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In search of a recognition memory engram.

Brown MW, Banks PJ - Neurosci Biobehav Rev (2014)

Bottom Line: Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe.The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated.A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening.

View Article: PubMed Central - PubMed

Affiliation: University of Bristol, School of Physiology and Pharmacology, Medical Sciences Building, Bristol BS8 1TD, UK. Electronic address: M.W.Brown@Bristol.ac.uk.

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Schematic representation of memory decays (‘forgetting curves’) produced by selective cholinergic and glutamatergic antagonists. The curves are based on forgetting curves derived from population measures of monkey perirhinal neuronal responses to novel and familiar stimuli after different delays for novelty (N) and familiarity (F) neuronal types (Xiang and Brown, 1998). If kainate (KAR) and muscarinic receptor antagonists target ‘novelty’ (fast synaptic change) neurons, while NMDA and nicotinic receptor antagonists target ‘familiarity’ (slow synaptic change) neurons, then the different forgetting curves provide potential explanation for the different amnesic effects observed: NMDA or muscarinic antagonism results in short-term memory followed by forgetting at longer intervals, whereas kainate (KAR) or muscarinic antagonism produces short-term forgetting followed by long-term remembrance.
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fig0015: Schematic representation of memory decays (‘forgetting curves’) produced by selective cholinergic and glutamatergic antagonists. The curves are based on forgetting curves derived from population measures of monkey perirhinal neuronal responses to novel and familiar stimuli after different delays for novelty (N) and familiarity (F) neuronal types (Xiang and Brown, 1998). If kainate (KAR) and muscarinic receptor antagonists target ‘novelty’ (fast synaptic change) neurons, while NMDA and nicotinic receptor antagonists target ‘familiarity’ (slow synaptic change) neurons, then the different forgetting curves provide potential explanation for the different amnesic effects observed: NMDA or muscarinic antagonism results in short-term memory followed by forgetting at longer intervals, whereas kainate (KAR) or muscarinic antagonism produces short-term forgetting followed by long-term remembrance.

Mentions: Extrapolating across species from monkey to rat, the different temporal patterns of amnesia produced by different glutamatergic and cholinergic antagonists is potentially explicable if: (i) kainate and muscarinic antagonists interfere with plasticity mechanisms underlying the development of the fast-change responses while leaving slow-change mechanisms intact; whereas (ii) NMDA and nicotinic antagonists interfere with plasticity mechanisms underlying the development of the slow-change responses while leaving fast-change mechanisms intact (Brown et al., 2010, 2012) (Fig. 3).


In search of a recognition memory engram.

Brown MW, Banks PJ - Neurosci Biobehav Rev (2014)

Schematic representation of memory decays (‘forgetting curves’) produced by selective cholinergic and glutamatergic antagonists. The curves are based on forgetting curves derived from population measures of monkey perirhinal neuronal responses to novel and familiar stimuli after different delays for novelty (N) and familiarity (F) neuronal types (Xiang and Brown, 1998). If kainate (KAR) and muscarinic receptor antagonists target ‘novelty’ (fast synaptic change) neurons, while NMDA and nicotinic receptor antagonists target ‘familiarity’ (slow synaptic change) neurons, then the different forgetting curves provide potential explanation for the different amnesic effects observed: NMDA or muscarinic antagonism results in short-term memory followed by forgetting at longer intervals, whereas kainate (KAR) or muscarinic antagonism produces short-term forgetting followed by long-term remembrance.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4382520&req=5

fig0015: Schematic representation of memory decays (‘forgetting curves’) produced by selective cholinergic and glutamatergic antagonists. The curves are based on forgetting curves derived from population measures of monkey perirhinal neuronal responses to novel and familiar stimuli after different delays for novelty (N) and familiarity (F) neuronal types (Xiang and Brown, 1998). If kainate (KAR) and muscarinic receptor antagonists target ‘novelty’ (fast synaptic change) neurons, while NMDA and nicotinic receptor antagonists target ‘familiarity’ (slow synaptic change) neurons, then the different forgetting curves provide potential explanation for the different amnesic effects observed: NMDA or muscarinic antagonism results in short-term memory followed by forgetting at longer intervals, whereas kainate (KAR) or muscarinic antagonism produces short-term forgetting followed by long-term remembrance.
Mentions: Extrapolating across species from monkey to rat, the different temporal patterns of amnesia produced by different glutamatergic and cholinergic antagonists is potentially explicable if: (i) kainate and muscarinic antagonists interfere with plasticity mechanisms underlying the development of the fast-change responses while leaving slow-change mechanisms intact; whereas (ii) NMDA and nicotinic antagonists interfere with plasticity mechanisms underlying the development of the slow-change responses while leaving fast-change mechanisms intact (Brown et al., 2010, 2012) (Fig. 3).

Bottom Line: Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe.The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated.A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening.

View Article: PubMed Central - PubMed

Affiliation: University of Bristol, School of Physiology and Pharmacology, Medical Sciences Building, Bristol BS8 1TD, UK. Electronic address: M.W.Brown@Bristol.ac.uk.

Show MeSH
Related in: MedlinePlus