Biology subjects

Gutfreund, Y.

Publications and source records attributed to Gutfreund, Y..

3 recordsLinked to original sources

bioRxiv2024

Small animal brain surgery with neither a brain atlas nor a stereotaxic frame

Stereotaxic surgery is a cornerstone in brain research for the precise positioning of electrodes and probes, but its application is limited to species with available brain atlases and tailored stereotaxic frames. Addressing this limitation, we introduce an alternative technique for small animal brain surgery that requires neither an aligned brain atlas nor a standard stereotaxic frame. This method requires a high-contrast MRI scan of a specimen and access to a microCT scanner. The process involves attaching miniature markers to the skull, followed by CT scanning of the head. Subsequently, MRI and CT images are co-registered using standard image processing software and the targets for recordings in the brain are marked in the MRI image. During surgery, the animals head is stabilized in any convenient orientation, and the probes 3D position and angle are tracked using a multi-camera system. We have developed a software that utilizes the on-skull markers as fiducial points to align the CT/MRI 3D model with the surgical positioning system, and in turn instructs the surgeon how to move the probe to reach the targets within the brain. Our technique allows the execution of insertion tracks connecting two points in the brain. We successfully applied this method for neuropixels probe positioning in owls, quails, and mice, demonstrating its versatility and its potential to open new avenues for research in non-standard and novel animal models.

neuroscience↗

bioRxiv2021

Spatial coding in the hippocampus of flying owls

The elucidation of spatial coding in the hippocampus requires exploring diverse animal species. While robust place-cells are found in the mammalian hippocampus, much less is known about spatial coding in the hippocampus of birds - and nothing is known about avian spatial representation during flight. Here we used a wireless-electrophysiology system to record single neurons in the hippocampus and related pallial structures from freely flying barn owls (Tyto alba) - a central-place nocturnal predator species with excellent navigational abilities. The owls 3D position was monitored while it flew back and forth between two perches. We found place cells - neurons that robustly represented the owls location during flight, and its flight-direction - as well as neurons that coded the owls perching position between flights. Spatial coding was invariant to changes in lighting conditions and to the position of a salient object in the room. Place cells were found in the anterior hippocampus and in the adjacent posterior hyperpallium apicale, and to a much lesser extent in the visual Wulst (visual-cortex homologue). The finding of place-cells in flying owls suggests commonalities in spatial coding across a variety of species - including rodents, bats and owls.

neuroscience↗

bioRxiv2020

Head-Direction Coding in the Hippocampal Formation of Birds

Birds strongly rely on spatial memory and navigation. Therefore, it is of utmost interest to reveal how space is represented in the avian brain. Here we used tetrodes to record neurons from the hippocampal formation of Japanese quails - a ground-dwelling species - while the quails roamed a 1x1-meter arena (>2,100 neurons from 23 birds). Whereas spatially-modulated cells (place-cells, border-cells, etc.) were generally not encountered, the firing-rate of 12% of the neurons was unimodally and significantly modulated by the head-azimuth - i.e. these were head-direction cells (HD cells). Typically, HD cells were maximally active at one preferred-direction and minimally at the opposite null-direction, with preferred-directions spanning all 360{degrees}. The HD tuning was relatively broad (mean width [~]130{degrees}), independent of the animals position and speed, and was stable during the recording-session. Similarly to findings in rodents, the HD tuning usually rotated with the rotation of a salient visual cue in the arena. These findings support the existence of an allocentric head-direction representation in the quail hippocampal formation, and provide the first demonstration of head-direction cells in birds.

neuroscience↗