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Assessment of sensorimotor gating following selective lesions of cholinergic pedunculopontine neurons
Author(s) -
MacLaren Duncan A. A.,
Markovic Tamara,
Clark Stewart D.
Publication year - 2014
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12716
Subject(s) - neuroscience , gating , cholinergic , pedunculopontine nucleus , pedunculopontine tegmental nucleus , psychology , medicine , deep brain stimulation , parkinson's disease , disease
Sensorimotor gating is the state‐dependent transfer of sensory information into a motor system. When this occurs at an early stage of the processing stream it enables stimuli to be filtered out or partially ignored, thereby reducing the demands placed on advanced systems. Prepulse inhibition ( PPI ) of the acoustic startle reflex ( ASR ) is the standard measure of sensorimotor gating. A brainstem–midbrain circuitry is widely viewed as mediating both PPI and ASR . In this circuitry, the pedunculopontine tegmental nucleus ( PPT g) integrates sensory input and cortico‐basal ganglia output and, via presumed cholinergic signaling, inhibits ASR ‐generating neurons within the reticular formation. Non‐selective damage to all neuronal types within PPT g reduces PPI . We assessed whether this effect originates in the loss of cholinergic signaling by examining ASR and PPI in rats bearing non‐selective (excitotoxic) or selective cholinergic (Dtx‐ UII ) lesions of PPT g. Excitotoxic lesions had no effect on ASR but reduced PPI at all prepulse levels tested. In contrast, selective depletion of cholinergic neurons reduced ASR to the extent that PPI was not measurable with standard (10–20 s) inter‐trial intervals. Subsequent testing revealed appreciable ASR s could be generated when the inter‐trial interval was increased (180 s). Under these conditions, PPI was assessed and no deficits were found after lesions of cholinergic PPT g neurons. These results show that cholinergic output from PPT g is essential for rapidly regenerating the ASR , but has no influence on PPI . Results are discussed in terms of sensorimotor integration circuitry and psychiatric disorders that feature disrupted ASR and PPI .