Oscillations in the embryonic chick olfactory bulb: initial expression and development revealed by optical imaging...

Area of Science:

• Neuroscience
• Developmental Biology
• Olfactory System Research

Background:

• Previous studies confirmed synaptic transmission in embryonic chick olfactory bulbs by days 6-7.
• Neural oscillations are a known feature in the olfactory systems of various species.

Purpose of the Study:

• To investigate the emergence and developmental trajectory of neural oscillations in the embryonic chick olfactory bulb.
• To characterize the temporal profiles and spatial distribution of these oscillations during embryogenesis.

Main Methods:

• Utilized a multiple-site optical recording technique with voltage-sensitive dyes.
• Stimulated the olfactory nerve and recorded postsynaptic responses in embryonic chick olfactory bulbs at various developmental stages (days 6-12).

Main Results:

• Simple monophasic postsynaptic signals were observed at embryonic days 6-8.
• Multi-phasic signals and oscillatory events, primarily in the distal olfactory bulb, appeared by embryonic day 9.
• Oscillation incidence, duration, and waveform complexity increased with development, lasting up to a minute by day 12.
• Oscillation frequency slightly increased but remained within the theta range (days 9-12).

Conclusions:

• Neural oscillations are generated in the embryonic chick olfactory bulb starting around embryonic day 9.
• The ontogenetic dynamics reveal a progressive increase in oscillatory activity complexity and duration during development.
• These findings provide insights into the functional maturation of the developing olfactory system.