The goal of the Helfrich lab is to unravel the neural network mechanisms supporting higher cognitive functions and their disturbances underlying neuropsychiatric disorders. We study the functional architecture of human cognition with a spatiotemporal resolution spanning single units to large-scale network activity. In particular, we seek to understand context-dependent, goal-directed behavior in humans through the study of neural network dynamics with a particular emphasis on prefrontal cortex (PFC) physiology. The key hypothesis is that context dependent endogenous brain activity shapes cognitive processing in different cortical states, i.e. wakefulness or sleep. A core interest is the systematic investigation of the functional network architecture of cortico-cortical and subcortico-cortical interactions supporting cognitive processes such as attention and memory and their impairment in healthy aging and neurodegenerative diseases.
Currently, much of our understanding of the neural basis of cognition stems from invasive primate recordings or non-invasive recordings in humans. The limited spatiotemporal resolution of non-invasive imaging hampers scientific progress in our understanding of health and disease. Human intracranial electrophysiology has the promise of significant insights into the neural mechanisms that guide behavior. Several clinical procedures provide the unique opportunity to record directly from the human brain at the single neuron or population level. A key goal of our lab is to bridge the gap between different imaging modalities in different species. Translationally, we integrate cognitive and clinical neurophysiology to increase our understanding of cognitive decline and reduced arousal levels such as sleep, anesthesia and coma.
If you are interested in a Bachelor, Master or PhD thesis in the lab, please send an email stating your research interests and your CV to randolph.helfrichmed.uni-tuebingen.de or check the section "Open positions" below.
Find out more: www.helfrich-lab.com
Google Scholar Profile: scholar.google.de/citations
I. Rhythmic building blocks of human attention: How network oscillations link perception and action.
Attention is a fundamental cognitive function necessary to efficiently translate sensory experiences into goal-directed actions . Traditionally, attention has been conceptualized as a constant spotlight that amplifies behaviorally-relevant information. Recently, several lines of inquiry probing attention on a fine-grained temporal scale revealed frequency-specific behavioral fluctuations that align with ongoing brain oscillations, indicating that attention is a discrete process. Our aim is to understand the structural and functional basis as well as the physiologic purpose of attentional rhythmic fluctuations.
See also: Helfrich et al. (2018b) Neuron, Helfrich et al. (2019) Current Opinion in Psychology
II. Context-dependent predictive processing in human prefrontal cortex.
Over the last few decades, several lines of research indicated that the prefrontal cortex (PFC) provides the structural basis for goal-directed behavior based on endogenous predictions, but its functional architecture is not well understood. Our goal is to investigate how predictions are implemented in the human brain to optimize sensory processing and goal-directed behavior.
Background reading Helfrich and Knight (2016) Trends in Cognitive Sciences; Helfrich et al. (2017) PNAS, Weber et al. (2022) bioRxiv preprint
III. (Patho-) Physiology of human memory networks during wakefulness and sleep
Hippocampus-Prefrontal interactions are central to memory formation in the human brain. Critically, this network also constitutes a predilection site for various pathological entities that are associated with memory deficits. Our goal is to further dissect and understand the network circuitry underlying memory disorders in various patient populations (epilepsy, stroke and degenerative diseases)
Additional information: Helfrich et al. (2018a) Neuron; Hahn et al. (2020) eLife; Helfrich et al. (2021) Trends in Cognitive Sciences; Hahn et al. (2022) eLife; Lendner et al. (2022) bioRxiv preprint
IV. Principles of neuronal network organization in the sleeping and the unconscious (anesthesia, coma) brain.
How do different network states impact different behavioral states? Understanding principles of network organization is critical to understand disorders of consciousness. We will work with several patient populations to understand large-scale network mechanisms underlying reduced arousal states.
See also Helfrich et al. (2019) Nature Communications; Lendner, Helfrich et al. (2020) eLife
We are inviting applications for fully funded positions for
two PhD students
with an interest in the neuronal network dynamics underlying cognitive processing. The lab is conducting cognitive neuroscience studies in a clinical environment. Our key goal is to understand the network neuroscience underlying higher cognitive functions in the human brain.
We offer two PhD positions to investigate the mechanisms that enable cognitive flexibility and context-dependent predictive processing in human prefrontal cortex.
See the full description here.
The Helfrich lab at the Center for Neurology and Hertie Institute for Clinical Brain Research at the University of Tübingen and the Myers lab at the School of Psychology at the University of Nottingham invite applications for a fully funded position for
a PhD student
with an interest in the neural basis of memory. The PhD project will focus on understanding the flexible use of memory using high-precision neuroimaging. A key goal is to develop novel analytical approaches to maximize the context-dependent readout of mnemonic content. The project will be conducted jointly between Tübingen and Nottingham with approximately half the time spent at each site.
See the full description here.
If we have sparked your interest, please send your application, including a CV, relevant certificates or diplomas and a cover letter outlining your research interest in English or German to firstname.lastname@example.org
Weber J, Solbakk AK, Blenkmann AO, Llorens A, Funderud I, Leske S, Larsson PG, Ivanovic J, Knight RT, Endestad T, Helfrich RF (2022) Population coding and oscillatory subspace synchronization integrate context into actions. (preprinted on the bioRxiv; under review)
Lendner JD, Mander BA, Schuh-Hofer S, Schmidt H, Knight RT, Walker MP, Lin JJ, Helfrich RF (2022) Human REM sleep controls neural excitability in support of memory formation. (preprinted on the bioRxiv; under review)
Hahn MA, Bothe K, Heib D, Schabus M, Helfrich RF, Hoedlmoser K (2022) Slow oscillation-spindle coupling strength predicts real-life gross-motor learning in adolescents and adults. Elife
Helfrich RF, Lendner JD, Knight RT (2021) Aperiodic sleep networks promote memory consolidation. Trends Cogn Sci
Lendner JD, Helfrich RF, Mander BA, Romundstad L, Lin JJ, Walker MP, Larsson PG, Knight RT (2020) An electrophysiological marker of arousal level in humans. Elife
Hahn MA, Heib D, Schabus M, Hoedlmoser K, Helfrich RF (2020) Slow oscillation-spindle coupling predicts enhanced memory formation from childhood to adolescence. Elife
Helfrich RF, Lendner JD, Mander BA, Guillen H, Paff M, Mnatsakanyan L, Vadera S, Walker MP, Lin JJ, Knight RT (2019) Bidirectional prefrontal-hippocampal dynamics organize information transfer during sleep in humans. Nature Communications
Helfrich, RF, Fiebelkorn, IC, Szczepanski, SM, Lin, JJ, Parvizi, J, Knight, RT, and Kastner, S (2018b). Neural Mechanisms of Sustained Attention Are Rhythmic. Neuron
Helfrich, RF, Mander, BA, Jagust, WJ, Knight, RT, and Walker, MP (2018a). Old Brains Come Uncoupled in Sleep: Slow Wave-Spindle Synchrony, Brain Atrophy, and Forgetting. Neuron
Helfrich, R.F., Huang, M., Wilson, G., and Knight, R.T. (2017). Prefrontal cortex modulates posterior alpha oscillations during top-down guided visual perception. PNAS
Helfrich, R.F., and Knight, R.T. (2016). Oscillatory Dynamics of Prefrontal Cognitive Control. Trends in Cognitive Sciences
Center of Neurology
Hertie Institute for Clinical Brain Research
Phone: +49 (0)7071 29-80442