Heiko C. Bergmann | Radboud University Nijmegen (original) (raw)

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Papers by Heiko C. Bergmann

Background: Emotion can either facilitate or impair memory, depending on what, when and how memor... more Background: Emotion can either facilitate or impair memory, depending on what, when and how memory is tested and whether the paradigm at hand is administered as a working memory (WM) or a long-term memory (LTM) task. Whereas emotionally arousing single stimuli are more likely to be remembered, memory for the relationship between two or more component parts (i.e., relational memory) appears to be worse in the presence of emotional stimuli, at least in some relational memory tasks. The current study investigated the effects of both valence (neutral vs. positive vs. negative) and arousal (low vs. high) in an inter-item WM binding and LTM task.

"Increasing evidence suggests a role for the hippocampus not only in long-term memory (LTM) but a... more "Increasing evidence suggests a role for the hippocampus not only in long-term memory (LTM) but also in relational working memory (WM) processes, challenging the view of the hippocampus as being solely involved in episodic LTM. However, hippocampal involvement reported in some neuroimaging studies using “classical” WM tasks may at least partly reflect incidental LTM encoding. To disentangle WM processing and LTM formation we administered a delayed-match-to-sample associative WM task in an event-related fMRI study design. Each trial of the WM task consisted of four pairs of faces and houses, which had to be maintained during a delay of 10 s. This was followed by a probe phase consisting of three consecutively presented pairs; for each pair participants were to indicate whether it matched one of the pairs of the encoding phase. After scanning, an unexpected recognition-memory (LTM) task was administered. Brain activity during encoding was analyzed based on WM and LTM performance. Hence, encoding-related activity predicting WM success in the absence of successful LTM formation could be isolated. Furthermore, regions critical for successful LTM formation for pairs previously correctly processed in WM were analyzed. Results showed that the left parahippocampal gyrus including the fusiform gyrus predicted subsequent accuracy on WM decisions. The right anterior hippocampus and left inferior frontal gyrus, in contrast, predicted successful LTM for pairs that were previously correctly classified in the WM task. Our results suggest that brain regions associated with higher-level visuo-perceptual processing are involved in successful associative WM encoding, whereas the anterior hippocampus and left inferior frontal gyrus are involved in successful LTM formation during incidental encoding.

Keywords:
Hippocampus; Medial temporal lobe; Associative memory; Recognition memory; Delayed-match-to-sample task; Subsequent memory effects
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Both neuroimaging work and studies investigating amnesic patients have shown involvement of the m... more Both neuroimaging work and studies investigating amnesic patients have shown involvement of the medial temporal lobe during working memory tasks, especially when multiple items or features have to be associated. However, so far no study has examined the relationship between working memory and subsequent episodic memory in patients using similar tasks. In this study, we compared patients with amnesia due to Korsakoff's syndrome (n = 19) with healthy controls (n = 18) on an associative working memory task followed by an unexpected subsequent episodic memory task. The computerized working memory task required participants to maintain two pairs of faces and houses for either short (3 s) or long (6 s) delays. Approximately 5 minutes after completion of the working memory task, an unexpected subsequent recognition task with a two-alternative forced choice paradigm was administered. By directly comparing working memory and subse- quent episodic memory, we were able to examine long-term encoding processes that may take place after longer delays. As expected, patients performed at chance level on the epi- sodic memory task. Interestingly, patients also showed significantly impaired working memory performance (p<.01), even at short delays. Longer delays did not result in better subsequent memory, indicating that they do not facilitate long-term encoding processes. Our results are discussed in relation to Baddeley's working memory model as the episodic buffer is assumed to be a short-term store for maintaining bound representations. In light of these results, the long-standing view that working memory and long-term memory are strictly dissociated may need to be revisited.

Emotional content typically facilitates subsequent memory, known as the emotional enhancement eff... more Emotional content typically facilitates subsequent memory, known as the emotional enhancement effect. We investigated whether emotional content facilitates spatial and item memory in patients with Alzheimer's dementia (AD). Twenty-three AD patients, twenty-three healthy elderly, and twenty-three young adults performed a picture relocation task and a delayed recognition task with positive, negative, and neutral stimuli. AD patients showed a benefit in immediate spatial memory for positive pictures, while healthy young and older participants did not benefit from emotional content. No emotional enhancement effects on delayed item recognition were seen. We conclude that AD patients may have a memory bias for positive information in spatial memory. Discrepancies between our findings and earlier studies are discussed.

Previous studies found that information is more persuasive when self-generated (high self-involve... more Previous studies found that information is more persuasive when self-generated (high self-involvement), rather than when simply read or heard (low self-involvement). In two studies, we investigated whether differences in self-involvement concerning smoking issues would influence immediate smoking behaviour. As predicted, results indicate that participants who developed their own arguments against smoking waited longer before lighting up a cigarette than those who read arguments against smoking that were developed by other participants (Study 1). Further, participants who additionally generated their own arguments were less likely to smoke within 30 min than those who read prepared arguments against smoking (Study 2). In sum, our studies illustrate that personal involvement in generating anti-smoking arguments can reduce short term
smoking behaviour.

Zeitschrift für …, Jan 1, 2010

In der vorliegenden Arbeit werden Normdaten für eine Wortanfangsergänzungsaufgabe vorgestellt, d... more In der vorliegenden Arbeit werden Normdaten für eine
Wortanfangsergänzungsaufgabe vorgestellt, die zu einem Großteil online erhoben wurden. Die Teilnehmer erhielten insgesamt 75 aus drei Buchstaben bestehende Wortanfänge. In der ersten von zwei Studien (501 Probanden, 16 bis 94 Jahre) mussten diese Wortanfänge zu einem deutschen Nomen, das aus insgesamt fünf, sechs oder sieben Buchstaben bestehen sollte, ergänzt werden. In der zweiten Studie (624 Probanden, 15 bis 70 Jahre) wurde die Limitierung der Buchstabenzahl aufgehoben: Die zu ergänzenden Nomina durften vier oder mehr Buchstaben haben. Für beide Studien werden die Ergebnisse der Gesamtstichprobe sowie diverser Subgruppen (stratifiziert nach Alter und Bildung) in Tabellenform präsentiert.

Keywords:
Hippocampus; Medial temporal lobe; Associative memory; Recognition memory; Delayed-match-to-sample task; Subsequent memory effects
"

Zeitschrift für …, Jan 1, 2010