Aberrant Phase Precession of Lateral Septal Cells in a Maternal Immune Activation Model of Schizophrenia Risk May Disrupt the Integration of Location with Reward

Area of Science:

• Neuroscience
• Schizophrenia Research
• Behavioral Neuroscience

Background:

• Schizophrenia is associated with disrupted spatial memory and reward processing.
• The lateral septum (LS) integrates spatial and reward information.
• Maternal immune activation (MIA) is a risk factor for schizophrenia.

Purpose of the Study:

• To investigate the impact of MIA on spatial representation in the rat LS.
• To determine if MIA affects the phase coding of location-reward relationships.

Main Methods:

• Electrophysiological recordings in the rostral LS of adult male rats.
• Analysis of LS cell firing phase relative to hippocampal theta oscillations.
• Comparison between control and MIA-exposed rats navigating a linear track toward a reward.

Main Results:

• LS cells exhibit phase precession, encoding spatial location relative to reward.
• MIA rats showed steeper phase precession slopes, indicating ambiguous location coding.
• Phase convergence toward reward location was weaker and shifted in MIA rats, disrupting reward signaling.

Conclusions:

• MIA disrupts the phase-based encoding of location-reward relationships in the LS.
• This disruption may lead to smeared reward representations, potentially contributing to schizophrenia pathophysiology.
• The LS plays a critical role in converting hippocampal spatial information into reward-related signals.