Biomedical Engineering Reference
In-Depth Information
Fig. 5.5
Pre- and postsynaptic Ca
2+
imaging of interneuron 10-3. (
a
) Ca
2+
responses to air-current
stimuli applied from the anterior orientation (0°). The left two (monochrome) images are raw pre-
stimulus fl uorescent images. A series of six images to the right of the baseline images are pseudo-
colored images indicating the [Ca
2+
]
i
elevation in the sensory afferents (
upper
) and the interneuron
10-3 (
lower
). (
b
) The time courses of changes in
Δ
F/F
at 535 nm wavelength (presynaptic) Ca
2+
signals (
blue traces
) and
F/F
at 610 nm wavelength (postsynaptic) Ca
2+
signals (
magenta traces
).
These traces were recorded in the dendritic branch shown as
ROIs
in the raw fl uorescent images in
(
a
). The air-current stimuli were applied from eight different orientations (modifi ed from Ogawa
et al.
2008
)
Δ
wavelength), which indicates an elevation in [Ca
2+
]
i
at the dendritic region of the
postsynaptic GI. Simultaneous measurement of light with 535 nm wavelength at
the same recording area showed a fl uorescence increase of OGB-1 indicating a rise
in Ca
2+
in the sensory afferents. We recorded the pre- and postsynaptic local
responses to the air-current stimuli on each dendrite of the GIs. We applied air-
current stimuli from eight different directions in the horizontal plane and examined
the directional sensitivity of the Ca
2+
responses of the sensory afferents and of the
GI. Figure
5.5
shows typical responses to the air-current stimuli in the pre- and
postsynaptic Ca
2+
changes, which were measured at three different dendritic
branches of the GI named 10-3. Presynaptic and postsynaptic Ca
2+
responses
showed directional tuning properties in their response amplitudes. Although the
directional tuning properties of postsynaptic responses on individual dendrites var-
ied from each other, the directional sensitivity of dendritic Ca
2+
responses corre-
sponded to those indicated by Ca
2+
signals in presynaptic afferents arborizing on
that dendrite. This similarity in the directional sensitivity between the pre- and post-
synaptic Ca
2+
responses suggests that the individual dendrite with a distinct tuning
