Distinct Ventral Hippocampus Network Properties in Dissociated Cultures

Area of Science:

• Neuroscience
• Cellular Neuroscience
• Hippocampal Neurophysiology

Background:

• The hippocampus plays a critical role in cognitive and affective functions.
• Distinct functional properties exist between the dorsal hippocampus (DH) and ventral hippocampus (VH) along its axial dimension.
• Longitudinal pathways modulate functional differences between DH and VH sectors.

Purpose of the Study:

• To identify intrinsic functional differences between prenatal dorsal hippocampus (DH) and ventral hippocampus (VH) neurons.
• To compare the spontaneous activity and network burst generation of dissociated DH and VH cultures.

Main Methods:

• Dissociated monolayer cultures were prepared from prenatal DH and VH.
• Spontaneous neuronal network activity was imaged using Fluo-2 AM calcium indicator.
• Network burst generation was assessed following electrical stimulation of single cells.

Main Results:

• DH and VH cultures displayed similar morphological attributes.
• VH cultures exhibited significantly higher spontaneous network activity than DH cultures.
• VH neurons were more effective in triggering postsynaptic network bursts upon stimulation and showed higher excitability.

Conclusions:

• Dissociated VH neurons are intrinsically more excitable and sensitive to electrical stimulation than DH neurons.
• VH's heightened excitability suggests a greater propensity for network burst generation and potential epileptic activity.
• These findings highlight intrinsic functional divergence between hippocampal sectors even in simplified culture models.