The response of cells to fimbria or thalamus single-pulse stimula

The response of cells to fimbria or thalamus single-pulse stimulation 50 ms following single-pulse stimulation of the PFC was also considered in a subgroup of cells (n =

13). In some cases (n = 12), we injected depolarizing current through the recording electrode (between −0.2 and 0.2 nA) to record an F1 or T1 response during a depolarized membrane potential similar to that at which F2 and T2 responses were evoked. A subset of cells (n = 13) was also subjected to a stimulus protocol in which a single-pulse stimulus was delivered to the PFC (1.0 mA; 0.5 ms; PFC1), followed at a 500 ms latency by a train stimulation of the fimbria or thalamus (50 Hz train of ten pulses; 1.0 mA; 0.5 ms), after which a second pulse was delivered to the PFC (1.0 mA; 0.5 ms; PFC2). In all cases, responses to stimulation were averaged over all of the repetitions selleckchem delivered to the cell. To calculate the magnitude of EPSP suppression, we first determined the Cilengitide cost ratio of the control and test pulses. For instance, in the cases in which we stimulated the fimbria, we calculated F2/F1 using response amplitudes. As this quotient represents the proportion of the response retained following PFC train stimulation, we expressed the difference between 1 and F2/F1 as a percentage to indicate the magnitude of EPSP suppression. After baseline

and stimulus-response recordings were collected, cells were filled with Neurobiotin by passing positive current (1 nA, 200 ms pulses, 2 Hz) for at least 10 min through the recording electrode. Upon completion of recording experiments, animals unless were euthanized with an overdose of sodium pentobarbital (100 mg/kg) and transcardially perfused with cold saline followed by 4% paraformaldehyde. Brains were then removed and postfixed in 4% paraformaldehyde for at least 24 hr before being transferred to a 30% sucrose solution in 0.1 M phosphate buffer. After at least 48 hr in sucrose, brains were cut into 50 μm sections using a freezing microtome and placed

into phosphate buffer. Sections through PFC and fimbria or thalamus were mounted on gelatin-coated slides and Nissl stained to verify placement of stimulating electrodes. Sections through VS were processed for visualization of Neurobiotin-filled cells and then mounted on gelatin-coated slides and Nissl stained. All stained slides were coverslipped and examined microscopically for cell and electrode location. This work was supported by grants from the National Institutes of Health (R01 MH060131) to P.O.’D. and (R31 MH092043) to G.G.C. “
“Coordinated movement relies on the integration of sensory feedback signals with core motor circuits. In mammals, motor performance is refined by sensory feedback signals that convey information from proprioceptive afferents as well as from mechanoreceptive afferents activated by diverse cutaneous receptors.

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