Linked Life Data

18057204

Source:http://linkedlifedata.com/resource/pubmed/id/18057204

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
2007-12-6
pubmed:abstractText
Models of hippocampal function suggest that the modulation of CA3 afferent input during theta rhythm allows for a rapid alternation between encoding and retrieval states, with each phase enhancing either extrinsic or intrinsic CA3 afferents, favoring either encoding or retrieval, respectively. Here, we show that during the initial exploration of a novel environment by rats, intrinsic CA3-CA3 synaptic inputs are attenuated on CA3 theta peaks, favoring extrinsic CA3 inputs, whereas extrinsic perforant path-CA3 synaptic inputs are attenuated on CA3 theta troughs, favoring intrinsic CA3 inputs. This modulation is absent when animals are re-exposed to the same environment 2 or 48 h later and thus habituates with familiarity, suggesting a process involved in learning. Modulation of CA3 synaptic inputs during novelty was blocked by atropine at a dose that blocks type 2 theta rhythm. Re-exposure to the same novel environment 48 h later in the absence of atropine did not result in habituation, but instead modulated CA3 synaptic responses as though the environment were novel and explored for the first time. The NMDA receptor antagonist (+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP), administered in a dose that blocks long-term potentiation induction, did not alter CA3 synaptic modulation during initial exploration. However, like atropine, CPP blocked the habituation of synaptic modulation normally observed with re-exposure, as though the environment were novel and explored for the first time. Thus, as predicted theoretically, recurrent and cortical CA3 afferents are differentially modulated during phases of theta rhythm. This modulation is atropine sensitive and habituates in an NMDA receptor-dependent manner, suggesting an NMDA receptor-dependent process that, in conjunction with theta rhythm, contributes to encoding of novel information in the hippocampus.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
5
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13457-67
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Modulation of CA3 afferent inputs by novelty and theta rhythm.
pubmed:affiliation
Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249-0662, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, N.I.H., Extramural