In this article we will review available evidence concerning the effects of forebrain
catecholaminergic and cholinergic activity on verbal perseveration. The anatomy and
physiology of these two major neuropharmacological systems make it likely that they
influence speech and language functioning directly as well as the cognitive systems
that have an indirect impact on speech and language functions. Both catecholaminergic
and cholinergic agents have been shown to influence executive cognitive functions
(ECFs) such as “resistance to interference” and “attentional switching” as well as
mnemonic encoding and retrieval processes. The ECF effects are most likely mediated
by prefrontal cortex; mnemonic processes are mediated by both prefrontal and temporal
lobes. Although no full-scale clinical trials on the effects of pharmacological agents
on verbal perseveration have been conducted as yet, existing preclinical trials suggest
that both presynaptic and postsynaptic dopaminergic agents can reduce perseverative
responding by increasing inhibitory control processes. Cholinesterase inhibitors and
other cholinergic agents can reduce perseverative responding by reducing verbal intrusions.
Perseveration - catecholamines - dopamine - norepinephrine - acetylcholine - executive
function - prefrontal cortex - inhibition
