Neural oscillations

Neural oscillations are often proposed to support brain computation by routing information, organizing cell assemblies, or shaping coding dynamics. Yet these ideas usually assume rhythms that are strong, sustained, and regular, whereas in vivo oscillations are often weak, transient, noisy, and variable in frequency and phase. In this talk, I will argue that such “no-metronome” oscillations are not just noisy fluctuations, but coordinated complex dynamics with functional consequences. Combining analyses of neural activity recordings during actual behavior (mice and non-human-primate LFPs and hu

Predicting the location of expected upcoming stimuli is a key function in sensory processing. Noise in the environment reduces the reliability of sensory input and increases the importance of prior information. Yet, sudden changes in the environment can render this prior information irrelevant. In such cases, observers should reset their beliefs and establish new priors using current sensory evidence. To study these dynamics of perceptual belief updating, we conducted a human EEG experiment (N = 29) investigating auditory spatial localization in noisy volatile environments and analyzed the ass

…that event-related potentials and neural oscillations are valuable biomarkers fo

…In this study, we tracked how neural oscillations and corticospinal excitability reflect the acquisition and reversal of pain expectations. Using a Pavlovian conditioning task, participants learned to anticipate the occurrence of lateralized aversive shocks. Specifically, during acquisition neutral visual stimuli predicted shocks to either the left (CS+L) or right (CS+R) arm, while another stimulus (CS-) never predicted s

Disrupted neural oscillations and memory are common features of Alzheimer's disease (AD). Our previous studies have demonstrated the potential to restore theta oscillations by utilizing LFP-guided closed-loop optogenetic stimulation of local parvalbumin-positive (PV+) interneurons in the CA1 region of the hippocampus in APP/PS1dE9 mice. Furthermore, employing the same protocol, we successfully enhanced the performance of transgenic mice in a spatial memory tests. Based on these findings, our objective is to investigate the impact of PV+ stimulation on circuit function within the CA1 region. To

Neural oscillations play a crucial role in various cognitive processes within the mammalian brain. Beyond the spectral properties typically reported in the literature, the waveform shape of oscillatory activity offers valuable insights into local physiology, and is related to the underlying cortical circuitry and to dynamically changing or aberrant cortical states. Notwithstanding the importance of oscillatory waveform shape to gain insights into cortical physiology, how the waveform shape of ongoing oscillations differs across distant yet functionally and anatomically connected cortical areas

…the examination of interconnected neural regions, such as the posterior parietal cortex (PPC). The PPC, intricately linked with the hippocampus and essential to memory functions, particularly spatial memory, is vital for decoding early symptoms and the pr

…with a phase adjustment of ongoing neural oscillations aligning with the expected onset of upcoming stimuli. In ageing, there is some evidence that these mechanisms might be altered; however, findings are inconsistent. Thus, we aimed to investigate how anticipatory oscillatory markers of temporal prediction change with ageing, adapting a previously used temporal prediction task while measuring electro

Flexibility is a key skill to deal with unexpected emergencies. However, successful flexible behaviour can necessitate different types of cognitive and behavioural changes depending on the current task demands. For example, sometimes we might have to flexibly shift our attention (sensory flexibility), alter our actions (motor flexibility), or change our task goals (goal flexibility). So far, it is unclear if flexible alterations of different aspects of cognitive functions rely on a same, shared set of mechanisms (e.g., a general “flexibility network” in the brain) or several domain-specific me

Neural oscillations provide unique insights into brain function in health and disease. Recently, the non-sinusoidal waveform shape of oscillations has gained interest as a promising biomarker of underlying network physiology. However, the relationship between spiking activity and the oscillatory shape of population signals such as the local field potential (LFP) is unknown. To address this, we simultaneously recorded LFP and multi-unit spiking activity in 8 different cortical and subcortical brain areas of macaque monkeys. We applied Fourier-based waveform analysis to LFP oscillations and syst

Neural oscillations have been associated with different functions and disorders of the brain. Recently, the non-sinusoidal waveform of oscillations has gained interest as a biomarker for neurological and psychiatric diseases, and as an indicator of underlying network physiology. However, waveform analysis in the time domain has been limited to dominant neuronal oscillations and by pre-selection of waveform features. Here, we contribute a novel Fourier-series waveform analysis that is noise resistant and provides a complete description of waveforms. We applied Fourier-based waveform analysis to

Neural oscillations are ubiquitously observed in many brain areas. One proposed functional role of these oscillations is that they serve as an internal clock, or ‘frame of reference’ relative to which information can be encoded. In line with this hypothesis, there have been many empirical observations of this phase code in the brain. What are the latent dynamics and circuits that support phase coding with neural oscillations? Here, we propose a new computational hypothesis which is derived from analyzing trained recurrent neural networks (RNNs). We train RNNs on a working memory task, while al

…Oscillations, for example, are paradigmatic synchronous patterns of neural activity with a defined temporal scale. Neuronal avalanches, in contrast, do not show characteristic spatial and temporal scales, and are often considered as evidence of brain tuning to quasi-criticality. While models have been developed to account for oscillations or neuronal avalanches separately, they typically do not explain both phenomena, are too complex to analyze analytically, or intractable to infer from data

Flexibility in a dynamic and uncertain world is critical for individuals to survive and thrive. An appropriately flexible agent should know when to exploit a known resource or explore for a potentially better one. Previous research indicates that prefrontal brain regions including the orbitofrontal cortex (OFC) and medial prefrontal cortex (mPFC), as well as the anterior insula are critical for value computation and decision-making. However, how these brain regions encode and transfer computed values to resolve the exploration-exploitation dilemma still remains unknown. We studied human cogni

The question of how syntactic structure can be built at the neural level has come to the forefront of cognitive neuroscience in the last decade. Neural oscillations have been widely recognised as playing an important role in building syntactic representations. In this talk I will review existing oscillatory approaches to syntactic structure building and assess their functionality in light of basic properties of a hierarchical syntactic structure, such as varied length of syntactic phrases, nesting of constituents, overlap in length between different levels of the syntactic hierarchy and others

The ability to remember spatial environments is critical for everyday life. In this talk, I will discuss my lab’s findings on how the human brain supports spatial memory and navigation based on our experiments with direct brain recordings from neurosurgical patients performing virtual-reality spatial memory tasks. I will show that humans have a network of neurons that represent where we are located and trying to go. This network includes some cell types that are similar to those seen in animals, such as place and grid cells, as well as others that have not been seen before in animals, such as