Field potential recordings in dentate gyrus of anesthetized rats: Stability of baseline

Gilbert, Mary E.; Mack, Cina M.

doi:10.1002/(sici)1098-1063(1999)9:3<277::aid-hipo7>3.0.co;2-h

Cited by 28 publications

(13 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2B). As already reported for basal synaptic transmission in the hippocampus during acute (Gilbert and Mack 1999) and chronic ) recordings, pseudoconditioned animals (both control and mutant mice) did not present any significant change in basal fEPSP slopes for up to 19 d. Linear relationship between acquisition of eyeblink conditioning and plastic changes at the CA3-CA1 synapses…”

Section: Resultssupporting

confidence: 79%

Mutation at the TrkB PLCγ-docking site affects hippocampal LTP and associative learning in conscious mice

Gruart

Sciarretta²,

Valenzuela-Harrington³

et al. 2007

Learn. Mem.

View full text Add to dashboard Cite

Previous in vitro studies have characterized the electrophysiological properties and molecular events associated with long-term potentiation (LTP), but as yet there are no in vivo data from molecular-level dissection that directly identify LTP as the biological substrate for learning and memory. Understanding whether the molecular pathways required for learning are also those generating LTP when measured directly on the relevant circuit of a learning animal is clearly important, although so far has proved technically difficult. Here, for the first time, we combine highly defined genetic mouse models with behavior and in vivo recordings. We recorded the activity-dependent changes taking place at the CA3-CA1 synapses during the acquisition and extinction of a simple form of an associative learning task in mice carrying point mutations on specific docking sites of TrkB receptors (trkBThe learning task consisted of a classical eyeblink conditioning using a trace paradigm. The conditioned stimulus (CS) consisted of a tone and was followed by a periorbital electrical shock as an unconditioned stimulus (US). The US started 500 msec after the end of the CS. We show that a single pulse presented to the Schaffer collateral-commissural pathway during the CS-US interval evoked a monosynaptic field excitatory postsynaptic potential (fEPSP) at the CA1 pyramidal cells, with a slope linearly related to learning evolution in controls and trkB SHC mutants, but the relationship was impaired in trkB PLC mice. These data support a link between the PLC␥-docking site downstream of TrkB and the activity-dependent synaptic changes evoked at the CA3-CA1 synapses during associative learning in conscious mice, and indicate that TrkB PLC␥-site-activated molecular pathway(s) underlie both associative learning and LTP triggered at the CA3-CA1 synapse.

show abstract

Section: Resultssupporting

confidence: 79%

Mutation at the TrkB PLCγ-docking site affects hippocampal LTP and associative learning in conscious mice

Gruart

Sciarretta²,

Valenzuela-Harrington³

et al. 2007

Learn. Mem.

View full text Add to dashboard Cite

show abstract

“…In this way, it can be determined that the expression of LTP in the chronic mouse preparation results from high frequency stimulation (HFS) and LTD results from low frequency stimulation (LFS) rather than changes in the stimulation pattern or in the number of pulses. Another factor that may account for the differences seen in previous studies of PSA amplitude may be suppression of various neuronal projections to and from the hippocampus by anesthetics (Gilbert and Mack, 1999).…”

Section: Discussionmentioning

confidence: 89%

“…Both anesthetized and freely behaving in vivo techniques suffer from surgical trauma and local tissue damage due to electrode insertion; some effects on neuronal function may persist for several hours or days (Gilbert and Mack, 1999). Anesthetized models suffer additionally from alterations in neuronal excitability due to the presence of anesthetics, which often have an overall depressing effect on LTP (Izaki et al, 2004;Simon et al, 2001;Takamatsu et al, 2005;Wei et al, 2002) and upward drift effects on tonic neuronal excitability (Gilbert and Mack, 1999). Chronic in vivo recordings in freely behaving animals avoid some of these limitations and complications (summarized in Table 1).…”

Section: In Vitro In Vivo Anesthetizedmentioning

confidence: 99%

Bidirectional synaptic plasticity in the dentate gyrus of the awake freely behaving mouse

Koranda

Masino

Blaise

2008

Journal of Neuroscience Methods

View full text Add to dashboard Cite

There is significant interest in in vivo synaptic plasticity in mice due to the many relevant genetic mutants now available. Nevertheless, use of in vivo models remains limited. To date long-term potentiation (LTP) has been studied infrequently, and long-term depression (LTD) has not been characterized in the mouse in vivo. Herein we describe protocols and improved methodologies we developed to record hippocampal synaptic plasticity reliably from the dentate gyrus of the awake freely behaving mouse. Seven days prior to recording, we implanted microelectrodes encapsulated within a lightweight, low profile head stage assembly. On the day of recording, we induced either LTP or LTD in the awake freely behaving animal, and monitored subsequent changes in population spike amplitude for at least 24h. Using this protocol we attained 80% success in inducing and maintaining either LTP or LTD. Recording from a chronic implant using this improved methodology is best suited to reveal naturally occurring brain activity and avoids both acute effects of local electrode insertion and drifts in neuronal excitability associated with anesthesia. Ultimately a reliable freely behaving mouse model of bi-directional synaptic plasticity is invaluable for full characterization of genetic models of disease states and manipulations of the mechanisms implicated in learning and memory.

show abstract

“…Although urethane is known to stimulate the activation of the HPA axis and to increase the level of circulating corticosterone (Hamstra et al, 1984;Smythe et al, 1987), urethane-induced increase in circulating corticosterone did not affect the ability to induce LTP in control animals (Shirasaka and Wasterlain, 1995;Gilbert and Mack, 1999), indicating that relatively high levels of circulating corticosterone are required to block the induction of LTP in DG.…”

Section: Discussionmentioning

confidence: 99%

Contrasting Roles of Corticosteroid Receptors in Hippocampal Plasticity

Avital

Segal²,

Richter‐Levin³

2006

J. Neurosci.

View full text Add to dashboard Cite

Elevated levels of corticosteroid hormones, presumably occupying both mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs), have been reported to impair synaptic plasticity in the hippocampus as well as the acquisition of hippocampus-dependent memories. In contrast, recent evidence suggests that activation of MRs enhance cognitive functions. To clarify the roles of different steroid receptors in hippocampal plasticity, young adult rats were injected with the GR antagonist RU38486 (mifepristone) or the MR antagonist Spironolactone before the exposure to an acute swim stress. Hippocampal responses to perforant path stimulation were then recorded in anesthetized rats. Stress combined with RU38486 produced a striking facilitation of LTP. Spironolactone enabled only short-term potentiation that reversed to long-term depression (LTD) in the stressed animals. Finally, the blockade of both MRs and GRs led to impairment of long-term potentiation. These findings indicate that MRs and GRs assume opposite roles in regulation of synaptic plasticity after acute exposure to stressors.

show abstract

Field potential recordings in dentate gyrus of anesthetized rats: Stability of baseline

Cited by 28 publications

References 26 publications

Mutation at the TrkB PLCγ-docking site affects hippocampal LTP and associative learning in conscious mice

Mutation at the TrkB PLCγ-docking site affects hippocampal LTP and associative learning in conscious mice

Bidirectional synaptic plasticity in the dentate gyrus of the awake freely behaving mouse

Contrasting Roles of Corticosteroid Receptors in Hippocampal Plasticity

Contact Info

Product

Resources

About