2025
Abstract Cortical excitability (CE) is commonly assessed via motor evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation (sp-TMS). While the motor threshold (MT) remains the most widely used measure of CE, it provides a limited, one-dimensional measure based on a fixed MEP amplitude criterion. In contrast, the recruitment curve (RC) offers a more comprehensive characterization of corticospinal recruitment dynamics. To date, the few preclinical TMS studies measuring RC in non-human primates have been conducted under anaesthesia with limited translational relevance. Hence, we characterised CE in 20 sessions of 4 awake rhesus macaques by recording RCs at nine stimulation intensity levels and parametrising them using exponentiated sigmoid functions. The traditional 100 µV MEP MT criterion level (SI100µV) aligned most closely with the inflection point of the RC sigmoid fit and was consistent with relative frequency-based traditional MT (tradMT) measured in separate sessions. The onset of the logarithmic recruitment phase of the sigmoid (lower ankle point) was found at 0.9 × SI100µV/tradMT. Well-formed MEPs were measured below the SI100µV/tradMT, but not below the lower ankle point, which is a physiologically relevant response threshold. Thus, in rhesus macaques the 100-µV criterion may be suitable to approximate the RC inflection point, but not the physiological motor threshold. The overall RC shape was consistent with previous human data, however, plateau MEP amplitudes were substantially smaller than those reported in humans. These results lay the groundwork for the adaptation of TMS protocols and CE metrics to non-human primates that is necessary for translationally valid research. https://www.sciencedirect.com/science/article/pii/S105381192500309X?via%3Dihub
2024

Inkeller J, Knakker B, Kovács P, Lendvai B, Hernádi I. Intrinsic anticipatory motives in non-human primate food consumption behavior. iScience. 2024 Mar 8;27(4):109459. doi: 10.1016/j.isci.2024.109459. PMID: 38558930; PMCID: PMC10981109.
2023

Bali ZK, Nagy LV, Bruszt N, Bodó K, Engelmann P, Hernádi Z, Göntér K, Tadepalli SA, Hernádi I. Increased brain cytokine level associated impairment of vigilance and memory in aged rats can be alleviated by alpha7 nicotinic acetylcholine receptor agonist treatment. Geroscience. 2024 Feb;46(1):645-664. doi: 10.1007/s11357-023-01019-6. Epub 2023 Nov 23. PMID: 37994990; PMCID: PMC10828177.
2022

Bali ZK, Bruszt N, Kőszegi Z, Nagy LV, Atlasz T, Kovács P, Csupor D, Csupor-Löffler B, Hernádi I. Aconitum Alkaloid Songorine Exerts Potent Gamma-Aminobutyric Acid-A Receptor Agonist Action In Vivo and Effectively Decreases Anxiety without Adverse Sedative or Psychomotor Effects in the Rat. Pharmaceutics. 2022; 14(10):2067. https://doi.org/10.3390/pharmaceutics14102067

Kostyalik D, Kelemen K, Lendvai B, Hernádi I, Román V, Lévay G. Response-related sensorimotor rhythms under scopolamine and MK-801 exposures in the touchscreen visual discrimination test in rats. Sci Rep. 2022 May 17;12(1):8168. doi: 10.1038/s41598-022-12146-z. PMID: 35581280; PMCID: PMC9114334.
2021

Knakker, B., Oláh, V., Trunk, A., Lendvai, B., Lévay, G., & Hernádi, I. (2021). Delay-dependent cholinergic modulation of visual short-term memory in rhesus macaques. BEHAVIOURAL BRAIN RESEARCH, 396. http://doi.org/10.1016/j.bbr.2020.112897
2020

Bali, Z. K., Bruszt, N., Tadepalli, S. A., Csurgyók, R., Nagy, L. V., Tompa, M., & Hernádi, I. (2019). Cognitive Enhancer Effects of Low Memantine Doses Are Facilitated by an Alpha7 Nicotinic Acetylcholine Receptor Agonist in Scopolamine-Induced Amnesia in Rats. FRONTIERS IN PHARMACOLOGY, 10. http://doi.org/10.3389/fphar.2019.00073

Oyama, K., Tateyama, Y., Hernadi, I., Tobler, P., Iijima, T., & Tsutsui, K. (2015). Discrete coding of stimulus value, reward expectation, and reward prediction error in the dorsal striatum. JOURNAL OF NEUROPHYSIOLOGY, 114(5), 2600–2615. http://doi.org/10.1152/jn.00097.2015

Grabenhorst, F., Hernadi, I., & Schultz, W. (2016). Primate amygdala neurons evaluate the progress of self-defined economic choice sequences. ELIFE, 5. http://doi.org/10.7554/eLife.18731

Vecsei, Z., Knakker, B., Juhász, P., Thuróczy, G., Trunk, A., & Hernádi, I. (2018). Short-term radiofrequency exposure from new generation mobile phones reduces EEG alpha power with no effects on cognitive performance. SCIENTIFIC REPORTS, 8(1). http://doi.org/10.1038/s41598-018-36353-9

Nagy, S. A., Vranesics, A., Varga, Z., Csabai, D., Bruszt, N., Bali, Z. K., … Czéh, B. (2020). Stress-Induced Microstructural Alterations Correlate With the Cognitive Performance of Rats: A Longitudinal in vivo Diffusion Tensor Imaging Study. FRONTIERS IN NEUROSCIENCE, 14. http://doi.org/10.3389/fnins.2020.00474

Bali, Z. K., Inkeller, J., Csurgyók, R., Bruszt, N., Horváth, H., & Hernádi, I. (2015). Differential effects of α7 nicotinic receptor agonist PHA-543613 on spatial memory performance of rats in two distinct pharmacological dementia models. BEHAVIOURAL BRAIN RESEARCH, 278(0), 404–410. http://doi.org/10.1016/j.bbr.2014.10.030

Budai, D., Vizvári, A. D., Bali, Z. K., Márki, B., Nagy, L. V., Kónya, Z., … Hernádi, I. (2018). A novel carbon tipped single micro-optrode for combined optogenetics and electrophysiology. PLOS ONE, 13(3). http://doi.org/10.1371/journal.pone.0193836

Szarka, N., Toth, L., Czigler, A., Kellermayer, Z., Ungvari, Z., Amrein, K., … Toth, P. (2019). Single Mild Traumatic Brain Injury Induces Persistent Disruption of the Blood-Brain Barrier, Neuroinflammation and Cognitive Decline in Hypertensive Rats. INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 20(13). http://doi.org/10.3390/ijms20133223

Trunk, A., Stefanics, G., Zentai, N., Bacskay, I., Felinger, A., Thuroczy, G., & Hernadi, I. (2015). Effects of concurrent caffeine and mobile phone exposure on local target probability processing in the human brain. SCIENTIFIC REPORTS, 5(23). http://doi.org/10.1038/srep14434

Gellen, B., Volgyi, K., Gyorffy, B., Balogh, B., Darula, Z., Hunyadi-Gulyás, E., … Kekesi, K. (2017). Proteomic investigation of the prefrontal cortex in the rat clomipramine model of depression. JOURNAL OF PROTEOMICS, 153, 53–64. http://doi.org/10.1016/j.jprot.2016.06.027

Kamm, K., Pomschar, A., Ruscheweyh, R., Straube, A., Reiser, M., Hernadi, I., … Ertl-Wagner, B. (2019). Static magnetic field-exposure in 1.5 and 3 Tesla MR scanners does not influence pain and touch perception in healthy volunteers. EUROPEAN JOURNAL OF PAIN, 23(2), 250–259. http://doi.org/10.1002/ejp.1299

Oláh, V., Knakker, B., Trunk, A., Lendvai, B., & Hernádi, I. (2020). Dissociating cholinergic influence on alertness and temporal attention in primates in a simple reaction time paradigm. EUROPEAN JOURNAL OF NEUROSCIENCE. http://doi.org/10.1111/ejn.14852

Zentai, N., Fiocchi, S., Parazzini, M., Trunk, A., Juhász, P., Ravazzani, P., … Thuróczy, G. (2015). Characterization and Evaluation of a Commercial WLAN System for Human Provocation Studies. BIOMED RESEARCH INTERNATIONAL, 2015. http://doi.org/10.1155/2015/289152

Hernadi, I., Grabenhorst, F., & Schultz, W. (2015). Planning activity for internally generated reward goals in monkey amygdala neurons. NATURE NEUROSCIENCE, 18(3), 461–469. http://doi.org/10.1038/nn.3925

Vecsei, Z., Thuroczy, G., & Hernadi, I. (2018). The Effect of a Single 30-Min Long Term Evolution Mobile Phone-Like Exposure on Thermal Pain Threshold of Young Healthy Volunteers. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, 15(9). http://doi.org/10.3390/ijerph15091849

Tadepalli, S. A., Bali, Z. K., Bruszt, N., Nagy, L. V., Amrein, K., Fazekas, B., … Hernádi, I. (2020). Long-term cognitive impairment without diffuse axonal injury following repetitive mild traumatic brain injury in rats. BEHAVIOURAL BRAIN RESEARCH, 378. http://doi.org/10.1016/j.bbr.2019.112268

Zentai, N., Csathó, Á., Trunk, A., Fiocchi, S., Parazzini, M., Ravazzani, P., … Hernádi, I. (2015). No Effects of Acute Exposure to Wi-Fi Electromagnetic Fields on Spontaneous EEG Activity and Psychomotor Vigilance in Healthy Human Volunteers. RADIATION RESEARCH, 184(6), 568–577. http://doi.org/10.1667/RR13896.1

Bali, Z., Nagy, L., & Hernadi, I. (2017). Alpha7 Nicotinic Acetylcholine Receptors Play a Predominant Role in the Cholinergic Potentiation of N-Methyl-D-Aspartate Evoked Firing Responses of Hippocampal CA1 Pyramidal Cells. FRONTIERS IN CELLULAR NEUROSCIENCE, 11. http://doi.org/10.3389/fncel.2017.00271