A5067961795- Neural dynamics and brain function
- EEG and Brain-Computer Interfaces
- Functional Brain Connectivity Studies
- Visual perception and processing mechanisms
- Neuroscience and Neural Engineering
- Multisensory perception and integration
- Neural and Behavioral Psychology Studies
- Memory and Neural Mechanisms
- Photoreceptor and optogenetics research
- Olfactory and Sensory Function Studies
- Neuroscience and Neuropharmacology Research
- Advanced Thermodynamics and Statistical Mechanics
- Nonlinear Dynamics and Pattern Formation
- Advanced Neuroimaging Techniques and Applications
- Advanced MRI Techniques and Applications
- Retinal Development and Disorders
- Electrochemical Analysis and Applications
- Visual Attention and Saliency Detection
- Animal Vocal Communication and Behavior
- Neurobiology and Insect Physiology Research
- Pancreatitis Pathology and Treatment
- Tactile and Sensory Interactions
- Abdominal Surgery and Complications
- Biochemical Analysis and Sensing Techniques
- Abdominal Trauma and Injuries
University Medical Center Hamburg-Eppendorf
2015-2025
Universität Hamburg
2015-2025
German Primate Center
2003-2017
Eppendorf (Belgium)
2015
Nephrologisches Zentrum Goettingen
2007
Abstract Optogenetic manipulation of neuronal activity through excitatory and inhibitory opsins has become an indispensable experimental strategy in neuroscience research. For many applications bidirectional control allowing both excitation inhibition the same neurons a single experiment is desired. This requires low spectral overlap between opsin, matched photocurrent amplitudes fixed expression ratio. Moreover, independent activation two distinct populations with different optogenetic...
The activity of neurons in the primate lateral prefrontal cortex (LPFC) is strongly modulated by visual attention. Such a modulation has mostly been documented averaging independently recorded over repeated experimental trials. However, realistic settings, ensembles simultaneously active LPFC must generate attentional signals on single-trial basis, despite individual and correlated variability neuronal responses. Whether, under these circumstances, can reliably unclear. Here, we show that...
Neurons in the primate lateral prefrontal cortex (LPFC) encode working memory (WM) representations via sustained firing, a phenomenon hypothesized to arise from recurrent dynamics within ensembles of interconnected neurons. Here, we tested this hypothesis by using microelectrode arrays examine spike count correlations (rsc ) LPFC neuronal during spatial WM task. We found pattern pairwise rsc maintenance indicative stronger coupling between similarly tuned neurons and increased inhibition...
Local field potentials (LFPs) are fluctuations of extracellular voltage that may reflect the physiological phenomena occurring within a volume neural tissue. It is known allocation spatial attention modulates amplitude LFPs in visual areas primates. An issue remains poorly investigated whether and how executive brain areas, such as lateral prefrontal cortex (LPFC), thought to be involved origins attention. We addressed this by recording from multielectrode arrays implanted LPFC two macaques....
Throughout each day, the brain displays transient changes in state, as evidenced by shifts behavior and vigilance. While electrophysiological correlates of states have been studied for some time, it remains unclear how large-scale cortico-cortical functional connectivity systematically reconfigures across states. Here, we investigate state-dependent cortical recording local field potentials (LFPs) during spontaneous behavioral transitions ferret using chronically implanted...
Complex behavior and task execution require fast changes of local activity functional connectivity in cortical networks at multiple scales. The roles that power play during these processes are still not well understood. Here, we study how fluctuations coupling across different brain areas determine performance an audiovisual, lateralized detection the ferret. We hypothesized dynamic variations network’s state animals’ performance. evaluated by quantifying phase visual, auditory parietal...
Phase coherence and amplitude correlations across brain regions are two main mechanisms of connectivity that govern dynamics at multiple scales. However, despite the increasing evidence associates these with functions cognitive processes, relationship between different coupling modes is not well understood. Here, we study causal relation both types functional cortical areas. While most studies adopt a definition based on pairs electrodes or interest, here employ multichannel approach...
Single neurons in primate dorsolateral prefrontal cortex (dLPFC) are known to encode working memory (WM) representations of visual space. Psychophysical studies have shown that the horizontal and vertical meridians field can bias spatial information maintained WM. However, most models tacitly assumed dLPFC represent mnemonic space homogenously. The anatomical organization these has also eluded clear parametric description. We investigated issues by recording from neuronal ensembles macaque...
Common trends observed in many visual and oculomotor-related cortical areas include retinotopically organized receptive movement fields exhibiting a Gaussian shape increasing size with eccentricity. These are demonstrated the frontal eye fields, areas, superior colliculus but have not been thoroughly characterized prearcuate area 8Ar of prefrontal cortex. This is important since 8Ar, located anterior to more cytoarchitectonically similar than premotor areas. Here we recorded responses 166...
Brain signal irreversibility has been shown to be a promising approach study neural dynamics. Nevertheless, the relation with cortical hierarchy and influence of different electrophysiological features is not completely understood. In this study, we recorded local field potentials (LFPs) during spontaneous behavior, including awake sleep periods, using custom micro-electrocorticographic (μECoG) arrays implanted in ferrets. contrast humans, ferrets remain less time each state across...
Neurons within the primate dorsolateral prefrontal cortex (dlPFC) are clustered in microcolumns according to their visuospatial tuning. One issue that remains poorly investigated is how this anatomical arrangement influences functional interactions between neurons during behavior. To investigate question we implanted 4 mm×4 mm multielectrode arrays two macaques' dlPFC area 8a and measured spike count correlations (rsc) responses of simultaneously recorded when animals maintained stationary...
During the last two decades ferrets (Mustela putorius) have been established as a highly efficient animal model in different fields neuroscience. Here we asked whether integrate sensory information according to same principles for other species. Since only few methods and protocols are available behaving developed head-free, body-restrained approach allowing standardized stimulation position utilization of ferret's natural response behavior. We behavioral paradigm test audiovisual...
Abstract Synchronous spiking of multiple neurons is a key phenomenon in normal brain function and pathologies. Recently, approaches to record spikes from the intact cortical surface using small high‐density arrays microelectrodes have been reported. It remained unaddressed how epicortical relates intracortical unit activity. We introduced mesoscale approach an array 64 electrodes with intermediate diameter (250 μm) combined large‐coverage recordings ferrets via laminar probes. Empirical data...
Audiovisual integration is facilitated by the context-specific dynamical reconfiguration of cortical intrinsic coupling.
In the superior colliculus (SC), visual afferent inputs from various sources converge in a highly organized way such that all layers form topographically aligned representations of contralateral external space. Despite this anatomical organization, it remains unclear how layer-specific termination different input pathways is reflected nature response properties and their distribution across layers. To uncover physiological correlates underlying laminar organization SC, we recorded multiunit...
Neurons in the lateral prefrontal cortex (LPFC) encode sensory and cognitive signals, as well commands for goal-directed actions. Therefore, LPFC might be a good signal source goal-selection brain-computer interface (BCI) that decodes intended goal of motor action previous to its execution. As first step development BCI, we set out determine if could decode simple behavioral intentions direct gaze eight different locations space from single-trial neural activity. We recorded neuronal spiking...
Cortical single neuron activity and local field potential patterns change at different depths of general anesthesia. Here, we investigate the associated network level changes functional connectivity. We recorded ongoing electrocorticographic (ECoG) from temporo-parieto-occipital cortex 6 ferrets various levels isoflurane/nitrous oxide anesthesia determined connectivity by computing amplitude envelope correlations. Through hierarchical clustering, derived typical corresponding to light,...
In the absence of sensory stimulation or motor output, brain exhibits complex spatiotemporal patterns intrinsically generated neural activity. Analysis ongoing dynamics has identified prevailing modes cortico-cortical interaction; however, little is known about how such activity are correlated between cortical and subcortical areas. We investigate correlation structure superior colliculus (SC) across multiple spatial temporal scales. Ongoing cortico-tectal interaction was characterized by...
Abstract Optogenetic manipulation of neuronal activity has become an indispensable experimental strategy in neuroscience research. A large repertoire excitatory and inhibitory tools allows precise activation or inhibition genetically targetable populations. However, optogenetic tool for reliable bidirectional control allowing both up- downregulation the same neurons a single experiment is still missing. Here we report BiPOLES, potent excitation population with light two different colors....
Intrinsic coupling modes (ICMs) can be observed in ongoing brain activity at multiple spatial and temporal scales. Two families of ICMs distinguished: phase envelope ICMs. The principles that shape these remain partly elusive, particular their relation to the underlying structure. Here we explored structure-function relationships ferret between quantified from recorded with chronically implanted micro-ECoG arrays structural connectivity (SC) obtained high-resolution diffusion MRI...
Abstract The integration of visual and auditory spatial information is important for building an accurate perception the external world, but fundamental mechanisms governing such audiovisual interaction have only partially been resolved. earliest interface between processing pathways in midbrain, where superior ( SC ) inferior colliculi IC are reciprocally connected loop. Here, we investigate midbrain by recording neural signals from simultaneously anesthetized ferrets. Visual stimuli...
Abstract Methylphenidate (MPH), commonly known as Ritalin, is the most widely prescribed drug worldwide to treat patients with attention deficit disorders. Although MPH thought modulate catecholamine neurotransmission in brain, it remains unclear how these neurochemical effects influence neuronal activity and lead attentional enhancements. Studies rodents overwhelmingly point lateral prefrontal cortex (LPFC) a main site of action MPH. To understand mechanism primate we recorded responses...
Abstract Lateral prefrontal cortex (LPFC) neurons signal the allocation of voluntary attention; however, neural computations underlying this function remain unknown. To investigate this, we recorded from neuronal ensembles in LPFC two Macaca fascicularis performing a visuospatial attention task. responses to single stimulus were normalized when additional stimuli/distracters appeared across visual field and well-characterized by an averaging computation. Deploying toward individual...