Randolph Helfrich

Rhythmic sampling of multiple decision alternatives in the human brain - Nature Communications How humans process competing information when making multi-alternative decisions remains unclear. Here, the authors show that the brain resolves the trade-off between “evaluating within” and “comparin...

New paper alert 📣 #Neuroskyence

"Rhythmic sampling of multiple decision alternatives in the human brain" @natcomms.nature.com

together with @ycaoneuro.bsky.social @maryamtohidi.bsky.social @donnerlab.bsky.social @ktsetsos.bsky.social

www.nature.com/articles/s41...
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Aperiodic 1/f noise drives ripple activity in humans - Nature Communications How aperiodic 1/f noise drives ripple activity in human brain and impacts on ripple detections is not fully understood. Here authors show that ripple detections should be driven by the 1/f noise, whic...

Ripple oscillations are central for memory and sleep.

But ripple detection in humans remains challenging. Here we introduce a simulation approach in @natcomms.nature.com as common ripple detectors mainly pick up 1/f noise and not genuine oscillations

👇
www.nature.com/articles/s41...

#neuroskyence

𝗪𝗵𝗮𝘁 𝗶𝘀 𝗻𝗼𝗶𝘀𝗲 𝗶𝗻 𝘁𝗵𝗲 𝗯𝗿𝗮𝗶𝗻?
Almost always we average responses thus equating response variability with noise.
Well, we shouldn't because variability is also signal, not noise to be entirely discarded.
#neuroskyence
doi.org/10.1016/j.ne...

We show that population-level analyses are feasible in human iEEG and that evidence accumulation expands the neural space. Within this enlarged neural repertoire, it is easier to differentiate sensory stimuli based on the context, which hallmarks behavior and enables flexible behavior (4/4).

We specifically asked whether evidence integration is driven by a noise reduction or by increased pattern separability. Our results reveal that an enlarged neural space (more activity in a larger distributed network) supports integration by rendering sensory representations more distinct (3/4)

Previously, we showed that overlapping neural representations elicit behavioral costs, which can be reduced by subspace partitioning to separate distracting information. www.pnas.org/doi/10.1073/.... We now asked how behaviorally-relevant information is integrated in population activity (2/4)

Conjunctive population coding integrates sensory evidence to guide adaptive human behavior. New work led by @jonasterlau.bsky.social in @pnas.org. We used human intracranial EEG to understand how coordinated population activity supports context-dependent behavior. www.pnas.org/doi/10.1073/.... (1/4)

Wu Tsai Institute: Making the right connections With state-of-the-art research facilities and collaborative spaces, Yale's Wu Tsai Institute is on a mission to understand human cognition by bridging academic disciplines.

Understanding the mind takes many ways of seeing.

Faculty at the Wu Tsai Institute are working across neuroscience, engineering, and psychology to study how the mind works. A look inside the institute’s new home shows how shared spaces and new tools are supporting discovery through collaboration.

A cautionary tale that aperiodic activity is also prone to the Fourier fallacy. Spectral estimates are difficult to interpret when pathologic waveforms are present. Likely relevant for other clinical conditions as well (as expertly reviewed by @tomdonoghue.bsky.social in @ejneuroscience.bsky.social)

Aperiodic Activity Reflects Pathologic Waveform Shapes in Focal Epilepsy Epilepsy constitutes a clinically manifest excitability disorder that is characterized by aberrant electrophysiological activity in the electroencephalogram (EEG). The correct identification of the se...

Aperiodic activity reflects pathological waveforms in epilepsy (and not necessarily hyper-excitability or altered E/I-balance). The 1/f slope goes up *or* down as function of waveforms during seizures. New work by Laura Heidiri and Frank van Schalkwijk from the lab: www.jneurosci.org/content/45/5...

High-frequency bursts facilitate fast communication for human spatial attention - Nature Neuroscience Using intracranial electroencephalography from patients with epilepsy during spatial attention tasks, this study shows that high-frequency bursts facilitate fast communications in brain networks and s...

Our new paper is out in @natneuro.nature.com

How do large-scale brain networks route information about where/what to attend at fast timescales?

High-frequency bursts facilitate fast communication for human spatial attention

www.nature.com/articles/s41...

This work adds a new perspective on the role of neural variability for human behavior and contributes to resolving the evoked response paradox that Buzsaki elegantly described in his @sfn.org autobiography: Variability and its consequences differ at opposite ends of the cortical hierarchy (4/4)

To provide additional mechanistic insight, we reanalyzed a large intracranial electrical stimulation dataset published by @dorahermes.bsky.social, which provided causal evidence for the idea that neural variability captures recurrent connectivity along the cortical hierarchy (3/4)

This work builds on the insight that behavior needs variability by Waschke, @nielskloosterman.bsky.social, @jonasobleser.bsky.social and @garrettneuro.bsky.social and seminal NHP work by Churchland on neural quenching. It resolves how variability is related to different facets of cognition (2/4)

Structure in noise: Recurrent connectivity shapes neural variability to balance perceptual and cognitive demands in the human brain Does neural variability reflect random noise or a feature that benefits adaptive behavior? Using intracranial recordings in humans, Terlau et al. demonstrate that neural variability results from the r...

New work from the lab published in @cp-neuron.bsky.social by @jonasterlau.bsky.social and Jan Martini. We describe that trial-by-trial variability indexes recurrent connectivity across the cortical hierarchy, which supports reliable and flexible coding www.cell.com/neuron/abstr... (1/4)

Too kind. Thanks @colinwhoy.bsky.social

For postdocs: Check out the WTI postdoc program (wti.yale.edu/initiatives/...) - great opportunity to join the Yale community. Application deadline is Nov 10. I'll also be posting more postdoc opportunities in my lab in the coming weeks (for spring '26). Please reach out if you want to learn more

For PhD students: I’ll be accepting new students (fall 2026) either through the Psychology program (psychology.yale.edu/graduate/adm...) or the Interdisciplinary neuroscience program (medicine.yale.edu/inp/academic...). The application deadline is December 1st. Reach out if you have any questions.

New position, new social media account. After 5 fantastic years in Tuebingen, I moved to @yale.edu and the @wutsaiyale.bsky.social this summer - which means that I’ll be recruiting PhD students and postdocs. Please help me to spread the word and see current opportunities below 👇