Abstract
Actions expressed prematurely without regard for their consequences are considered impulsive. Such behaviour is governed by a network of brain regions including the prefrontal cortex (PFC) and nucleus accumbens (NAcb) and is prevalent in disorders including attention deficit hyperactivity disorder (ADHD) and drug addiction. However, little is known of the relationship between neural activity in these regions and specific forms of impulsive behaviour. In the present study we investigated local field potential (LFP) oscillations in distinct sub-regions of the PFC and NAcb on a 5-choice serial reaction time task (5-CSRTT), which measures sustained, spatially-divided visual attention and action restraint. The main findings show that power in gamma frequency (50–60 Hz) LFP oscillations transiently increases in the PFC and NAcb during both the anticipation of a cue signalling the spatial location of a nose-poke response and again following correct responses. Gamma oscillations were coupled to low-frequency delta oscillations in both regions; this coupling strengthened specifically when an error response was made. Theta (7–9 Hz) LFP power in the PFC and NAcb increased during the waiting period and was also related to response outcome. Additionally, both gamma and theta power were significantly affected by upcoming premature responses as rats waited for the visual cue to respond. In a subgroup of rats showing persistently high levels of impulsivity we found that impulsivity was associated with increased error signals following a nose-poke response, as well as reduced signals of previous trial outcome during the waiting period. Collectively, these in-vivo neurophysiological findings further implicate the PFC and NAcb in anticipatory impulsive responses and provide evidence that abnormalities in the encoding of rewarding outcomes may underlie trait-like impulsive behaviour.
Highlights
Impulsivity is a multi-faceted behaviour encompassing actions that are inappropriately timed and executed without due consideration of their consequences
To investigate 5-choice serial reaction time task (5-CSRTT) related local field potential (LFP) activity, we focused on 2 key task events: (i) the time the rat left the food magazine and began scanning and waiting behaviour; defined as ‘‘wait-start’’; and (ii) the time the rat made a nose-poke response in one of the 5 target apertures
We report several LFP correlates of waiting behaviour and reward anticipation and outcome in the prefrontal cortex (PFC) and nucleus accumbens (NAcb) of rats performing a behavioural task involving visual attention and action restraint
Summary
Impulsivity is a multi-faceted behaviour encompassing actions that are inappropriately timed and executed without due consideration of their consequences. It is a major component of several neuropsychiatric disorders, including attention deficit hyperactivity disorder (ADHD), drug addiction and Parkinson’s disease [1,2,3], and can be divided into several sub-categories including delay aversion, action cancellation, reflection impulsivity and action restraint [2,4,5,6]. In the present study, we investigated the neurophysiological substrates of impulsivity in rats performing the 5-choice serial reaction time task (5-CSRTT). The 5-CSRTT is a widely used paradigm to assess sustained visual attention and action restraint, requiring rats to wait for the presentation of visual cues instructing which action to select [33]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.