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  • 1
    Electronic Resource
    Electronic Resource
    Effects of cholinergic enhancement on conditioning-related responses in human auditory cortex (2002)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 16 (2002), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has previously been shown that cholinergic blockade attenuates conditioning-related neuronal responses in human auditory cortex. The present study was conducted to investigate the effect of cholinergic enhancement on such experience-dependent cortical responses. The cholinesterase inhibitor physostigmine, or a placebo control, were continuously infused into healthy young volunteers, during differential aversive conditioning whilst brain activity was measured using event-related functional magnetic resonance imaging (fMRI). Volunteers were presented with two tones, one of which (CS+) was conditioned by pairing with an electrical shock whereas the other was always presented without the shock (CS–). Conditioning-related activations, expressed as an enhanced blood oxygenation level dependent (BOLD) response to the salient CS+, were evident in left auditory cortex under placebo but not under physostigmine. This absence of conditioning-related activations under physostigmine was due to enhanced responses to the CS– under physostigmine as compared to placebo. We suggest that an overactive cholinergic system leads to increased processing of behaviourally irrelevant stimuli and thus attenuates differential conditioning-related cortical activations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2002.02272.x
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  • 2
    Electronic Resource
    Electronic Resource
    The Neural Correlates of the Noradrenergic Modulation of Human Attention, Arousal and Learning (1997)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 9 (1997), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The prefrontal cortex has been suggested as a site of action for the noradrenergic modulation of cognition. In healthy volunteers attentional deficits can be induced by the α2 adrenoceptor agonist clonidine, without impairment of more explicit tests of frontal lobe function. It is therefore possible that the effects of noradrenaline cannot be localized to a specific brain area such as the prefrontal cortex, but instead involve structures in a more widespread attentional network. A 1.5 μg/kg dose of clonidine or placebo was administered to 13 healthy male volunteers performing the rapid visual information processing task, which places demands on both sustained attention and working memory. Twelve positron emission tomography measurements of regional cerebral blood flow (rCBF) were collected during performance of this task and also during a rest state. A second experiment in 12 healthy volunteers examined the effects of a 1.3 μg/kg dose of clonidine on the rCBF changes associated with performance of a paired associates learning task compared with passive listening to word pairs. Comparison of each of the experimental tasks with its respective control replicated previous findings. A significant drug × task interaction, common to the two studies, was found in the right thalamus. Inspection of the adjusted rCBF values showed that the effect was due to attenuation of thalamic rCBF during the control states rather than to any effects of clonidine during performance of the cognitive tasks, although the effect was stronger in the rapid visual information processing study than in the paired associates learning study. The significant effect of clonidine during the control as opposed to the ‘cognitive’ activation state is consistent with previous findings in animals and humans demonstrating greater effects of clonidine during states of relatively low arousal. The results suggest neuroanatomical dissociation of the noradrenergic modulation of arousal (via the thalamus) and attention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1997.tb01635.x
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  • 3
    Electronic Resource
    Electronic Resource
    Activation of reward circuitry in human opiate addicts (1999)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 11 (1999), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The neurobiological mechanisms of opiate addictive behaviour in humans are unknown. A proposed model of addiction implicates ascending brainstem neuromodulatory systems, particularly dopamine. Using functional neuroimaging, we assessed the neural response to heroin and heroin-related cues in established opiate addicts. We show that the effect of both heroin and heroin-related visual cues are maximally expressed in the sites of origin of ascending midbrain neuromodulatory systems. These context-specific midbrain activations predict responses to salient visual cues in cortical and subcortical regions implicated in reward-related behaviour. These findings implicate common neurobiological processes underlying drug and drug-cue-related effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.1999.00522.x
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  • 4
    Electronic Resource
    Electronic Resource
    How the brain learns to see objects and faces in an impoverished context (1997)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 389 (1997), S. 596-599 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A degraded image of an object or face, which appearsmeaningless when seen for the first time, is easily recognizableafter viewing an undegraded version of the same image. The neural mechanisms by whichthis form of rapid perceptual learning facilitates perception are notwell understood. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/39309
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  • 5
    Electronic Resource
    Electronic Resource
    A differential neural response in the human amygdala to fearful and happy facial expressions (1996)
    [s.l.] : Nature Publishing Group
    Nature 383 (1996), S. 812-815 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Facial expressions are a mechanism through which internal emotional states and intentions become available as external signals, consequently the face is vital in social cognition1'9'10. The primate amygdala is thought to be involved in processing facial expression and in controlling emotional and ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/383812a0
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  • 6
    Electronic Resource
    Electronic Resource
    Dopaminergic modulation of impaired cognitive activation in the anterior cingulate cortex in schizophrenia (1995)
    [s.l.] : Nature Publishing Group
    Nature 378 (1995), S. 180-182 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We measured brain activity, indexed by regional cerebral blood flow (rCBF), in 12 normal male volunteer subjects and 12 unmedicated male schizophrenic patients under two conditions. We scanned all subjects while they performed a paced verbal fluency task and a baseline paced verbal repetition task ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/378180a0
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Where in the brain does visual attention select the forest and the trees? (1996)
    [s.l.] : Nature Publishing Group
    Nature 382 (1996), S. 626-628 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We measured brain activity, indexed by regional cerebral blood flow (rCBF), in two separate experiments using 'hierarchically' organized visual stimuli (Fig. 1). In the first experiment, subjects were asked to attend to and name either the global or the local aspect of the figures in separate ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/382626a0
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  • 8
    Electronic Resource
    Electronic Resource
    Dissociating prefrontal and hippocampal function in episodic memory encoding (1997)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 388 (1997), S. 582-585 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Human lesion data indicate that an intact left hippocampal formation is necessary for auditory–verbal memory. By contrast, functional neuroimaging has highlighted the role of the left prefrontal cortex but has generally failed to reveal the predicted left hippocampal activation. Here we ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/388582a0
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    Brain regions associated with acquisition and retrieval of verbal episodic memory (1994)
    [s.l.] : Nature Publishing Group
    Nature 368 (1994), S. 633-635 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Brain activity was measured in six volunteers while they learned and, in another six, while they retrieved verbal material. All volunteers heard 15 paired associates, consisting of categories and relatively uncommon exemplars (such as furniture-sideboard) and were told they would have to recall ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/368633a0
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  • 10
    Electronic Resource
    Electronic Resource
    Conscious and unconscious emotional learning in the human amygdala (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 393 (1998), S. 467-470 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] If subjects are shown an angry face as a target visual stimulus for less than forty milliseconds and are then immediately shown an expressionless mask, these subjects report seeing the mask but not the target. However, an aversively conditioned masked target can elicit an emotional response ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/30976
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