PhD Scientific Days 2026

Poster Session 3.N - Neurosciences

In Vivo and In Vitro Human Cortical Recordings Reveal Layer Specific Structure–Function Relationships

Name of the presenter

Tóth, Katalin Zsófia

Institute/workplace of the presenter

Hun-Ren Research Centre for Natural Sciences

Authors

Katalin Zsófia Tóth¹, Réka Bod¹, Yossef Michaeli², Orsolya Farkas³, Loránd Erőss⁴, László Entz⁴, Dániel Fabó⁴, István Ulbert¹, Kinga Tóth¹, Lucia Wittner¹
1: HUN-REN Research Centre for Natural Sciences
2: Semmelweis University
3: Péter Pázmány Catholic University
4: Semmelweis University Clinics of Neurosurgery and Neurointervention

Text of the abstract

Introduction
Our understanding of how cortical microstructure relates to neuronal firing in the human brain remains limited, particularly across layers.

Aims
To investigate layer-specific relationships between neuronal density, inhibitory interneuron organization, and firing dynamics using combined in vivo and in vitro recordings.

Methods
Chronic intracortical recordings were obtained in vivo during wakefulness and sleep. Following surgical resection, acute in vitro recordings were performed on adjacent cortical tissue using identical 24-channel linear arrays (150 µm spacing). Histological analyses were conducted on tissue near in vivo recording sites and from distal regions used in vitro. Neuronal density was quantified using NeuN immunohistochemistry. Parvalbumin (PV) interneurons were additionally assessed for density and coverage (percentage area).

Results
NeuN-positive density was higher in supragranular than infragranular layers. In vivo, higher supragranular density was associated with increased firing rates, reduced burstiness, and more regular firing, whereas infragranular layers showed the opposite pattern. In vitro, these relationships were weaker, although supragranular density remained predictive. PV interneuron analysis revealed layer-dependent differences in inhibitory density and coverage. In patients with paired datasets, supragranular physiology was consistently predicted by anatomical measures, while infragranular in vivo activity was better explained by locally sampled anatomy.

Conclusion
Structure–function relationships in the human cortex are layer-dependent and differ between in vivo and in vitro conditions, shaped by both neuronal density and inhibitory organization.

Funding
This project was supported by the SE 250+ Excellence PhD Scholarship, the Hungarian Brain Research Program (NAP2022-I-2/2022), and the Pharmaceutical Research and Development Laboratory Project (PharmaLab, RRF-2.3.1-21-2022-00015). This work was further supported by OTKA K137886 and Advanced 150799.