Brain Functional and Structural Predictors of Language Performance
The relation between brain function and behavior on the one hand and the relation between structural changes and behavior on the other as well as the link between the 2 aspects are core issues in cognitive neuroscience. It is an open question, however, whether brain function or brain structure is the better predictor for age-specific cognitive performance. Here, in a comprehensive set of analyses, we investigated the direct relation between hemodynamic activity in 2 pairs of frontal and temporal cortical areas, 2 long-distance white matter fiber tracts connecting each pair and sentence comprehension performance of 4 age gr...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Skeide, M. A., Brauer, J., Friederici, A. D. Tags: Articles Source Type: research
Developmental Trajectories of Auditory Cortex Synaptic Structures and Gap-Prepulse Inhibition of Acoustic Startle Between Early Adolescence and Young Adulthood in Mice
Cortical excitatory and inhibitory synapses are disrupted in schizophrenia, the symptoms of which often emerge during adolescence, when cortical excitatory synapses undergo pruning. In auditory cortex, a brain region implicated in schizophrenia, little is known about the development of excitatory and inhibitory synapses between early adolescence and young adulthood, and how these changes impact auditory cortex function. We used immunohistochemistry and quantitative fluorescence microscopy to quantify dendritic spines and GAD65-expressing inhibitory boutons in auditory cortex of early adolescent, late adolescent, and young ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Moyer, C. E., Erickson, S. L., Fish, K. N., Thiels, E., Penzes, P., Sweet, R. A. Tags: Articles Source Type: research
Frequency-Dependent Gating of Hippocampal-Neocortical Interactions
We report that localized activation of CA3 neurons in dorsal hippocampus produced activity propagation within the hippocampal formation, including the subiculum and entorhinal cortex, which increased monotonically with frequency to a maximum at 20–40 Hz. However, robust extrahippocampal propagation was seen specifically at theta–beta frequencies (10–20 Hz), reaching a network of midline neocortical and mesolimbic structures. Activation in those regions correlated with a frequency-dependent facilitation of spiking activity recorded in CA1. These results provide a mechanistic link between the dynamic proper...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Moreno, A., Morris, R. G. M., Canals, S. Tags: Articles Source Type: research
Integration of Distinct Objects in Visual Working Memory Depends on Strong Objecthood Cues Even for Different-Dimension Conjunctions
What makes an integrated object in visual working memory (WM)? Past evidence suggested that WM holds all features of multidimensional objects together, but struggles to integrate color–color conjunctions. This difficulty was previously attributed to a challenge in same-dimension integration, but here we argue that it arises from the integration of 2 distinct objects. To test this, we examined the integration of distinct different-dimension features (a colored square and a tilted bar). We monitored the contralateral delay activity, an event-related potential component sensitive to the number of objects in WM. The resu...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Balaban, H., Luria, R. Tags: Articles Source Type: research
Age-Dependent Long-Term Potentiation Deficits in the Prefrontal Cortex of the Fmr1 Knockout Mouse Model of Fragile X Syndrome
The most common inherited monogenetic cause of intellectual disability is Fragile X syndrome (FXS). The clinical symptoms of FXS evolve with age during adulthood; however, neurophysiological data exploring this phenomenon are limited. The Fmr1 knockout (Fmr1 KO) mouse models FXS, but studies in these mice of prefrontal cortex (PFC) function are underrepresented, and aging linked data are absent. We studied synaptic physiology and activity-dependent synaptic plasticity in the medial PFC of Fmr1 KO mice from 2 to 12 months. In young adult Fmr1 KO mice, NMDA receptor (NMDAR)-mediated long-term potentiation (LTP) is intact; ho...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Martin, H. G. S., Lassalle, O., Brown, J. T., Manzoni, O. J. Tags: Articles Source Type: research
BOLD Variability is Related to Dopaminergic Neurotransmission and Cognitive Aging
Dopamine (DA) losses are associated with various aging-related cognitive deficits. Typically, higher moment-to-moment brain signal variability in large-scale patterns of voxels in neocortical regions is linked to better cognitive performance and younger adult age, yet the physiological mechanisms regulating brain signal variability are unknown. We explored the relationship among adult age, DA availability, and blood oxygen level-dependent (BOLD) signal variability, while younger and older participants performed a spatial working memory (SWM) task. We quantified striatal and extrastriatal DA D1 receptor density with [11C]SC...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Guitart-Masip, M., Salami, A., Garrett, D., Rieckmann, A., Lindenberger, U., Bäckman, L. Tags: Articles Source Type: research
Cognitive Control Network Contributions to Memory-Guided Visual Attention
Visual attentional capacity is severely limited, but humans excel in familiar visual contexts, in part because long-term memories guide efficient deployment of attention. To investigate the neural substrates that support memory-guided visual attention, we performed a set of functional MRI experiments that contrast long-term, memory-guided visuospatial attention with stimulus-guided visuospatial attention in a change detection task. Whereas the dorsal attention network was activated for both forms of attention, the cognitive control network (CCN) was preferentially activated during memory-guided attention. Three posterior n...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Rosen, M. L., Stern, C. E., Michalka, S. W., Devaney, K. J., Somers, D. C. Tags: Articles Source Type: research
Altered Structural Brain Networks in Tuberous Sclerosis Complex
Tuberous sclerosis complex (TSC) is characterized by benign hamartomas in multiple organs including the brain and its clinical phenotypes may be associated with abnormal neural connections. We aimed to provide the first detailed findings on disrupted structural brain networks in TSC patients. Structural whole-brain connectivity maps were constructed using structural and diffusion MRI in 20 TSC (age range: 3–24 years) and 20 typically developing (TD; 3–23 years) subjects. We assessed global (short- and long-association and interhemispheric fibers) and regional white matter connectivity, and performed graph theor...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Im, K., Ahtam, B., Haehn, D., Peters, J. M., Warfield, S. K., Sahin, M., Ellen Grant, P. Tags: Articles Source Type: research
Distributed Cortical Phase Synchronization in the EEG Reveals Parallel Attention and Working Memory Processes Involved in the Attentional Blink
Attentional blink (AB) describes a visuo-perceptual phenomenon in which the second of 2 targets within a rapid serial visual presentation stream is not detected. There are several cognitive models attempting to explain the fundamentals of this information processing bottleneck. Here, we used electroencephalographic recordings and the analysis of interregional phase synchronization of rhythmical brain activity to investigate the neural bases of the AB. By investigating the time course of interregional phase synchronization separately for trials in which participants failed to report the second target correctly (AB trials) a...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Glennon, M., Keane, M. A., Elliott, M. A., Sauseng, P. Tags: Articles Source Type: research
Concept Representation Reflects Multimodal Abstraction: A Framework for Embodied Semantics
Recent research indicates that sensory and motor cortical areas play a significant role in the neural representation of concepts. However, little is known about the overall architecture of this representational system, including the role played by higher level areas that integrate different types of sensory and motor information. The present study addressed this issue by investigating the simultaneous contributions of multiple sensory-motor modalities to semantic word processing. With a multivariate fMRI design, we examined activation associated with 5 sensory-motor attributes—color, shape, visual motion, sound, and ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Fernandino, L., Binder, J. R., Desai, R. H., Pendl, S. L., Humphries, C. J., Gross, W. L., Conant, L. L., Seidenberg, M. S. Tags: Articles Source Type: research
Short-Term Memory Depends on Dissociable Medial Temporal Lobe Regions in Amnestic Mild Cognitive Impairment
We examined STM for individual objects, locations, and object-location conjunctions in amnestic mild cognitive impairment (MCI), often associated with prodromal AD. Relative to age-matched, cognitively normal controls, MCI patients not only displayed impairment on object-location conjunctions but were similarly impaired for non-bound objects and locations. Moreover, across all participants, these conditions displayed dissociable correlations of cortical thinning along the long axis of the MTL and associated cortical nodes of anterior and posterior MTL networks. These findings support the role of the MTL in visual STM tasks...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Das, S. R., Mancuso, L., Olson, I. R., Arnold, S. E., Wolk, D. A. Tags: Articles Source Type: research
The Representation of Color across the Human Visual Cortex: Distinguishing Chromatic Signals Contributing to Object Form Versus Surface Color
Many theories of visual object perception assume the visual system initially extracts borders between objects and their background and then "fills in" color to the resulting object surfaces. We investigated the transformation of chromatic signals across the human ventral visual stream, with particular interest in distinguishing representations of object surface color from representations of chromatic signals reflecting the retinal input. We used fMRI to measure brain activity while participants viewed figure-ground stimuli that differed either in the position or in the color contrast polarity of the foreground object (the ...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Seymour, K. J., Williams, M. A., Rich, A. N. Tags: Articles Source Type: research
NMDA Receptor Antagonist Ketamine Distorts Object Recognition by Reducing Feedback to Early Visual Cortex
It is a well-established fact that top-down processes influence neural representations in lower-level visual areas. Electrophysiological recordings in monkeys as well as theoretical models suggest that these top-down processes depend on NMDA receptor functioning. However, this underlying neural mechanism has not been tested in humans. We used fMRI multivoxel pattern analysis to compare the neural representations of ambiguous Mooney images before and after they were recognized with their unambiguous grayscale version. Additionally, we administered ketamine, an NMDA receptor antagonist, to interfere with this process. Our re...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: van Loon, A. M., Fahrenfort, J. J., van der Velde, B., Lirk, P. B., Vulink, N. C. C., Hollmann, M. W., Steven Scholte, H., Lamme, V. A. F. Tags: Articles Source Type: research
Nogo Receptor 1 Limits Ocular Dominance Plasticity but not Turnover of Axonal Boutons in a Model of Amblyopia
The formation and stability of dendritic spines on excitatory cortical neurons are correlated with adult visual plasticity, yet how the formation, loss, and stability of postsynaptic spines register with that of presynaptic axonal varicosities is unknown. Monocular deprivation has been demonstrated to increase the rate of formation of dendritic spines in visual cortex. However, we find that monocular deprivation does not alter the dynamics of intracortical axonal boutons in visual cortex of either adult wild-type (WT) mice or adult NgR1 mutant (ngr1–/–) mice that retain critical period visual plasticity. Restor...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Frantz, M. G., Kast, R. J., Dorton, H. M., Chapman, K. S., McGee, A. W. Tags: Articles Source Type: research
A Working Memory Buffer in Parahippocampal Regions: Evidence from a Load Effect during the Delay Period
In this study, we tested the prediction that a putative WM buffer would demonstrate a load-dependent effect during a WM delay. Using high-resolution fMRI, we examined whether activity within the hippocampus (CA3/DG, CA1, and subiculum) and surrounding medial temporal cortices (PrC, EC, and parahippocampal cortex—PHC) is modulated in a load-dependent manner. We employed a delayed matching-to-sample task with novel scenes at 2 different WM loads. A contrast between high- and low-WM load showed greater activity within CA1 and subiculum during the encoding phase, and greater EC, PrC, and PHC activity during WM maintenanc...
Source: Cerebral Cortex - April 12, 2016 Category: Neurology Authors: Schon, K., Newmark, R. E., Ross, R. S., Stern, C. E. Tags: Articles Source Type: research
