Professor Bertram Opitz


Professor in Neuroimaging and Cognitive Neuroscience
+44 (0)1483 689449
28 AC 04

Biography

Areas of specialism

Neuroscience/Neurocognition; Feedback Processing in Educational Contexts; Learning and Memory; Second Language Aqcuisition; Neuroimaging - fMRI/EEG/Neurostimulation

University roles and responsibilities

  • Chair of the Faculty of Health and Medical Sciences Ethics Committee

Research

Research interests

Courses I teach on

Undergraduate

Supervision

Postgraduate research supervision

My publications

Highlights

Learning & Memory

Some publications highlighting the neural underpinnings of successful learning. While the hippocampus seems to be involved in learning the relationship between elements of the same learning event (e.g., a single lecture)  the prefrontal cortex is capable of generalising the commonalities across multiple such events to generate a long-lasting memory of this newly learned knowledge. 

Opitz, B. (2010) Neural binding mechanisms in learning and memory. Neuroscience & Biobehavioral Reviews 34, 1036-1046 doi: 10.1016/j.neubiorev.2009.11.001

Spitzer, B.J., Hanslmayr, S., Opitz, B., Mecklinger, A. & Bäuml, K.-H. (2009) Oscillatory Correlates of Retrieval-Induced Forgetting in Recognition Memory. Journal of Cognitive Neuroscience 21, 976-990. doi:10.1162/jocn.2009.21072

Doeller, C. F., Opitz, B., Krick,C. M., Mecklinger, A. & Reith, W. (2005) Prefrontal-hippocampal dynamics involved in learning regularities across episodes. Cerebral Cortex 15, 1123-1133. doi: 10.1093/cercor/bhh211

Feedback Processing & Cognitive Training

A few papers looking into possibilities to enhance learning. An important aspect that should be looked at is how the information provided by feedback is actually processed in the brain. Here the timing seems of special importance. In addition, training of some cognitive abilities like working memory seems to be beneficial for a broad variety of learning scenarios like second language acquisition

Opitz, B., Ferdinand, N.K. & Mecklinger, A. (2011) Timing matters: The impact of immediate and delayed feedback on artificial language learning. Frontiers in Human Neuroscience 5:8, doi: 10.3389/fnhum.2011.00008

Ferdinand, N. K. & Opitz, B. (2014) Different aspects of performance feedback engage different brain areas: Disentangling the neural correlates of valence and expectancy in feedback processing. Scientific Reports 4, Article number: 5986 doi:10.1038/srep05986.

Opitz, B., Schneiders, J. A., Krick, C. & Mecklinger, A. (2014) Selective Transfer of Visual Working Memory Training on Chinese Character Learning. Neuropsychologia 53, 1-11 doi:10.1016/j.neuropsychologia.2013.10.017

 

Artificial Language Learning

Two papers highlighting that two distinct learning mechanisms concur during the acquisition of a second (artificial) language. Initially, people learn the grammar of a language by judging the similarity of novel sentence in reference to known sentences previously encountered. During the course of learning grammatical rules are abstracted and used more and more effectively.

Opitz, B. & Hofmann, J. (2015) Concurrence of rule- and similarity-based mechanisms in artificial grammar learning. Cognitive Psychology 77, 77–99. doi:10.1016/j.cogpsych.2015.02.003

Opitz, B. & Friederici, A.D. (2003) Interactions of the hippocampal system and the prefrontal cortex in learning language like-rules. NeuroImage 19, 1730-1737. doi: 10.1016/S1053-8119(03)00170-8

Publications

Opitz B (2010) Context-dependent repetition effects on recognition memory., Brain and Cognition 73 (2) pp. 110-118 Elsevier
One widely acknowledged way to improve our memory performance is to repeatedly study the to be learned material. One aspect that has received little attention in past research regards the context sensitivity of this repetition effect, that is whether the item is repeated within the same or within different contexts. The predictions of a neuro-computational model (O'Reilly & Norman, 2002) were tested in an experiment requiring participants to study visual objects either once or three times. Crucially, for half of the repeated objects the study context (encoding task, background color and screen position) remained the same (within context repetition) while for the other half the contextual features changed across repetitions (across context repetition). In addition to behavioral measures, event-related potentials (ERP) were recorded that provide complementary information on the underlying neural mechanisms during recognition. Consistent with dual-process models behavioral estimates (remember/know-procedure) demonstrate differential effects of context on memory performance, namely that recognition judgements were more dependent on familiarity when repetition occurs across contexts. In accordance with these behavioral results ERPs showed a larger early frontal old/new effect for across context repetitions as compared to within context repetitions and single presentations, i.e. an increase in familiarity following repetition across study contexts. In contrast, the late parietal old/new effect, indexing recollection did not differ between both repetition conditions. These results suggest that repetition differentially affects familiarity depending on whether it occurs within the same context or across different contexts.
Kipp KH, Opitz B, Becker M, Hofmann J, Krick C, Gortner L, Mecklinger A (2012) Neural correlates of recognition memory in children with febrile seizures: evidence from functional magnetic resonance imaging., Frontiers in Human Neuroscience 6 Frontiers Research Foundation
Febrile seizures (FS) are assumed to not have adverse long-term effects on cognitive development. Nevertheless, FS are often associated with hippocampal sclerosis which can imply episodic memory deficits. This interrelation has hardly been studied so far. In the current study 13 children who had suffered from FS during infancy and 14 control children (7 to 9-years-old) were examined for episodic and semantic memory with standardized neuropsychological tests. Furthermore, using functional magnetic resonance imaging (fMRI) we studied neuronal activation while the children performed a continuous recognition memory task. The analysis of the behavioral data of the neuropsychological tests and the recognition memory experiment did not reveal any between-group differences in memory performance. Consistent with other studies fMRI revealed repetition enhancement effects for both groups in a variety of brain regions (e.g., right middle frontal gyrus, left parahippocampal gyrus) and a repetition suppression effect in the right superior temporal gyrus. Different neural activation patterns between both groups were obtained selectively within the right supramarginal gyrus (BA 40). In the control group correct rejections of new items were associated with stronger activation than correctly identified old items (HITs) whereas in the FS group no difference occurred. On the background that the right supramarginal gyrus is assumed to mediate a top-down process to internally direct attention toward recollected information, the results could indicate that control children used strategic recollection in order to reject new items (recall-to-reject). In contrast, the missing effect in the FS group could reflect a lack of strategy use, possibly due to impaired recollective processing. This study demonstrates that FS, even with mainly benign courses, can be accompanied by selective modifications in the neural structures underlying recognition memory.
Brod G, Opitz B (2012) Does it really matter? Separating the effects of musical training on syntax acquisition., Frontiers in Psychology 3 Frontiers Research Foundation
The possible transfer of musical expertise to the acquisition of syntactical structures in first and second language has emerged recently as an intriguing topic in the research of cognitive processes. However, it is unlikely that the benefits of musical training extend equally to the acquisition of all syntactical structures. As cognitive transfer presumably requires overlapping processing components and brain regions involved in these processing components, one can surmise that transfer between musical ability and syntax acquisition would be limited to structural elements that are shared between the two. We propose that musical expertise transfers only to the processing of recursive long-distance dependencies inherent in hierarchical syntactic structures. In this study, we taught fifty-six participants with widely varying degrees of musical expertise the artificial language BROCANTO, which allows the direct comparison of long-distance and local dependencies. We found that the quantity of musical training (measured in accumulated hours of practice and instruction) explained unique variance in performance in the long-distance dependency condition only. These data suggest that musical training facilitates the acquisition specifically of hierarchical syntactic structures.
Within the dual-process perspective of recognition memory, it has been claimed that familiarity is sufficient to support recognition of single items, but recollection is necessary for associative recognition of item pairs. However, there are some reports suggesting that familiarity might support associative recognition judgments when the items form an easy to access bound representation. In contrast, recollection seems to be required for the recognition of bindings that might be flexibly rearranged in novel situations. We investigated whether both forms of binding are mediated by different mechanisms as reflected by a qualitatively different spatiotemporal eventrelated potential (ERP) pattern. In a recognition memory experiment, subjects gave old/new judgments to words learned by focusing either on interitem associations or on size relation of word triplets. Results revealed higher hit rates in the relational condition as compared to the associative condition. In addition, the proportion of triplets from which all three items were remembered was significantly larger in the relational condition suggesting that memory retrieval in this condition relies primarily on bound representations of word triplets. The ERP revealed a late parietal old/new effect for both conditions, with relational processing resulting in a greater effect. In contrast, an early frontal old/new effect was solely present in the associative condition. Taken together, these data provide evidence that familiarity might support associative recognition if the associated components are coherently encoded into a bound representation. Recollection might foster the recognition of relational bindings among items. This indicates that the contribution of familiarity and recollection to associative recognition depends on the kind of binding operations performed on the items rather than on the single versus multiple item distinction.
Spitzer B, Hanslmayr S, Opitz B, Mecklinger A, Baeuml K-H (2009) Oscillatory Correlates of Retrieval-induced Forgetting in Recognition Memory, Journal of Cognitive Neuroscience 21 (5) pp. 976-990 Massachusetts Institute of Technology Press (MIT Press)
Retrieval practice on a subset of previously studied material enhances later memory for practiced material but can inhibit memory for related unpracticed material. The present study examines the effects of prior retrieval practice on evoked (ERPs) and induced (oscillatory power) measures of electrophysiological activity underlying recognition of practiced and unpracticed words. Compared to control material, recognition of unpracticed words was characterized by reduced amplitudes of the P2 ERP component and by reduced early (200?400 msec) oscillatory theta power. The reduction in P2 amplitude was associated with decreased evoked theta power but not with decreased theta phase locking (phase-locking index). Recognition of unpracticed material was further accompanied by a reduction in occipital gamma power (>250 msec). In contrast, the beneficial effects of retrieval practice on practiced words were reflected by larger parietal ERP positivity (>500 msec) and by a stronger decrease in oscillatory alpha power in a relatively late time window (>700 msec). The results suggest that the beneficial and detrimental effects of retrieval practice are mediated by different processes. In particular, they suggest that reduced theta (4?7 Hz) and gamma (60?90 Hz) power reflect the specific effects of inhibitory processes on the unpracticed material's memory representation.
Recent functional magnetic resonance imaging (fMRI) evidence shows differential involvement of the inferior frontal gyrus (IFG) and the ventral premotor cortex (PMv) in syntactic processing. Our main goal is to specify the precise role of the PMv in the processing of sequential structures and whether these processes are a necessary prerequisite for the successful acquisition of grammatical structure.
Kipp KH, Opitz B, Becker M, Hofmann J, Krick C, Gortner L, Mecklinger A (2012) Selective modifications in the neural memory network in children with febrile seizures: Evidence from functional magnetic resonance imaging, Frontiers in Human Neuroscience (JANUARY 2012)
Febrile seizures (FS) are assumed to not have adverse long-term effects on cognitive development. Nevertheless, FS are often associated with hippocampal sclerosis which can imply episodic memory deficits. This interrelation has hardly been studied so far. In the current study 13 children who had suffered from FS during infancy and 14 control children (7-9 years old) were examined for episodic and semantic memory with standardized neuropsychological tests. Furthermore, using functional magnetic resonance imaging (fMRI) we studied neuronal activation while the children performed a continuous recognition memory task. The analysis of the behavioral data of the neuropsychological tests and the recognition memory experiment did not reveal any between group differences in memory performance. Consistent with other studies fMRI revealed repetition enhancement effects for both groups in a variety of brain regions (e.g. right middle frontal gyrus, left parahippocampal gyrus) and a repetition suppression effect in the right superior temporal gyrus. Different neural activation patterns between both groups were obtained selectively within the right supramarginal gyrus (BA 40). In the control group correct rejections of new items (CRs) were associated with stronger activation than correctly identified old items (HITs) whereas in the FS group no difference occurred. On the background that the right supramarginal gyrus is assumed to mediate a top-down process to internally direct attention towards recollected information, the results could indicate that control children used strategic recollection in order to reject new items (recall-to-reject). In contrast, the missing effect in the FS group could reflect a lack of strategy use, possibly due to impaired recollective processing. This study demonstrates that FS, even with mainly benign courses, can be accompanied by selective modifications in the neural structures underlying recognition memory. © 2012 Kipp, Opitz, Becker, Hofmann, Krick, Gortner and Mecklinger.
Doeller CF, Opitz B, Krick CM, Mecklinger A, Reith W (2006) Differential hippocampal and prefrontal-striatal contributions to instance-based and rule-based learning, NEUROIMAGE 31 (4) pp. 1802-1816 ACADEMIC PRESS INC ELSEVIER SCIENCE
Opitz B, Ferdinand NK, Mecklinger A (2011) Timing matters: the impact of immediate and delayed feedback on artificial language learning., Frontiers in Human Neuroscience 5 Frontiers Research Foundation
In the present experiment, we used event-related potentials (ERP) to investigate the role of immediate and delayed feedback in an artificial grammar learning (AGL) task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of 1 s. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP) elicited by positive feedback only. The feedback-related negativity (FRN), however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for AGL as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.
Kotz SA, Opitz B, Friederici AD (2007) ERP effects of meaningful and non-meaningful sound processing in anterior temporal patients, RESTORATIVE NEUROLOGY AND NEUROSCIENCE 25 (3-4) pp. 273-284 IOS PRESS
Hauser MF, Hofmann J, Opitz B (2012) Rule and similarity in grammar: their interplay and individual differences in the brain., Neuroimage 60 (4) pp. 2019-2026 Elsevier
Previous research on artificial grammar has indicated that the human ability to classify sentences or letter strings according to grammaticality relies on two types of knowledge. One is a superficial, familiarity-based understanding of a grammar the other is the knowledge of rules and critical features underlying a grammar. The fundamentally different characteristics of these systems permit an analysis of receiver-operating characteristics (ROC), which measures the extent to which each type of knowledge is used in grammaticality judgments. Furthermore, violations of a grammar can be divided into hierarchical and local violations. The present study is the first to combine the use of ROC analyses, fMRI and a grammaticality dichotomy. Based on previous neuroimaging studies, it was hypothesized that judgments based on rule knowledge, as extracted from individual ROC analyses, involve the left inferior frontal gyrus (IFG), whereas similarity would involve right IFG, as well as left hippocampal regions. With regards to violation types, it was hypothesized that hierarchical violations would recruit the opercular part of the left IFG as well as the posterior operculum, whereas local violations would bilaterally activate the premotor cortex (PMC). Results indicated that for greater reliance on rule knowledge, a ventral part of the left PMC was activated for ungrammatical items, whereas other PMC areas show a differentiated response for grammaticality for individuals less reliant on similarity. The right IFG was related to ungrammatical items as a function of similarity. Results are discussed with regards to possible error detection systems and differentiated efficiencies for respective classification strategies.
Ferdinand NK, Mecklinger A, Opitz B (2015) Learning context modulates the processing of expectancy violations, BRAIN RESEARCH 1629 pp. 72-84 ELSEVIER SCIENCE BV
Opitz B, Degner J (2012) Emotionality in a second language: it's a matter of time., Neuropsychologia 50 (8) pp. 1961-1967 Elsevier
The present study investigated the well acknowledged phenomenon of a different sense of emotionality in a person's first (L1) and second language (L2). Event-related potentials were recorded during the reading of pleasant, unpleasant and neutral words in L1 and L2. Enhanced processing of both emotional compared to neutral words was reflected in an amplified early posterior negativity (EPN) about 280?430 ms after word onset. While the EPN did not differ in amplitude between L1 and L2, it was delayed for L2. Interestingly, a better task performance in L2 but not L1 predicted longer delays of the EPN. These results might indicate that the affective valence of L2 words is processed in a less immediate way due to delayed lexical access. This is interpreted in terms of interference in a highly integrated L1/L2 mental lexicon.
Opitz B, Hofmann J (2015) Concurrence of rule- and similarity-based mechanisms in artificial grammar learning, Cognitive Psychology 77 pp. 77-99
© 2015 Elsevier Inc.A current theoretical debate regards whether rule-based or similarity-based learning prevails during artificial grammar learning (AGL). Although the majority of findings are consistent with a similarity-based account of AGL it has been argued that these results were obtained only after limited exposure to study exemplars, and performance on subsequent grammaticality judgment tests has often been barely above chance level. In three experiments the conditions were investigated under which rule- and similarity-based learning could be applied. Participants were exposed to exemplars of an artificial grammar under different (implicit and explicit) learning instructions. The analysis of receiver operating characteristics (ROC) during a final grammaticality judgment test revealed that explicit but not implicit learning led to rule knowledge. It also demonstrated that this knowledge base is built up gradually while similarity knowledge governed the initial state of learning. Together these results indicate that rule- and similarity-based mechanisms concur during AGL. Moreover, it could be speculated that two different rule processes might operate in parallel; bottom-up learning via gradual rule extraction and top-down learning via rule testing. Crucially, the latter is facilitated by performance feedback that encourages explicit hypothesis testing.
Schneiders JA, Opitz B, Krick CM, Mecklinger A (2011) Separating intra-modal and across-modal training effects in visual working memory: an fMRI investigation., Cerebral Cortex 21 (11) pp. 2555-2564 Oxford University Press
Working memory training is a useful tool to examine dissociations between specific working memory processes. Although current models propose a distinction between modality-specific working memory processes, to our knowledge no study has directly examined the effects of visual versus auditory working memory training. Functional magnetic resonance imaging was used to investigate whether visual working memory processes can be trained specifically and whether those effects can be separated from across-modal training effects. We found decidedly larger training gains after visual working memory training compared with auditory or no training on a visual 2-back task. These effects were accompanied by specific training-related decreases in the right middle frontal gyrus arising from visual training only. Likewise, visual and auditory training led to decreased activations in the superior portion of the right middle frontal gyrus and the right posterior parietal lobule. We infer that the combination of effects resulted from increased neural efficiency of intra-modal (visual) processes on the one hand and of across-modal (general control) processes on the other hand. Therefore, visual processes of working memory can be trained specifically, and these effects can be functionally dissociated from alterations in general control processes common to both working memory trainings.
Opitz, Bertram (2012) Selective modifications in the neural memory network in children with febrile seizures: Evidence from functional magnetic resonance imaging, Frontiers in Human Neuroscience (JANUARY 2012)
Febrile seizures (FS) are assumed to not have adverse long-term effects on cognitive development. Nevertheless, FS are often associated with hippocampal sclerosis which can imply episodic memory deficits. This interrelation has hardly been studied so far. In the current study 13 children who had suffered from FS during infancy and 14 control children (7-9 years old) were examined for episodic and semantic memory with standardized neuropsychological tests. Furthermore, using functional magnetic resonance imaging (fMRI) we studied neuronal activation while the children performed a continuous recognition memory task. The analysis of the behavioral data of the neuropsychological tests and the recognition memory experiment did not reveal any between group differences in memory performance. Consistent with other studies fMRI revealed repetition enhancement effects for both groups in a variety of brain regions (e.g. right middle frontal gyrus, left parahippocampal gyrus) and a repetition suppression effect in the right superior temporal gyrus. Different neural activation patterns between both groups were obtained selectively within the right supramarginal gyrus (BA 40). In the control group correct rejections of new items (CRs) were associated with stronger activation than correctly identified old items (HITs) whereas in the FS group no difference occurred. On the background that the right supramarginal gyrus is assumed to mediate a top-down process to internally direct attention towards recollected information, the results could indicate that control children used strategic recollection in order to reject new items (recall-to-reject). In contrast, the missing effect in the FS group could reflect a lack of strategy use, possibly due to impaired recollective processing. This study demonstrates that FS, even with mainly benign courses, can be accompanied by selective modifications in the neural structures underlying recognition memory. © 2012 Kipp, Opitz, Becker, Hofmann, Krick, Gortner and Mecklinger.
Memory enhancement after repeated presentation of to-be-learned material is a wellknown
phenomenon. It has been assumed that the repeated presentation of features
common to a number of specific instances leads to decontextualized facts about the
world, i.e., semantic knowledge. To investigate this issue, subjects studied celebrity faces
along with faces of unknown individuals. Crucially, half of the unknown faces were
repeated within the same study context (background and biographical information)
while for the other half the contextual features changed across repetitions. Celebrity
faces were chosen because they carry with them biographical information. The electrophysiological
correlates of conceptual priming and explicit memory for these faces
were examined. Explicit memory retrieval was associated with the early frontal old/new
effect, the ERP correlate of familiarity, and the late parietal old/new effect, indexing
recollection. Both ERP effects were elicited by celebrity faces and non-famous faces
repeatedly studied in different contexts, whereas non-famous faces repeated in the same
context elicited only the parietal old/new effect. Furthermore, conceptual priming was
indexed by positive brain potentials over fronto-central regions, in addition to faster
reaction times for previously presented faces. Again, a striking similarity between effects
elicited by celebrity faces and non-famous faces repeated in varying contexts was observed.
This indicates that repetition of features across different contexts bears some
similarity to semantic knowledge.
Logographic Chinese differs from alphabetic languages in aspects of orthography and
phonology. While there are different neural networks involved in processing orthography
across these language systems, there is evidence for a common neural network
across languages for auditory phonology. Since lexical tones are phonemically relevant
in Chinese only, learning Chinese phonology should benefit more from auditory than
visual working memory (WM) training and result in activation decreases in its underlying
neural circuitry. We used an n-back WM training procedure to investigate the
differential impact of auditory and visual WM training on phonological proficiency
while Germans learned the phonology of Chinese words. Training-inducedmodulations
in language-related networkswere examined bymeans offMRI. Behavioral data did not
show any transfer from auditory and visual WM training to phonological proficiency
compared to a control group. Brain imaging analyses during pretest revealed activations
in the left medial frontal gyrus, anterior cingulate gyrus and pallidum. Importantly,
volume-of-interest analyses in these regions showed training-induced activation
decreases in the medial frontal gyrus for the auditory training group but not for the
other two groups. These results suggest that the training of auditoryWMleads - even in
the absence of behavioral transfer effects - to more efficient processing within the
left dorsal prefrontal cortex when learning Chinese phonology probably reflecting
facilitated attentional selection of phonetic information in spoken Chinese words.
Schneiders JA, Opitz B, Tang H, Deng Y, Xie C, Li H, Mecklinger A (2012) The impact of auditory working memory training on the fronto-parietal working memory network., Frontiers in Human Neuroscience 6 Frontiers Research Foundation
Working memory training has been widely used to investigate working memory processes. We have shown previously that visual working memory benefits only from intra-modal visual but not from across-modal auditory working memory training. In the present functional magnetic resonance imaging study we examined whether auditory working memory processes can also be trained specifically and which training-induced activation changes accompany theses effects. It was investigated whether working memory training with strongly distinct auditory materials transfers exclusively to an auditory (intra-modal) working memory task or whether it generalizes to a (across-modal) visual working memory task. We used adaptive n-back training with tonal sequences and a passive control condition. The memory training led to a reliable training gain. Transfer effects were found for the (intra-modal) auditory but not for the (across-modal) visual transfer task. Training-induced activation decreases in the auditory transfer task were found in two regions in the right inferior frontal gyrus. These effects confirm our previous findings in the visual modality and extents intra-modal effects in the prefrontal cortex to the auditory modality. As the right inferior frontal gyrus is frequently found in maintaining modality-specific auditory information, these results might reflect increased neural efficiency in auditory working memory processes. Furthermore, task-unspecific (amodal) activation decreases in the visual and auditory transfer task were found in the right inferior parietal lobule and the superior portion of the right middle frontal gyrus reflecting less demand on general attentional control processes. These data are in good agreement with amodal activation decreases within the same brain regions on a visual transfer task reported previously.
Recollection, an effortful process relying on the integrity of a brain network including the hippocampus, is generally required to remember arbitrary associations whereas a simple familiarity signal arising in the perirhinal cortex is sufficient to recognize single items. However, the integration of separate items into a single configuration (unitization) leads to reduced involvement of recollection and greater reliance on familiarity. This seems to imply that unitized associations are processed similar to single items. Here, using functional magnetic resonance imaging, we investigated the effects of unitization as encoding strategy on retrieval processes in a between-group-design. A definition was provided that allows combining two unrelated words into a novel conceptual unit (e.g., milk taxi = a delivery service, which is directly dispatched from a farm). We compared this to an encoding strategy in which the words were studied as parts of a sentence. We included pairs in reversed order at test because reversing a unitized word pair is assumed to disrupt the unit while leaving item familiarity for the single constituents intact. This enabled us to compare recognition memory for novel units and single items. Sentence encoding led to a flexible recruitment of brain areas previously associated with recollection, irrespective of the order of the test pair. Unitization encoding reduced the involvement of the recollection network and specifically engaged regions within the parahippocampal cortex and the medial prefrontal cortex for novel units. In contrast, recognition of reversed pairs involved activation of BA 45 in the left inferior frontal gyrus. This possibly suggests that familiarity for novel units and single items are associated with different brain networks.
Opitz B, Schneiders J, Krick C, Mecklinger A (2014) Selective transfer of visual working memory training on Chinese character learning, NEUROPSYCHOLOGIA 53 pp. 1-11 PERGAMON-ELSEVIER SCIENCE LTD
Kipp KH, Opitz B, Becker M, Hofmann J, Mecklinger A, Krick C, Gortner L (2012) Selective modifications in the neural memory network in children with febrile seizures: Evidence from functional magnetic resonance imaging, Frontiers in Human Neuroscience (JANUARY 2012)
Febrile seizures (FS) are assumed to not have adverse long-term effects on cognitive development. Nevertheless, FS are often associated with hippocampal sclerosis which can imply episodic memory deficits. This interrelation has hardly been studied so far. In the current study 13 children who had suffered from FS during infancy and 14 control children (7-9 years old) were examined for episodic and semantic memory with standardized neuropsychological tests. Furthermore, using functional magnetic resonance imaging (fMRI) we studied neuronal activation while the children performed a continuous recognition memory task. The analysis of the behavioral data of the neuropsychological tests and the recognition memory experiment did not reveal any between group differences in memory performance. Consistent with other studies fMRI revealed repetition enhancement effects for both groups in a variety of brain regions (e.g. right middle frontal gyrus, left parahippocampal gyrus) and a repetition suppression effect in the right superior temporal gyrus. Different neural activation patterns between both groups were obtained selectively within the right supramarginal gyrus (BA 40). In the control group correct rejections of new items (CRs) were associated with stronger activation than correctly identified old items (HITs) whereas in the FS group no difference occurred. On the background that the right supramarginal gyrus is assumed to mediate a top-down process to internally direct attention towards recollected information, the results could indicate that control children used strategic recollection in order to reject new items (recall-to-reject). In contrast, the missing effect in the FS group could reflect a lack of strategy use, possibly due to impaired recollective processing. This study demonstrates that FS, even with mainly benign courses, can be accompanied by selective modifications in the neural structures underlying recognition memory. © 2012 Kipp, Opitz, Becker, Hofmann, Krick, Gortner and Mecklinger.
Evaluating the positive and negative outcomes of our behaviour is important for action selection and learning. Such reinforcement learning has been shown to engage a specific neural circuitry including the mesencephalic dopamine system and its target areas, the striatum and medial frontal cortex, especially the anterior cingulate cortex (ACC). An intensively pursued debate regards the prevailing influence of feedback expectancy and feedback valence on the engagement of these two brain regions in reinforcement learning and their respective roles are far from being understood. To this end, we used a time estimation task with three different types of feedback that allows disentangling the effect of feedback valence and expectancy using functional magnetic resonance imaging (fMRI). Our results show greater ACC activation after unexpected positive and unexpected negative feedback than after expected feedback and by this sensitivity to unexpected events in general irrespective of their valence.
Opitz B, Friederici AD (2007) Neural basis of processing sequential and hierarchical syntactic structures., Hum Brain Mapp 28 (7) pp. 585-592
The psychological processes through which humans learn a language have gained considerable interest over the past years. It has been previously suggested that language acquisition partly relies on a rule-based mechanism that is mediated by the frontal cortex. Interestingly, the actual structure involved within the frontal cortex varies with the kind of rules being processed. By means of functional MRI we investigated the neural underpinnings of rule-based language processing using an artificial language that allows direct comparisons between local phrase structure dependencies and hierarchically structured long-distance dependencies. Activation in the left ventral premotor cortex (PMC) was related to the local character of rule change, whereas long-distance dependencies activated the opercular part of the inferior frontal gyrus (Broca's area (BA) 44). These results suggest that the brain's involvement in syntactic processing is determined by the type of rule used, with BA 44/45 playing an important role during language processing when long-distance dependencies are processed. In contrast, the ventral PMC seems to subserve the processing of local dependencies. In addition, hippocampal activity was observed for local dependencies, indicating that the processing of such dependencies may be mediated by a second mechanism.
Nickels S, Opitz B, Steinhauer K (2013) ERPs show that classroom-instructed late second language learners rely on the same prosodic cues in syntactic parsing as native speakers, Neuroscience Letters 557 (PB) pp. 107-111
The loss of brain plasticity after a 'critical period' in childhood has often been argued to prevent late language learners from using the same neurocognitive mechanisms as native speakers and, therefore, from attaining a high level of second language (L2) proficiency [7,11]. However, more recent behavioral and electrophysiological research has challenged this 'Critical Period Hypothesis', demonstrating that even late L2 learners can display native-like performance and brain activation patterns [17], especially after longer periods of immersion in an L2 environment. Here we use event-related potentials (ERPs) to show that native-like processing can also be observed in the largely under-researched domain of speech prosody - even when L2 learners are exposed to their second language almost exclusively in a classroom setting. Participants listened to spoken sentences whose prosodic boundaries would either cooperate or conflict with the syntactic structure. Previous work had shown that this paradigm is difficult for elderly native speakers, however, German L2 learners of English showed very similar ERP components for on-line prosodic phrasing as well as for prosody-syntax mismatches (garden path effects) as the control group of native speakers. These data suggest that L2 immersion is not always necessary to master complex L2 speech processing in a native-like way. © 2013 Elsevier Ireland Ltd.
Shao H, Weng X, Opitz B, Yang J (2015) Recollection reduces unitised familiarity effect, Memory
Two types of encoding tasks have been employed in previous research to investigate the beneficial effect of unitisation on familiarity-based associative recognition (unitised familiarity effect), namely the compound task and the interactive imagery task. Here we show how these two tasks could differentially engage subsequent recollection-based associative recognition and consequently lead to the turn-on or turn-off of the unitised familiarity effect. In the compound task, participants studied unrelated word pairs as newly learned compounds. In the interactive imagery task, participants studied the same word pairs as interactive images. An associative recognition task was used in combination with the Remember/Know procedure to measure recollection-based and familiarity-based associative recognition. The results showed that the unitised familiarity effect was present in the compound task but was absent in the interactive imagery task. A comparison of the compound and the interactive imagery task revealed a dramatic increase in recollection-based associative recognition for the interactive imagery task. These results suggest that unitisation could benefit familiarity-based associative recognition; however, this effect will be eliminated when the memory trace formed is easily accessed by strong recollection without the need for a familiarity assessment.
Opitz B (2014) Memory function and the hippocampus, The Hippocampus in Clinical Neuroscience 34 pp. 51-59 Karger
There has been a long tradition in memory research of adopting the view of a vital role of the medial temporal lobe and especially the hippocampus in declarative memory. Despite the broad support for this notion, there is an ongoing debate about what computations are performed by the different substructures. The present chapter summarizes several accounts of hippocampal functions in terms of the cognitive processes subserved by these structures, the information processed, and the underlying neural operations. Firstly, the value of the distinction between recollection and familiarity for the understanding of the role the hippocampus plays in memory is discussed. Then multiple lines of evidence for the role of the hippocampus in memory are considered. Cumulating evidence suggests that the hippocampus fosters the binding of disparate cortical representations of items and their spatiotemporal context into a coherent representation by means of a sparse conjunctive neural coding. This association of item and context will then lead to the phenomenological experience of recollection. In contrast, surrounding cortical areas have broader neural coding that provide a scalar signal of the similarity between two inputs (e.g. between the encoding and the retrieval). By this they form the basis of a feeling of familiarity, but also might encode the commonalities between these different inputs. However, a more complete picture of the importance of the hippocampus for declarative memories can only be drawn when the interactions of the medial temporal lobe with other brain areas are also taken into account.
Opitz B (2010) Neural binding mechanisms in learning and memory., Neuroscience and Biobehavioral Reviews 34 (7) pp. 1036-1046 Elsevier
Binding mechanisms are considered as basic cognitive operations, performing different functions in learning and memory. This review will cover two of these binding mechanisms: relational binding of information about stimuli and actions with their spatio-temporal context into a circumscribed cognitive event and representational binding of feature representations common to a number of such events, thereby integrating these representations with existing knowledge and, thus, leading to decontextualized knowledge about the world. I will survey evidence from recent neuropsychological, electrophysiological and neuroimaging studies, including my own work, demonstrating that relational binding operations are performed within the hippocampal system, whereas representational binding is subserved by the surrounding medial-temporal lobe cortex and prefrontal brain areas. I then present examples of conditions that differentially implement both binding mechanisms. Lastly, summarizing the extant literature on binding mechanisms I speculate on whether these binding mechanism operate in a similar way across different cognitive domains or whether they are domain-specific.
Dean PJA, Arikan G, Opitz B, Sterr AM (2017) Potential for use of creatine supplementation following mild traumatic brain injury, Concussion 2 (2) Future Medicine
There is significant overlap between the neuropathology of mild traumatic brain injury (mTBI) and the cellular role of creatine, as well as evidence of neural creatine alterations after mTBI. Creatine supplementation has not been researched in mTBI, but shows some potential as a neuroprotective when administered prior to or after TBI. Consistent with creatine?s cellular role, supplementation reduced neuronal damage, protected against the effects of cellular energy crisis and improved cognitive and somatic symptoms. A variety of factors influencing the efficacy of creatine supplementation are highlighted, as well as avenues for future research into the potential of supplementation as an intervention for mTBI. In particular, the slow neural uptake of creatine may mean that greater effects are achieved by pre-emptive supplementation in at-risk groups.

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