Search results for " Short-Term"
showing 10 items of 173 documents
Distraction and reorientation in children: A behavioral and ERP study
2004
In the context of distraction, involuntary orienting to task-irrelevant deviations and the following reorienting to task-relevant stimulus information were studied in children aged 5-6 years. In an auditory distraction paradigm, reaction times were prolonged by 51 ms in trials including a task-irrelevant stimulus deviancy. Event-related potentials (ERPs) revealed a mismatch response (MMR) at 252 ms and a reorienting negativity (RON) 476 ms post-stimulus in response to deviating sounds. These behavioral and ERP effects resemble those reported for adults. We conclude that kindergarten children are prone to distraction, although they can quite effectively but not fully shield working memory op…
Basic operations in working memory: contributions from functional imaging studies.
2010
Abstract Working memory (WM) constitutes a fundamental aspect of human cognition. It refers to the ability to keep information active for further use, while allowing it to be prioritized, modified and protected from interference. Much research has addressed the storage function of WM, however, its ‘working’ aspect still remains underspecified. Many operations that work on the contents of WM do not appear specific to WM. The present review focuses on those operations that we consider “basic” because they operate in the service of memory itself, by providing its basic functionality of retaining information active, in a stable yet flexible way. Based on current process models of WM we review f…
Computation of inverse functions in a model of cerebellar and reflex pathways allows to control a mobile mechanical segment.
2003
Abstract The command and control of limb movements by the cerebellar and reflex pathways are modeled by means of a circuit whose structure is deduced from functional constraints. One constraint is that fast limb movements must be accurate although they cannot be continuously controlled in closed loop by use of sensory signals. Thus, the pathways which process the motor orders must contain approximate inverse functions of the bio-mechanical functions of the limb and of the muscles. This can be achieved by means of parallel feedback loops, whose pattern turns out to be comparable to the anatomy of the cerebellar pathways. They contain neural networks able to anticipate the motor consequences …
Pheromone-induced olfactory memory in newborn rabbits: Involvement of consolidation and reconsolidation processes.
2009
Mammary pheromone (MP)-induced odor memory is a new model of appetitive memory functioning early in a mammal, the newborn rabbit. Some properties of this associative memory are analyzed by the use of anisomycin as an amnesic agent. Long-term memory (LTM) was impaired by anisomycin delivered immediately, but not 4 h after either acquisition or reactivation. Thus, the results suggest that this form of neonatal memory requires both consolidation and reconsolidation. By extending these notions to appetitive memory, the results reveal that consolidation and reconsolidation processes are characteristics of associative memories of positive events not only in the adult, but also in the newborn.
Single neuron binding properties and the magical number 7
2008
When we observe a scene, we can almost instantly recognize a familiar object or can quickly distinguish among objects differing by apparently minor details. Individual neurons in the medial temporal lobe of humans have been shown to be crucial for the recognition process, and they are selectively activated by different views of known individuals or objects. However, how single neurons could implement such a sparse and explicit code is unknown and almost impossible to investigate experimentally. Hippocampal CA1 pyramidal neurons could be instrumental in this process. Here, in an extensive series of simulations with realistic morphologies and active properties, we demonstrate how n radial (ob…
The self-organizing consciousness
2003
We propose that the isomorphism generally observed between the representations composing our momentary phenomenal experience and the structure of the world is the end-product of a progressive organization that emerges thanks to elementary associative processes that take our conscious representations themselves as the stuff on which they operate, a thesis that we summarize in the concept of Self-Organizing Consciousness (SOC).
Auditory discrimination profiles of speech sound changes in 6-year-old children as determined with the multi-feature MMN paradigm.
2009
Objective: A linguistic multi-feature mismatch negativity (MMN) paradigm with five types of changes (vowel, vowel-duration, consonant, frequency (F0), and intensity) in Finnish syllables was used to determine speech-sound discrimination in 17 normally-developing 6-year-old children. The MMNs for vowel and vowel-duration were also recorded in an oddball condition in order to compare the two paradigms. Similar MMNs in the two paradigms would suggest that they tap the same processes. This would promote the usefulness of the more time-efficient multi-feature paradigm for future studies in children. Methods: MMNs to five deviant types were recorded in the multi-feature paradigm in which these de…
Inhibition of adult hippocampal neurogenesis disrupts contextual learning but spares spatial working memory, long-term conditional rule retention and…
2009
Neurogenesis in the adult dentate gyrus (DG) of the hippocampus has been implicated in neural plasticity and cognition but the specific functions contributed by adult-born neurons remain controversial. Here, we have explored the relationship between adult hippocampal neurogenesis and memory function using tasks which specifically require the participation of the DG. In two separate experiments several groups of rats were exposed to fractionated ionizing radiation (two sessions of 7 Gy each on consecutive days) applied either to the whole brain or focally, aiming at a region overlying the hippocampus. The immunocytochemical assays showed that the radiation significantly reduced the expressio…
Lesion load may predict long-term cognitive dysfunction in multiple sclerosis patients
2015
Background: Magnetic Resonance Imaging (MRI) techniques provided evidences into the understanding of cognitive impairment (CIm) in Multiple Sclerosis (MS). Objectives: To investigate the role of white matter (WM) and gray matter (GM) in predicting long-term CIm in a cohort of MS patients. Methods: 303 out of 597 patients participating in a previous multicenter clinical-MRI study were enrolled (49.4% were lost at follow-up). The following MRI parameters, expressed as fraction (f) of intracranial volume, were evaluated: cerebrospinal fluid (CSF-f), WM-f, GM-f and abnormal WM (AWM-f), a measure of lesion load. Nine years later, cognitive status was assessed in 241 patients using the Symbol Dig…
Early handling effect on female rat spatial and non-spatial learning and memory
2014
This study aims at providing an insight into early handling procedures on learning and memory performance in adult female rats. Early handling procedures were started on post-natal day 2 until 21, and consisted in 15 min, daily separations of the dams from their litters. Assessment of declarative memory was carried out in the novel-object recognition task; spatial learning, reference- and working memory were evaluated in the Morris water maze (MWM). Our results indicate that early handling induced an enhancement in: (1) declarative memory, in the object recognition task, both at 1h and 24h intervals; (2) reference memory in the probe test and working memory and behavioral flexibility in the…