Assessing the Cognitive Translational Potential of a Mouse Model of the 22q11.2 Microdeletion Syndrome
A chromosomal microdeletion at the 22q11.2 locus is associated with extensive cognitive impairments, schizophrenia and other psychopathology in humans. Previous reports indicate that mouse models of the 22q11.2 microdeletion syndrome (22q11.2DS) may model the genetic basis of cognitive deficits relevant for neuropsychiatric disorders such as schizophrenia. To assess the models usefulness for drug discovery, a novel mouse (Df(h22q11)/+) was assessed in an extensive battery of cognitive assays by partners within the NEWMEDS collaboration (Innovative Medicines Initiative Grant Agreement No. 115008). This battery included clas...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Nilsson, S. R., Fejgin, K., Gastambide, F., Vogt, M. A., Kent, B. A., Nielsen, V., Nielsen, J., Gass, P., Robbins, T. W., Saksida, L. M., Stensbol, T. B., Tricklebank, M. D., Didriksen, M., Bussey, T. J. Tags: Original Articles Source Type: research
Phase Dependency of the Human Primary Motor Cortex and Cholinergic Inhibition Cancelation During Beta tACS
The human motor cortex has a tendency to resonant activity at about 20 Hz so stimulation should more readily entrain neuronal populations at this frequency. We investigated whether and how different interneuronal circuits contribute to such resonance by using transcranial magnetic stimulation (TMS) during transcranial alternating current stimulation (tACS) at motor (20 Hz) and a nonmotor resonance frequency (7 Hz). We tested different TMS interneuronal protocols and triggered TMS pulses at different tACS phases. The effect of cholinergic short-latency afferent inhibition (SAI) was abolished by 20 Hz tACS, linking cortical ...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Guerra, A., Pogosyan, A., Nowak, M., Tan, H., Ferreri, F., Di Lazzaro, V., Brown, P. Tags: Original Articles Source Type: research
Texture Segregation Causes Early Figure Enhancement and Later Ground Suppression in Areas V1 and V4 of Visual Cortex
Segregation of images into figures and background is fundamental for visual perception. Cortical neurons respond more strongly to figural image elements than to background elements, but the mechanisms of figure–ground modulation (FGM) are only partially understood. It is unclear whether FGM in early and mid-level visual cortex is caused by an enhanced response to the figure, a suppressed response to the background, or both.
We studied neuronal activity in areas V1 and V4 in monkeys performing a texture segregation task. We compared texture-defined figures with homogeneous textures and found an early enhancement of th...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Poort, J., Self, M. W., van Vugt, B., Malkki, H., Roelfsema, P. R. Tags: Original Articles Source Type: research
Longitudinal Evidence for Dissociation of Anterior and Posterior MTL Resting-State Connectivity in Aging: Links to Perfusion and Memory
Neuroimaging studies of spontaneous signal fluctuations as measured by resting-state functional magnetic resonance imaging have revealed age-related alterations in the functional architecture of brain networks. One such network is located in the medial temporal lobe (MTL), showing structural and functional variations along the anterior–posterior axis. Past cross-sectional studies of MTL functional connectivity (FC) have yielded discrepant findings, likely reflecting the fact that specific MTL subregions are differentially affected in aging. Here, using longitudinal resting-state data from 198 participants, we investi...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Salami, A., Wahlin, A., Kaboodvand, N., Lundquist, A., Nyberg, L. Tags: Original Articles Source Type: research
Cortical Entropy, Mutual Information and Scale-Free Dynamics in Waking Mice
Some neural circuits operate with simple dynamics characterized by one or a few well-defined spatiotemporal scales (e.g. central pattern generators). In contrast, cortical neuronal networks often exhibit richer activity patterns in which all spatiotemporal scales are represented. Such "scale-free" cortical dynamics manifest as cascades of activity with cascade sizes that are distributed according to a power-law. Theory and in vitro experiments suggest that information transmission among cortical circuits is optimized by scale-free dynamics. In vivo tests of this hypothesis have been limited by experimental techniques with ...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Fagerholm, E. D., Scott, G., Shew, W. L., Song, C., Leech, R., Knöpfel, T., Sharp, D. J. Tags: Original Articles Source Type: research
Individual Differences in the Alignment of Structural and Functional Markers of the V5/MT Complex in Primates
Extrastriate visual area V5/MT in primates is defined both structurally by myeloarchitecture and functionally by distinct responses to visual motion. Myelination is directly identifiable from postmortem histology but also indirectly by image contrast with structural magnetic resonance imaging (sMRI). First, we compared the identification of V5/MT using both sMRI and histology in Rhesus macaques. A section-by-section comparison of histological slices with in vivo and postmortem sMRI for the same block of cortical tissue showed precise correspondence in localizing heavy myelination for V5/MT and neighboring MST. Thus, sMRI i...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Large, I., Bridge, H., Ahmed, B., Clare, S., Kolasinski, J., Lam, W. W., Miller, K. L., Dyrby, T. B., Parker, A. J., Smith, J. E. T., Daubney, G., Sallet, J., Bell, A. H., Krug, K. Tags: Original Articles Source Type: research
A Hedonism Hub in the Human Brain
Human values are abstract ideals that motivate behavior. The motivational nature of human values raises the possibility that they might be underpinned by brain structures that are particularly involved in motivated behavior and reward processing. We hypothesized that variation in subcortical hubs of the reward system and their main connecting pathway, the superolateral medial forebrain bundle (slMFB) is associated with individual value orientation. We conducted Pearson's correlation between the scores of 10 human values and the volumes of 14 subcortical structures and microstructural properties of the medial forebrain bund...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Zacharopoulos, G., Lancaster, T. M., Bracht, T., Ihssen, N., Maio, G. R., Linden, D. E. J. Tags: Original Articles Source Type: research
Modulatory Effects of the Ipsi and Contralateral Ventral Premotor Cortex (PMv) on the Primary Motor Cortex (M1) Outputs to Intrinsic Hand and Forearm Muscles in Cebus apella
The ventral premotor cortex (PMv) is a key node in the neural network involved in grasping. One way PMv can carry out this function is by modulating the outputs of the primary motor cortex (M1) to intrinsic hand and forearm muscles. As many PMv neurons discharge when grasping with either arm, both PMv within the same hemisphere (ipsilateral; iPMv) and in the opposite hemisphere (contralateral; cPMv) could modulate M1 outputs. Our objective was to compare modulatory effects of iPMv and cPMv on M1 outputs to intrinsic hand and forearm muscles. We used paired-pulse protocols with intracortical microstimulations in capuchin mo...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Quessy, S., Cote, S. L., Hamadjida, A., Deffeyes, J., Dancause, N. Tags: Original Articles Source Type: research
Words in Context: The Effects of Length, Frequency, and Predictability on Brain Responses During Natural Reading
Word length, frequency, and predictability count among the most influential variables during reading. Their effects are well-documented in eye movement studies, but pertinent evidence from neuroimaging primarily stem from single-word presentations. We investigated the effects of these variables during reading of whole sentences with simultaneous eye-tracking and functional magnetic resonance imaging (fixation-related fMRI). Increasing word length was associated with increasing activation in occipital areas linked to visual analysis. Additionally, length elicited a U-shaped modulation (i.e., least activation for medium...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Schuster, S., Hawelka, S., Hutzler, F., Kronbichler, M., Richlan, F. Tags: Original Articles Source Type: research
How the Non-attending Brain Hears Its Owner's Name
We used functional magnetic resonance imaging to investigate how attended and non-attended hearing of a subject's own name (SON) captures his or her attention. It has been reported that SON presentation activates the medial prefrontal cortex (mPFC), which is considered to be the key region for self-recognition. However, it remains unclear whether non-attended SON presentation also activates the mPFC. We hypothesized that an attended SON should activate mPFC more than a non-attended SON. To test this hypothesis, we designed an experiment in which we manipulated the task-relevance of SON; in a name-detection task, SON was a ...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Nakane, T., Miyakoshi, M., Nakai, T., Naganawa, S. Tags: Original Articles Source Type: research
New Role of ATM in Controlling GABAergic Tone During Development
The capacity to guarantee the proper excitatory/inhibitory balance is one of the most critical steps during early development responsible for the correct brain organization, function, and plasticity. GABAergic neurons guide this process leading to the right structural organization, brain circuitry, and neuronal firing. Here, we identified the ataxia telangiectasia mutated (ATM), a serine/threonine protein kinase linked to DNA damage response, as crucial in regulating neurotransmission. We found that reduced levels of ATM in the hippocampal neuronal cultures produce an excitatory/inhibitory unbalance toward inhibition as in...
Source: Cerebral Cortex - September 18, 2016 Category: Neurology Authors: Pizzamiglio, L., Focchi, E., Murru, L., Tamborini, M., Passafaro, M., Menna, E., Matteoli, M., Antonucci, F. Tags: Original Articles Source Type: research
Effects of a Neonatal Experience Involving Reward Through Maternal Contact on the Noradrenergic System of the Rat Prefrontal Cortex
The noradrenergic system plays an important role in prefrontal cortex (PFC) function. Since early life experiences play a crucial role in programming brain function, we investigated the effects of a neonatal experience involving reward through maternal contact on the noradrenergic system of the rat PFC. Rat pups were exposed during Postnatal days (PNDs) 10–13, to a T-maze in which contact with the mother was used as a reward (RER). RER males had higher norepinephrine levels in the PFC both on PND 13 and in adulthood. The RER experience resulted in adulthood in increased levels of the active demethylase GADD45b, hypom...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Kalpachidou, T., Raftogianni, A., Melissa, P., Kollia, A.-M., Stylianopoulou, F., Stamatakis, A. Tags: Original Articles Source Type: research
Aging Effects on Whole-Brain Functional Connectivity in Adults Free of Cognitive and Psychiatric Disorders
In this study, resting-state fMRI was acquired from 59 adults free of cognitive and psychiatric disorders according to standardized criteria and based on extensive neuropsychological and clinical assessments. We tested for associations between age and whole-brain RSFC using Partial Least Squares, a multivariate technique. We found that normal aging is not only characterized by decreased RSFC within the DMN but also by ubiquitous increases in internetwork positive correlations and focal internetwork losses of anticorrelations (involving mainly connections between the DMN and the attentional networks). Our results reinforce ...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Ferreira, L. K., Regina, A. C. B., Kovacevic, N., Martin, M. d. G. M., Santos, P. P., Carneiro, C. d. G., Kerr, D. S., Amaro, E., McIntosh, A. R., Busatto, G. F. Tags: Original Articles Source Type: research
Smaller Primary Visual Cortex Is Associated with Stronger, but Less Precise Mental Imagery
Despite mental imagery's ubiquitous role in human perception, cognition and behavior, one standout question remains unanswered: Why does imagery vary so much from one individual to the next? Here, we used a behavioral paradigm that measures the functional impact of a mental image on subsequent conscious perception and related these measures to the anatomy of the early visual cortex estimated by fMRI retinotopic mapping. We observed a negative relationship between primary visual cortex (V1) surface area and sensory imagery strength, but found positive relationships between V1 and imagery precision (spatial location and orie...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Bergmann, J., Genc, E., Kohler, A., Singer, W., Pearson, J. Tags: Original Articles Source Type: research
Altered Human Memory Modification in the Presence of Normal Consolidation
Following initial learning, the memory is stabilized by consolidation mechanisms, and subsequent modification of memory strength occurs via reconsolidation. Yet, it is not clear whether consolidation and memory modification are the same or different systems-level processes. Here, we report disrupted memory modification in the presence of normal consolidation of human motor memories, which relate to differences in lesioned brain structure after stroke. Furthermore, this behavioral dissociation was associated with macrostructural network architecture revealed by a graph-theoretical approach, and with white-matter microstruct...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Censor, N., Buch, E. R., Nader, K., Cohen, L. G. Tags: Original Articles Source Type: research
