Implantable silicon neural probes with nanophotonic phased arrays for single-lobe beam steering.

In brain activity mapping with optogenetics, patterned illumination is crucial for targeted neural stimulation. However, due to optical scattering in brain tissue, light-emitting implants are needed to bring patterned illumination to deep brain regions. A promising solution is silicon neural probes with integrated nanophotonic circuits that form tailored beam patterns without lenses.

3D-printed microstructured alginate scaffolds for neural tissue engineering.

Alginate (Alg) is a versatile biopolymer for scaffold engineering and a bioink component widely used for direct cell printing. However, due to a lack of intrinsic cell-binding sites, Alg must be functionalized for cellular adhesion when used as a scaffold. Moreover, direct cell-laden ink 3D printing requires tedious disinfection procedures and cell viability is compromised by shear stress.

Implantable photonic neural probes with 3D-printed microfluidics and applications to uncaging.

Advances in chip-scale photonic-electronic integration are enabling a new generation of foundry-manufacturable implantable silicon neural probes incorporating nanophotonic waveguides and microelectrodes for optogenetic stimulation and electrophysiological recording in neuroscience research. Further extending neural probe functionalities with integrated microfluidics is a direct approach to achieve neurochemical injection and sampling capabilities. In this work, we use two-photon polymerization 3D printing to integrate microfluidic channels onto photonic neural probes, which include silicon nitride nanophotonic waveguides and grating emitters.

3D printed neural tissues with in situ optical dopamine sensors.

Engineered neural tissues serve as models for studying neurological conditions and drug screening. Besides observing the cellular physiological properties, in situ monitoring of neurochemical concentrations with cellular spatial resolution in such neural tissues can provide additional valuable insights in models of disease and drug efficacy. In this work, we demonstrate the first three-dimensional (3D) tissue cultures with embedded optical dopamine (DA) sensors.

Neuroplastin expression is essential for hearing and hair cell PMCA expression.

Hearing deficits impact on the communication with the external world and severely compromise perception of the surrounding. Deafness can be caused by particular mutations in the neuroplastin (Nptn) gene, which encodes a transmembrane recognition molecule of the immunoglobulin (Ig) superfamily and plasma membrane Calcium ATPase (PMCA) accessory subunit. This study investigates whether the complete absence of neuroplastin or the loss of neuroplastin in the adult after normal development lead to hearing impairment in mice analyzed by behavioral, electrophysiological, and in vivo imaging measurements.

Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits.

The primary auditory cortex (A1) is an essential, integrative node that encodes the behavioral relevance of acoustic stimuli, predictions, and auditory-guided decision-making. However, the realization of this integration with respect to the cortical microcircuitry is not well understood. Here, we characterize layer-specific, spatiotemporal synaptic population activity with chronic, laminar current source density analysis in Mongolian gerbils (Meriones unguiculatus) trained in an auditory decision-making Go/NoGo shuttle-box task.

Ketamine anaesthesia induces gain enhancement via recurrent excitation in granular input layers of the auditory cortex.

Key Points: Ketamine is a common anaesthetic agent used in research and more recently as medication in treatment of depression. It has known effects on inhibition of interneurons and cortical stimulus-locked responses, but the underlying functional network mechanisms are still elusive. Analysing population activity across all layers within the auditory cortex, we found that doses of this anaesthetic induce a stronger activation and stimulus-locked response to pure-tone stimuli.

Optogenetic stimulation of the VTA modulates a frequency-specific gain of thalamocortical inputs in infragranular layers of the auditory cortex.

Reward associations during auditory learning induce cortical plasticity in the primary auditory cortex. A prominent source of such influence is the ventral tegmental area (VTA), which conveys a dopaminergic teaching signal to the primary auditory cortex. Yet, it is unknown, how the VTA influences cortical frequency processing and spectral integration.

Dopaminergic neuromodulation of high gamma stimulus phase-locking in gerbil primary auditory cortex mediated by D1/D5-receptors.

Cortical release of the neurotransmitter dopamine has been implied in adapting cortical processing with respect to various functions including coding of stimulus salience, expectancy, error prediction, behavioral relevance and learning. Dopamine agonists have been shown to modulate recurrent cortico-thalamic feedback, and should therefore also affect synchronization and amplitude of thalamo-cortical oscillations. In this study, we have used multitaper spectral and time-frequency analysis of stimulus-evoked and spontaneous current source density patterns in primary auditory cortex of Mongolian gerbils to characterize dopaminergic neuromodulation of the oscillatory structure of current sources and sinks.