1. |
- Arshamian, Artin, et al.
(author)
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The functional neuroanatomy of odor evoked autobiographical memories cued by odors and words
- 2013
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 51:1, s. 123-131
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Journal article (peer-reviewed)abstract
- Behavioral evidence indicates that odor evoked autobiographical memories (OEAMs) are older, more emotional, less thought of and induce stronger time traveling characteristics than autobiographical memories (AMs) evoked by other modalities. The main aim of this study was to explore the neural correlates of AMs evoked by odors as a function of retrieval cue. Participants were screened for specific OEAMs and later presented with the odor cue and its verbal referent in an fMRI paradigm. Because the same OEAM was retrieved across both cue formats (odor and word), potential cue dependent brain activations were investigated. The overall results showed that odor and word cued OEAMs activated regions typically associated with recollection of autobiographical information. Although no odors were presented, a verbal cuing of the OEAMs activated areas associated with olfactory perception (e.g., piriform cortex). However, relative to word cuing, an odor cuing of OEAMs resulted in more activity in MTL regions such as the parahippocampus, and areas involved in visual vividness (e.g., occipital gyrus and precuneus). Furthermore, odor cues activated areas related to emotional processing, such as limbic and tempopolar regions significantly more. In contrast, word cues relative to odor cues recruited a more widespread and bilateral prefrontal activity. Hippocampus activity did not vary as function of the remoteness of the memory, but recollection of OEAMs from the 1st vs the 2nd decade of life showed specific activation in the right OFC, whereas the 2nd reflected a higher activation in the left inferior frontal gyrus.
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2. |
- Bellander, M, et al.
(author)
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Preliminary evidence that allelic variation in the LMX1A gene influences training-related working memory improvement
- 2011
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In: NEUROPSYCHOLOGIA. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 49:7, s. 1938-1942
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Journal article (peer-reviewed)abstract
- LMX1A is a transcription factor involved in the development of dopamine (DA)-producing neurons in midbrain. Previous research has shown that allelic variations in three LMX1A single nucleotide polymorphisms (SNPs) were related to risk of Parkinson's disease (PD), suggesting that these SNPs may influence the number of mesencephalic DA neurons. Prompted by the established link between striatal DA functions and working memory (WM) performance, we examined two of these SNPs in relation to the ability to benefit from 4 weeks of WM training. One SNP (rs4657412) was strongly associated with the magnitude of training-related gains in verbal WM. The allele linked to larger gains has previously been suggested to be associated with higher dopaminergic nerve cell density. No differential gains of either SNP were observed for spatial WM, and the genotype groups were also indistinguishable in tests of attention, interference control, episodic memory, perceptual speed, and reasoning for both SNPs. This pattern of data is in agreement with previous findings from our group, suggesting that cognitive effects of DA-related genes may be more easily detected in a training context than for single-assessment performance scores.
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5. |
- Domellöf, Erik, 1970-, et al.
(author)
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Handedness in preterm born children : a systematic review and a meta-analysis
- 2011
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 49:9, s. 2299-2310
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Journal article (peer-reviewed)abstract
- It has been proposed that left and/or non-right handedness (NRH) is over-represented in children with a history of preterm birth because such births are associated with a greater incidence of insult to the brain. We report an approximate two-fold increase in left and/or non-right handedness based on a systematic search of the literature from 1980 to September 2010 for English-language articles reporting handedness status in preterm children compared with fullterm controls either as a main focus of the study or as a secondary finding. In total, thirty articles met the inclusion criteria. However, there was a great variation between the included studies in terms of objectives, population characteristics, sample size and methodologies used. While the majority of studies reported a higher incidence of NRH in preterm than fullterm children, this was not a consistent finding. A quality assessment was made to explore the differences in overall study quality and handedness assessment methodology between studies. A random-effects model meta-analysis was then performed to estimate the accumulated effect of preterm birth on handedness (18 studies; 1947 cases and 8170 controls). Preterm children displayed a significantly higher occurrence of NRH than fullterm children (odds ratio [OR]: 2.12; 95% confidence interval [CI]: 1.59–2.78). Sources of heterogeneity were investigated by supplementary meta-analyses considering studies with high or low overall and handedness assessment quality. Publication bias was assessed by Egger’s test of the intercept and Duvall and Tweedie’s trim-and-fill method. The outcomes of these procedures did not jeopardize the overall finding of reliably increased OR for NRH in preterm children. The present review suggests that a preterm birth is indeed associated with a greater than two-fold likelihood of NRH. Several studies also explored the relationship between handedness and neuropsychological functioning (cognition mainly) with an array of methods. Although not without disagreement, this association was found to be concordant. Studying handedness in preterm children, therefore, is a potentially important index of hemispheric organization and cognitive and sensory–motor functions following neurodevelopmental disturbance.
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6. |
- Elsner, Claudia, et al.
(author)
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The motor cortex is causally related to predictive eye movements during action observation
- 2013
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 51:3, s. 488-492
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Journal article (peer-reviewed)abstract
- We examined the hypothesis that predictive gaze during observation of other people's actions depends on the activation of corresponding action plans in the observer. Using transcranial magnetic stimulation and eye-tracking technology we found that stimulation of the motor hand area, but not of the leg area, slowed gaze predictive behavior (compared to no TMS). This result shows that predictive eye movements to others' action goals depend on a somatotopical recruitment of the observer's motor system. The study provides direct support for the view that a direct matching process implemented in the mirror-neuron system plays a functional role for real-time goal prediction.
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7. |
- Falck-Ytter, Terje, et al.
(author)
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Human infants orient to biological motion rather than audiovisual synchrony
- 2011
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 49:7, s. 2131-2135
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Journal article (peer-reviewed)abstract
- Both orienting to audiovisual synchrony and to biological motion are adaptive responses. The ability to integrate correlated information from multiple senses reduces processing load and underlies the perception of a multimodal and unified world. Perceiving biological motion facilitates filial attachment and detection of predators/prey. In the literature, these mechanisms are discussed in isolation. In this eye-tracking study, we tested their relative strengths in young human infants. We showed five-month-old infants point-light animation pairs of human motion, accompanied by a soundtrack. We found that audiovisual synchrony was a strong determinant of attention when it was embedded in biological motion (two upright animations). However, when biological motion was shown together with distorted biological motion (upright animation and inverted animation, respectively), infants looked at the upright animation and disregarded audiovisual synchrony. Thus, infants oriented to biological motion rather than multimodally unified physical events. These findings have important implications for understanding the developmental trajectory of brain specialization in early human infancy.
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10. |
- Himmelbach, Marc, et al.
(author)
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20 years later : A second look on DF’s motor behaviour
- 2012
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 50:1, s. 139-144
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Journal article (peer-reviewed)abstract
- The so-called action vs. perception model represents one of the currently dominating models addressing visual processing in primates. One of the crucial cornerstones of the action vs. perception model of visual processing is the dissociation of impaired perception versus intact visuomotor control in neurological patients with visual form agnosia (VFA). In fact, virtually all evidence related to VFA supporting the model was reported from only one patient: patient D.F. Through the last two decades D.F. became as important as only very few other exemplar cases in the neurosciences. However, a large corpus of experiments with this individual used methods that were insufficient to reveal less obvious impairments on a single subject level. We reanalysed the data of D.F. and identified basic visuomotor impairments that had been overlooked so far. Our reanalysis underlines the fact that the widespread and popular presentation of strong dissociations between distinct visual systems seems to be exaggerated.
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11. |
- Jacobs, S, et al.
(author)
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Neglect: a multisensory deficit?
- 2012
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In: Neuropsychologia. - : Elsevier BV. - 1873-3514 .- 0028-3932. ; 50:6, s. 1029-1044
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Journal article (peer-reviewed)
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12. |
- Kauppi, Karolina, 1985-, et al.
(author)
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Decreased medial temporal lobe activation in BDNF 66Met allele carriers during memory encoding
- 2013
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 51:12, s. 2462-2468
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Journal article (peer-reviewed)abstract
- The Met allele of the Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has been associated with impaired activity-dependent secretion of BDNF protein and decreased memory performance. Results from imaging studies relating Val66Met to brain activation during memory processing have been inconsistent, with reports of both increased and decreased activation in the Medial Temporal Lobe (MTL) in Met carriers relative to Val homozygotes. Here, we extensively studied BDNF Val66Met in relation to brain activation and white matter integrity as well as memory performance in a large imaging (n=194) and behavioral (n=2229) sample, respectively. Functional magnetic resonance imaging (fMRI) was used to investigate MTL activation in healthy participants in the age of 55–75 years during a face-name episodic encoding and retrieval task. White matter integrity was measured using diffusion tensor imaging.BDNF Met allele carriers had significantly decreased activation in the MTL during encoding processes, but not during retrieval processes. In contrast to previous proposals, the effect was not modulated by age and the polymorphism was not related to white matter integrity. Met carriers had lower memory performance than Val homozygotes, but differences were subtle and not significant. In conclusion, the BDNF Met allele has a negative influence on MTL functioning, preferentially during encoding processes, which might translate into impaired episodic memory function.
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13. |
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14. |
- Lövdén, Martin, et al.
(author)
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Experience-dependent plasticity of white-matter microstructure extends into old age
- 2010
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 48:13, s. 3878-3883
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Journal article (peer-reviewed)abstract
- Experience-dependent alterations in the human brain's white-matter microstructure occur in early adulthood, but it is unknown whether such plasticity extends throughout life. We used cognitive training, diffusion-tensor imaging (DTI), and structural MRI to investigate plasticity of the white-matter tracts that connect the left and right hemisphere of the frontal lobes. Over a period of about 180 days, 20 younger adults and 12 older adults trained for a total of one hundred and one 1-h sessions on a set of three working memory, three episodic memory, and six perceptual speed tasks. Control groups were assessed at pre- and post-test. Training affected several DTI metrics and increased the area of the anterior part of the corpus callosum. These alterations were of similar magnitude in younger and older adults. The findings indicate that experience-dependent plasticity of white-matter microstructure extends into old age and that disruptions of structural interhemispheric connectivity in old age, which are pronounced in aging, are modifiable by experience and amenable to treatment.
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15. |
- Makin, Alexis D J, et al.
(author)
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Coherent illusory contours reduce microsaccade frequency.
- 2011
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In: Neuropsychologia. - : Elsevier BV. - 1873-3514 .- 0028-3932. ; 49:9, s. 2798-801
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Journal article (peer-reviewed)abstract
- Synchronized high-frequency gamma band oscillations (30-100 Hz) are thought to mediate the binding of single visual features into whole-object representations. For example, induced gamma band oscillations (iGBRs) have been recorded ∼ 280 ms after the onset of a coherent Kanizsa triangle, but not after an incoherent equivalent shape. However, several recent studies have provided evidence that the EEG-recorded iGBR may be a by-product of small saccadic eye movements (microsaccades). Considering these two previous findings, one would hypothesis that there should be more microsaccades following the onset of a coherent Kanizsa triangle. However, we found that microsaccade rebound rate was significantly higher after an incoherent triangle was presented. This result suggests that microsaccades are not a reliable indicator of perceptual binding, and, more importantly, implies that iGBR cannot be universally produced by ocular artefacts.
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16. |
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17. |
- Pantzar, Alexandra, et al.
(author)
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Interactive effects of KIBRA and CLSTN2 polymorphisms on episodic memory in old-age unipolar depression
- 2014
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 62, s. 137-142
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Journal article (peer-reviewed)abstract
- The KIBRA (rs17070145) C-allele and the CLSTN2 (rs6439886) T-allele have both been associated with poorer episodic memory performance. Given that episodic memory is affected in depression, we hypothesized that the combination of these risk alleles would be particularly detrimental to episodic memory performance in depressed persons. In the population-based SNAC-K study, 2170 participants (>= 60 years) without dementia (DSM-IV criteria) and antidepressant pharmacotherapy were clinically examined and diagnosed following ICD-10 criteria for unipolar depression, and genotyped for KIBRA and CLSTN2. Participants were categorized according to unipolar depression status (yes, no) and genotype combinations (KIBRA: CC, any T; CLSTN2: TT, any C). Critically, a three-way interaction effect showed that the CC/TT genotype combination was associated with poorer episodic recall and recognition performance only in depressed elderly persons, with depressed CC/TT carriers consistently performing at the lowest level. This finding supports the view that effects of genetic polymorphisms on cognitive functioning may be most easily disclosed at suboptimal levels of cognitive ability, such as in old-age depression.
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18. |
- Papenberg, Goran, et al.
(author)
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Higher intraindividual variability is associated with more forgetting and dedifferentiated memory functions in old age
- 2011
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In: Neuropsychologia. - Oxford : Pergamon Press. - 0028-3932 .- 1873-3514. ; 49:7, s. 1879-1888
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Journal article (peer-reviewed)abstract
- Intraindividual trial-to-trial reaction time (RT) variability is commonly found to be higher in clinical populations or life periods that are associated with impaired cognition. In the present study, higher within-person trial-to-trial RT variability in a perceptual speed task is related to more forgetting and dedifferentiation of memory functions in older adults (aged 60-71 years). More specifically, our study showed that individuals in a high-variability group (n=175) forgot more memory scenes over a 1-week retention interval than individuals in the low-variability group (n=174). In contrast, slower RT speed was associated with poorer episodic memory in general, but unrelated to the amount of forgetting. Moreover, results from multiple group latent factor analyses showed that episodic memory and working memory functions were more highly correlated in the high-variability (r=.63) than in the low-variability (r=.25) group. Given that deficits in dopamine (DA) modulation may underlie increases in RT variability, the present findings are in line with (i) recent animal studies implicating DA in long-term episodic memory consolidation and (ii) neurocomputational work linking DA modulation of performance variability to dedifferentiation of cognitive functions in old age.
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19. |
- Pfabigan, D. M., et al.
(author)
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Feelings of helplessness increase ERN amplitudes in healthy individuals
- 2013
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932. ; 51:4, s. 613-621
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Journal article (peer-reviewed)abstract
- Experiencing feelings of helplessness has repeatedly been reported to contribute to depressive symptoms and negative affect. In turn, depression and negative affective states are associated, among others, with impairments in performance monitoring. Thus, the question arises whether performance monitoring is also affected by feelings of helplessness. To this end, after the induction of feelings of helplessness via an unsolvable reasoning task, 37 participants (20 females) performed a modified version of a Flanker task. Based on a previously validated questionnaire, 17 participants were classified as helpless and 20 as not-helpless. Behavioral measures revealed no differences between helpless and not-helpless individuals. However, we observed enhanced Error-Related Negativity (ERN) amplitude differences between erroneous and correct responses in the helpless compared to the not-helpless group. Furthermore, correlational analysis revealed that higher scores of helplessness were associated with increased ERN difference scores. No influence of feelings of helplessness on later stages of performance monitoring was observed as indicated by Error-Positivity (Pe) amplitude. The present study is the first to demonstrate that feelings of helplessness modulate the neuronal correlates of performance monitoring. Thus, even a short-lasting subjective state manipulation can lead to ERN amplitude variation, probably via modulation of mesencephalic dopamine activity.
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20. |
- Preuschhof, Claudia, et al.
(author)
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KIBRA and CLSTN2 polymorphisms exert interactive effects on human episodic memory
- 2010
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 48:2, s. 402-408
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Journal article (peer-reviewed)abstract
- Individual differences in episodic memory are highly heritable. Several studies have linked a polymorphism in the gene encoding the KIBRA protein to episodic memory performance. Results regarding CLSTN2, the gene encoding the synaptic protein calsyntenin 2, have been less consistent, possibly pointing to interactions with other genes. Given that both KIBRA and CLSTN2 are expressed in the medial temporal lobe and have been linked to synaptic plasticity, we investigated whether KIBRA and CLSTN2 interactively modulate episodic memory performance (n=383). We replicated the beneficial effect of the KIBRA T-allele on episodic memory, and discovered that this effect increases with the associative demands of the memory task. Importantly, the memory-enhancing effect of the KIBRA T-allele was boosted by the presence of the CLSTN2 C-allele, which positively affected memory performance in some previous studies. In contrast, the presence of CLSTN2 C-allele led to reduced performance in subjects homozygous for the KIBRA C-allele. Overall, these findings suggest that KIBRA and CLSTN2 interactively modulate episodic memory performance, and underscore the need for delineating the interactive effects of multiple genes on brain and behavior.
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21. |
- Rosander, Kerstin, et al.
(author)
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Predictive gaze shifts elicited during observed and performed actions in 10-month-old infants and adults
- 2011
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In: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 49:10, s. 2911-2917
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Journal article (peer-reviewed)abstract
- We asked whether people's actions are understood by projecting them onto one's own action programs, according to the direct matching hypothesis, and whether this mode of control functions in infants. Adults' and infants' gaze and hand movements were measured in two live situations. The task was either to move an object between two places in the visual field, or to observe the corresponding action performed by another person. When performing the action, infants and adults behaved strikingly similar. Hand and gaze movements were simultaneously initiated and gaze arrived at the goal ahead of the hand. When observing the actions, the initiation of the gaze shift was delayed relative to the observed hand movement in both infants and adults, but it still arrived at the goal ahead of the hand. For both the performance and observation of actions the proactiveness of gaze shifts was associated with saccades ahead of the velocity peak of the hand. The close similarity between adults' and infants' actions when performing the movements and the great advantage of the adults when observing them support the conclusion that one's own motor actions develop ahead of the ability to predict other people's actions.
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22. |
- Rosburg, Timm, et al.
(author)
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Strategic retrieval and retrieval orientation in reality monitoring studied by event-related potentials (ERPs)
- 2013
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In: Neuropsychologia. - : Elsevier BV. - 1873-3514 .- 0028-3932. ; 51:3, s. 557-571
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Journal article (peer-reviewed)abstract
- Reality monitoring requires the differentiation between perceived and imagined events or between our own actions and the actions of others. The role of control processes in reality monitoring is yet not fully understood. In the current event-related potential (ERP) study, we investigated such control processes in the form of retrieval orientation and strategic retrieval of nontarget information. At study, complete or incomplete object words were presented in sentences. Participants had to identify the words as the subject of the sentence (perceive condition) or had to complete them upon presentation of a word fragment (self-generate condition). The participants' memory accuracy was better for generated items than for perceived items, as tested in a subsequent memory exclusion task. Comparison of ERPs to new items between the two test conditions (i.e. assessing retrieval orientation) showed more positive ERPs when generated object names were targeted. Retrieval orientation also modulated the early midfrontal old/new effect: Items of the self- generate condition elicited this effect irrespective of their target/nontarget status, while in response to the less well remembered items of the perceive condition it was only found when these items were defined as targets. Target retrieval (as reflected in the left-parietal old/new effect) occurred in both test conditions, but nontarget retrieval was observed only for generated items (when perceived items were targeted). Current findings indicate that retrieval orientation can modulate familiarity-related processes. The selective occurrence of nontarget retrieval for generated items corroborates the concept that the ease with which nontarget information can be accessed promotes nontarget retrieval.
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23. |
- Rosburg, Timm, et al.
(author)
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Strategic retrieval in a reality monitoring task
- 2011
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In: Neuropsychologia. - : Elsevier BV. - 1873-3514 .- 0028-3932. ; 49, s. 2957-2969
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Journal article (peer-reviewed)abstract
- Abstract in UndeterminedStrategic recollection refers to control processes that allow the retrieval of information that is relevant for a specific situation. These processes can be studied in memory exclusion tasks, which require the retrieval of particular kinds of episodic information. In the current study, we investigated strategic recollection in reality monitoring by event-related potentials (ERPs). Participants studied object words, followed by a picture of the denoted object (perceive condition) or followed by the instruction to imagine such a picture (imagine condition). At test, subjects had to identify words of one study condition and to reject words of the second study condition together with newly presented items. Data analysis showed that object names were better identified when items of the perceive condition were targeted. In this test condition, a left parietal old/new effect (the ERP correlate of recollection) was observed only in response to targets. In contrast, both targets and nontargets elicited this old/new effect when items of the imagine condition were targeted. The magnitude of the left parietal old/new effect to nontargets in this condition (but no other left parietal old/new effect) correlated positively with the discrimination indices of both test condi- tions. In addition, ERPs to targets and nontargets differed at right frontal electrode sites at longer latencies (1500–1800 ms), with more positive ERPs for targets. Findings indicate that subjects retrieved nontarget information in the more difficult task condition, while they relied on target information alone in the less difficult task. This kind of strategic retrieval was not mirrored in other old/new effects. The correlation between the left parietal old/new effect for nontargets in the imagined item target condition and the discrimination indices of both conditions may indicate that the ease of nontarget retrieval, rather than the difficulty of target retrieval, increases the likelihood that nontarget information is actually retrieved.
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24. |
- Rudner, Mary, 1958-, et al.
(author)
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Levels of processing and language modality specificity in working memory
- 2013
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 51:4, s. 656-666
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Journal article (peer-reviewed)abstract
- Neural networks underpinning working memory demonstrate sign language specific components possibly related to differences in temporary storage mechanisms. A processing approach to memory systems suggests that the organisation of memory storage is related to type of memory processing as well. In the present study, we investigated for the first time semantic, phonological and orthographic processing in working memory for sign- and speech-based language. During fMRI we administered a picture-based 2-back working memory task with Semantic, Phonological, Orthographic and Baseline conditions to 11 deaf signers and 20 hearing non-signers. Behavioural data showed poorer and slower performance for both groups in Phonological and Orthographic conditions than in the Semantic condition, in line with depth-of-processing theory. An exclusive masking procedure revealed distinct sign-specific neural networks supporting working memory components at all three levels of processing. The overall pattern of sign-specific activations may reflect a relative intermodality difference in the relationship between phonology and semantics influencing working memory storage and processing.
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25. |
- Salminen-Vaparanta, Niina, et al.
(author)
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Neuronavigated transcranial magnetic stimulation suggests that area V2 is necessary for visual awareness
- 2012
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In: Neuropsychologia. - : Elsevier. - 0028-3932 .- 1873-3514. ; 50:7, s. 1621-1627
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Journal article (peer-reviewed)abstract
- The primary visual cortex (V1) has been shown to be critical for visual awareness, but the importance of other low-level visual areas has remained unclear. To clarify the role of human cortical area V2 in visual awareness, we applied transcranial magnetic stimulation (TMS) over V2 while participants were carrying out a visual discrimination task and rating their subjective awareness. Individual retinotopic maps and modelling of the TMS-induced electric field in V1, V2 and V3d ensured that the electric field was at or under the phosphene threshold level in V1 and V3d, whereas in V2 it was at the higher suppressive level. As earlier shown for the V1, our results imply that also V2 is necessary for conscious visual experience. Visual awareness of stimulus presence was completely suppressed when the TMS pulse was delivered 44-84 ms after the onset of visual stimulus. Visual discrimination and awareness of stimulus features was impaired when the TMS pulse was delivered 44-104 ms after the visual stimulus onset. These results suggest that visual awareness cannot be generated without an intact V2. (C) 2012 Elsevier Ltd. All rights reserved.
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