All procedures in non-human primates reported here followed the guidelines of the National Institutes of Health and were approved by the Massachusetts Institute of Technology’s Committee on Animal Care.
The local field potential (LFP) was recorded from a rhesus macaque (Macaca mulatta) aged 8 years (female, 6.6 kg). Ketamine was administered as a single 20 mg/kg bolus intramuscular dose. Fifteen minutes prior to ketamine administration, glycopyrrolate (0.01 mg/kg) was delivered to reduce salivation and airway secretions. The LFP was recorded from an 8 × 8 iridium-oxide contact microelectrode array (‘Utah array’, MultiPort: 1.0 mm shank length, 400 μm spacing, Blackrock Microsystems, Salt Lake City, UT) implanted in the frontal cortex (vlPFC). The LFP was continuously recorded from 1–5 minutes prior to ketamine injection up to 18–20 minutes following ketamine injection. The LFP recorded at 30 kHz, was low-pass filtered to 250 Hz and then downsampled to 1 kHz. The LFP was bandpass filtered between 0.5–100 Hz using a 2nd order butterworth filter and plotted. The spectrogram was derived using the discrete fourier transform.
The local field potential (LFP) was recorded from a rhesus macaque (Macaca mulatta) aged 8 years (female, 6.6 kg). Ketamine was administered as a single 20 mg/kg bolus intramuscular dose. Fifteen minutes prior to ketamine administration, glycopyrrolate (0.01 mg/kg) was delivered to reduce salivation and airway secretions. The LFP was recorded from an 8 × 8 iridium-oxide contact microelectrode array (‘Utah array’, MultiPort: 1.0 mm shank length, 400 μm spacing, Blackrock Microsystems, Salt Lake City, UT) implanted in the frontal cortex (vlPFC). The LFP was continuously recorded from 1–5 minutes prior to ketamine injection up to 18–20 minutes following ketamine injection. The LFP recorded at 30 kHz, was low-pass filtered to 250 Hz and then downsampled to 1 kHz. The LFP was bandpass filtered between 0.5–100 Hz using a 2nd order butterworth filter and plotted. The spectrogram was derived using the discrete fourier transform.