Experience and Plasticity in the Central Nervous System

Horn, G.; Rose, Steven; Bateson, Patrick

doi:10.1126/science.181.4099.506

Cited by 133 publications

(12 citation statements)

References 106 publications

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“…These changes have been measured either in single identified neurons or in their immediate vicinity and can account for storage and recall of a Pavlovian conditioned response by the intact animal. Morphological changes of neurons, unlike those changes just mentioned, have never been directly related to associative memory of Hermissenda or any other species, although they have been observed to occur in a variety of developmental (8)(9)(10)(11)(12)(13) and training (14)(15)(16)(17)(18) contexts. An inherent difficulty with the training experiments is to distinguish those training-induced modifications due to motor activity and sensory stimulation themselves from those that store memory for later recall.…”

mentioning

confidence: 91%

Contraction of neuronal branching volume: an anatomic correlate of Pavlovian conditioning.

Alkon¹,

Ikeno²,

Dworkin³

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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Associative memory of the mollusc Hermissenda crassicornis, previously correlated with changes of specific K+ currents, protein phosphorylation, and increased synthesis of mRNA and specific proteins, is here shown to be accompanied by macroscopic alteration in the structure of a single identified neuron, the medial type B photoreceptor cell. Four to five days after training, terminal arborizations of B cells iontophoretically injected with Ni2+ ions and then treated with rubeanic acid were measured with charge-coupled device (CCD)-digitized pseudocolor images of optical sections under "blind" conditions. Boundary volumes enclosing medial-type B-cell arborizations from classically conditioned animals were unequivocally reduced compared with volumes for naive animals or those trained with unpaired stimuli. Branch volume magnitude was correlated with input resistance of the medial type B-cell soma. Such associative learning-induced structural changes may share function with "synapse elimination" described in developmental contexts.Associative memory of the mollusc Hermissenda crassicornis-i.e., a remembered link between at least two discrete stimuli previously associated in time-has been shown to be accompanied by changes of membrane currents (1-4), changes in protein phosphorylation (5), and changes in synthesis of mRNA and of specific proteins (6, 7). These changes have been measured either in single identified neurons or in their immediate vicinity and can account for storage and recall of a Pavlovian conditioned response by the intact animal. Morphological changes of neurons, unlike those changes just mentioned, have never been directly related to associative memory of Hermissenda or any other species, although they have been observed to occur in a variety of developmental (8-13) and training (14)(15)(16)(17)(18) contexts. An inherent difficulty with the training experiments is to distinguish those training-induced modifications due to motor activity and sensory stimulation themselves from those that store memory for later recall. Such a distinction is possible with an associative paradigm that includes a control group receiving sensory stimuli not associated in time but with intensity and duration identical to those used to associatively train the animals.Here we report marked anatomic changes in a single identified neuron (the medial type B cell) of Hermissenda in animals (paired group, n = 8) that had been associatively trained with paired visual and vestibular stimuli. These changes were measured in comparison with neurons from animals receiving either no training stimuli (naive group, n = 8) or to neurons from animals receiving stimuli that were explicitly unpaired at randomly varying temporal intervals (unpaired group, n = 8). Because there were no differences between type B cells from naive animals compared with cells from unpaired animals, the anatomic changes described below for the paired group were specific to the temporal association of the training stimuli and, therefore, are not due to the...

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mentioning

confidence: 91%

Contraction of neuronal branching volume: an anatomic correlate of Pavlovian conditioning.

Alkon¹,

Ikeno²,

Dworkin³

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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“…It has not been easy to test this proposition, since any detected change in connectivity could represent some nonspecific consequence of training (3). The comparable problem of interpreting changes in certain aspects of brain biochemistry following learning has largely been overcome in the case of imprinting in domestic chicks.…”

mentioning

confidence: 99%

Learning and memory: regional changes in N-methyl-D-aspartate receptors in the chick brain after imprinting.

McCabe

Horn

1988

Proc. Natl. Acad. Sci. U.S.A.

285

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An extensive series of experiments has implicated a restricted region of the chick forebrain in the learning process of imprinting. The region is the intermediate and medial part of the hyperstriatum ventrale (IMHV). Previous studies have shown that training is associated with an increase in the area of the postsynaptic density of axospinous synapses in the left but not the right IMHV. The postsynaptic density is a site of high receptor density, and at least some axospinous synapses are excitatory. We found that imprinting is associated with a 59% increase in N-methyl-D-aspartate-sensitive binding of the excitatory amino acid L-[3lHJglutamic acid in the left IMHV. The increase is probably due to an increased number of binding sites. The profile of sensitivity of the sites to a series of amino-, phosphono-substituted carboxylic acids (2-amino-3-phosphonopropionate to 2-amino-8-phosphonooctanoate) is characteristic of N-methyl-D-aspartate-type receptors. There were no significant effects of training on binding in the right IMHV. The effect of training on left IMHV binding could not be attributed to light exposure, arousal, or motor activity per se but was a function of how much the chicks learned. The changes in the left IMHV could increase the effectiveness of synaptic transmission in a region crucial for information storage and so form a neural basis for recognition memory.

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“…The investigators found enhanced production of RNA and protein, accompanied by elevation of adenylate cyclase activity in the anterior forebrain roof of chicks imprinted with flashlight stimulation [8,30,31,53]. No such change was found in the forebrain bases or midbrain.…”

Section: Strategies For Neurochemical Studies Of Learning and Memorymentioning

confidence: 99%

Molecular approaches to learning and memory.

Tsukada

1988

Jpn.J.Physiol

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Learning and memory are thought to be one of the higher nervous functions performed in the brain, and their neurophysiological processes can be explained by the plasticity of neural mechanisms in the brain. It means that biological responses induced by physiological stimuli from outside are fixed as permanent functional changes in the neuronal networks of the brain. On the basis of this concept, we can make physiological observations on learning as the modification and reorganization of behavior through experiences in individual organisms, and on memory as the ability of individuals to perform behavior modified through learning experiences, i.e., the capacity to store information in the central nervous system [62].Behavior as the physical activity of living organisms takes various forms according to genetic and environmental factors at each of the evolutionary stages from the bacterium to mankind. Even in some lower species having no nervous system, habituation or sensitization is seen with corresponding changes of Cat + flux, maintained for tens of minutes, in the cells receiving stimuli [21]. In higher animals, learned behavior is acquired with the change of purposive modification of biological responses in individuals, on the premise of a storage of information in the nervous system. This is a sort of memory, which can be divided into the short-term memory (STM) with transient and reversible neurochemical changes in the synapses, and the long-term memory (LTM) with enduring and irreversible molecular events.The process of STM appears to involve transient change of transmission efficiency in the synapses, which probably accompanies readily reversible chemical modification of constituent molecules in the cell membrane, but not involving protein synthesis or structural change. The LTM process is supposed to involve reorganization of the neuronal networks, resulting from neogenesis and reconnection of the functioning synapses accompanied by production and accumulation of new molecules [4,47]. This process requires consolidation of memories, of which molecular mechanism is one of the crucial subjects of neurobiology.

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Experience and Plasticity in the Central Nervous System

Cited by 133 publications

References 106 publications

Contraction of neuronal branching volume: an anatomic correlate of Pavlovian conditioning.

Contraction of neuronal branching volume: an anatomic correlate of Pavlovian conditioning.

Learning and memory: regional changes in N-methyl-D-aspartate receptors in the chick brain after imprinting.

Molecular approaches to learning and memory.

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