Search results for " Short-Term"
showing 10 items of 173 documents
Age at surgery as a predictor of cognitive improvements in patients with drug-resistant temporal epilepsy
2017
Temporal lobe epilepsy (TLE) surgery is an effective procedure that can produce cognitive changes. However, the prognostic factors related with cognitive outcomes need to be better understood. The aim of the present study is to know if age at surgery is a reliable predictor of verbal memory competence and considering factors such as: hemisphere; type of surgery; pre-surgical seizure frequency; and epilepsy duration. Sixty-one typically dominant patients with drug-resistant TLE (34 with left TLE [L-TLE] and 27 with right TLE [R-TLE]) underwent a neuropsychological assessment before and a year after surgery. Results showed that R-TLE patients had better evolution in short- and long-term verba…
Separable neural bases for subprocesses of recognition in working memory.
2011
Working memory supports the recognition of objects in the environment. Memory models have postulated that recognition relies on 2 processes: assessing the degree of similarity between an external stimulus and memory representations and testing the resulting summed-similarity value against a critical level for recognition. Here, we varied the similarity between samples held in working memory and a probe to investigate these 2 processes with magnetoencephalography. Two separable components matched our expectations: First, from 280 ms after probe onset, clearly nonmatching probes differed from both similar nonmatches and matches over left frontal cortex. At 350--400 ms, these signals evolved i…
Double-decision lexical tasks in thought-disordered schizophrenic patients: a path towards cognitive remediation?
2005
Abstract It has been shown that schizophrenics have certain difficulties in the processing of semantic context. These difficulties have usually been evaluated using lexical decision tasks with semantic priming. In this study, we chose to examine the idea of an abnormality in the early stages of semantic context processing in thought-disordered schizophrenics using two double lexical decision tasks: one with a high (25%) and one with a low (15%) proportion of related words to assess the participants’ competency in controlled and possibly also more automatic context processing. The results obtained in 40 control participants and 40 schizophrenic patients revealed no significant differences in…
Spatial Inferences in Narrative Comprehension: the Role of Verbal and Spatial Working Memory
2016
During the comprehension of narrative texts, readers keep a mental representation of the location of protagonists and objects; a breach in spatial coherence is detected by longer online reading times (consistency effect). We addressed whether these spatial inferences involve verbal or spatial working memory in two experiments, combining the consistency paradigm with selective verbal and spatial working memory concurrent tasks. The first experiment found longer reading times with a concurrent spatial task under imagery instructions (t33 = 2.87, p =.021). The second experiment, under comprehension reading instructions, found effects of verbal interference on reading times and accuracy. With a…
The formation of structurally relevant units in artificial grammar learning
2002
A total of 78 adult participants were asked to read a sample of strings generated by a finite state grammar and, immediately after reading each string, to mark the natural segmentation positions with a slash bar. They repeated the same task after a phase of familiarization with the material, which consisted, depending on the group involved, of learning items by rote, performing a short term matching task, or searching for the rules of the grammar. Participants formed the same number of cognitive units before and after the training phase, thus indicating that they did not tend to form increasingly large units. However, the number of different units reliably decreased, whatever the task that…
Integration of cognitive allocentric information in visuospatial short-term memory through the hippocampus
2005
Visuospatial short-term memory relies on a widely distributed neocortical network: some areas support the encoding process of the visually acquired spatial information, whereas other ares are more involved in the active maintenance of the encoded information. Recently, in a pointing to remembered targets task, it has been shown in healthy subjects that, for memory delays of 5 s, spatial errors are affected also by cognitive allocentric information, i.e., covert spatial information derived from a pure mental representation. We tested the effect of a lesion of the hippocampus on the accuracy of pointing movements toward remembered targets, with memory delays falling in the 0.5-30 s range. The…
Dynamics of brain activity underlying working memory for music in a naturalistic condition
2014
We aimed at determining the functional neuroanatomy of working memory (WM) recognition of musical motifs that occurs while listening to music by adopting a non-standard procedure. Western tonal music provides naturally occurring repetition and variation of motifs. These serve as WM triggers, thus allowing us to study the phenomenon of motif tracking within real music. Adopting a modern tango as stimulus, a behavioural test helped to identify the stimulus motifs and build a time-course regressor of WM neural responses. This regressor was then correlated with the participants' (musicians') functional magnetic resonance imaging (fMRI) signal obtained during a continuous listening condition. In…
Frontal–posterior theta oscillations reflect memory retrieval during sentence comprehension
2015
Abstract Successful working-memory retrieval requires that items be retained as distinct units. At the neural level, it has been shown that theta-band oscillatory power increases with the number of to-be-distinguished items during working-memory retrieval. Here we hypothesized that during sentence comprehension, verbal-working-memory retrieval demands lead to increased theta power over frontal cortex, supposedly supporting the distinction amongst stored items during verbal-working-memory retrieval. Also, synchronicity may increase between the frontal cortex and the posterior cortex, with the latter supposedly supporting item retention. We operationalized retrieval by using pronouns, which r…
Visuospatial learning is fostered in migraine: evidence by a neuropsychological study
2018
Cognitive profile in migraine patients still remains undefined. Contradictory evidence has been provided, with impairments in different cognitive domains, normal cognition, or even better performance compared to healthy controls (HC). The latter is of particular interest considering the evidence of glutamatergic upregulation in migraine, particularly in the visual cortex, and the role of the glutamatergic system in synaptic plasticity and learning. The aim of our study is to compare cognitive performance for visuospatial memory and learning (supraspan modality) between migraineurs without aura (MwoA) and HC. Twenty-one subjects suffering from MwoA and 21 HC were enrolled. Migraineurs during…
Metabolic connectivity as index of verbal working memory
2015
Positron emission tomography (PET) data are commonly analyzed in terms of regional intensity, while covariant information is not taken into account. Here, we searched for network correlates of healthy cognitive function in resting state PET data. PET with [18F]-fluorodeoxyglucose and a test of verbal working memory (WM) were administered to 35 young healthy adults. Metabolic connectivity was modeled at a group level using sparse inverse covariance estimation. Among 13 WM-relevant Brodmann areas (BAs), 6 appeared to be robustly connected. Connectivity within this network was significantly stronger in subjects with above-median WM performance. In respect to regional intensity, i.e., metaboli…