| 1. |
- Lindgren, Magnus, et al.
(författare)
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Directed forgetting, event-related potentials and nicotine
- 1999
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Ingår i: Human Psychopharmacology. - 0885-6222 .- 1099-1077. ; 14, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- Fifteen male users of oral snuff performed a directed forgetting task after over-night abstinence and after administration of oral snuff. Directed forgetting tasks use cues to classify items for differential reporting at test, emphasising the need for strategic encoding. Recognition was better after nicotine administration, but we found no evidence for greater strategic control, as hypothetically reflected in successful compliance with the directed forgetting instructions. Reaction time decreased after nicotine administration. Performance among fifteen controls was unaffected over two sessions.
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| 2. |
- Lindgren, Magnus, et al.
(författare)
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Effects of nicotine in a bimodal attention task
- 1998
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Ingår i: Neuropsychobiology. - 0302-282X .- 1423-0224. ; 38, s. 42-49
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Tidskriftsartikel (refereegranskat)abstract
- Fifteen male users of oral snuff participated in an experiment where we used an auditory-visual vigilance task to study nicotine effects on P300 and response parameters. Quantitative EEG was also studied. Fifteen male non-users served as a control group.We found some decrease of response times, and slightly improved signal detection. P300 parameters were not affected in this study. Quantitative EEG-analysis indicated an expected increase of arousal, as activity within the alpha band shifted towards higher frequencies.
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| 3. |
- Lindgren, M., et al.
(författare)
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Restitution of neurophysiological functions, performance, and subjective symptoms after moderate insulin-induced hypoglycaemia in non-diabetic men
- 1996
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Ingår i: Diabetic Medicine. - : Wiley-Blackwell. - 0742-3071 .- 1464-5491. ; 13:3, s. 218-25
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Tidskriftsartikel (refereegranskat)abstract
- The restoration of cognitive function was studied in 10 healthy men aged 26 years (25.5 +/- 1.2 years; mean +/- SD) after insulin-induced hypoglycaemia (arterialized blood glucose 2.5 +/- 0.4 mmol l-1) for 62 +/- 8 min. Another group of six men participated in a single blind sham study for comparison. The hypoglycaemic event caused a significant increase (p = 0.006) in serum adrenaline levels. Ratings of adrenergically mediated symptoms increased during hypoglycaemia (p = 0.006), as did neuroglycopenic symptoms (p = 0.002), although neuroglycopenia ratings increased in both studies. During hypoglycaemia, P300 amplitudes in a relatively demanding visual search task decreased (p = 0.02), whereas easier tasks were unaffected. The amplitudes were restored after 40 min of normoglycaemia. Reaction time deteriorated after restoration of normoglycaemia, suggesting an effect of hypoglycaemia on learning. Thus, hypoglycaemia at a blood glucose level that is common among patients treated with insulin causes clear cognitive dysfunction, although restoration of the cognitive dysfunction to normal was fast.
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| 4. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Judging words at face value : interference in a word processing task reveals automatic processing of affective facial expressions
- 1998
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Ingår i: Cognition & Emotion. - 0269-9931 .- 1464-0600. ; 12:6, s. 755-782
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Tidskriftsartikel (refereegranskat)abstract
- Earlier research has indicated that some characteristics of facial expressions may be automatically processed. This study investigated automaticity as evidenced by involuntary interference in a word evaluation task. Compound stimuli, consisting of words superimposed on pictures of affective faces, were presented to subjects who were given the task of evaluating the affective valence of the words while disregarding the faces. Results of three experiments showed that word evaluation was influenced by the concurrently shown affective faces. Overall, negative words were found to require longer latencies, indicating that more processing resources are invested in negative than in positive stimuli. This speed advantage for positive words was modified by the faces. Negative words were facilitated, relative to positive ones, when shown with a negative expression, e.g. a sad face. Correspondingly, negative words were inhibited, relative to positive ones, when shown with a positive expression, e.g. a happy face. The results are consistent with automatic, involuntary semantic processing of affective facial expressions.
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| 5. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Personality dimensions and regional cerebral blood flow
- 1996
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Ingår i: International Journal of Psychology, vol. 31, no. 3-4. ; , s. 331-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Measures of regional cerebral blood flow (rCBF) indicate patterns of brain activity with great potential usefulness for exploring the biological bases of personality traits. We have examined the distribution of cortical rCBF induced by spontaneous mental activity in the resting state, and correlated regional activation with questionnaire measures of personality traits. Our main interest has been in the dimension of extraversion-/introversion. Over a series of three studies (total N=75), results have consistently shown a relationship between high temporal lobe activity and introversion. Task-induced mental activation has tended to diminish the personality differences found at rest.
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| 6. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Semantic processing of words without conscious identification : an ERP study
- 1998
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Ingår i: International Journal of Psychophysiology, vol. 30. no. 1-2. ; , s. 97-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study examined the question whether semantic content can be accessed from words that are displayed under conditions (brief exposure, pattern masking) where they are not consciously identified. Thirty subjects performed a combined categorization and word identification task. Category labels (e.g. "fruit") were shown followed by masked, briefly exposed words, either validly cued by the category (e.g. "apple") or invalidly cued (e.g. "horse"). The subjects' task was to verify the category by pressing a button, and to identify the word by a verbal response. Exposure durations were selected to allow the subjects to identify approximately 50 % of the words. Four ERP averages were formed: for identified/unidentified words * validly/invalidly cued words. For identified words, there was a marked difference in the ERP response between validly and invalidly cued words. The difference was due to an N400 component for the invalidly cued words. For unidentified words, there was also a significant difference between validly and invalidly cued words, although smaller in size (23 % of that for the identified words). It had the same direction, and appeared in the same time range and with the same general topography as for the identified words. The results show that some semantic processing can operate on words that are not consciously identified
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| 7. |
- Stenberg, Georg, 1947-
(författare)
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Subliminal perception
- 1995
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Ingår i: Åström, K., Engström, C., Marklund, K. (red), Nationalencyklopedin. - Höganäs : Bra böcker. ; , s. 392-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Stenberg, Georg, 1947-, et al.
(författare)
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The picture superiority effect in a cross-modality recognition task
- 1995
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Ingår i: Memory & Cognition. - 0090-502X .- 1532-5946. ; 23:4, s. 425-441
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Tidskriftsartikel (refereegranskat)abstract
- Words and pictures were studied, and recognition tests were given in which each studied object was to be recognized in both word and picture format. The main dependent variable was the latency of the recognition decision. The purpose was to investigate the effects of study modality (word or picture), of congruence between study and test modalities, and of priming resulting from repeated testing. Experiments 1 and 2 used the same basic design, but the latter also varied retention interval. Exp. 3 added a manipulation of instructions to name studied objects, and Exp. 4 deviated from the others by presenting both picture and word referring to the same object together for study. The results showed that congruence between study and test modalities consistently facilitated recognition. Furthermore, items studied as pictures were more rapidly recognized than items studied as words. With repeated testing, the second instance was affected by its predecessor, but the facilitating effect of picture-to-word priming exceeded that of word-to-picture priming. The findings suggest a two-stage recognition process, in which the first is based on perceptual familiarity, and the second uses semantic links for a retrieval search. Common-code theories which grant privileged access to the semantic code for pictures are supported by the findings, or alternatively dual-code theories which assume mnemonic superiority for the image code. Explanations of the picture superiority effect as resulting from dual encoding of pictures are not supported by the data.
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