Perturbation of Posterior Inferior Temporal Cortical Activity Impairs Coarse Orientation Discrimination
It is reasonable to assume that the discrimination of simple visual stimuli depends on the activity of early visual cortical neurons, because simple visual features are supposedly coded in these areas whereas more complex features are coded in late visual areas. Recently, we showed that training monkeys in a coarse orientation discrimination task modified the response properties of single neurons in the posterior inferior temporal (PIT) cortex, a late visual area. Here, we examined the contribution of PIT to coarse orientation discrimination using causal perturbation methods. Electrical stimulation (ES) of PIT with current...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Adab, H. Z., Vogels, R. Tags: Original Articles Source Type: research
The Association Between Eye Movements and Cerebellar Activation in a Verbal Working Memory Task
It has been argued that cerebellar activations during cognitive tasks may masquerade as cognition, while actually reflecting processes related to movement planning or motor learning. The present study investigated whether the cerebellar load effect for verbal working memory, that is, increased activations in lobule VI/Crus I and lobule VIIB/VIIIA, is related to eye movements and oculomotor processing. Fifteen participants performed an fMRI-based Sternberg verbal working memory task. Oculomotor and cognitive task demands were manipulated by using closely and widely spaced stimuli, and high and low cognitive load. Trial-base...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Peterburs, J., Cheng, D. T., Desmond, J. E. Tags: Original Articles Source Type: research
Multisensory Convergence of Visual and Vestibular Heading Cues in the Pursuit Area of the Frontal Eye Field
Both visual and vestibular sensory cues are important for perceiving one's direction of heading during self-motion. Previous studies have identified multisensory, heading-selective neurons in the dorsal medial superior temporal area (MSTd) and the ventral intraparietal area (VIP). Both MSTd and VIP have strong recurrent connections with the pursuit area of the frontal eye field (FEFsem), but whether FEFsem neurons may contribute to multisensory heading perception remain unknown. We characterized the tuning of macaque FEFsem neurons to visual, vestibular, and multisensory heading stimuli. About two-thirds of FEFsem neurons ...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Gu, Y., Cheng, Z., Yang, L., DeAngelis, G. C., Angelaki, D. E. Tags: Original Articles Source Type: research
Stimulus Load and Oscillatory Activity in Higher Cortex
Exploring and exploiting a rich visual environment requires perceiving, attending, and remembering multiple objects simultaneously. Recent studies have suggested that this mental "juggling" of multiple objects may depend on oscillatory neural dynamics. We recorded local field potentials from the lateral intraparietal area, frontal eye fields, and lateral prefrontal cortex while monkeys maintained variable numbers of visual stimuli in working memory. Behavior suggested independent processing of stimuli in each hemifield. During stimulus presentation, higher-frequency power (50–100 Hz) increased with the number of stim...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Kornblith, S., Buschman, T. J., Miller, E. K. Tags: Original Articles Source Type: research
Differential Roles of Ventral and Dorsal Streams for Conceptual and Production-Related Components of Tool Use in Acute Stroke Patients
Impaired tool use despite preserved basic motor functions occurs after stroke in the context of apraxia, a cognitive motor disorder. To elucidate the neuroanatomical underpinnings of different tool use deficits, prospective behavioral assessments of 136 acute left-hemisphere stroke patients were combined with lesion delineation on magnetic resonance imaging (MRI) images for voxel-based lesion-symptom mapping. Deficits affecting both the selection of the appropriate recipient for a given tool (ToolSelect, e.g., choosing the nail for the hammer), and the performance of the typical tool-associated action (ToolUse, e.g., hamme...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Martin, M., Beume, L., Kümmerer, D., Schmidt, C. S. M., Bormann, T., Dressing, A., Ludwig, V. M., Umarova, R. M., Mader, I., Rijntjes, M., Kaller, C. P., Weiller, C. Tags: Original Articles Source Type: research
Spatial Reference Memory is Associated with Modulation of Theta-Gamma Coupling in the Dentate Gyrus
Spatial reference memory in rodents represents a unique opportunity to study brain mechanisms responsible for encoding, storage and retrieval of a memory. Even though its reliance on hippocampal networks has long been established, the precise computations performed by different hippocampal subfields during spatial learning are still not clear. To study the evolution of electrophysiological activity in the CA1–dentate gyrus axis of the dorsal hippocampus over an iterative spatial learning paradigm, we recorded local field potentials in behaving mice using a newly designed appetitive version of the Barnes maze. We firs...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Bott, J.-B., Muller, M.-A., Jackson, J., Aubert, J., Cassel, J.-C., Mathis, C., Goutagny, R. Tags: Original Articles Source Type: research
Genetic Effects on Fine-Grained Human Cortical Regionalization
Various brain structural and functional features such as cytoarchitecture, topographic mapping, gyral/sulcal anatomy, and anatomical and functional connectivity have been used in human brain parcellation. However, the fine-grained intrinsic genetic architecture of the cortex remains unknown. In the present study, we parcellated specific regions of the cortex into subregions based on genetic correlations (i.e., shared genetic influences) between the surface area of each pair of cortical locations within the seed region. The genetic correlations were estimated by comparing the correlations of the surface area between monozyg...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Cui, Y., Liu, B., Zhou, Y., Fan, L., Li, J., Zhang, Y., Wu, H., Hou, B., Wang, C., Zheng, F., Qiu, C., Rao, L.-L., Ning, Y., Li, S., Jiang, T. Tags: Original Articles Source Type: research
Functional Connectivity Patterns of Visual Cortex Reflect its Anatomical Organization
The brain is continuously active, even without external input or task demands. This so-called resting-state activity exhibits a highly specific spatio-temporal organization. However, how exactly these activity patterns map onto the anatomical and functional architecture of the brain is still unclear. We addressed this question in the human visual cortex. We determined the representation of the visual field in visual cortical areas of 44 subjects using fMRI and examined resting-state correlations between these areas along the visual hierarchy, their dorsal and ventral segments, and between subregions representing foveal ver...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Genc, E., Schölvinck, M. L., Bergmann, J., Singer, W., Kohler, A. Tags: Original Articles Source Type: research
Mutation of the Dyslexia-Associated Gene Dcdc2 Enhances Glutamatergic Synaptic Transmission Between Layer 4 Neurons in Mouse Neocortex
In this study, we sought to determine whether Dcdc2 mutation affects functional synaptic circuitry in neocortex. We found mutation in Dcdc2 resulted in elevated spontaneous and evoked glutamate release from neurons in somatosensory cortex. The probability of release was decreased to wild-type level by acute application of N-methyl-d-aspartate receptor (NMDAR) antagonists when postsynaptic NMDARs were blocked by intracellular MK-801, and could not be explained by elevated ambient glutamate, suggesting altered, nonpostsynaptic NMDAR activation in the mutants. In addition, we determined that the increased excitatory transmiss...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Che, A., Truong, D. T., Fitch, R. H., LoTurco, J. J. Tags: Original Articles Source Type: research
Sensory Response of Transplanted Astrocytes in Adult Mammalian Cortex In Vivo
Glial precursor transplantation provides a potential therapy for brain disorders. Before its clinical application, experimental evidence needs to indicate that engrafted glial cells are functionally incorporated into the existing circuits and become essential partners of neurons for executing fundamental brain functions. While previous experiments supporting for their functional integration have been obtained under in vitro conditions using slice preparations, in vivo evidence for such integration is still lacking. Here, we utilized in vivo two-photon Ca2+ imaging along with immunohistochemistry, fluorescent indicator labe...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Zhang, K., Chen, C., Yang, Z., He, W., Liao, X., Ma, Q., Deng, P., Lu, J., Li, J., Wang, M., Li, M., Zheng, L., Zhou, Z., Sun, W., Wang, L., Jia, H., Yu, Z., Zhou, Z., Chen, X. Tags: Original Articles Source Type: research
Neuroimaging Evidence for 2 Types of Plasticity in Association with Visual Perceptual Learning
Visual perceptual learning (VPL) is long-term performance improvement as a result of perceptual experience. It is unclear whether VPL is associated with refinement in representations of the trained feature (feature-based plasticity), improvement in processing of the trained task (task-based plasticity), or both. Here, we provide empirical evidence that VPL of motion detection is associated with both types of plasticity which occur predominantly in different brain areas. Before and after training on a motion detection task, subjects' neural responses to the trained motion stimuli were measured using functional magnetic reso...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Shibata, K., Sasaki, Y., Kawato, M., Watanabe, T. Tags: Original Articles Source Type: research
Neural Correlates of Auditory Figure-Ground Segregation Based on Temporal Coherence
To make sense of natural acoustic environments, listeners must parse complex mixtures of sounds that vary in frequency, space, and time. Emerging work suggests that, in addition to the well-studied spectral cues for segregation, sensitivity to temporal coherence—the coincidence of sound elements in and across time—is also critical for the perceptual organization of acoustic scenes. Here, we examine pre-attentive, stimulus-driven neural processes underlying auditory figure-ground segregation using stimuli that capture the challenges of listening in complex scenes where segregation cannot be achieved based on spe...
Source: Cerebral Cortex - August 29, 2016 Category: Neurology Authors: Teki, S., Barascud, N., Picard, S., Payne, C., Griffiths, T. D., Chait, M. Tags: Original Articles Source Type: research
From Neuron Biophysics to Orientation Selectivity in Electrically Coupled Networks of Neocortical L2/3 Large Basket Cells
In the neocortex, inhibitory interneurons of the same subtype are electrically coupled with each other via dendritic gap junctions (GJs). The impact of multiple GJs on the biophysical properties of interneurons and thus on their input processing is unclear. The present experimentally based theoretical study examined GJs in L2/3 large basket cells (L2/3 LBCs) with 3 goals in mind: (1) To evaluate the errors due to GJs in estimating the cable properties of individual L2/3 LBCs and suggest ways to correct these errors when modeling these cells and the networks they form; (2) to bracket the GJ conductance value (0.05–0.2...
Source: Cerebral Cortex - July 24, 2016 Category: Neurology Authors: Amsalem, O., Van Geit, W., Muller, E., Markram, H., Segev, I. Tags: Original Articles Source Type: research
Presynaptic Spike Timing-Dependent Long-Term Depression in the Mouse Hippocampus
Spike timing-dependent plasticity (STDP) is a Hebbian learning rule important for synaptic refinement during development and for learning and memory in the adult. Given the importance of the hippocampus in memory, surprisingly little is known about the mechanisms and functions of hippocampal STDP. In the present work, we investigated the requirements for induction of hippocampal spike timing-dependent long-term potentiation (t-LTP) and spike timing-dependent long-term depression (t-LTD) and the mechanisms of these 2 forms of plasticity at CA3-CA1 synapses in young (P12–P18) mouse hippocampus. We found that both t-LTP...
Source: Cerebral Cortex - July 24, 2016 Category: Neurology Authors: Andrade-Talavera, Y., Duque-Feria, P., Paulsen, O., Rodriguez-Moreno, A. Tags: Original Articles Source Type: research
Place Cell Networks in Pre-weanling Rats Show Associative Memory Properties from the Onset of Exploratory Behavior
Place cells are hippocampal pyramidal cells that are active when an animal visits a restricted area of the environment, and collectively their activity constitutes a neural representation of space. Place cell populations in the adult rat hippocampus display fundamental properties consistent with an associative memory network: the ability to 1) generate new and distinct spatial firing patterns when encountering novel spatial contexts or changes in sensory input ("remapping") and 2) reinstate previously stored firing patterns when encountering a familiar context, including on the basis of an incomplete/degraded set of sensor...
Source: Cerebral Cortex - July 24, 2016 Category: Neurology Authors: Muessig, L., Hauser, J., Wills, T. J., Cacucci, F. Tags: Original Articles Source Type: research
