Semantic Memory

We examined the hypothesis that formal education and literacy impact the richness and precision of semantic knowledge but not the organization of semantic categories and basic mechanisms of access to them. In Experiment 1, adults of varying levels of formal education were presented with semantic fluency tests and a superordinate naming task. Experiment 2 examined the impact of reading proficiency on adults of varying degrees of literacy. They were presented with simple semantic, alternating semantic and phonemic fluency tasks, as well as with literacy-related, reasoning and memory tests. Fluency was analyzed in terms of overall performance, sequential order and speed of responses. Despite lower performance, illiterates and adults with null or limited formal education displayed taxonomic clustering and retrieval by semantic subcategory, as did participants with higher formal education levels. Yet, formal education and literacy slightly speed up access to categories, probably providing useful cues for generating category exemplars.

■ Studies of semantic dementia and repetitive TMS have sug- gested that the bilateral anterior temporal lobes (ATLs) underpin a modality-invariant representational hub within the semantic system. However, it is not clear whether all ATL subregions contribute in the same way. We utilized distortion-corrected fMRI to investigate the pattern of activation in the left and right ATL when participants performed a semantic decision task on auditory words, environmental sounds, or pictures. This showed that the ATL is not functionally homogeneous but is more graded. Both left and right ventral ATL (vATL) responded to all modalities in keeping with the notion that this region underpins multimodality semantic processing. In addition, there were graded differences across the hemispheres. Semantic processing of both picture and environmental sound stimuli was associated with equivalent bilateral vATL activation, whereas auditory words generated greater activation in left than right vATL. This graded specialization for auditory stimuli would appear to reflect the input from the left superior ATL, which responded solely to semantic decisions on the basis of spoken words and environmental sounds, suggesting that this region is specialized to auditory stimuli. A final noteworthy result was that these regions were activated for domain level decisions to singly presented stimuli, which appears to be incompatible with the hypotheses that the ATL is dedicated (a) to the representation of specific entities or (b) for combinatorial semantic processes. ■

■ Most contemporary theories of semantic memory assume that concepts are formed from the distillation of information arising in distinct sensory and verbal modalities. The neural basis of this distillation or convergence of information was the focus of this study. Specifically, we explored two commonly posed hypotheses: (a) that the human middle temporal gyrus (MTG) provides a crucial semantic interface given the fact that it interposes auditory and visual processing streams and (b) that the anterior temporal region-especially its ventral surface (vATL)-provides a critical region for the multimodal integration of information. By utilizing distortion-corrected fMRI and an established semantic association assessment (commonly used in neuropsychological investigations), we compared the activation patterns observed for both the verbal and nonverbal versions of the same task. The results are consistent with the two hypotheses simultaneously: Both MTG and vATL are activated in common for word and picture semantic processing. Additional planned, ROI analyses show that this result follows from two principal axes of convergence in the temporal lobe: both lateral (toward MTG) and longitudinal (toward the anterior temporal lobe). ■

Most contemporary theories of semantic memory assume that concepts are formed from the distillation of information arising in distinct sensory and verbal modalities. The neural basis of this distillation or convergence of information was the focus of this study. Specifically, we explored two commonly posed hypotheses: (a) that the human middle temporal gyrus (MTG) provides a crucial semantic interface given the fact that it interposes auditory and visual processing streams and (b) that the anterior temporal region—especially its ventral surface (vATL)—provides a critical region for the multimodal integration of information. By utilizing distortion-corrected fMRI and an established semantic association assessment (commonly used in neuropsychological investigations), we compared the activation patterns observed for both the verbal and nonverbal versions of the same task. The results are consistent with the two hypotheses simultaneously: Both MTG and vATL are activated in common for wo...

Introduction: Semantic memory is impaired in mild cognitive impairment (MCI). Two main hypotheses about this finding are debated and refer to the degradation of stored knowledge versus the impairment of semantic access mechanisms. The aim of our study is to evaluate semantic impairment in MCI versus healthy subjects (HS) by an experiment evaluating semantic priming. Methods: We enrolled 27 MCI and 20 HS. MCI group were divided, according to follow up, into converters-MCI and non converters-MCI. The semantic task consisted of 108 pairs of words, 54 of which were semantically associated. Stimuli were presented 250 or 900 ms later the appearance of the target in a randomized manner. Data were analyzed using factorial ANOVA. Results: Both HS and MCI answered more quickly for word than for non-word at both stimulus onset asynchrony (SOA) intervals. At 250 ms, both MCI and HS experienced a shorter time of response for related-word than for unrelated words (priming effect), while only the ...

The present paper describes two attempts to replicate a recent study of ours in the semantic priming domain . In that study, we observed that semantic priming for forward associates (e.g., panda-bear) completely evaporated when participants' working memory was taxed, whereas backward (e.g., baby-stork) and symmetric associates (e.g., cat-dog) showed no ill-effects of a secondary task. This was the case for relatively long and short stimulus onset asynchronies (i.e., 1,200 ms and 200 ms, respectively). The results thus suggested that prospective target activation is, contrary to what some theories of semantic memory posit, not an automatic process. However, the two replication studies reported here cast serious doubt on this conclusion. A Bayesian analysis of all the available data indicated that there is at least substantial evidence for a priming effect in every condition, except for forward associates in the short SOA condition. The null hypothesis is still supported in the latter condition, though the replication studies weakened the evidence for a null effect. The theoretical implications of these findings are discussed.

The present paper describes two attempts to replicate a recent study of ours in the semantic priming domain . In that study, we observed that semantic priming for forward associates (e.g., panda-bear) completely evaporated when participants' working memory was taxed, whereas backward (e.g., baby-stork) and symmetric associates (e.g., cat-dog) showed no ill-effects of a secondary task. This was the case for relatively long and short stimulus onset asynchronies (i.e., 1,200 ms and 200 ms, respectively). The results thus suggested that prospective target activation is, contrary to what some theories of semantic memory posit, not an automatic process. However, the two replication studies reported here cast serious doubt on this conclusion. A Bayesian analysis of all the available data indicated that there is at least substantial evidence for a priming effect in every condition, except for forward associates in the short SOA condition. The null hypothesis is still supported in the latter condition, though the replication studies weakened the evidence for a null effect. The theoretical implications of these findings are discussed.

Decline in semantic cognition in early stages of Parkinson’s disease (PD) is a leading risk factor for future dementia, yet the underlying neural mechanisms are not understood. The present study addressed this gap by investigating the functional connectivity of regions involved in semantic recollection. We further examined whether microtubule-associated protein tau (MAPT) risk variants, which may accelerate cognitive decline, altered the strength of regional functional connections. Cognitively normal PD and healthy elder controls underwent fMRI while performing a fame-discrimination task, which activates the semantic network. Analyses focused on disturbances in fame-modulated functional connectivity in PD for regions that govern semantic recollection and interrelated processes. Group differences were found in multiple connectivity features, which were reduced into principal components that reflected the strength of fame-modulated regional couplings with other brain areas. Despite th...

Intuitively, deriving meaning from an abstract image is a uniquely human, idiosyncratic experience. Here we show that, despite having no universally recognised lexical association, abstract images spontaneously elicit specific concepts conveyed by words, with a consistency akin to that of concrete images. We presented a group of naïve participants with abstract picture-word pairs construed as 'related' or 'unrelated' according to a preliminary norming procedure conducted with different participants. Surprisingly, the naïve participants with no prior exposure to the abstract images or any hints regarding their possible meaning, displayed a reaction time priming effect for 'related' versus 'unrelated' picture-word pairs. Critically, this behavioural priming effect, and an associated decrease in N400 mean amplitude indexing semantic priming, both correlated significantly with the degree of relatedness established in the preliminary norming procedure. Given that ratings and electrophysiological measures were obtained in different groups of individuals, our results show that abstract images evoke consistent meaning across observers, as has been shown in the case of music. Abstract images, such as a works of art, are a powerful means of eliciting individualized emotional reactions and general impressions in the observer 1-3 . Yet, it is currently unknown how abstract images activate brain processes associated with meaning. Here, we used a simple picture-word semantic priming paradigm to examine whether abstract images are systematically linked to specific abstract concepts. Semantic priming typically refers to the automatic processing advantage observed for words that are preceded by semantically related content . In event-related potentials (ERPs), semantic priming is reflected by a modulation of N400 mean amplitude. The N400 is a negative deflection peaking between 350-500 ms post stimulus onset with a frontal-central to central-parietal scalp distribution, with unrelated stimulus pairs eliciting more negative N400 amplitudes than related ones . A substantial literature documents 'N400 effects' in online linguistic analysis, but the effect is also robust to modality changes between context and target word 8 . Thus, picture-word priming experiments reliably show a processing advantage for target concrete words (e.g., dog) when the preceding context is congruent with the target word (e.g., a picture of a dog) 9,10 , consistent with the widely accepted theory that concrete concepts are represented by a rich network of visual-verbal representations 11 . Whereas concrete images provide a visual referent for concrete concepts, analogous representations underpinning abstract images are less well understood. We do know that when faced with an initially uninterpretable image, the visual system is driven to bind correlated features in an attempt to create the illusion of unitary objects . Indeed, abstract images depicted in artworks, for example, often comprise 'supernormal' stimuli -a composite caricature of the viewer's previous visual experiences-to excite form areas in the brain more strongly than natural stimuli 15 . Even abstract images can therefore represent concrete concepts, but to our knowledge no previous study has examined whether abstract images also spontaneously elicit specific abstract concepts. Here, we tested whether abstract images semantically prime abstract concepts. We measured participants' N400 responses to target words preceded by an abstract picture, in which picture-word pairs had been previously categorized as 'related' or 'unrelated' on the basis of ratings provided by a different group of participants (Fig. ). Whilst the semantic representations of abstract concepts are traditionally conceptualized as linguistic , recent theorizing emphasizes the rich, multi-contextual array of sensory as well as linguistic episodic traces that give rise to concepts such as dread, beauty, fury, and enlightenment . Assuming that undefinable forms presented in abstract images can also partially represent the sensory-visual experiences of abstract concepts, we hypothesized that 'related' picture-word pairs would elicit shorter RTs and reduced N400 amplitudes compared with 'unrelated' pictures. Alternatively, if regularities in ratings are underpinned by subjective, re-evaluative processing, we expected that any systematic trend in the initial rating study would not carry over to online measures of semantic processing collected in a different group of participants.

Background: Creativity is a fundamental cognitive skill enabling the generation of original and effective ideas. While research has focused on creative idea generation, relatively little is known about creative idea evaluation, particularly from a metacognitive perspective. Understanding how knowledge structures relate to metacognitive processes that accompany creative thinking can further elucidate its complexity.
Methods: Using the relatedness judgment task, we constructed participants’ (N = 106) semantic memory networks. These networks provide individual-level measures such as network integration (efficiency), local connectivity, and community structure. These metrics were related to participants’ performance in the alternative uses task (AUT), which was used to assess both creative performance and participants’ subjective judgments of the originality of their responses.
Results: Objective originality was predicted by semantic memory networks that were broadly connected and avoided tightly knit clusters. In contrast, originality judgments were predicted by semantic memory networks that
were highly integrated and efficient. These findings suggest a dissociation between objective originality performance and individuals’ self-assessments of originality. Finally, the number of ideas generated in the AUT was a consistent and strong predictor of both creative performance and individuals’ self-assessments of originality.
Conclusions: Our findings reveal how different aspects of semantic memory structure contribute to creative thinking and metacognitive judgments.

Background: Creativity is a fundamental cognitive skill enabling the generation of original and effective ideas. While research has focused on creative idea generation, relatively little is known about creative idea evaluation, particularly from a metacognitive perspective. Understanding how knowledge structures relate to metacognitive processes that accompany creative thinking can further elucidate its complexity. Methods: Using the relatedness judgment task, we constructed participants' (N = 106) semantic memory networks. These networks provide individual-level measures such as network integration (efficiency), local connectivity, and community structure. These metrics were related to participants' performance in the alternative uses task (AUT), which was used to assess both creative performance and participants' subjective judgments of the originality of their responses. Objective originality was predicted by semantic memory networks that were broadly connected and avoided tightly knit clusters. In contrast, originality judgments were predicted by semantic memory networks that were highly integrated and efficient. These findings suggest a dissociation between objective originality performance and individuals' selfassessments of originality. Finally, the number of ideas generated in the AUT was a consistent and strong predictor of both creative performance and individuals' self-assessments of originality. Our findings reveal how different aspects of semantic memory structure contribute to creative thinking and metacognitive judgments.

To understand a dialogue, we need to know the topics that are being discussed. This enables us to integrate our knowledge of what was said previously to interpret the current dialogue. This study involved a large-scale behavioral experiment conducted online and a separate fMRI experiment, both testing human participants. In both, we selectively manipulated knowledge about the narrative content of dialogues presented in short videos. The clips were scenes from situation comedies that were split into two parts. The speech in the part 1 clips could either be presented normally or spectrally rotated to render it unintelligible. The part 2 clips that concluded the scenes were always presented normally. The behavioral experiment showed that knowledge of the preceding narrative boosted memory for the part 2 clips as well as increased the intersubject semantic similarity of recalled descriptions of the dialogues. The fMRI experiment replicated the finding that prior knowledge improved memory for the conclusions of the dialogues. Furthermore, prior knowledge strengthened temporal intersubject correlations in brain regions including the left angular gyrus and inferior frontal gyrus. Together, these findings show that (1) prior knowledge constrains the interpretation of a dialogue to be more similar across individuals; and (2), consistent with this, the activation of brain regions involved in semantic control processing is also more similar between individuals who share the same prior knowledge. Processing in these regions likely supports the activation and integration of prior knowledge, which helps people to better understand and remember dialogues as they unfold.

Despite the well-documented observation of odor identification deficits in schizophrenia, less is known about where the disruption in the process of correctly identifying an odor occurs. This study aimed to determine the potential moderating effects of semantic processing on the observed olfactory dysfunction in schizophrenia. Schizophrenia patients and healthy comparison subjects completed two versions of the University of Pennsylvania Smell Identification Test (UPSIT): an uncued free-response version and the standard multiple-choice paradigm, as well as three semantic measures: The Boston Naming Test, Animal Naming, and Pyramids and Palm Tree Test. Schizophrenia patients yielded significantly lower scores than the comparison group on the standard UPSIT and on semantic measures. No relationship was observed between olfactory and semantic task performance in patients. These data suggest that odor identification deficits may not be primarily due to semantic processing deficits in schizophrenia.

Hyperspace Analog to Language" (HAL ; peuvent être qualifiés d'abstractifs (Tiberghien, 1997) car ils modélisent le résultat d'une généralisation sémantique sur un ensemble d'épisodes d'apprentissage. Ces modèles analysent statistiquement la distribution de mots dans de larges corpus textuels pour élaborer un espace sémantique dans lequel chaque mot est représenté par un vecteur. L'objectif de cet article est de décrire ces deux modèles en les comparant. Nous montrons que ces modèles sont capables de prédire des résultats d'amorçage sémantique et qu'ils peuvent être couplés à des modèles de compréhension tels que Construction-Intégration (Kintsch, 1988) pour simuler les activités psychologiques d''accès à la signification, de prédication et de construction d'une représentation mentale cohérente d'un texte.

A computational model of children's semantic memory is built from the Latent Semantic Analysis (LSA) of a multisource child corpus. Three tests of the model are described, simulating a vocabulary test, an association test and a recall task. For each one, results from experiments with children are presented and compared to the model data. Adequacy is correct, which means that this simulation of children's semantic memory can be used to simulate a variety of children's cognitive processes.

Les modèles "Latent Semantic Analysis" (LSA ; Landauer et Dumais, 1997) et "Hyperspace Analog to Language" (HAL ; Lund et Burgess, 1996) peuvent être qualifiés d'abstractifs (Tiberghien, 1997) car ils modélisent le résultat d'une généralisation sémantique sur un ensemble d'épisodes d'apprentissage. Ces modèles analysent statistiquement la distribution de termes dans de larges corpus textuels pour élaborer un espace sémantique dans lequel chaque terme est représenté par un vecteur. L'objectif de cet article est de décrire ces deux modèles en les comparant. Nous montrons que ces modèles sont capables de prédire des résultats d'amorçage sémantique et qu'ils peuvent être couplés à des modèles de compréhension tels que Construction-Intégration (Kintsch, 1988) pour simuler l'accès à la signification, la prédication et la construction d'une représentation mentale cohérente d'un texte.

Neuropsychological and activation studies on the neural correlates of abstract and concrete words have produced contrasting results. The present study explores the anatomical substrates of abstract/concrete words in 22 brain-damaged patients with a single vascular lesion either in the right or left hemisphere. One hundred and twenty (60 concrete and 60 abstract) noun triplets were used for a semantic similarity judgment task. We found a significant interaction in word type × group since left temporal brain-damaged patients performed significantly better with concrete than abstract words. Lesion mapping of patients with predominant temporal damage showed that the left superior and middle temporal gyri and the insula were the areas of major overlapping, while the anterior portion of the left temporal lobe was generally spared. Errors on abstract words mainly concerned (although at a non-significant level) semantically associate targets, while in the case of concrete words, coordinate targets were significantly more impaired than associate ones. Our results suggest that the left superior and middle temporal gyri and the insula are crucial regions in processing abstract words. They also confirm the hypothesis of a semantic similarity vs. associative organization of concrete and abstract concepts.

Neuropsychological and activation studies on the neural correlates of abstract and concrete words have produced contrasting results. The present study explores the anatomical substrates of abstract/concrete words in 22 brain-damaged patients with a single vascular lesion either in the right or left hemisphere. One hundred and twenty (60 concrete and 60 abstract) noun triplets were used for a semantic similarity judgment task. We found a significant interaction in word type × group since left temporal brain-damaged patients performed significantly better with concrete than abstract words. Lesion mapping of patients with predominant temporal damage showed that the left superior and middle temporal gyri and the insula were the areas of major overlapping, while the anterior portion of the left temporal lobe was generally spared. Errors on abstract words mainly concerned (although at a non-significant level) semantically associate targets, while in the case of concrete words, coordinate targets were significantly more impaired than associate ones. Our results suggest that the left superior and middle temporal gyri and the insula are crucial regions in processing abstract words. They also confirm the hypothesis of a semantic similarity vs. associative organization of concrete and abstract concepts.

Recent neuropsychological and neurophysiological studies have suggested that the neural correlates of idiom processing are predominantly located in the left Brodmann's area (BA) 22 and, to some extent, in the prefrontal cortex. The present study explores the temporal dynamics of left prefrontal and temporal cortex in idiom processing by using repetitive transcranial magnetic stimulation (rTMS) in normal subjects. Forty-five opaque highly familiar idioms and 45 literal sentences were used. Forty-three subjects completed 5 blocks of 18 trials (9 idioms, 9 literal sentences) corresponding to 4 stimulation conditions (left prefrontal, left temporal, vertex, no-stimulation baseline). Each subject was assigned to one of three groups, which differed in the timing of stimulation delivery. A selective impairment in accuracy for idioms was found when rTMS was applied to the prefrontal and temporal cortex 80 ms after picture presentation, confirming the role of these regions in this task. Moreover, rTMS to the prefrontal cortex, but not to the temporal cortex, continued to affect the performance with idiomatic sentences at the later time of 120 ms. The results seem to suggest that the prefrontal region is involved in both the retrieval of the figurative meaning from semantic memory and the monitoring of the response by inhibiting alternative interpretations when a picture-matching task is used.

We investigated the representation and breakdown of verb knowledge employing different syntactic and semantic classes of verbs in a group of individuals with probable Alzheimer's Disease (pAD). In an action naming task with coloured photographs Standardized stimuli and procedures for investigating the retrieval of lexical and conceptual knowledge for action. Memory and Cognition, 25(4), 543-569. ), pAD individuals were impaired for naming actions compared to objects. Verb tense was also affected, with simple-past (e.g., chopped) being more difficult to name than the gerundial form (e.g., chopping). Employing action-naming with short movies depicting events and states, we contrasted three verb classes based on their hypothetical structural and semantic/conceptual properties: argument structure, thematic structure, and conceptual templates. The three classes were: causatives (peel), verbs of perception (hear), and verbs of motion (run) Overall, results suggest that individuals with pAD are selectively impaired for verb tense and thematic assignment, but not conceptual-template complexity. Methodologically, we also show that dynamic scenes are more ecologically valid than static scenes to probe verb knowledge in AD.

We used fMRI in 35 healthy participants to investigate how two neighbouring subregions in the lateral anterior temporal lobe (LATL) contribute to semantic matching and object naming. Four different levels of processing were considered: (A) recognition of the object concepts; (B) search for semantic associations related to object stimuli; (C) retrieval of semantic concepts of interest; and (D) retrieval of stimulus specific concepts as required for naming. During semantic association matching on picture stimuli or heard object names, we found that activation in both subregions was higher when the objects were semantically related (mug-kettle) than unrelated (car-teapot). This is consistent with both LATL subregions playing a role in (C), the successful retrieval of amodal semantic concepts. In addition, one subregion was more activated for object naming than matching semantically related objects, consistent with (D), the retrieval of a specific concept for naming. We discuss the implications of these novel findings for cognitive models of semantic processing and left anterior temporal lobe function.

Objective. Activation of semantic networks is indexed by the N400 effect. We used a twin study design to investigate whether N400 effect abnormalities reflect genetic/trait liability or are related to psychopathological processes in schizophrenia.Methods. We employed robust linear regression to compare N400 and behavioral priming effects across 36 monozygotic twin pairs (6 pairs concordant for schizophrenia/schizoaffective disorder, 11 discordant pairs, and 19 healthy control pairs) performing a lexical decision task. Moreover, we examined the correlation between Brief Psychiatric Rating Scale (BPRS) score and the N400 effect and the influence of medication status on this effect.Results. Regression yielded a significant main effect of group on the N400 effect only in the direct priming condition (p=0.003). Indirect condition and behavioral priming effect showed no significant effect of group. Planned contrasts with the control group as a reference group revealed that affected concor...

The organization of semantic information in the brain has been mainly explored through category-based models, on the assumption that categories broadly reflect the organization of conceptual knowledge. However, the analysis of concepts as individual entities, rather than as items belonging to distinct superordinate categories, may represent a significant advancement in the comprehension of how conceptual knowledge is encoded in the human brain. Here, we studied the individual representation of thirty concrete nouns from six different categories, across different sensory modalities (i.e., auditory and visual) and groups (i.e., sighted and congenitally blind individuals) in a core hub of the semantic network, the left angular gyrus, and in its neighboring regions within the lateral parietal cortex. Four models based on either perceptual or semantic features at different levels of complexity (i.e., low- or high-level) were used to predict fMRI brain activity using representational simi...

How conceptual knowledge is represented in the human brain remains to be determined. To address the differential role of low-level sensory-based and high-level abstract features in semantic processing, we combined behavioral studies of linguistic production and brain activity measures by functional magnetic resonance imaging in sighted and congenitally blind individuals while they performed a property-generation task with concrete nouns from eight categories, presented through visual and/or auditory modalities. Patterns of neural activity within a large semantic cortical network that comprised parahippocampal, lateral occipital, temporo-parieto-occipital and inferior parietal cortices correlated with linguistic production and were independent both from the modality of stimulus presentation (either visual or auditory) and the (lack of) visual experience. In contrast, selected modality-dependent differences were observed only when the analysis was limited to the individual regions wit...

Semantic memory has been studied from various fields. The first models emerged from cognitive psychology from the hand of the division proposed by Tulving between semantic and episodic memory. Over the past thirty years there have been parallel developments in the fields of psycholinguistics, cognitive psychology and cognitive neuropsychology. The present work is to review the contributions that have emerged within the neuropsychology to the study of semantic memory and to present an updated overview of the points of consensus. First, it is defined the term "semantics" conceptually within the field of neuropsychology. Then, there is a dichotomy that passes through both psychological and neuropsychological models on semantic memory: the existence of modals versus amodal representations. Third, there are  developed the main theoretical models in neuropsychology that emerged in an attempt to explain categoryspecific semantic deficits. Finally, more robust contributions and po...

Under adverse listening conditions, prior linguistic knowledge about the form (i.e., phonology) and meaning (i.e., semantics) help us to predict what an interlocutor is about to say. Previous research has shown that accurate predictions of incoming speech increase speech intelligibility, and that semantic predictions enhance the perceptual clarity of degraded speech even when exact phonological predictions are possible. In addition, working memory (WM) is thought to have specific influence over anticipatory mechanisms by actively maintaining and updating the relevance of predicted vs. unpredicted speech inputs. However, the relative impact on speech processing of deviations from expectations related to form and meaning is incompletely understood. Here, we use MEG to investigate the cortical temporal processing of deviations from the expected form and meaning of final words during sentence processing. Our overall aim was to observe how deviations from the expected form and meaning modulate cortical speech processing under adverse listening conditions and investigate the degree to which this is associated with WM capacity. Results indicated that different types of deviations are processed differently in the auditory N400 and Mismatch Negativity (MMN) components. In particular, MMN was sensitive to the type of deviation (form or meaning) whereas the N400 was sensitive to the magnitude of the deviation rather than its type. WM capacity was associated with the ability to process phonological incoming information and semantic integration. -Mismatch Negativity amplitude reflects the difficulty in phonological sensory perception.

Several experiments carried out with a subset of patients with temporal lobe epilepsy have demonstrated normal memory performance at standard delays of recall (i.e. minutes to hours) but impaired performance over longer delays (i.e. days or weeks), suggesting altered long-term consolidation mechanisms. These mechanisms were specifically investigated in a group of five adult-onset pharmaco-sensitive patients with temporal lobe epilepsy, exhibiting severe episodic memory complaints despite normal performance at standardized memory assessment. In a first experiment, the magnitude of autobiographical memory loss was evaluated using retrograde personal memory tasks based on verbal and visual cues. In both conditions, results showed an unusual U-shaped pattern of personal memory impairment, encompassing most of the patients' life, sparing however, periods of the childhood, early adulthood and past several weeks. This profile was suggestive of a long-term consolidation impairment of personal episodes, adequately consolidated over 'short-term' delays but gradually forgotten thereafter. Therefore, in a subsequent experiment, patients were submitted to a protocol specifically devised to investigate short and long-term consolidation of contextually-bound experiences (episodic memory) and context-free information (semantic knowledge and single-items). In the short term (1 h), performance at both contextually-free and contextually-bound memory tasks was intact. After a 6-week delay, however, contextually-bound memory performance was impaired while contextually-free memory performance remained preserved. This effect was independent of task difficulty and the modality of retrieval (recall and recognition). Neuroimaging studies revealed the presence of mild metabolic changes within medial temporal lobe structures. Taken together, these results show the existence of different consolidation systems within declarative memory. They suggest that mild medial temporal lobe dysfunction can impede the building and stabilization of episodic memories but leaves long-term semantic and single-items mnemonic traces intact.

Nicotinic mechanisms may play a role in the cognitive deficits of Parkinson's disease (PD). Recently, on a cognitively demanding strategy-based priming task, nicotine selectively affected controlled semantic processing in young adult non-smokers as reported by Holmes et al. (International Journal of Neuropsychopharmacology 11, 389-399, 2008). Such controlled semantic processing is compromised in PD. This study investigated the effects of acute transdermal nicotine on controlled semantic processing in nonsmokers with PD (n=10) and non-smoking matched controls (n=16) using a strategy-based semantic priming paradigm. Transdermal nicotine patches (7 mg/24 h) were administered in a double-blind, placebo-controlled, crossover design. Participants were instructed to expect target words from specified semantic categories based on the primes, while unexpected targets were also presented. Priming conditions included those concurring with trained expectations (expected-related and expected-unrelated), those which did not (unexpected-related and unexpected-unrelated), and neutral-baseline conditions. Controls evidenced significant expectancy effects (i.e. reaction-time differences for expected vs. unexpected conditions) under both drug states. An expectancy effect was not evident for PD under placebo due to a lack of reaction-time slowing for unexpected conditions. However, under nicotine an expectancy effect was present for PD at a level comparable to controls. Overall the findings indicate that nicotine can improve impaired controlled semantic processing in PD possibly via enhanced expectancy or inhibitory mechanisms.

Identifying beneficial foods in the environment, while avoiding ingesting something toxic is a crucial task humans face on a daily basis. Here we directly examined adults’ implicit and explicit safety evaluations of the same foods presented with different degrees of processing, ranging from unprocessed (raw) to processed (cut or cooked). Moreover, we investigated whether individual characteristics (e.g., Body Mass Index, food neophobia and hunger) modulated their evaluations. We hypothesized that adults would associate the processed form of a food with safety more than its unprocessed form since processing techniques, which are ubiquitously applied in different cultures, often reduce the toxicity of foods, and signal previous human intervention and intended consumption. Adults (N = 109, 43 females) performed an implicit Go/No-Go association task (GNAT) online, assessing the association between safety attributes and food images differing on their degree of processing; both unfamiliar...

The aim of this experiment was to investigate the postural response to specific types of long-term memory (episodic vs. semantic) in young adults performing an unperturbed upright stance. Although a similar level of steadiness (mean distance) was observed, dual tasking induced a higher velocity, more energy in the higher frequency range (power spectral density), and less regularity (sample entropy) compared with a simple postural task. Moreover, mean velocity was always greater in the semantic than in the episodic task. The differences in postural control during dual tasking may result from the types of processes involved in the memory task. Findings suggest a spatial process sharing between posture and episodic memory.

Objective-Impairment in odor naming ability and in verbal and visual semantic networks raised the hypothesis of a breakdown in the semantic network for odors in Alzheimer's disease (AD). The current study addressed this hypothesis. Method-Twenty-four individuals, half patients with probable AD and half control participants, performed triadic-similarity judgments for odors and colors, separately, which, utilizing the multidimensional scaling (MDS) technique of individual difference scaling analysis (INDSCAL), generated two-dimensional configurations of similarity. The abilities to match odors and colors with written name labels were assessed to investigate disease-related differences in ability to identify and conceptualize the stimuli. In addition, responses on attribute-sorting tasks, requiring the odor and color perceptions to be categorized as one polarity of a certain dimension, were obtained to allow for objective interpretation of the MDS spatial maps. Results-Whereas comparison subjects generated spatial maps based predominantly on relatively abstract characteristics, AD patients classified odors on perceptual characteristics. AD patients' maps did also show disorganized groupings and loose associations between odors. Their normal configurations for colors imply that the patients were able to comprehend the task per se. The data for label matching and for attribute sorting provide further evidence for a disturbance in semantic odor memory in AD. The patients performed poorer than controls on both these odor tasks, implying that the ability to identify and/or conceptualize odors is impaired in AD. The results provide clear evidence for deterioration of the structure of semantic knowledge for odors in AD.

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Autobiographical memories in young and elderly normal subjects are drawn mostly from the recent past but elderly subjects relate a second peak of memories from early adulthood. Memory for remote past public events is relatively preserved in dementia, possibly reflecting integrity of semantic relative to episodic memory. We examined recall of specific, consistent autobiographical episodes in Alzheimer's disease (AD) in response to cue words. Patients and control subjects drew most memories from the recent 20 years: episode age related to anterograde memory function but not subject age or dementia. Subjects also related a secondary peak of memories from early adulthood; episode age related to subject age and severity of dementia. The results suggest that preferential recall of memories from early adulthood is based on the salience of retrieval cues, altered by age and dementia, superimposed on a temporal gradient of semantic memory. Further, AD shows behavioural similarity to norm...

The hippocampus has classically been associated with episodic memory, but is sometimes also recruited during semantic memory tasks, especially for the skilled exploration of familiar information. Cognitive control mechanisms guiding semantic memory search may benefit from the set of cognitive processes at stake during musical training. Here, we examined using functional magnetic resonance imaging, whether musical expertise would promote the top-down control of the left inferior frontal gyrus (LIFG) over the generation of hippocampally based goal-directed thoughts mediating the familiarity judgment of proverbs and musical items. Analyses of behavioral data confirmed that musical experts more efficiently access familiar melodies than non-musicians although such increased ability did not transfer to verbal semantic memory. At the brain level, musical expertise specifically enhanced the recruitment of the hippocampus during semantic access to melodies, but not proverbs. Additionally, hippocampal activation contributed to speed of access to familiar melodies, but only in musicians. Critically, causal modeling of neural dynamics between LIFG and the hippocampus further showed that top-down excitatory regulation over the hippocampus during familiarity decision specifically increases with musical expertise -an effect that generalized across melodies and proverbs. At the local level, our data show that musical expertise modulates the online recruitment of hippocampal response to serve semantic memory retrieval of familiar melodies. The reconfiguration of memory network dynamics following musical training could constitute a promising framework to understand its ability to preserve brain functions.

La memoria semántica es un tipo de memoria a largo plazo que permite acceder a recuerdos de significados de los conceptos, a la comprensión de dichos recuerdos y a la disposición de otro tipo de conocimiento que se basa en ideas y conocimientos generales. Desde su conceptualización se afirmaba que, con el paso de los años, este tipo de memoria no sufría deterioro, sin embargo, estudios recientes afirman que pueden existir disminuciones asociadas al envejecimiento en algunas tareas relacionadas con este tipo de memoria. Nuestro objetivo es comprobar si la memoria semántica aumenta ejercitándola de manera específica con ejercicio físico o con tareas de estimulación cognitiva. Se ha diseñado un estudio cuasi experimental con medida pretest y postest en dos tiempos. Los grupos experimentales están conformados por los asistentes a los talleres de Neurogym y Fisiogym del programa Actíva-te con SABIEX y el grupo control se encuentra formado por alumnos

Anticholinergic drug use is common in older adults and has been related to increased dementia risk. This suggests that users of these drugs may experience accelerated cognitive decline. So far, however, longitudinal data on this topic are absent and the available evidence is inconclusive with respect to effects on specific cognitive domains due to suboptimal control of confounding variables. We investigated whether anticholinergic medication use is associated with cognitive decline over 6 years in a population-based study of older adults (aged 60-90; n = 1473) without dementia. We found that users (n = 29) declined more on episodic memory over 6 years compared to nonusers (n = 1418). These results were independent of age, sex, education, overall drug intake, physical activity, depression, cardiovascular risk burden, and cardiovascular disease. By contrast, anticholinergic drug use was unrelated to performance in processing speed, semantic memory, short-term memory, verbal fluency, a...

The lexical-semantic relatedness effect supposes different activation in the semantic memory of related versus unrelated word-pairs. Semantically related pairs are considered to result in a larger spread of activation as the activation of concept nodes is dependent on shared lexical-semantic features of concepts. The increased activation of concepts in the semantic memory in individuals with schizophrenia is found to be, faster spreading and lacking in inhibition in relation to healthy control subjects. The aim of this study was to examine whether the lexical-semantic relatedness effect influences processing in individuals with early course psychosis by utilizing an explicit semantic matching task with 0ms SOA (Stimulus Onset Asynchrony) to analyse the strategy-free automatic spreading activation process. Overall, the patient group had lower accuracy and longer reaction times compared with healthy subjects, as well as better accuracy for related word-pairs and longer reaction times are for unrelated word-pairs. In clinical practice, the determination of language classifiers for early course psychosis could potentially enable the creation of reliable diagnostic markers and instruments for identifying the population with an elevated risk ofdeveloping disorders within a spectrum of schizophrenia, and predicting the course of the disorder.

Sex differences exist for several cognitive tasks and estrogen has been suggested to influence these differences. Eighteen men and 18 women were matched on age and estradiol level. Potential sex differences were assessed in episodic memory, semantic memory, verbal fluency, problem solving, and visuospatial ability. Significant sex differences, favoring women, were found for tasks assessing episodic memory. Correlations between estradiol level and cognitive performance were significant for face recognition in females. Since sex differences remained in verbal episodic memory tasks and face recognition despite matched levels of estradiol, circulating estradiol does not appear to be of paramount consequence for observed sex differences in episodic memory.

Individuals in industrialized societies frequently include processed foods in their diet. However, overconsumption of heavily-processed foods leads to imbalanced calorie intakes as well as negative health consequences and environmental impacts. In the present study, normal-weight healthy individuals were recruited in order to test whether associative learning (Evaluative Conditioning, EC) could strengthen the association between food-types (minimally-processed and heavily-processed foods) and concepts (e.g., healthiness), and whether these changes would be reflected at the implicit associations, at the explicit ratings and in behavioral choices. A semantic congruency task with Electroencephalography recordings was used to examine the neural signature of newly acquired food. The accuracy after EC towards minimally-processed food (MP-food) in the SC task significantly increased, indicating strengthened associations between MP-food and the concept of healthiness through EC. At neural l...

The hallmark of Alzheimer's disease (AD) is declarative memory loss, but deficits in semantic fluency are also observed. We assessed how semantic fluency relates to cortical atrophy to identify specific regions that play a role in the loss of access to semantic information. Whole-brain structural magnetic resonance imaging (MRI) data were analyzed from 9 Normal Control (NC)(M=76.7, SD=5.6), 40 Mild Cognitive Impairment (MCI) (M=74.4, SD=8.6), and 10 probable AD (M=72.4, SD=8.0) subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI). They all were administered the Category Fluency (CF) animals and vegetables tests. Poorer semantic fluency was associated with bilateral cortical atrophy of the inferior parietal lobule (Brodman areas (BA) 39 and 40) and BA 6, 8, and 9 in the frontal lobe, as well as BA 22 in the temporal lobe. More diffuse frontal associations were seen in the left hemisphere involving BA 9, 10, 32, 44, 45, and 46. Additional cortical atrophy was seen in the temporoparietal (BA 37) and the right parastriate (BA 19, 18) cortices. Associations were more diffuse for performance on vegetable fluency than animal fluency. The permutation-corrected map-wise significance for CF animals was pcorrected=0.01 for the left hemisphere, and pcorrected=0.06 for the right hemisphere. The permutation-corrected map-wise significance for CF vegetables was pcorrected=0.009 for the left hemisphere, and pcorrected=0.03 for the right hemisphere. These results demonstrate the profound effect of cortical atrophy on semantic fluency. Specifically, tapping into semantic knowledge involves the frontal lobe in addition to the language cortices of the temporoparietal region.

The purpose of the present study was to investigate different memory systems among children of different school ages. Ninety children who attend schools within the Rio de Janeiro municipality school system, ages 6 to 10 years, were studied. The study excluded children with learning disabilities. All children underwent a neuropsychological evaluation. A two-way analysis of variance revealed significant gender differences in the free delay episodic memory. Age differences were found for the free delay episodic memory and recognition on the Rey Auditory Verbal Learning Test (RAVLT) as well as the recall of the Rey Figure . Semantic memory correlated with Semantic Verbal Fluency. Working Memory as measured by Digit Span subtest of the WISC correlated with the first list learning of the RAVLT. Overall, study results indicated a lower performance among 6-year-old children and gender differences in children 8 and 10 years of age. Data are consistent with the literature and show a distinction in the evolution of different memory systems throughout life.

Event-related potentials (ERPs) can provide valuable information about cognitive capabilities in severely braindamaged patients. This study examined 120 patients with severe brain damage using event related potentials ERPs (N 400) to gain information about their remaining semantic processing capabilities and to contribute to differential diagnosis. Patients were classified into three diagnostic groups: patients in vegetative state (VS), patients in near vegetative state (NEVS) and patients not in vegetative state (NOVS). N400 ERPs were analyzed on an individual basis. All three groups could be differentiated by N400. While VS-patients as a group were least likely to show N400, some VS-patients (approx. 12%) showed clear semantic N400 potentials as an indication of semantic processing capabilities. Patients in NEVS showed significantly more intact semantic capabilities (76.74%) than the VS-group despite little clinical differences between the two groups. Thus, ERPs provide valuable information about patients with brain injury whose clinical conditions often do not allow a true assessment of their cognitive capabilities. Given these findings, we would espouse that both ethical and legal debate should take into account results of ERP studies of such patients.

Objective: A majority of BCI systems, enabling communication with patients with locked-in syndrome, are based on electroencephalogram (EEG) frequency analysis (e.g., linked to motor imagery) or P300 detection. Only recently, the use of event-related brain potentials (ERPs) has received much attention, especially for face or music recognition, but neuro-engineering research into this new approach has not been carried out yet. The aim of this study was to provide a variety of reliable ERP markers of visual and auditory perception for the development of new and more complex mind-reading systems for reconstructing the mental content from brain activity. Methods: A total of 30 participants were shown 280 color pictures (adult, infant, and animal faces; human bodies; written words; checkerboards; and objects) and 120 auditory files (speech, music, and affective vocalizations). This paradigm did not involve target selection to avoid artifactual waves linked to decision-making and response preparation (e.g., P300 and motor potentials), masking the neural signature of semantic representation. Overall, 12,000 ERP waveforms × 126 electrode channels (1 million 512,000 ERP waveforms) were processed and artifact-rejected. Results: Clear and distinct category-dependent markers of perceptual and cognitive processing were identified through statistical analyses, some of which were novel to the literature. Results are discussed from the view of current knowledge of ERP functional properties and with respect to machine learning classification methods previously applied to similar data. The data showed a high level of accuracy (p ≤ 0.01) in the discriminating the perceptual categories eliciting the various electrical potentials by statistical analyses. Therefore, the ERP markers identified in this study could be significant tools for optimizing BCI systems [pattern recognition or artificial intelligence (AI) algorithms] applied to EEG/ERP signals.