Neuroscience 2005 Abstract
| Presentation Number: | 539.9 |
|---|---|
| Abstract Title: | Systemic blockade of NMDA receptors with CPP does not alter firing rate or bursting of medial prefrontal cortex neurons. |
| Authors: |
Burgos-Robles, A.*1
; Vidal-Gonzalez, I.1
; Quirk, G. J.1
1Dept Physiol, Ponce School of Medicine, Ponce, Puerto Rico |
| Primary Theme and Topics |
Cognition and Behavior - Animal Cognition and Behavior -- Emotional learning, memory systems, and modulation of memory |
| Secondary Theme and Topics | Neural Excitability, Synapses, and Glia: Cellular Mechanisms<br />- Synaptic Plasticity<br />-- Spines and structural plasticity |
| Session: |
539. Extinction Poster |
| Presentation Time: | Monday, November 14, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # NN13 |
| Keywords: | extinction, NMDA, prefrontal cortex, amygdala |
Systemic blockade of NMDA receptors with the competitive antagonist CPP impairs long-term but not short-term memory for fear extinction. We recently demonstrated that infusing CPP directly into the ventromedial prefrontal cortex (vmPFC) had the same effect (Burgos-Robles et al., SFN 2004), in agreement with lesion and unit-recording data implicating the vmPFC in consolidation of fear extinction. However, it was recently reported that administration of the non-competitive NMDA antagonist MK-801 dramatically increased the spontaneous firing rate and decreased the bursting of prelimbic (PL) vmPFC neurons (Jackson et al., 2004). This suggests that the behavioral effects of CPP we observed might have been due to alterations in firing rate or bursting, rather than impaired synaptic plasticity. To investigate this possibility, rats were chronically implanted with movable microelectrodes aimed at PL or infralimbic (IL) vmPFC. Following recovery, rats were systemically injected with saline followed one hour later by CPP at the same dose used in our behavioral study (10 mg/kg). A total of 29 neurons (21 in PL, 8 in IL) from 4 rats were studied. The mean firing rate with CPP (4.24 ± 1.21 Hz) did not significantly differ from saline (3.58 ± 1.00 Hz). The mean % bursting (based on surprise method, S = 5) did not differ between CPP and saline (7.71 ± 2.10 and 8.65 ± 1.42, respectively). The proportion of cells showing a significant increase (99% confidence) in firing rate under CPP (31%) was not different from the proportion showing significant decrease (24%). These data suggest that impaired fear extinction after CPP is not due to increased vmPFC excitability during training. MK-801 induced increases in firing rate might be due to increased dopamine release in vmPFC following MK-801 administration (Mathe et al. 1999).
Supported by R01-MH58883, S06-GM08239, and R21-MH072156
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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