Fig. 3: Auditory cortex directly projects to layer 2/3, and not layer 5, pyramidal neurons in the primary somatosensory cortex.
From: Auditory input enhances somatosensory encoding and tactile goal-directed behavior
a Schematic of experimental paradigm. Photoactivatable opsin (ChR2) was injected into the auditory cortex (AuCx) and recordings were performed in the primary somatosensory cortex (S1). b Example of voltage responses in a L2/3 pyramidal neuron to photoactivation of auditory cortex axons with increasing LED power (470 nm, 2 ms, 0.16–5 mW). Inset, Average synaptic response to increasing LED (n = 16 neurons). c Example synaptic responses in a L2/3 pyramidal neuron to LED (470 nm; 2 ms) in control (black) and during bath application of DNQX + AP5 (orange). Inset, Average LED-evoked voltage responses in control (black), DNQX + AP5 (orange; p = 0.0023), and washout (green; n = 5 neurons; p = 0.128). d Example of voltage in a L2/3 pyramidal neuron to somatic current pulse alone (gray; 200 pA, 100 ms) and paired with LED (blue; 470 nm; 2 ms). e Rheobase during control current injection (gray) and paired with LED (blue; 470 nm; 2 ms) in L2/3 pyramidal neurons (n = 6 neurons; p = 0.03; pshuffled = 0.813). f Action potential (AP) threshold during control somatic current injection (gray) and current injection paired with LED (blue; 470 nm; 2 ms) in L2/3 pyramidal neurons (n = 6 neurons; p = 0.12; pshuffled = 0.313). g Patch-clamp recordings were performed in L2/3 and L5 pyramidal neurons in the same somatosensory brain slice. h Average light-evoked synaptic responses to photoactivation of auditory cortex axons (470 nm, 2 ms) in different L2/3 (black) and L5 (gray) pyramidal neurons. i Histogram of peak amplitudes of LED-evoked synaptic responses in L2/3 (black) and L5 (gray) pyramidal neurons. Inset, Histogram of L5 pyramidal neuron responses. j Same as (d) for a L5 pyramidal neuron. k Same as (e) for L5 pyramidal neurons (n = 8 neurons; p = 0.41; pshuffled = 0.297). l Same as (f) for L5 pyramidal neurons (n = 8 neurons; p = 0.56; pshuffled = 0.57). Two-tailed Wilcoxon matched-pairs signed rank test. Error bars represent S.E.M. *p < 0.05.
