Hippocampal slices were prepared as previously described28 (link) from Baf53b+/− het mice, BAF53ΔHDlow, BAF53ΔHDhigh, and wildtype mice (approximately 2 months of age). Transverse hippocampal slices (300 μm) through the mid-third of the septotemporal axis of the hippocampus were placed in an interface recording chamber containing preheated artificial cerebrospinal fluid (ACSF; in mM): 124 NaCl, 3 KCl, 1.25 KH2PO4, 1.5 MgSO4, 2.5 CaCl2, 26 NaHCO3, and 10 D-glucose and maintained at 31 ± 1°C). Slices were continuously perfused with at a rate of 1.75-2 ml/min while the surface was exposed to warm, humidified 95% O2 / 5% CO2. Recordings began following at least 2 hr of incubation.
Field excitatory postsynaptic potentials (fEPSPs) were recorded from CA1b stratum radiatum using a single glass pipette (2-3 MΩ). Bipolar stainless steel stimulation electrodes (25 μm diameter, FHC) were positioned at two sites (CA1a and CA1c) in the apical Schaffer collateral-commissural projections to provide activation of separate converging pathways of CA1b pyramidal cells. Pulses were administered in an alternating fashion to the two electrodes at 0.03 Hz using a current that elicited a 50% maximal response. After establishing a stable baseline, long-term potentiation (LTP) was induced by delivering 5 or 10 ‘theta’ bursts (each burst was four pulses at 100 Hz and bursts were separated by 200 msec). Data were collected and digitized by NAC 2.0 Neurodata Acquisition System (Theta Burst Corp.).
Slices used for whole-cell recordings were prepared as previously described23 (link),56 (link). Briefly, slices were placed in a submerged recording chamber and continuously perfused at 2–3 ml/min with oxygenated (95% O2/5% CO2) ACSF at 32°C. Whole-cell recordings were made with 3–5 MΩ recording pipettes filled with solution of the following composition (in mM): 130 K-gluconate, 0.1 EGTA, 0.5 MgCl2, 10 HEPES, 2 ATP (pH 7.25, 285 mosM) using an Axopatch 200A amplifier (Molecular Devices). Miniature excitatory postsynaptic currents (mEPSCs) were recorded at a holding potential of −70 mV in the presence of tetrodotoxin (1 μM) and bicuculline (50 μM). Data were filtered at 2 kHz, digitized at 1–5 kHz, stored on a computer, and analyzed off-line using Mini Analysis Program (Synaptosoft), Origin (OriginLab), and pCLAMP 7 (Molecular Devices) software.
Field excitatory postsynaptic potentials (fEPSPs) were recorded from CA1b stratum radiatum using a single glass pipette (2-3 MΩ). Bipolar stainless steel stimulation electrodes (25 μm diameter, FHC) were positioned at two sites (CA1a and CA1c) in the apical Schaffer collateral-commissural projections to provide activation of separate converging pathways of CA1b pyramidal cells. Pulses were administered in an alternating fashion to the two electrodes at 0.03 Hz using a current that elicited a 50% maximal response. After establishing a stable baseline, long-term potentiation (LTP) was induced by delivering 5 or 10 ‘theta’ bursts (each burst was four pulses at 100 Hz and bursts were separated by 200 msec). Data were collected and digitized by NAC 2.0 Neurodata Acquisition System (Theta Burst Corp.).
Slices used for whole-cell recordings were prepared as previously described23 (link),56 (link). Briefly, slices were placed in a submerged recording chamber and continuously perfused at 2–3 ml/min with oxygenated (95% O2/5% CO2) ACSF at 32°C. Whole-cell recordings were made with 3–5 MΩ recording pipettes filled with solution of the following composition (in mM): 130 K-gluconate, 0.1 EGTA, 0.5 MgCl2, 10 HEPES, 2 ATP (pH 7.25, 285 mosM) using an Axopatch 200A amplifier (Molecular Devices). Miniature excitatory postsynaptic currents (mEPSCs) were recorded at a holding potential of −70 mV in the presence of tetrodotoxin (1 μM) and bicuculline (50 μM). Data were filtered at 2 kHz, digitized at 1–5 kHz, stored on a computer, and analyzed off-line using Mini Analysis Program (Synaptosoft), Origin (OriginLab), and pCLAMP 7 (Molecular Devices) software.
