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Article ; Online: Distinct neuronal representation of small and large numbers in the human medial temporal lobe.

Kutter, Esther F / Dehnen, Gert / Borger, Valeri / Surges, Rainer / Mormann, Florian / Nieder, Andreas

Nature human behaviour

2023 Volume 7, Issue 11, Page(s) 1998–2007

Abstract: Whether small numerical quantities are represented by a special subitizing system that is distinct from a large-number estimation system has been debated for over a century. Here we show that two separate neural mechanisms underlie the representation of ... ...

Abstract	Whether small numerical quantities are represented by a special subitizing system that is distinct from a large-number estimation system has been debated for over a century. Here we show that two separate neural mechanisms underlie the representation of small and large numbers. We performed single neuron recordings in the medial temporal lobe of neurosurgical patients judging numbers. We found a boundary in neuronal coding around number 4 that correlates with the behavioural transition from subitizing to estimation. In the subitizing range, neurons showed superior tuning selectivity accompanied by suppression effects suggestive of surround inhibition as a selectivity-increasing mechanism. In contrast, tuning selectivity decreased with increasing numbers beyond 4, characterizing a ratio-dependent number estimation system. The two systems with the coding boundary separating them were also indicated using decoding and clustering analyses. The identified small-number subitizing system could be linked to attention and working memory that show comparable capacity limitations.
MeSH term(s)	Humans ; Attention/physiology ; Memory, Short-Term/physiology ; Temporal Lobe ; Neurons ; Mathematics
Language	English
Publishing date	2023-10-02
Publishing country	England
Document type	Journal Article
ISSN	2397-3374
ISSN (online)	2397-3374
DOI	10.1038/s41562-023-01709-3
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Article ; Online: How coupled slow oscillations, spindles and ripples coordinate neuronal processing and communication during human sleep.

Staresina, Bernhard P / Niediek, Johannes / Borger, Valeri / Surges, Rainer / Mormann, Florian

Nature neuroscience

2023 Volume 26, Issue 8, Page(s) 1429–1437

Abstract: Learning and plasticity rely on fine-tuned regulation of neuronal circuits during offline periods. An unresolved puzzle is how the sleeping brain, in the absence of external stimulation or conscious effort, coordinates neuronal firing rates (FRs) and ... ...

Abstract	Learning and plasticity rely on fine-tuned regulation of neuronal circuits during offline periods. An unresolved puzzle is how the sleeping brain, in the absence of external stimulation or conscious effort, coordinates neuronal firing rates (FRs) and communication within and across circuits to support synaptic and systems consolidation. Using intracranial electroencephalography combined with multiunit activity recordings from the human hippocampus and surrounding medial temporal lobe (MTL) areas, we show that, governed by slow oscillation (SO) up-states, sleep spindles set a timeframe for ripples to occur. This sequential coupling leads to a stepwise increase in (1) neuronal FRs, (2) short-latency cross-correlations among local neuronal assemblies and (3) cross-regional MTL interactions. Triggered by SOs and spindles, ripples thus establish optimal conditions for spike-timing-dependent plasticity and systems consolidation. These results unveil how the sequential coupling of specific sleep rhythms orchestrates neuronal processing and communication during human sleep.
MeSH term(s)	Humans ; Electroencephalography/methods ; Sleep/physiology ; Hippocampus/physiology ; Temporal Lobe ; Learning ; Memory Consolidation
Language	English
Publishing date	2023-07-10
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1420596-8
ISSN	1546-1726 ; 1097-6256
ISSN (online)	1546-1726
ISSN	1097-6256
DOI	10.1038/s41593-023-01381-w
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Zs.A 4891: Show issues			Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (2.OG) ab Jg. 2022: Lesesaal (EG)
Zs.MG 67: Show issues

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Article ; Online: A key role of the hippocampal P3 in the attentional blink.

Derner, Marlene / Reber, Thomas P / Faber, Jennifer / Surges, Rainer / Mormann, Florian / Fell, Juergen

NeuroImage

2023 Volume 271, Page(s) 120028

Abstract: The attentional blink (AB) refers to an impaired identification of target stimuli (T2), which are presented shortly after a prior target (T1) within a rapid serial visual presentation (RSVP) stream. It has been suggested that the AB is related to a ... ...

Abstract	The attentional blink (AB) refers to an impaired identification of target stimuli (T2), which are presented shortly after a prior target (T1) within a rapid serial visual presentation (RSVP) stream. It has been suggested that the AB is related to a failed transfer of T2 into working memory and that hippocampus (HC) and entorhinal cortex (EC) are regions crucial for this transfer. Since the event-related P3 component has been linked to inhibitory processes, we hypothesized that the hippocampal P3 elicited by T1 may impact on T2 processing within HC and EC. To test this hypothesis, we reanalyzed microwire data from 21 patients, who performed an RSVP task, during intracranial recordings for epilepsy surgery assessment (Reber et al., 2017). We identified T1-related hippocampal P3 components in the local field potentials (LFPs) and determined the temporal onset of T2 processing in HC/EC based on single-unit response onset activity. In accordance with our hypothesis, T1-related single-trial P3 amplitudes at the onset of T2 processing were clearly larger for unseen compared to seen T2-stimuli. Moreover, increased T1-related single-trial P3 peak latencies were found for T2[unseen] versus T2[seen] trials in case of lags 1 to 3, which was in line with our predictions. In conclusion, our findings support inhibition models of the AB and indicate that the hippocampal P3 elicited by T1 plays a central role in the AB.
MeSH term(s)	Humans ; Attentional Blink/physiology ; Attention/physiology ; Memory, Short-Term/physiology ; Chemokine CCL4 ; Hippocampus
Chemical Substances	Chemokine CCL4
Language	English
Publishing date	2023-03-14
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1147767-2
ISSN	1095-9572 ; 1053-8119
ISSN (online)	1095-9572
ISSN	1053-8119
DOI	10.1016/j.neuroimage.2023.120028
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Zs.A 3664: Show issues			Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (2.OG) ab Jg. 2022: Lesesaal (EG)
Zs.MO 7: Show issues

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Article ; Online: The Architecture of Human Memory: Insights from Human Single-Neuron Recordings.

Rutishauser, Ueli / Reddy, Leila / Mormann, Florian / Sarnthein, Johannes

The Journal of neuroscience : the official journal of the Society for Neuroscience

2020 Volume 41, Issue 5, Page(s) 883–890

Abstract: Deciphering the mechanisms of human memory is a central goal of neuroscience, both from the point of view of the fundamental biology of memory and for its translational relevance. Here, we review some contributions that recordings from neurons in humans ... ...

Abstract	Deciphering the mechanisms of human memory is a central goal of neuroscience, both from the point of view of the fundamental biology of memory and for its translational relevance. Here, we review some contributions that recordings from neurons in humans implanted with electrodes for clinical purposes have made toward this goal. Recordings from the medial temporal lobe, including the hippocampus, reveal the existence of two classes of cells: those encoding highly selective and invariant representations of abstract concepts, and memory-selective cells whose activity is related to familiarity and episodic retrieval. Insights derived from observing these cells in behaving humans include that semantic representations are activated before episodic representations, that memory content and memory strength are segregated, and that the activity of both types of cells is related to subjective awareness as expected from a substrate for declarative memory. Visually selective cells can remain persistently active for several seconds, thereby revealing a cellular substrate for working memory in humans. An overarching insight is that the neural code of human memory is interpretable at the single-neuron level. Jointly, intracranial recording studies are starting to reveal aspects of the building blocks of human memory at the single-cell level. This work establishes a bridge to cellular-level work in animals on the one hand, and the extensive literature on noninvasive imaging in humans on the other hand. More broadly, this work is a step toward a detailed mechanistic understanding of human memory that is needed to develop therapies for human memory disorders.
MeSH term(s)	Electrodes, Implanted ; Hippocampus/cytology ; Hippocampus/physiology ; Humans ; Memory Disorders/diagnosis ; Memory Disorders/physiopathology ; Memory, Episodic ; Memory, Short-Term/physiology ; Mental Recall/physiology ; Neurons/physiology ; Temporal Lobe/cytology ; Temporal Lobe/physiology
Language	English
Publishing date	2020-11-30
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
ZDB-ID	604637-x
ISSN	1529-2401 ; 0270-6474
ISSN (online)	1529-2401
ISSN	0270-6474
DOI	10.1523/JNEUROSCI.1648-20.2020
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Zs.A 1668: Show issues

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Article ; Online: Neuronal codes for arithmetic rule processing in the human brain.

Kutter, Esther F / Boström, Jan / Elger, Christian E / Nieder, Andreas / Mormann, Florian

Current biology : CB

2022 Volume 32, Issue 6, Page(s) 1275–1284.e4

Abstract: Arithmetic is a cornerstone of scientifically and technologically advanced human culture, but its neuronal mechanisms are poorly understood. Calculating with numbers requires temporary maintenance and manipulation of numerical information according to ... ...

Abstract	Arithmetic is a cornerstone of scientifically and technologically advanced human culture, but its neuronal mechanisms are poorly understood. Calculating with numbers requires temporary maintenance and manipulation of numerical information according to arithmetic rules. We explored the brain mechanisms involved in simple arithmetic operations by recording single-neuron activity from the medial temporal lobe of human subjects performing additions and subtractions. We found abstract and notation-independent codes for addition and subtraction in neuronal populations. The neuronal codes of arithmetic in different brain areas differed drastically. Decoders applied to time-resolved recordings demonstrate a static code in hippocampus based on persistently rule-selective neurons, in contrast to a dynamic code in parahippocampal cortex originating from neurons carrying rapidly changing rule information. The implementation of abstract arithmetic codes suggests different cognitive functions for medial temporal lobe regions in arithmetic.
MeSH term(s)	Brain/physiology ; Brain Mapping ; Humans ; Mathematics ; Neurons/physiology ; Temporal Lobe/physiology
Language	English
Publishing date	2022-02-14
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1071731-6
ISSN	1879-0445 ; 0960-9822
ISSN (online)	1879-0445
ISSN	0960-9822
DOI	10.1016/j.cub.2022.01.054
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Zs.A 3208: Show issues

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Article ; Online: Assessing criticality in pre-seizure single-neuron activity of human epileptic cortex.

Hagemann, Annika / Wilting, Jens / Samimizad, Bita / Mormann, Florian / Priesemann, Viola

PLoS computational biology

2021 Volume 17, Issue 3, Page(s) e1008773

Abstract: Epileptic seizures are characterized by abnormal and excessive neural activity, where cortical network dynamics seem to become unstable. However, most of the time, during seizure-free periods, cortex of epilepsy patients shows perfectly stable dynamics. ... ...

Abstract	Epileptic seizures are characterized by abnormal and excessive neural activity, where cortical network dynamics seem to become unstable. However, most of the time, during seizure-free periods, cortex of epilepsy patients shows perfectly stable dynamics. This raises the question of how recurring instability can arise in the light of this stable default state. In this work, we examine two potential scenarios of seizure generation: (i) epileptic cortical areas might generally operate closer to instability, which would make epilepsy patients generally more susceptible to seizures, or (ii) epileptic cortical areas might drift systematically towards instability before seizure onset. We analyzed single-unit spike recordings from both the epileptogenic (focal) and the nonfocal cortical hemispheres of 20 epilepsy patients. We quantified the distance to instability in the framework of criticality, using a novel estimator, which enables an unbiased inference from a small set of recorded neurons. Surprisingly, we found no evidence for either scenario: Neither did focal areas generally operate closer to instability, nor were seizures preceded by a drift towards instability. In fact, our results from both pre-seizure and seizure-free intervals suggest that despite epilepsy, human cortex operates in the stable, slightly subcritical regime, just like cortex of other healthy mammalians.
MeSH term(s)	Electroencephalography ; Epilepsy/physiopathology ; Humans ; Neurons/physiology ; Seizures/physiopathology ; Signal Processing, Computer-Assisted ; Temporal Lobe/physiology ; Temporal Lobe/physiopathology
Language	English
Publishing date	2021-03-08
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2193340-6
ISSN	1553-7358 ; 1553-734X
ISSN (online)	1553-7358
ISSN	1553-734X
DOI	10.1371/journal.pcbi.1008773
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Single-neuron mechanisms of neural adaptation in the human temporal lobe.

Reber, Thomas P / Mackay, Sina / Bausch, Marcel / Kehl, Marcel S / Borger, Valeri / Surges, Rainer / Mormann, Florian

Nature communications

2023 Volume 14, Issue 1, Page(s) 2496

Abstract: A central function of the human brain is to adapt to new situations based on past experience. Adaptation is reflected behaviorally by shorter reaction times to repeating or similar stimuli, and neurophysiologically by reduced neural activity in bulk- ... ...

Abstract	A central function of the human brain is to adapt to new situations based on past experience. Adaptation is reflected behaviorally by shorter reaction times to repeating or similar stimuli, and neurophysiologically by reduced neural activity in bulk-tissue measurements with fMRI or EEG. Several potential single-neuron mechanisms have been hypothesized to cause this reduction of activity at the macroscopic level. We here explore these mechanisms using an adaptation paradigm with visual stimuli bearing abstract semantic similarity. We recorded intracranial EEG (iEEG) simultaneously with spiking activity of single neurons in the medial temporal lobes of 25 neurosurgical patients. Recording from 4917 single neurons, we demonstrate that reduced event-related potentials in the macroscopic iEEG signal are associated with a sharpening of single-neuron tuning curves in the amygdala, but with an overall reduction of single-neuron activity in the hippocampus, entorhinal cortex, and parahippocampal cortex, consistent with fatiguing in these areas.
MeSH term(s)	Humans ; Temporal Lobe/physiology ; Entorhinal Cortex/physiology ; Neurons/physiology ; Hippocampus/physiology ; Amygdala
Language	English
Publishing date	2023-04-29
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-38190-5
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Article ; Online: Seizure prediction: making mileage on the long and winding road.

Mormann, Florian / Andrzejak, Ralph G

Brain : a journal of neurology

2016 Volume 139, Issue Pt 6, Page(s) 1625–1627

Language	English
Publishing date	2016-06
Publishing country	England
Document type	Journal Article
ZDB-ID	80072-7
ISSN	1460-2156 ; 0006-8950
ISSN (online)	1460-2156
ISSN	0006-8950
DOI	10.1093/brain/aww091
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Ui II Zs.26: Show issues

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Article: A key role of the hippocampal P3 in the attentional blink

Derner, Marlene / Reber, Thomas P. / Faber, Jennifer / Surges, Rainer / Mormann, Florian / Fell, Juergen

NeuroImage

2023

Title translation	Eine Schlüsselrolle des hippocampalen P3 beim Attentional Blink
Abstract	The attentional blink (AB) refers to an impaired identification of target stimuli (T2), which are presented shortly after a prior target (T1) within a rapid serial visual presentation (RSVP) stream. It has been suggested that the AB is related to a failed transfer of T2 into working memory and that hippocampus (HC) and entorhinal cortex (EC) are regions crucial for this transfer. Since the event-related P3 component has been linked to inhibitory processes, we hypothesized that the hippocampal P3 elicited by T1 may impact on T2 processing within HC and EC. To test this hypothesis, we reanalyzed microwire data from 21 patients, who performed an RSVP task, during intracranial recordings for epilepsy surgery assessment (Reber et al., 2017). We identified T1-related hippocampal P3 components in the local field potentials (LFPs) and determined the temporal onset of T2 processing in HC/EC based on single-unit response onset activity. In accordance with our hypothesis, T1-related single-trial P3 amplitudes at the onset of T2 processing were clearly larger for unseen compared to seen T2-stimuli. Moreover, increased T1-related single-trial P3 peak latencies were found for T2[unseen] versus T2[seen] trials in case of lags 1 to 3, which was in line with our predictions. In conclusion, our findings support inhibition models of the AB and indicate that the hippocampal P3 elicited by T1 plays a central role in the AB.
Keywords	Attentional Blink ; Aufmerksamkeitsblinzeln ; Entorhinal Cortex ; Entorhinaler Kortex ; Evoked Potentials ; Evozierte Potenziale ; Hippocampus ; Hippokampus ; Kurzzeitgedächtnis ; P300 ; Short Term Memory ; Visual Attention ; Visuelle Aufmerksamkeit
Language	English
Document type	Article
ZDB-ID	1147767-2
ISSN	1095-9572 ; 1053-8119
ISSN (online)	1095-9572
ISSN	1053-8119
DOI	10.1016/j.neuroimage.2023.120028
Database	PSYNDEX

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Zs.A 3664: Show issues			Location: Je nach Verfügbarkeit (siehe Angabe bei Bestand) bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular Jg. 1995 - 2021: Lesesall (2.OG) ab Jg. 2022: Lesesaal (EG)
Zs.MO 7: Show issues

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Article: Seizure Onset Zone Lateralization Using a Non-linear Analysis of Micro vs. Macro Electroencephalographic Recordings During Seizure-Free Stages of the Sleep-Wake Cycle From Epilepsy Patients.

Martínez, Cristina G B / Niediek, Johannes / Mormann, Florian / Andrzejak, Ralph G

Frontiers in neurology

2020 Volume 11, Page(s) 553885

Abstract: The application of non-linear signal analysis techniques to biomedical data is key to improve our knowledge about complex physiological and pathological processes. In particular, the use of non-linear techniques to study electroencephalographic (EEG) ... ...

Abstract	The application of non-linear signal analysis techniques to biomedical data is key to improve our knowledge about complex physiological and pathological processes. In particular, the use of non-linear techniques to study electroencephalographic (EEG) recordings can provide an advanced characterization of brain dynamics. In epilepsy these dynamics are altered at different spatial scales of neuronal organization. We therefore apply non-linear signal analysis to EEG recordings from epilepsy patients derived with intracranial hybrid electrodes, which are composed of classical macro contacts and micro wires. Thereby, these electrodes record EEG at two different spatial scales. Our aim is to test the degree to which the analysis of the EEG recorded at these different scales allows us to characterize the neuronal dynamics affected by epilepsy. For this purpose, we retrospectively analyzed long-term recordings performed during five nights in three patients during which no seizures took place. As a benchmark we used the accuracy with which this analysis allows determining the hemisphere that contains the seizure onset zone, which is the brain area where clinical seizures originate. We applied the surrogate-corrected non-linear predictability score (ψ), a non-linear signal analysis technique which was shown previously to be useful for the lateralization of the seizure onset zone from classical intracranial EEG macro contact recordings. Higher values of ψ were found predominantly for signals recorded from the hemisphere containing the seizure onset zone as compared to signals recorded from the opposite hemisphere. These differences were found not only for the EEG signals recorded with macro contacts, but also for those recorded with micro wires. In conclusion, the information obtained from the analysis of classical macro EEG contacts can be complemented by the one of micro wire EEG recordings. This combined approach may therefore help to further improve the degree to which quantitative EEG analysis can contribute to the diagnostics in epilepsy patients.
Language	English
Publishing date	2020-09-17
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2564214-5
ISSN	1664-2295
ISSN	1664-2295
DOI	10.3389/fneur.2020.553885
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