Journal: Communications Biology

Article Title: Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits

doi: 10.1038/s42003-020-1073-3

Figure Lengend Snippet: a Illustration of the two-way avoidance shuttle-box training with chronic recordings in behaving Mongolian gerbils. Subjects were trained to respond to two different pure tone frequencies (1 and 4 kHz; conditioned stimulus—CS) in a Go/NoGo task design to avoid an unconditioned stimulus (US—mild foot shock). During the discrimination phase the contingency of the CS can be either “Go” (CS+) or “NoGo” (CS−) leading to four possible behavioral outcomes (hit, miss, correct rejection—Corr. Rej., false alarm—FA). Right, Illustration of consecutive CS within a trial, length of the observation window (6 s), interstimulus interval (1.5 s) and behavioral choices. (Gerbil and loudspeaker images taken and modified from https://www.freepik.com/06/2019 ) ( b ). Averaged conditioned responses (CR) to both CS in the detection and discrimination phase as a function of training sessions (detection/discrimination: n = 9/8). During detection (gray area), hit rates reach almost 80% for both “Go”-stimuli (1 and 4 kHz). At the beginning of the discrimination phase (yellow area), conditioned responses dropped for both stimuli (<10% hit rate). The performance gradually increased reaching almost 80% for the hit rates, while false alarm rates stayed around 20%. Error bars indicate the standard error of mean (±s.e.m.). Single dots indicate CR rates of individual subjects. Supplementary Fig. shows corresponding d′ learning curves. c Histogram with distributions of the averaged CR reaction times over all trials separately for the detection (top) and discrimination (bottom) phase and hits (red) and false alarms (blue). The majority of CR’s happen after the second CS presentation. d In vivo multichannel LFP recordings were obtained by single-shank silicon probes chronically implanted perpendicular to the surface of the auditory cortex targeting all cortical layers (I–VI). From laminar LFP signals single-trial current source density (CSD) distributions were calculated (here shown is a CSD averaged over 30 repetitions). During CS presentation (200 ms) tone-evoked CSD components appeared as current sink (in blue) and source (in red) activity reflecting the well-known feedforward information flow of sensory information in the A1 , . Supplementary Fig. shows stability of CSD profiles recorded over the training period.

Article Snippet: If subjects incorrectly crossed within this 12–15 s, the behavioral choice was counted as “FA.” Conditioned stimuli (CS): As CS, we used auditory pure tone stimuli, which were generated in Matlab (MathWorks, R2012b), converted into an analog signal by a data acquisition card (NI PCI-6733, National Instruments), rooted through an attenuator (gPAH Guger, Technologies), and amplified (Black Cube Linear, Lehman).

Techniques: Modification, In Vivo, Activity Assay

Journal: Communications Biology

Article Title: Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits

doi: 10.1038/s42003-020-1073-3

Figure Lengend Snippet: a Representative example of an averaged CSD profile across all trials of the detection (left) and discrimination (right) phase of one subject. The CSD profiles show the tone-evoked activity after the first presentation of both conditioned stimuli within a trial (top: 1 kHz, bottom: 4 kHz; tone duration: 200 ms; indicated by dashed bar in upper left panel). Evoked CSD patterns between the two pure tones frequencies showed no obvious differences during the detection phase but yielded considerably different CSD patterns during discrimination for the CS+. b Corresponding raw AVREC traces (z-norm.) for the detection (left) and discrimination (right) phase for the two conditioned stimuli. The shaded error bars indicate the standard error of mean (±s.e.m) of the averaged AVREC traces. The raw traces between the two pure tones frequencies showed no obvious differences during the detection phase, but considerably different activity between CS+ and CS− trials during discrimination. c RMS values of the AVREC (time window of 500 ms beginning at each tone presentation and z-normalized) shown for each of the four consecutive CS and separated by the different behavioral outcomes during the two task phases (detection/discrimination: n = 9/8). Box plots represent median (bar) and interquartile range, and bars represent full range of data. Significance bar indicate differences revealed by pairwise testing (one-way rmANOVA; p < 0.05). Schematic illustration of the evoked cortical activity in dependence of stimulus frequency and task rule are shown in gray inserts.

Article Snippet: If subjects incorrectly crossed within this 12–15 s, the behavioral choice was counted as “FA.” Conditioned stimuli (CS): As CS, we used auditory pure tone stimuli, which were generated in Matlab (MathWorks, R2012b), converted into an analog signal by a data acquisition card (NI PCI-6733, National Instruments), rooted through an attenuator (gPAH Guger, Technologies), and amplified (Black Cube Linear, Lehman).

Techniques: Activity Assay