Recording mouse ultrasonic vocalizations to evaluate social communication.
Unsupervised analysis of mouse USVs. (A) Spectrogram showing frequency versus time for a 30s excerpt of USVs from a P7 saline treated mouse recording. (B) Left; examples of most highly represented syllable types learned from P7 data sets (‘‘repertoire units,’’ RUs). Right; repertoires showing 80 syllable types (RUs; black numbers) learned from processing recordings from P7 saline and naloxone treated groups. RUs are listed in order of frequency of use from left to right (1–80). Red rectangles highlight RUs that are distinct from a reference P7 control group. (C) Similarity matrix of the spectral shapes of pairs of RUs learned from P7 and P14 data sets. The matrix diagonal gives the Pearson correlation for sequential pairs for P7 saline, P14 saline and P7 naloxone treated mice (compared to a P7 reference dataset). Black boxes highlight RUs that show low similarity across groups (Pearson correlation ≤ 0.6). (D) Left; values obtained from diagonal of similarity matrices show a decrease in the average Pearson correlation for all P14 data sets, suggesting a developmental effect on vocalization patterns; Right; naloxone treated animals.
Imaging cortical dynamics in mouse models of neurodevelopmental disorders.
In vivo imaging of neuronal circuits during development. (A) Left; craniotomy performed in PND11 saline treated mouse. Dorsal view shows pial layer and superficial vasculature. Right; imaging area (from red inset in (Left) shows hundreds of cortical neurons in L2/3 expressing a genetically encoded calcium sensor (ROI, region of interest). (B) Example fluorescent calcium transients from individual P11 neurons are highly synchronized (left) and low in frequency (right). (C) Left; Pearson matrix, Center; percent of active cells and Right; mean Pearson of cortical activity at P10-12 and P21-24.
Dendritic protrusions are developmentally regulated in vivo.
Imaging spine dynamics in vivo. Scale bar = 2 mm
Charactering electrophysiological properties of L2/3 pyramidal neurons in medial prefrontal cortex.
Charactering electrophysiological properties of L2/3 pyramidal neurons on medial prefrontal cortex. (A) Mouse embryos were electroporated in utero with GFP-tagged plasmid at E14.5 and analyzed at P21. Scale bar represents 100 mm (left) and 40 mm (right). (B) Example trace of GFP-positive regular spiking L2/3 neuron. Scale bar represents 100 pA/20 mV, = 125 ms. (C) Input-output relationship fitted with a line (red). Slope = 0.10 ± 0.01 APs/pA. Rheobase = 62.25 ± 6.32 pA, resting Vm = -74.56 ± 0.34 mV. (D-E) Action potential kinetics from GFP-positive L2/3 neurons. Time-to-peak (TTP): 0.762 ± 0.05 ms. Half-width (HW) = 1.42 ± 0.05 ms. Decay 10-90%: 1.21 ± 0.05 ms. (F) Example of excitatory postsynaptic currents (EPSCs) recorded from GFP-positive L2/3 neurons. Scale bar represents 25 pA/100 ms. (G-H) EPSC amplitude = -61.21 ± 17.35 pA. EPSC inter-event interval (IEI): 81.67 ± 3.29 ms. EPSC Time-to-peak (TTP): 1.76 ± 0.01 ms. EPSC decay time: 5.40 ± 0.08 ms.
Connectivity of L2/3 prefrontal cortex networks examined with transsynaptic rabies mapping.
(A) Representative image of viral injection hot spot in L2/3 of the cortex (low magnification, left). Higher magnification images (right) showing starter cells (see merge, white arrowheads, containing AAV-TVA-Glyco-GFP, magenta, and RVdG-RFP, yellow). Scale bar = 20 mm. (B) Brain-wide connectivity maps of presynaptic networks that input to L2/3 mPFC excitatory neurons in P24 control mice. White arrow heads show magnified retrogradely labeled cells located in the orbitofrontal cortex (Orb. Ctx) and the anteromedial thalamic nucleus (Am Thal., a polymodal thalamic nucleus). Scale bar = 600 mm. Scale bar = 50 mm.
Behavioral tests: Maternal homing task. We performed a maternal homing task that exploits the tendency of juvenile mice (P18-P21) to maintain body contact with the mother, and tests olfactory, visual and motor capacities.
Behavioral tests: Elevated zero maze (EZM) and open field arena (OF). We used the OF and the EZM as paradigms to measure the effect of environmental and genetic manipulations on anxiety-like behavior.
Neuroscience at BU: Behavioral tracking during exploration in an anxiogenic environment (William Yen and Tushare Jinadasa, PhD)