title: Functional states of rat cortical circuits during the unpredictable availability of a reward-related cue.
abstract: Proper performance of acquired abilities can be disturbed by the unexpected occurrence of external changes. Rats trained with an operant conditioning task (to press a lever in order to obtain a food pellet) using a fixed-ratio (1:1) schedule were subsequently placed in a Skinner box in which the lever could be removed randomly. Field postsynaptic potentials (fPSPs) were chronically evoked in perforant pathway-hippocampal CA1 (PP-CA1), CA1-subiculum (CA1-SUB), CA1-medial prefrontal cortex (CA1-mPFC), mPFC-nucleus accumbens (mPFC-NAc), and mPFC-basolateral amygdala (mPFC-BLA) synapses during lever IN and lever OUT situations. While lever presses were accompanied by a significant increase in fPSP slopes at the five synapses, the unpredictable absence of the lever were accompanied by decreased fPSP slopes in all, except PP-CA1 synapses. Spectral analysis of local field potentials (LFPs) recorded when the animal approached the corresponding area in the lever OUT situation presented lower spectral powers than during lever IN occasions for all recording sites, apart from CA1. Thus, the unpredictable availability of a reward-related cue modified the activity of cortical and subcortical areas related with the acquisition of operant learning tasks, suggesting an immediate functional reorganization of these neural circuits to address the changed situation and to modify ongoing behaviors accordingly.
authors.affiliation: Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Fernández-Lamo
authors.affiliation: Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain.
authors.forename: Raudel
authors.initials: R
authors.lastname: Sánchez-Campusano
authors.affiliation: Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain.
authors.forename: Agnès
authors.initials: A
authors.lastname: Gruart
authors.affiliation: Division of Neurosciences, Pablo de Olavide University, Seville-41013, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Delgado-García
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D002540:Cerebral Cortex / Q000502:physiology*; D003213:Conditioning, Psychological; D003463:Cues; D020007:Implants, Experimental; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D011336:Probability; D017208:Rats, Wistar; D012201:Reward; D013569:Synapses / Q000502:physiology; D055366:Synaptic Potentials / Q000502:physiology; D013647:Task Performance and Analysis