Biology subjects

Berns, G.

Publications and source records attributed to Berns, G..

4 recordsLinked to original sources

bioRxiv2024

Lateralized cerebellar connectivity differentiates auditory pathways in echolocating and non-echolocating whales

We report the first application of diffusion tractography to a mysticete, which was analyzed alongside three odontocete brains, allowing the first direct comparison of strength and laterality of auditory pathways in echolocating and non-echolocating whales. Brains were imaged post-mortem at high resolution with a specialized steady state free precession diffusion sequence optimized for dead tissue. We conducted probabilistic tractography to compare the qualitative features, tract strength, and lateralization of potential ascending and descending auditory paths in the mysticete versus odontocetes. Tracts were seeded in the inferior colliculi (IC), a nexus for ascending auditory information, and the cerebellum, a center for sensorimotor integration. Direct IC to temporal lobe pathways were found in all animals, replicating previous cetacean tractography and suggesting conservation of the primary auditory projection path in the cetacean clade. Additionally, odontocete IC-cerebellum pathways exhibited higher overall tract strength than in the mysticete, suggesting a role as descending acousticomotor tracts supporting the rapid sensorimotor integration demands of echolocation. Further, in the mysticete, contralateral right IC to left cerebellum pathways were 17x stronger than those between left IC and right cerebellum, while in odontocetes, the laterality was reversed, and left IC to right cerebellum pathways were 2-4x stronger than those between right IC and left cerebellum. The stronger left IC-right cerebellum connectivity observed in odontocetes corroborates the theory that odontocetes preferentially echolocate with their right phonic lips, as the right phonic lips are likely innervated by left-cortical motor efferents that integrate with left-cortical auditory afferents in right cerebellum. This interpretation is further supported by the reversed lateralization of IC-cerebellar tracts observed in the non-echolocating mysticete. We also found differences in the specific subregions of cerebellum targeted by the IC, both between the mysticete and odontocetes, and between left and right sides. This study establishes foundational knowledge on mysticete auditory connectivity and extends knowledge on the neural basis of echolocation in odontocetes.

neuroscience↗

bioRxiv2020

An MRI protocol for anatomical and functional evaluation of the California sea lion brain

We describe a research MRI protocol for in vivo evaluation of pinniped brains using standard human clinical MRI hardware and pulse sequences. Our intended application is to study development of California sea lions (Zalophus californianus) exposed in utero to domoic acid (DOM) produced by harmful algae blooms in the coastal Pacific Ocean. In cases where the fetus survives to birth, exposure to the toxin in utero could result in developmental abnormalities leading to neurological and behavioral deficits. Prior studies on sea lions naturally exposed to DOM as adults have demonstrated hippocampal atrophy and altered mesial temporal connectivity. This MRI protocol is therefore intended to depict the hippocampal formation as the primary region of interest, and to provide longitudinal measures of brain functional and structural connectivity as well as quantitative anatomical evaluations. Scan quality and utility are assessed by comparison with prior studies in live and post mortem sea lion brains. We include the first determination of cerebral blood flow mapping using MRI, and also the first fiber tractography using diffusion-weighted imaging from a live sea lion brain. The protocol also facilitates screening for common neurological pathologies, including tumors, trauma and hemorrhages. We believe the protocol would be suitable for any pinniped that can fit inside a human MRI scanner.

neuroscience↗

bioRxiv2020

2D or Not 2D? An FMRI Study of How Dogs Visually Process Objects

ABSTRACTGiven humans’ habitual use of screens, they rarely consider potential differences when viewing two dimensional (2D) stimuli and real-world versions of dimensional stimuli. Dogs also have access to many forms of screens and touch pads, with owners even subscribing to dog-directed content. Humans understand that 2D stimuli are representations of real-world objects, but do dogs? In canine cognition studies, 2D stimuli are almost always used to study what is normally 3D, like faces, and may assume that both 2D and 3D stimuli are represented in the brain the same way. Here, we used awake fMRI of 15 dogs to examine the neural mechanisms underlying dogs’ perception of two- and three-dimensional objects after the dogs were trained on either a two- or three-dimensional version of the objects. Activation within reward processing regions and parietal cortex of the dog brain to 2D and 3D versions of objects was determined by their training experience, as dogs trained on one dimensionality showed greater activation to the dimension on which they were trained. These results show that dogs do not automatically generalize between two- and three-dimensional stimuli and caution against implicit assumptions when using pictures or videos with dogs.Competing Interest StatementG.B. & M.S. own equity in Dog Star Technologies and developed technology used in some of the research described in this paper. The terms of this arrangement have been reviewed and approved by Emory University in accordance with its conflict of interest policies.View Full Text

animal behavior and cognition↗

bioRxiv2017

Awake fMRI Reveals Mechanisms of Language Comprehension in Dogs

How do dogs understand human words? At a basic level, understanding would require the discrimination of words from non-words. To determine the mechanisms of such a discrimination, we trained 12 dogs to retrieve two objects based on object names, then probed the neural basis for these auditory discriminations using awake-fMRI. We compared the neural response to these trained words relative to \"oddball\" pseudowords the dogs had not heard before. Consistent with novelty detection, we found greater activation for pseudowords relative to trained words bilaterally in the parietotemporal cortex. To probe the neural basis for representations of trained words, searchlight multivoxel pattern analysis (MVPA) revealed that a subset of dogs had clusters of informative voxels that discriminated between the two trained words. These clusters included the left temporal cortex and amygdala, left caudate nucleus, and thalamus. These results demonstrate that dogs processing of human words utilizes basic processes like novelty detection, and for some dogs, may also include auditory and hedonic representations.

neuroscience↗