| 1. |
- Decety, Jean, et al.
(author)
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The cerebellum participates in mental activity : tomographic measurements of regional cerebral blood flow
- 1990
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In: Brain Research. - 0006-8993 .- 1872-6240. ; 535:2, s. 313-317
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Journal article (peer-reviewed)abstract
- Measurements in man of regional cerebral blood flow (rCBF) have demonstrated a number of cortical and subcortical events coupled to sensory stimulation or motor performance. It has also been shown that local activity changes take place in the cortex during 'pure' mental activity such as motor imagery (unaccompanied by sensory input or motor output). Thus, our group has previously shown that imagination of hand movements gives predominantly a frontal cortical rCBF activation while the corresponding hand movement activates the rolandic hand area mainly. In this paper we report tomographic rCBF measurements with a 133-Xenon SPECT technique during imagined tennis movements and silent counting. Both procedures gave rise to a significant cerebellar activation in addition to cortical rCBF changes. Apparently, the cerebellum may participate in pure mental activity. It possibly plays a role for the temporal organization of neuronal events related to cognition.
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| 2. |
- Eckert, B., et al.
(author)
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The recovery of brain function after hypoglycaemia in normal man
- 1992
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In: Diabetologia, 35, Suppl.1. ; , s. A43-
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Conference paper (other academic/artistic)abstract
- The aim of the present study was to evaluate the recovery of brain function after moderate hypoglycaemla in normal man. Hypoglycaemia was induced by an intravenous infusion of insulin (2.5 mU/kg) in seven healthy right-handed men aged 25.4+1.1 years (Mean • SD). The brain function was evaluated with P300-amplitude after auditory stimulus, reaction time measurements and EEG before, during (2.4+0.44 mmol/l for 70 min) and three times in the recovery period following hypoglycaemia. Hypoglycaemia caused a reduction in the P300-amplitude, a prolongation in reaction time and minor changes in the EEG-activity. 15 min after normalisation of the blood glucose level, the P300-amplitude was lower than during hypoglycaemia and still 1,5 hrs after normalisation of the blood glucose level, there was a marked reduction in the P3OO-amplitude. 4 hrs after normalisation of the blood glucose, the P300-amplitude was restituted. The reaction time was shorter 15 min after normalisation of the blood glucose compared to hypoglycaemia, but was not nermalised until 1,5 hrs after of recovery following hypoglycaemia. The EEG-changes were normalised 15 min after hypoglycaemia. We conclude that moderate hypglycaemia causes marked effects in P300 and reaction time and that brain function measured as P300 is not restored after 1,5 hrs but at 4 hrs after normalisation of hypoglycaemia.
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| 3. |
- Risberg, Jarl, et al.
(author)
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Regional cerebral blood flow correlates of anxiety and personality traits
- 1991
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In: Lassen, N.A., Ingvar, D.H., Raichle, M.E., Friberg, L. (eds), Brain work and mental activity. - Copenhagen : Munksgaard. - 8716106989 ; , s. 392-401
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Conference paper (other academic/artistic)
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| 4. |
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| 5. |
- Ryding, Erik, et al.
(author)
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Motor imagery activates the cerebellum regionally : a SPECT rCBF study with 99mTc-HMPAO
- 1993
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In: Cognitive Brain Research. - 0926-6410 .- 1872-6348. ; 1:2, s. 94-99
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Journal article (peer-reviewed)abstract
- Our earlier findings of a cerebellar activation during motor imagery (Brain Res., 535 (1990) 313-317) were made with a technique with low regional resolution. Therefore we could not elucidate the distribution of the cerebellar activation. In the present study the cerebellar regional cerebral blood flow (rCBF) changes during motor imagery (MI) was measured with a single photon emission computed tomography (SPECT) rCBF method (99mTc-HMPAO) with higher regional resolution during (1) silent counting, and (2) MI (which included silent counting) in 17 normal subjects. Comparing the SPECT results from the two tasks revealed the regional activations during MI. We confirmed that the most pronounced regional activations during MI were found in the cerebellum, especially in its infero-lateral parts on both sides.
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| 6. |
- Sano, Motoki, et al.
(author)
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Acute effects of alcohol on regional cerebral blood flow in man
- 1993
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In: Journal of Studies on Alcohol. - 0096-882X .- 1934-2683. ; 54:3, s. 369-376
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Journal article (peer-reviewed)abstract
- Acute effects of alcohol in a low (0.7 g/kg) and a high dose (1.5 g/kg) on regional cerebral blood flow (rCBF) were measured with 133Xe inhalation technique at resting conditions in 13 normals. Mean hemisphere CBF increased globally by 12% at the lower dose and 16% at the higher dose. A normal hyperfrontal flow pattern was seen in both alcohol conditions. There were, however, significant regional differences in response to alcohol. The largest rCBF increase was observed in prefrontal regions at the lower dose, and in temporal regions at the higher. Expressed in relative values (% of the whole brain CBF), the temporal rCBF increased linearly with increasing alcohol dosage, while the prefrontal rCBF showed a increase at the lower dose followed by a decrease at the higher dose. It is concluded that alcohol has two types of acute effects on rCBF, a global vasodilatory effect and some regional effects, most clearly seen in prefrontal and temporal regions. The prefrontal flow augmentation following acute alcohol intake may be related to a transient arousal reaction, which has been reported by others. The temporal flow increase may be related to effects of alcohol on emotions and mood.
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| 7. |
- Stenberg, Georg, 1947-
(author)
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Att veta utan att tänka
- 1994
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In: Ingvar, D. H. (red), Att tänka sig. - Stockholm : Svenska Dagbladet. - 9177383826 ; , s. 57-70
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Conference paper (other academic/artistic)
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| 8. |
- Stenberg, Georg, 1947-, et al.
(author)
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Attention and personality in augmenting/reducing of visual evoked potentials
- 1990
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In: Personality and Individual Differences. - 0191-8869 .- 1873-3549. ; 11:12, s. 1243-1254
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Journal article (peer-reviewed)abstract
- Earlier research has shown that extraverts tend to increase their visual evoked potential amplitudes with increasing light intensity (augmenting), while introverts reach their maximum amplitude at lower intensities (reducing). The evoked response has normally been measured from association areas of the brain (at the vertex). The present study measured VEP amplitudes over visual cortex and at the vertex, using four light intensities in two conditions, where attention was either directed towards the light stimuli, or away from them by a concurrent auditory task. Forty subjects were classified as extraverts or introverts based on the Eysenck Personality Inventory. The results show that attention interacted significantly with extraversion. Introverts exhibited a narrower focus of attention, with higher amplitudes and amplitude-intensity functions when attending to the light flashes and lower when distracted. Extraverts showed smaller differences between conditions, indicating a more evenly distributed attention. Higher arousal in introverts is the probable cause of their narrower focus of attention. There were marked differences in the distribution of activity between vertex and occipital cortex. Introverts showed relatively stronger occipital responses and extraverts stronger vertex responses across all intensities and in both conditions. The predisposition for mainly perceptual responses to aversive stimuli in introverts, and for general alerting and motor preparatory responses in extraverts, are interpreted as supportive of Brebner & Cooper's hypothesis that introverts are "geared to inspect" and extraverts are "geared to respond".
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| 9. |
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| 10. |
- Stenberg, Georg, 1947-
(author)
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Det kognitivt omedvetna
- 1994
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In: Åström, K., Engström, C., Marklund, K. (red), Nationalencyklopedin. - Höganäs : Bra böcker. ; , s. 440-
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Book chapter (other academic/artistic)
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