Both spindles and barques are normal entities of the hippocampal intracranial [[electroencephalogram]]. The presence of barques may also signify lack of epileptogenic properties in the hippocampus
((Kokkinos V, Hussein H, Frauscher B, Simon M, Urban A, Bush A, Bagić AI, Richardson RM. Hippocampal spindles and barques are normal intracranial electroencephalographic entities. Clin Neurophysiol. 2021 Dec;132(12):3002-3009. doi: 10.1016/j.clinph.2021.09.008. Epub 2021 Oct 9. PMID: 34715425.)).
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Kokkinos et al. identified 51 focal epilepsy patients implanted with a minimum of two electrodes - unilateral anterior and posterior - in either hippocampus. We used visual inspection of the intracranial electroencephalogram (iEEG) and 3D brain volume spectrum-based statistical parametric mapping (SPM) to localize [[barques]].

 In 18/51 patients (35.29%), barques were identified in 22/70 (31.42%) hippocampi. In all hippocampi (100%), barques were present in the posterior hippocampus, while 9 (40.90%) showed concurrent non-independent barque activity anteriorly (P < 0.0001). Statistical parametric mapping confirmed the posterior barque localization, with significant differences in t-values (t(27) = 8.08, P < 0.0001) and z-scores (t(24) = 6.85, P < 0.0001) between anterior and posterior hippocampal barque activity. Posterior lateral extrahippocampal contacts demonstrated phase reversals of positive polarity during barque activity (P = 0.0092, compared to anterior extrahippocampal contacts).

Conclusions: This study highlights the posterior hippocampal predominance of barques. Our findings are concordant with the posterior distribution of the scalp manifestation of barques as "14&6/sec positive spikes". The posterio-lateral hippocampal barque phase reversal can explain the positive polarity of scalp 14&6/sec spikes.

Significance: Understanding the properties of barques is critical for the iEEG interpretation in epilepsy surgery evaluations that include the hippocampus
((Kokkinos V, Urban A, Frauscher B, Simon M, Hussein H, Bush A, Williams Z, Bagić AI, Mark Richardson R. Barques are generated in posterior hippocampus and phase reverse over lateral posterior hippocampal surface. Clin Neurophysiol. 2022 Feb 4;136:150-157. doi: 10.1016/j.clinph.2022.01.132. Epub ahead of print. PMID: 35168029.)).