Reduced prepulse inhibition in rats with entorhinal cortex lesions

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Psychopharmacology

Background:

• Prepulse inhibition (PPI) is a measure of sensorimotor gating, reduced in neuropsychiatric disorders and dopamine-dysregulated states.
• The entorhinal cortex, crucial for hippocampal input, is implicated in cognitive functions potentially affected in disorders like schizophrenia.

Purpose of the Study:

• To investigate the relationship between the entorhinal cortex and prepulse inhibition (PPI).
• To examine the role of dopaminergic systems in mediating the entorhinal cortex's influence on sensorimotor gating.

Main Methods:

• Bilateral entorhinal cortex lesions were induced using ibotenic acid in rats.
• Acoustic startle experiments were conducted, assessing PPI during treatment with haloperidol (a dopamine antagonist) or saline.
• Startle movement amplitude was measured to control for non-specific effects.

Main Results:

• Bilateral entorhinal cortex lesions significantly reduced PPI.
• Haloperidol treatment partially restored PPI in lesioned rats.
• Neither ibotenic acid injection nor haloperidol affected the startle movement amplitude.

Conclusions:

• The entorhinal cortex is involved in sensorimotor gating, potentially through dopaminergic circuits.
• Dopaminergic modulation, possibly via the nucleus accumbens, may mediate the entorhinal cortex's effect on PPI.
• Entorhinal cortex dysfunction could contribute to cognitive deficits in disorders like schizophrenia due to its role in hippocampal function.