Axonal connections of thalamic posterior paralaminar nuclei with amygdaloid projection neurons to the cholinergic basal forebrain in the rat

Stimulation of the amygdala elicits cortical activation mediated by the cor ticopetal basal forebrain. An unresolved question is whether the involved a mygdala neurons that project to the basal forebrain receive direct thalamic input. Using combined retrograde and anterograde tracing techniques, we de monstrate a monosynaptic contact between thalamic posterior paralaminar nuc lei axons and neurons in the central amygdala that project to corticopetal cholinergic basal forebrain regions. These contacts may constitute the morp hological substrate for the induction of fast cortical arousal and attentio n triggered by emotional events. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.