slow development implies that experience plays a critical role in constructing the face-perception system (89,90). This conclusion does not follow, however, because some developmental changes that occur long after birth are primarily genetically, not experientially, determined (as in the case of puberty).…”

mentioning

confidence: 79%

“…A long-standing view has held that face perception develops very slowly in humans, not reaching adult levels until adolescence or later (87,88). Consistent with this view, several imaging papers (89,90) have argued that the FFA increases in size through and even beyond adolescence. Some have suggested that this slow development implies that experience plays a critical role in constructing the face-perception system (89,90).…”

mentioning

confidence: 97%

Functional specificity in the human brain: A window into the functional architecture of the mind

Kanwisher

2010

720

618

Is the human mind/brain composed of a set of highly specialized components, each carrying out a specific aspect of human cognition, or is it more of a general-purpose device, in which each component participates in a wide variety of cognitive processes? For nearly two centuries, proponents of specialized organs or modules of the mind and brain-from the phrenologists to Broca to Chomsky and Fodor-have jousted with the proponents of distributed cognitive and neural processing-from Flourens to Lashley to McClelland and Rumelhart. I argue here that research using functional MRI is beginning to answer this long-standing question with new clarity and precision by indicating that at least a few specific aspects of cognition are implemented in brain regions that are highly specialized for that process alone. Cortical regions have been identified that are specialized not only for basic sensory and motor processes but also for the high-level perceptual analysis of faces, places, bodies, visually presented words, and even for the very abstract cognitive function of thinking about another person's thoughts. I further consider the as-yet unanswered questions of how much of the mind and brain are made up of these functionally specialized components and how they arise developmentally.brain imaging | modularity | functional MRI | fusiform face area U nderstanding the nature of the human mind is arguably the greatest intellectual quest of all time. It is also one of the most challenging, requiring the combined insights not only of psychologists, computer scientists, and neuroscientists but of thinkers in nearly every intellectual pursuit, from biology and mathematics to art and anthropology. Here, I discuss one currently fruitful component of this grand enterprise: the effort to infer the architecture of the human mind from the functional organization of the human brain.The idea that the human mind/brain is made up of highly specialized components began with the Viennese physician Franz Joseph Gall (1758-1828). Gall proposed that the brain is the seat of the mind, that the mind is composed of distinct mental faculties, and that each mental faculty resides in a specific brain organ. A heated debate on localization of function in the brain raged over the next century (SI Text), with many of the major figures in the history of neuroscience weighing in (Broca, Brodmann, and Ferrier in favor, and Flourens, Golgi, and Lashley opposed). By the early 20th century, a consensus emerged that at least basic sensory and motor functions reside in specialized brain regions.The debate did not end there, however. Today, a century later, two questions are still fiercely contested. First, how functionally specialized are regions of the brain? The concept of functional specialization is not all or none but a matter of degree; a cortical region might be only slightly more engaged in one mental function than another, or it might be exclusively engaged in a single mental function. Many neuroscientists today challenge the strong (exclusive) version of ...