Nucleus Accumbens is Involved in Human Action Monitoring: Evidence from Invasive Electrophysiological Recordings.
Level 4 - case-series / case-control
Single-patient intraoperative electrophysiology case study
PubMed 18958225 · doi:10.3389/neuro.09.011.2007
What was done
In an awake patient with obsessive-compulsive disease (OCD) performing a choice reaction time task, researchers acquired invasive intraoperative electrophysiological recordings from the nucleus accumbens (Nacc) and a site 5 mm above it to assess action monitoring and error detection. Preoperatively, the patient's scalp-recorded error-related negativity (ERN) was compared to a normative control sample (n = 83). Cross-correlation analysis was performed to evaluate the temporal relationship between intraoperative Nacc activity and surface ERN.
What was found
The patient's preoperative scalp ERN was significantly increased compared to the 83 normal controls. Intraoperatively, error-related activity was detected in the Nacc but not 5 mm above it. Cross-correlation analysis revealed that error-related activity in the Nacc preceded surface scalp activity by 40 ms.
Why it matters
This study provides direct invasive electrophysiological evidence in humans that the nucleus accumbens participates in action monitoring and error processing, activating prior to medial frontal surface ERN signals.
Limits
The invasive electrophysiological findings are based on a single patient (n = 1) with severe OCD, whose action monitoring processes were abnormally heightened, limiting generalizability to normal brain function. The abstract does not report behavioral accuracy metrics or statistical effect sizes for the intracranial signals.
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