Periodic electroencephalographic discharges and epileptic spasms involve cortico-striatal-thalamic loops on Arterial Spin Labeling Magnetic Resonance Imaging

Cortical, striatal, and thalamic populations self-organize into a functionally connected circuit with long-term memory properties

The human brain is a complex organ with an intricate neuronal connectivity and diverse functional regions. Neurological disorders often disrupt the delicate balance among these anatomical compartments, resulting in severe impairments. The available therapeutic options constitute an incomplete solution as many patients respond partially, highlighting the need for continued research into causes and treatments. Bottom-up approaches, like in vitro models, offer insights into brain functions as they recreate the in vivo microenvironment that allows studying how specific features affect physiological and pathological conditions. In this work, we engineered the cortical-striatal-thalamic (CST) circuit, involved in many brain functions such as action initiation and selection, using a three-compartment polymeric device. We characterized the emerging spontaneous electrophysiological activity by using Micro-Electrode Arrays (MEAs). Cortical neurons exhibited complex bursting activity, which influenced the entire circuit. Striatal and thalamic neurons displayed predominantly tonic firing when isolated, while interconnections with the cortex synchronized and organized their neuronal activity, highlighting the cortical pivotal role in bursting activity and information processing. The CST circuit demonstrated self-organization abilities and displayed high entropy values, indicative of dynamic richness and information encoding potential. Furthermore, we proved the CST's involvement in learning and memory. Our CST model provides a platform for further exploration into brain circuitry and potential therapeutic interventions, underscoring the necessity of realistic in vitro models to fully understand neurological diseases' pathophysiology.

Electroclinical Landscape of Infantile Epileptic Spasms Syndrome

OBJECTIVES

To elucidate the electroclinical characteristics of infantile epileptic spasms syndrome (IESS) and to determine any potential association among these with underlying etiologies and response to therapy.

METHODS

Sixty-eight, treatment-naive children with IESS underwent long-term video electroencephalogram (EEG) recording, which was used to characterize the semiology, ictal, and inter-ictal EEG patterns. Children were further followed up to assess electroclinical predictors of etiologies and short-term therapeutic response.

RESULTS

Of 68 children enrolled (69% boys), the median age at enrollment was 10.5 mo (IQR-8). Eighty-eight percent of children had flexor spasms, followed by mixed (7%) and extensor (4.4%). Asymmetrical spasms were noted in 17.6% children, and all of them had underlying structural etiology. Two children had the status of epileptic spasms. In the present cohort, authors recognized five distinct ictal EEG correlates of epileptic spasms; the frontocentral dominant slow wave was the most prevalent (32%), followed by the generalized slow-wave complex with superimposed fast rhythm in 29.4%. The occipital dominant slow wave complex was a peculiar pattern in 16%. The major underlying etiologies were hypoxic-ischemic brain injuries (36.7%) and neonatal hypoglycemic brain injuries (22%). Besides asymmetric spasms, authors could not identify any significant association among electroclinical characteristics, underlying etiologies and response to therapy in this study.

CONCLUSIONS

The electroclinical landscape of IESS is peculiar and diverse in developing countries. The presence of asymmetrical spasms indicated underlying structural etiology.