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Autonomous University of Madrid | UAM · Basic Psychology

Accumulating evidence suggests a role for the medial temporal lobe (MTL) in working memory (WM). However, little is known concerning its functional interactions with other cortical regions in the distributed neural network subserving WM. To reveal these, we availed of subjects with MTL damage and characterized changes in effective connectivity whil...

An increasing amount of evidence supports a crucial role for the anterior temporal lobe (ATL) in semantic processing. Critically, a selective disruption of the functional connectivity between left and right ATLs in patients with chronic aphasic stroke has been illustrated. The aim of the current study was to evaluate the consequences that lesions o...

Selective attention mechanisms allow us to focus on information that is relevant to the current behavior and, equally important, ignore irrelevant information. An influential model proposes that oscillatory neural activity in the alpha band serves as an active functional inhibitory mechanism. Recent studies have shown that, in the same way that att...

The accumulation of similar interfering experiences hampers our ability to retrieve information. To reduce interference, pattern separation allows the separation similar memories and build detailed memory representations that are less easily confused. To investigate mnemonic interference, previous research has used a mnemonic discrimination paradig...

Mesial temporal lobe epilepsy (mTLE) is a neurological disorder associated with histopathological changes in different subfields of the hippocampus. These alterations have been associated with memory difficulties. In this study, we tested the hypothesis that these difficulties stem on mnemonic discrimination impairment due to a reduced ability to m...

Pattern separation has been studied in relation to both the retrieval and encoding processesis considered a crucial process that allow humans to store and remember allows us to distinguish among the highly similar items. Within this body of research,and overlapping experiences which constitute our episodic memory. Not only different episodes share...

Ongoing brain activity preceding visual stimulation has been suggested to shape conscious perception. According to the pulsed inhibition framework, bouts of functional inhibition arise in each alpha cycle (every ~100 ms), allowing information to be processed in a pulsatile manner. Consequently, it has been hypothesized that perceptual outcome can b...

Ongoing brain activity preceding visual stimulation has been suggested to shape conscious perception. The underlying mechanisms are still under adebate,lthough alpha oscillations have been pointed out as the main explanatory candidate. According to the pulsed-inhibition framework, bouts of functional inhibition arise in each alpha cycle, allowing i...

Introduction Pattern separation (PS) is a fundamental aspect of memory creation that defines the ability to transform similar memory representations into distinct ones, so they do not overlap when storing and retrieving them. Experimental evidence in animal models and the study of other human pathologies have demonstrated the role of the hippocampu...

There is broad consensus supporting the reciprocal influence of working memory (WM) and attention. Top-down mechanisms operate to cope with either environmental or internal demands. In that sense, it is possible to select an item within the contents of WM to endow it with prioritized access. Although evidence supports that maintaining an item in th...

Two main explanations for memory loss have been proposed. On the one hand, decay theories consider that over time memory fades away. On the other hand, interference theories sustain that when similar memories are encoded, they become more prone to confusion. The interference is greater as the degree of similarity between memories increases, and as...

It has been proposed that alpha oscillations reflect the endogenous modulation of visual cortex excitability. In particular, alpha power increases during the maintenance period in Working Memory (WM) tasks have been interpreted as a mechanism to avoid potential interference of incoming stimuli. In this study we tested whether alpha power was modula...

Brain oscillations are considered to play a pivotal role in neural communication. However, detailed information regarding the typical oscillatory patterns of individual brain regions is surprisingly scarce. In this study we applied a multivariate data-driven approach to create an atlas of the natural frequencies of the resting human brain on a voxe...

Working Memory (WM) is a limited capacity system for storing and processing information, which varies from subject to subject. Several works show the ability to predict the performance of WM with machine learning (ML) methods, and although good prediction results are obtained in these works, ignoring the intersubject variability and the temporal an...

Brain oscillations are considered to play a pivotal role in neural communication. However, detailed information regarding the typical oscillatory patterns of individual brain regions is surprisingly scarce. In this study we applied a multivariate data-driven approach to create an atlas of the natural frequencies of the resting human brain on a voxe...

Purpose: We hypothesized that epilepsy associated with temporal pole encephaloceles (ETPE) could be the consequence and an unrecognized manifestation of idiopathic intracranial hypertension (IIH). To test this hypothesis in patients with ETPEs we evaluated: 1) the frequency of two radiological signs of IIH and 2) whether these patients develop over...

Objective Stereoelectroencephalography (SEEG) is a technique for preoperative evaluation of patients with difficult-to-localise refractory focal epilepsy (DLRFE), enabling the study of deep cortical structures. The procedure, which is increasingly used in international epilepsy centres, has not been fully developed in Spain. We describe our experie...

Decades of research have increased the understanding of the contribution of the anterior temporal lobes (ATLs) to semantic cognition. Nonetheless, whether semantic processing of different types of information show a selective relationship with left and right ATLs, or whether semantic processing in the ATLs is independent of the modality of the inpu...

Objective: Stereoelectroencephalography (SEEG) is a technique for preoperative evaluation of patients with difficult-to-localize refractory focal epilepsy (DLRFE), enabling the study of deep cortical structures. The procedure, which is increasingly used in international epilepsy centres, has not been fully developed in Spain. We describe our experi...

Several lines of research have linked olfactory regions with the pathophysiology of focal epilepsies. Among those regions, the piriform cortex represents the major part of the primary olfactory cortex. According to these data, we raised the hypothesis that in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis exists a...

Visual object naming is a complex cognitive process that engages an interconnected network of cortical regions moving from occipitotemporal to anterior–inferior temporal cortices, and extending into the inferior frontal cortex. Naming can fail for diverse reasons, and different stages of the naming multi‐step process appear to be reliant upon the i...

Selective attention can enhance Working Memory (WM) performance by selecting relevant information, while preventing distracting items from encoding or from further maintenance. Alpha oscillatory modulations are a correlate of visuospatial attention. Specifically, an enhancement of alpha power is observed in the ipsilateral posterior cortex to the l...

Working Memory (WM) maintains flexible representations. Retrospective cueing studies indicate that selective attention can be directed to memory representations in WM improving performance. While most of the work has explored the neural substrates of orienting attention based on a spatial retro-cue, behavioral studies show that a feature other than...

Numerous electrophysiological findings support the notion that selective attention modulates alpha oscillatory activity. Specifically, alpha enhancement and suppression can be dissociated in time and space. It is now accepted that selective attention operates in either the perceptual or the representational environments. Lateralized alpha activity...

Background and purpose: We aimed to determine the correlation between subjective evaluations of mood and cognitive functions by patients and informants, and the findings of a battery of neuropsychological tests. Methods: We analyzed 74 subjects recruited from a general neurology clinic, comprising 37 patients with cognitive complaints and 37 inf...

Objective: Small temporal pole encephalocele (STPE) can be the pathologic substrate of epilepsy in a subgroup of patients with noninformative magnetic resonance imaging (MRI). Herein, we analyzed the clinical, neurophysiologic, and radiologic features of the epilepsy found in 22 patients with STPE, and the frequency of STPE in patients with refrac...

Objective: Naming difficulties are frequently observed in patients with temporal lobe epilepsy (TLE). Although damage/removal of regions of the anterior temporal neocortex including the temporal pole is considered critical for those difficulties, 1 relevant hypothesis proposes that hippocampal damage also has a role. Our aim was to better understa...

Accumulating evidence suggests that visual object understanding involves a rapid feedforward sweep, after which subsequent recurrent interactions are necessary. The extent to which recurrence plays a critical role in object processing remains to be determined. Recent studies have demonstrated that recurrent processing is modulated by increasing sem...

Background: The validity of neuropsychological tests for the differential diagnosis of degenerative dementias may depend on the clinical context. We constructed a series of logistic models taking into account this factor. Methods: We retrospectively analyzed the demographic and neuropsychological data of 301 patients with probable Alzheimer's di...

Naming is considered a left hemisphere function that operates according to a posterior-anterior specificity gradient, with more fine-grained information processed in most anterior regions of the temporal lobe (ATL), including the temporal pole (TP). Word finding difficulties are typically assessed using visual confrontation naming tasks, and have b...

Multi-store models of working memory (WM) have given way to more dynamic approaches that conceive WM as an activated subset of long-term memory (LTM). The resulting framework considers that memory representations are governed by a hierarchy of accessibility. The activated part of LTM holds representations in a heightened state of activation, some o...

Acetylcholine (ACh) is a neuromodulatory transmitter implicated in perception and learning under uncertainty. This study combined computational simulations and pharmaco-electroencephalography in humans, to test a formulation of perceptual inference based upon the free energy principle. This formulation suggests that ACh enhances the precision of bo...

Mesial temporal lobe epilepsy (mTLE) is the most prevalent form of focal epilepsy, and hippocampal sclerosis (HS) is considered the most frequent associated pathological finding. Recent connectivity studies have shown that abnormalities, either structural or functional, are not confined to the affected hippocampus, but can be found in other connect...

Hithertothelong-term memory (LTM)and the working memory (WM) have beenconsidered two completely separate processes because they have been associated with different brain structures (the temporal lobe and prefrontal and parietal areas, respectively). However, recent neuroimaging studies show that the medial temporal lobe (MTL) is involved in WM. The...

Working memory (WM) is the ability to transiently maintain and manipulate internal representations beyond its external availability to the senses. This process is thought to support high level cognitive abilities and been shown to be strongly predictive of individual intelligence and reasoning abilities. While early models of WM have relied on a mo...

It has been reported that mild cognitive impairment (MCI) patients, when compared with controls, show increased activity in different brain regions within the ventral pathway during memory tasks. A key question is whether this profile of increased activity could be useful to predict which patients will develop dementia. Herein, we present profiles...

Two representative subjects at two different stimulation rates (Experiment 1). The figure shows the transient template, the synthetic waveform and the recorded waveform for two subjects in the 7.1 rev/s and 20 rev/s conditions of Experiment 1. (0.55 MB TIF)

Voltage topography for both recorded and synthetic data synchronized to 100 ms (Experiment 2). As figure 8, the figure shows the scalp voltage topographies for the dominant frequency of each condition (rows) and phase angle (columns). In this figure, however, phase angles are referred to the common positive component corresponding to P100 (i.e. 0°...

Synthetic data using the traditional transient template (Experiment 1). A, Traditional template for the transient response. The template was extracted from the isochronic condition with the largest SOA (2.7 rev/s isochronic condition). To remove the influence of subsequent responses (shaded in dark grey), the template comprised a 500 ms time window...

One common criterion for classifying electrophysiological brain responses is based on the distinction between transient (i.e. event-related potentials, ERPs) and steady-state responses (SSRs). The generation of SSRs is usually attributed to the entrainment of a neural rhythm driven by the stimulus train. However, a more parsimonious account suggest...

Theta oscillations in the local field potential of neural ensembles are considered key mediators of human working memory. Theoretical accounts arising from animal hippocampal recordings propose that the phase of theta oscillations serves to instantiate sequential neuronal firing to form discrete representations of items held online. Human evidence...

The present study investigated the binding of verbal and spatial features in immediate memory. In a recent study, we demonstrated incidental and asymmetrical letter-location binding effects when participants attended to letter features (but not when they attended to location features) that were associated with greater oscillatory activity over pref...

Normative data for 884 neurologically normal adults (15-93) are provided for a six-trial administration of Form 1 of the Spanish version of the Verbal Selective Reminding Test (VSRT). Form 2 was also administered to 391 adults (18-87). Age was the most important predictor of performance on all VSRT scores in Forms 1 and 2. Additionally, women and h...

Mild cognitive impairment (MCI) has been considered an intermediate state between healthy aging and dementia. The early damage in anatomical connectivity and progressive loss of synapses that characterize early Alzheimer's disease suggest that MCI could also be a disconnection syndrome. Here, we compare the degree of synchronization of brain signal...

Cognitive processes require a functional interaction between specialized multiple, local and remote brain regions. Although these interactions can be strongly altered by an acquired brain injury, brain plasticity allows network reorganization to be principally responsible for recovery. The present work evaluates the impact of brain injury on functi...

In this study we demonstrated implicit verbal-spatial binding effects that were dependent on the task-relevant feature. We used MEG to measure brain activity underpinning the maintenance of verbal and spatial features in two recognition tasks, based on a letter-location paradigm previously used in binding studies. Both tasks were identical in terms...

The risk of cognitive decline after mesial temporal lobe (MTL) resection in the dominant hemisphere for treatment of epilepsy has been assessed with the intracarotid amytal procedure and functional neuroimaging. In this study we used magnetoencephalography (MEG) to analyze memory profiles in patients with left hippocampal sclerosis (HS). Biomagneti...

Many cognitive abilities involve the integration of information from different modalities, a process referred to as "binding." It remains less clear, however, whether the creation of bound representations occurs in an involuntary manner, and whether the links between the constituent features of an object are symmetrical. We used magnetoencephalogra...

It has been traditionally assumed that medial temporal lobe (MTL) is not required for working memory (WM). However, animal lesion and electrophysiological studies and human neuropsychological and neuroimaging studies have provided increasing evidences of a critical involvement of MTL in WM. Based on previous findings, the central aim of this study...

Biomagnetic responses were recorded from healthy elderly subjects (55-67 years) performing a working memory task during recognition. The objective was to identify differential spatio-temporal brain activity patterns with magnetoencephalography by the presentation of two types of retroactive interference, active and passive. We obtained increased ac...

The objective of this study was to establish whether stimulation at 5 Hz enables immediate words recall. A total of 20 participants received auditory stimulation at 5 Hz-theta, beta-13 Hz frequencies, white noise (WN) and words. The results indicate significant differences in the number of recalled words per day depending on the stimulation frequen...

Objective: To determine whether performing a recognition task under interference conditions produces changes in brain activity pattern compared with the activity seen under conditions of passive interference. Population and methods: Twenty healthy elderly subjects were subjected to magnetoencephalography. In each patient we applied the Wechsler Mem...

Mild cognitive impairment (MCI) patients represent an intermediary state between healthy aging and dementia. MCI activation profiles, recorded during a memory task, have been studied either through high spatial resolution or high temporal resolution techniques. However, little is known about the benefit of combining both dimensions. Here, we invest...

Neuropsychological models of depression highlight temporoparietal hypofunction associated with low emotional arousal in major depressive disorder (MDD). These models were derived from indirect measures such as neuropsychological tests and electroencephalography alpha band power. To determine if high-arousing stimuli directly modulated activity in a...

Most of human cognitive activity involves, to a greater or lesser extent, the integration of information from different modalities, a process also referred to as 'binding'. Although the neural basis of several forms of binding has been extensively investigated, the neurobiological mechanisms of the encoding phase of integration of words and their s...

Objectivesto study the efficacy of combined treatment (anticholinesterase drugs and cognitive stimulation) in improving cognitive function in patients with moderate dementia after a 2-year follow-up.

The presentation of stimuli interfering with the maintenance of previous information makes difficult the subsequent recognition of it. The interference resistance decreases in normal aging, which is evidenced as a worse performance in tasks affecting working memory and that could be related to an executive dysfunction. Our aim was to establish if p...

Subjects with mild cognitive impairment (MCI) are at a higher risk of experiencing Alzheimer disease (AD). Magnetoencephalographic temporoparietal dipole densities of low-frequency activity are good predictors of individuals' cognitive status, and might be a useful tool to investigate the conversion from MCI to AD. To investigate the role of low-fr...

Current theories suggest a role for frontal-striatal circuits in the pathogenesis of attention-deficit/hyperactivity disorder (ADHD). We used magnetoencephalography (MEG) to measure event-related brain activity during a simplified version of the Wisconsin Card Sorting Test in children with DSM-IV combined type ADHD (ADHD-C) or predominantly inatten...

Several studies have shown that pharmacological and cognitive treatments for Alzheimers's disease improve cognitive function for short periods, but fewer studies have evaluated the efficacy of those treatments for longer (2-year) periods. An initial sample of 68 subjects with mild Alzheimer's disease underwent clinical and cognitive evaluation. Aft...

Cognition declines as a function of age. However, some elders could develop more severe status such as mild cognitive impairment (MCI). The aim of this study was the early detection of neurophysiological patterns of brain activity that may predict the possibility of certain subjects to develop MCI. Brain magnetic activity was recorded from 15 healt...