Expectations of Task Demands Dissociate Working Memory and Long-Term Memory Systems
Many aspects of the complex relationship between working memory (WM) and long-term memory (LTM) remain unclear. Here, we manipulated task demands on a brief delayed-recognition paradigm to reveal behavioral and neural dissociations between these systems. Variations from a Baseline task included 3 challenges: increased delay duration, distraction during maintenance, and more closely matched memory probes, which were presented in behavioral experiments and during functional magnetic resonance imaging. Each of the challenges resulted in a significant decline in WM accuracy, and interestingly, a concurrent improvement in incid...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Zanto, T. P., Clapp, W. C., Rubens, M. T., Karlsson, J., Gazzaley, A. Tags: Original Articles Source Type: research
Sensory Deviancy Detection Measured Directly Within the Human Nucleus Accumbens
Rapid changes in the environment evoke a comparison between expectancy and actual outcome to inform optimal subsequent behavior. The nucleus accumbens (NAcc), a key interface between the hippocampus and neocortical regions, is a candidate region for mediating this comparison. Here, we report event-related potentials obtained from the NAcc using direct intracranial recordings in 5 human participants while they listened to trains of auditory stimuli differing in their degree of deviation from repetitive background stimuli. NAcc recordings revealed an early mismatch signal (50–220 ms) in response to all deviants. NAcc a...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Durschmid, S., Zaehle, T., Hinrichs, H., Heinze, H.-J., Voges, J., Garrido, M. I., Dolan, R. J., Knight, R. T. Tags: Original Articles Source Type: research
Fine Tuning of Synaptic Plasticity and Filtering by GABA Released from Hippocampal Autaptic Granule Cells
The functional consequence of -aminobutyric acid (GABA) release at mossy fiber terminals is still a debated topic. Here, we provide multiple evidence of GABA release in cultured autaptic hippocampal granule cells. In ~50% of the excitatory autaptic neurons, GABA, VGAT, or GAD67 colocalized with vesicular glutamate transporter 1-positive puncta, where both GABAB and GABAA receptors (Rs) were present. Patch-clamp recordings showed a clear enhancement of autaptic excitatory postsynaptic currents in response to the application of the GABABR antagonist CGP58845 only in neurons positive to the selective granule cell marker Prox1...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Valente, P., Orlando, M., Raimondi, A., Benfenati, F., Baldelli, P. Tags: Original Articles Source Type: research
Atypical Sulcal Pattern in Children with Developmental Dyslexia and At-Risk Kindergarteners
Developmental dyslexia (DD) is highly heritable and previous studies observed reduced cortical volume, white matter integrity, and functional alterations in left posterior brain regions in individuals with DD. The primary sulcal pattern has been hypothesized to relate to optimal organization and connections of cortical functional areas. It is determined during prenatal development and may reflect early, genetically influenced, brain development. We characterize the sulcal pattern using graph-based pattern analysis and investigate whether sulcal patterns in parieto-temporal and occipito-temporal regions are atypical in elem...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Im, K., Raschle, N. M., Smith, S. A., Ellen Grant, P., Gaab, N. Tags: Original Articles Source Type: research
Multisensory Plasticity in Superior Colliculus Neurons is Mediated by Association Cortex
The ability to integrate information from different senses, and thereby facilitate detecting and localizing events, normally develops gradually in cat superior colliculus (SC) neurons as experience with cross-modal events is acquired. Here, we demonstrate that the portal for this experience-based change is association cortex. Unilaterally deactivating this cortex whenever visual–auditory events were present resulted in the failure of ipsilateral SC neurons to develop the ability to integrate those cross-modal inputs, even though they retained the ability to respond to them. In contrast, their counterparts in the oppo...
Source: Cerebral Cortex - February 2, 2016 Category: Neurology Authors: Yu, L., Xu, J., Rowland, B. A., Stein, B. E. Tags: Original Articles Source Type: research
