LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 47

Search options

  1. Article ; Online: Neuroscience. Widespread cortical networks underlie memory and attention.

    Gaffan, David

    Science (New York, N.Y.)

    2005  Volume 309, Issue 5744, Page(s) 2172–2173

    MeSH term(s) Amnesia/physiopathology ; Animals ; Attention/physiology ; Axons/physiology ; Brain Mapping ; Frontal Lobe/physiology ; Humans ; Macaca ; Memory/physiology ; Nerve Net/physiology ; Neural Pathways/physiology ; Neurons/physiology ; Parietal Lobe/physiology ; Perceptual Disorders/physiopathology ; Space Perception/physiology
    Language English
    Publishing date 2005-09-30
    Publishing country United States
    Document type Comment ; Journal Article
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.1119445
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: Against memory systems.

    Gaffan, David

    Philosophical transactions of the Royal Society of London. Series B, Biological sciences

    2002  Volume 357, Issue 1424, Page(s) 1111–1121

    Abstract: The medial temporal lobe is indispensable for normal memory processing in both human and non-human primates, as is shown by the fact that large lesions in it produce a severe impairment in the acquisition of new memories. The widely accepted inference ... ...

    Abstract The medial temporal lobe is indispensable for normal memory processing in both human and non-human primates, as is shown by the fact that large lesions in it produce a severe impairment in the acquisition of new memories. The widely accepted inference from this observation is that the medial temporal cortex, including the hippocampal, entorhinal and perirhinal cortex, contains a memory system or multiple memory systems, which are specialized for the acquisition and storage of memories. Nevertheless, there are some strong arguments against this idea: medial temporal lesions produce amnesia by disconnecting the entire temporal cortex from neuromodulatory afferents arising in the brainstem and basal forebrain, not by removing cortex; the temporal cortex is essential for perception as well as for memory; and response properties of temporal cortical neurons make it impossible that some kinds of memory trace could be stored in the temporal lobe. All cortex is plastic, and it is possible that the same rules of plasticity apply to all cortical areas; therefore, memory traces are stored in widespread cortical areas rather than in a specialized memory system restricted to the temporal lobe. Among these areas, the prefrontal cortex has an important role in learning and memory, but is best understood as an area with no specialization of function.
    MeSH term(s) Amnesia/physiopathology ; Animals ; Humans ; Memory/physiology ; Neuronal Plasticity ; Prefrontal Cortex/physiology ; Temporal Lobe/physiology
    Language English
    Publishing date 2002-08-29
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 208382-6
    ISSN 1471-2970 ; 0962-8436 ; 0080-4622 ; 0264-3839
    ISSN (online) 1471-2970
    ISSN 0962-8436 ; 0080-4622 ; 0264-3839
    DOI 10.1098/rstb.2002.1110
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: Prefrontal-temporal disconnection impairs recognition memory but not familiarity discrimination.

    Browning, Philip G F / Baxter, Mark G / Gaffan, David

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2013  Volume 33, Issue 23, Page(s) 9667–9674

    Abstract: Neural mechanisms in the temporal lobe are essential for recognition memory. Evidence from human functional imaging and neuropsychology, and monkey neurophysiology and neuropsychology also suggests a role for prefrontal cortex in recognition memory. To ... ...

    Abstract Neural mechanisms in the temporal lobe are essential for recognition memory. Evidence from human functional imaging and neuropsychology, and monkey neurophysiology and neuropsychology also suggests a role for prefrontal cortex in recognition memory. To examine the interaction of these cortical regions in support of recognition memory we tested rhesus monkeys with prefrontal-inferotemporal (PFC-IT) cortical disconnection on two recognition memory tasks, a "constant negative" task, and delayed nonmatching-to-sample (DNMS). In the constant negative task monkeys were presented with sets of 100 discrimination problems. In each problem one unrewarded object was presented once every day, and became familiar over the course of several days testing. The other, rewarded object was always novel. In this task monkeys learned to avoid the familiar constant negatives and choose the novel objects, so performance on this task is guided by a sense of familiarity for the constant negatives. Following PFC-IT disconnection monkeys were severely impaired at reacquiring the rule (to avoid familiar items) but were subsequently unimpaired at acquiring new constant negative problems, thus displaying intact familiarity recognition. The same monkeys were impaired in the acquisition of the DNMS task, as well as memory for lists of objects. This dissociation between two tests of recognition memory is best explained in terms of our general hypothesis that PFC-IT interactions support the representation of temporally complex events, which is necessary in DNMS but not in constant negative. These findings, furthermore, indicate that stimulus familiarity can be represented in temporal cortex without input from prefrontal cortex.
    MeSH term(s) Animals ; Discrimination, Psychological/physiology ; Macaca mulatta ; Male ; Memory/physiology ; Photic Stimulation/methods ; Prefrontal Cortex/physiology ; Psychomotor Performance/physiology ; Random Allocation ; Recognition, Psychology/physiology ; Temporal Lobe/physiology
    Language English
    Publishing date 2013-06-05
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.5759-12.2013
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: The magnocellular mediodorsal thalamus is necessary for memory acquisition, but not retrieval.

    Mitchell, Anna S / Gaffan, David

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2008  Volume 28, Issue 1, Page(s) 258–263

    Abstract: Damage to the magnocellular mediodorsal thalamic nucleus (MDmc) in the human brain is associated with both retrograde and anterograde amnesia. In the present study we made selective neurotoxic MDmc lesions in rhesus monkeys and compared the effects of ... ...

    Abstract Damage to the magnocellular mediodorsal thalamic nucleus (MDmc) in the human brain is associated with both retrograde and anterograde amnesia. In the present study we made selective neurotoxic MDmc lesions in rhesus monkeys and compared the effects of these lesions on memory acquisition and retrieval. Monkeys learned 300 unique scene discriminations preoperatively and retention was assessed in a one-trial preoperative retrieval test. Bilateral neurotoxic lesions of the MDmc, produced by 10 x 1 microl injections of a mixture of ibotenate and NMDA did not affect performance in the postoperative one-trial retrieval test. In contrast, new postoperative learning of a further 100 novel scene discriminations was substantially impaired. Thus, MDmc is required for new learning of scene discriminations but not for their retention and retrieval. This finding is the first evidence that MDmc plays a specific role in memory acquisition.
    MeSH term(s) Animals ; Behavior, Animal ; Discrimination Learning/physiology ; Macaca mulatta ; Mediodorsal Thalamic Nucleus/injuries ; Mediodorsal Thalamic Nucleus/physiology ; Mental Recall/physiology ; Photic Stimulation/methods ; Retention, Psychology/physiology
    Language English
    Publishing date 2008-01-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.4922-07.2008
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article: Medial temporal and prefrontal function: recent behavioural disconnection studies in the macaque monkey.

    Gaffan, David / Wilson, Charles R E

    Cortex; a journal devoted to the study of the nervous system and behavior

    2008  Volume 44, Issue 8, Page(s) 928–935

    Abstract: In the macaque monkey, disconnection syndromes can be produced experimentally either by selective section of axonal pathways or by crossed unilateral asymmetrical ablations. Behavioural investigation of the effects of these disconnections gives ... ...

    Abstract In the macaque monkey, disconnection syndromes can be produced experimentally either by selective section of axonal pathways or by crossed unilateral asymmetrical ablations. Behavioural investigation of the effects of these disconnections gives information that cannot be derived either from clinical studies or from the effects of bilateral symmetrical ablations in the monkey. Disconnection experiments are particularly suited to the study of the interactions between the components of widespread cortical networks. We propose that memory acquisition is dependent on plastic cortical changes that are widespread, rather than limited to the medial temporal lobe. Further, memory acquisition depends on cortical-subcortical interactions to a greater extent than memory retrieval does. Prefrontal cortex, we suggest, is specifically important in the representation of temporally complex events.
    MeSH term(s) Animals ; Behavior, Animal/physiology ; Brain Mapping ; Functional Laterality ; Macaca ; Memory/physiology ; Neural Pathways/physiology ; Neuronal Plasticity/physiology ; Prefrontal Cortex/physiology ; Temporal Lobe/physiology
    Language English
    Publishing date 2008-05-23
    Publishing country Italy
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 280622-8
    ISSN 1973-8102 ; 0010-9452
    ISSN (online) 1973-8102
    ISSN 0010-9452
    DOI 10.1016/j.cortex.2008.03.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Prefrontal-inferotemporal interaction is not always necessary for reversal learning.

    Wilson, Charles R E / Gaffan, David

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2008  Volume 28, Issue 21, Page(s) 5529–5538

    Abstract: Prefrontal cortex (PFC) is thought to have a wide-ranging role in cognition, often described as executive function or behavioral inhibition. A specific example of such a role is the inhibition of representations in more posterior regions of cortex in a " ... ...

    Abstract Prefrontal cortex (PFC) is thought to have a wide-ranging role in cognition, often described as executive function or behavioral inhibition. A specific example of such a role is the inhibition of representations in more posterior regions of cortex in a "top-down" manner, a function thought to be tested by reversal learning tasks. The direct action of PFC on posterior regions can be directly tested by disconnecting PFC from the region in question. We tested whether PFC directly inhibits visual object representations in inferotemporal cortex (IT) during reversal learning by studying the effect, in macaque monkeys, of disconnecting PFC from IT by crossed unilateral ablations. We tested two visual object reversal learning tasks, namely serial and concurrent reversal learning. We found that the disconnection severely impairs serial reversal learning but leaves concurrent reversal learning completely intact. Thus, PFC cannot be said to always have direct inhibitory control over visual object representations in reversal learning. Furthermore, our results cannot be explained by generalized theories of PFC function such as executive function and behavioral inhibition, because those theories do not make predictions that differentiate different forms of reversal learning. The results do, however, support our proposal, based on other experimental evidence from macaque monkeys, that PFC has a highly specific role in the representation of temporally complex events.
    MeSH term(s) Analysis of Variance ; Animals ; Behavior, Animal ; Brain Mapping ; Discrimination Learning/physiology ; Functional Laterality ; Macaca fascicularis ; Male ; Photic Stimulation ; Prefrontal Cortex/injuries ; Prefrontal Cortex/physiology ; Psychomotor Performance/physiology ; Reversal Learning/physiology ; Reward ; Temporal Lobe/injuries ; Temporal Lobe/physiology
    Language English
    Publishing date 2008-05-21
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.0952-08.2008
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Prefrontal cortex function in the representation of temporally complex events.

    Browning, Philip G F / Gaffan, David

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2008  Volume 28, Issue 15, Page(s) 3934–3940

    Abstract: The frontal cortex and inferior temporal cortex are strongly functionally interconnected. Previous experiments on prefrontal function in monkeys have shown that a disconnection of prefrontal cortex from inferior temporal cortex impairs a variety of ... ...

    Abstract The frontal cortex and inferior temporal cortex are strongly functionally interconnected. Previous experiments on prefrontal function in monkeys have shown that a disconnection of prefrontal cortex from inferior temporal cortex impairs a variety of complex visual learning tasks but leaves simple concurrent object-reward association learning intact. We investigated the possibility that temporal components of visual learning tasks determine the sensitivity of those tasks to prefrontal-temporal disconnection by adding specific temporal components to the concurrent object-reward association learning task. Monkeys with crossed unilateral lesions of prefrontal cortex and inferior temporal cortex were impaired compared with unoperated controls at associating two-item sequences of visual objects with reward. The impairment was specific to the learning of visual sequences, because disconnection was without effect on object-reward association learning for an equivalent delayed reward. This result was replicated in monkeys with transection of the uncinate fascicle, thus determining the anatomical specificity of the dissociation. Previous behavioral results suggest that monkeys represent the two-item serial compound stimuli in a configural manner, similar to the way monkeys represent simultaneously presented compound stimuli. The representation of simultaneously presented configural stimuli depends on the perirhinal cortex. The present experiments show that the representation of serially presented compound stimuli depends on the interaction of prefrontal cortex and inferior temporal cortex. We suggest that prefrontal-temporal disconnection impairs a wide variety of learning tasks because in those tasks monkeys lay down similar temporally complex representations.
    MeSH term(s) Animals ; Association Learning/physiology ; Brain Mapping ; Denervation ; Macaca fascicularis ; Male ; Neural Pathways/physiology ; Prefrontal Cortex/physiology ; Reward ; Temporal Lobe/physiology ; Time Perception/physiology ; Visual Perception/physiology
    Language English
    Publishing date 2008-04-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.0633-08.2008
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article: Impairment in object-in-place scene learning after uncinate fascicle section in macaque monkeys.

    Browning, Philip G F / Gaffan, David

    Behavioral neuroscience

    2008  Volume 122, Issue 2, Page(s) 477–482

    Abstract: Three previous experiments have shown that a disconnection of frontal cortex from inferior temporal cortex in monkeys impairs a variety of visual learning tasks but leaves concurrent object discrimination learning intact. In the present experiment, three ...

    Abstract Three previous experiments have shown that a disconnection of frontal cortex from inferior temporal cortex in monkeys impairs a variety of visual learning tasks but leaves concurrent object discrimination learning intact. In the present experiment, three monkeys were trained on an object-in-place task where concurrent object discrimination learning took place within unique background scenes. After surgery to transect the uncinate fascicle, the monosynaptic route between prefrontal cortex and inferior temporal cortex, all three monkeys showed an impairment relative to their preoperative performance. Combined with previously reported impairments after uncinate fascicle transection, the interaction between frontal cortex and inferotemporal cortex is likely to be important in discrimination learning in background scenes because learning depends on associating the visual elements of a scene together with the appropriate choice object. This result adds to recent evidence showing that tasks such as object-in-place learning and conditional learning are impaired after disconnection of frontal cortex from inferior temporal cortex because those tasks require the representation of temporally extended events.
    MeSH term(s) Animals ; Association Learning/physiology ; Discrimination Learning/physiology ; Frontal Lobe/physiology ; Macaca mulatta ; Male ; Nerve Fibers/physiology ; Neural Pathways/physiology ; Photic Stimulation ; Space Perception/physiology ; Temporal Lobe/physiology
    Language English
    Publishing date 2008-04-15
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 230159-3
    ISSN 1939-0084 ; 0735-7044
    ISSN (online) 1939-0084
    ISSN 0735-7044
    DOI 10.1037/0735-7044.122.2.477
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article: Global retrograde amnesia but selective anterograde amnesia after frontal-temporal disconnection in monkeys.

    Browning, Philip G F / Gaffan, David

    Neuropsychologia

    2008  Volume 46, Issue 10, Page(s) 2494–2502

    Abstract: Prefrontal cortex and inferior temporal cortex interact in support of a wide variety of learning and memory functions. In macaque monkeys, a disconnection of prefrontal and temporal cortex produces severe new learning impairments in a range of complex ... ...

    Abstract Prefrontal cortex and inferior temporal cortex interact in support of a wide variety of learning and memory functions. In macaque monkeys, a disconnection of prefrontal and temporal cortex produces severe new learning impairments in a range of complex learning tasks such as visuo-motor conditional learning and object-in-place scene learning. The retrograde effects of this disconnection, however, have never been fully examined. We therefore assessed the postoperative retention of 128 preoperatively learned object discrimination problems in monkeys with prefrontal-temporal disconnection using 1 trial postoperative retention tests. Because previous experiments have suggested that both spatial and temporal factors may be important in engaging frontal-temporal interaction we used object discrimination problems with a variety of spatial and temporal properties. Postoperatively, although monkeys with prefrontal-temporal disconnection displayed a retrograde amnesia for all problem types, subsequent assessments of new learning revealed selective anterograde amnesia, which was limited to problems in which objects were presented as serial compound stimuli. The pattern of broad retrograde amnesia with selective anterograde amnesia contrasts with recent data from monkeys with lesions which disrupt subcortical-cortical connectivity and which show the opposite pattern, namely no retrograde amnesia but severe anterograde amnesia. These results support the hypothesis that visual memory acquisition is supported by subcortical-cortical interactions while the retrieval of visual memories normally depends on the interaction between prefrontal cortex and inferior temporal cortex.
    MeSH term(s) Amnesia, Anterograde/etiology ; Amnesia, Retrograde/etiology ; Animals ; Behavior, Animal ; Conditioning, Operant/physiology ; Denervation/adverse effects ; Denervation/methods ; Discrimination Learning/physiology ; Frontal Lobe/physiology ; Macaca fascicularis ; Male ; Neural Pathways/physiology ; Photic Stimulation/methods ; Task Performance and Analysis ; Temporal Lobe/physiology
    Language English
    Publishing date 2008-04-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 207151-4
    ISSN 1873-3514 ; 0028-3932
    ISSN (online) 1873-3514
    ISSN 0028-3932
    DOI 10.1016/j.neuropsychologia.2008.04.012
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article: Prospective memory in the formation of learning sets by rhesus monkeys (Macaca mulatta).

    Murray, Elisabeth A / Gaffan, David

    Journal of experimental psychology. Animal behavior processes

    2006  Volume 32, Issue 1, Page(s) 87–90

    Abstract: In conventional discrimination learning-set formation, it is possible that rhesus monkeys (Macaca mulatta) learn to lay down prospective memories by anticipating the next trial and deciding in advance what choice will be made. To test this hypothesis, ... ...

    Abstract In conventional discrimination learning-set formation, it is possible that rhesus monkeys (Macaca mulatta) learn to lay down prospective memories by anticipating the next trial and deciding in advance what choice will be made. To test this hypothesis, the authors administered discrimination problems with 24-hr intertrial intervals, predicting that these long intervals would disrupt or prevent the putative anticipation of the next trial. Confirming their expectation, the authors found no indication of learning-set formation under these conditions.
    MeSH term(s) Animals ; Discrimination (Psychology) ; Learning ; Macaca mulatta ; Memory ; Reward ; Visual Perception
    Language English
    Publishing date 2006-01
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2067423-5
    ISSN 1939-2184 ; 0097-7403
    ISSN (online) 1939-2184
    ISSN 0097-7403
    DOI 10.1037/0097-7403.32.1.87
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top