Functional mapping of single spines in cortical neurons in vivo

Chen, X., Leischner, U., Rochefort, N.L., Nelken, I., Konnerth, A. (2011). Functional mapping of single spines in cortical neurons in vivo. Nature 475.

Two-photon (LOTUS) imaging of individual spines in auditory cortex. Present tone stimuli at different frequencies and volumes. Spines show a variety of tuning properties, but no clear clustering on dendrites is observed.

Figure 3 | Frequency tuning and heterogeneous distribution of individual
active spines. a,Upper panel: two-photonimage of a dendritic segment of a layer
2/3 neuron (average of 6,250 frames). Lower panel: calciumresponses (average of
five trials) from two spines (S) marked by red arrowheads in the upper panel,
during 11 pure tones (from 2kHz to 40 kHz at 0 dB attenuation). Two
neighbouring spines indicated by blue arrowheads did not respond to any of the
11pure tones.b,Upper panel: frequency tuning curve of thenarrowly tuned spine
S1 shown in a. Data points are the mean values of response amplitudes from
five trials. Lower panel: average tuning curve normalized to the highestamplitude
(n538 spines, 10 neurons). c,Upper panel: frequency tuning curve of thewidelytuned
spine S2 shown in a. Lower panel: average tuning curve, normalized to the
highest amplitude (n546 spines, 10 neurons). Error bars in b and c show s.e.m.
d, Distribution of frequency tuning widths (DFrequency) of pure-tone-activated
spines (n584 spines, 10 neurons). e, Heterogeneous distribution of pure-toneactivated
spines along dendrites. Cartoons of dendritic segments from four
neurons, with numbers indicating the effective frequencies for each active spine.
Narrowly tuned and widely tuned spines are indicated by red and blue dots,
respectively. The neurons correspond to, respectively, neuron 25, neuron 27,
neuron 29 and neuron 30 in Supplementary Table 1. f, Plot of the most effective
frequency of a given spine versus themost effective frequency of its nearest active
spine (seeMethods).Dots along the red line correspond to pairs of spines that had
the same most-effective frequency (n569 pairs, 24 dendrites, 10neurons).
g, Plot of the distance between neighbouring active spines versus the difference
between their respective most-effective frequencies. For each pair of spines, the
reference spine (blue circle) was defined as the left spine and the test spine (red
circle) was defined as the neighbouring active spine on the right. The
measurements were performed sequentially from left to right in each dendrite
(n551 pairs, 24 dendrites, 10 neurons). Dots along the red line correspond to
spine pairs that had the same most-effective frequency. Numbers on the right
indicate distance ranges between pairs of spines with a difference between their
most effective frequencies of 0–1, 1–2, 2–3 and 3–4 octaves.