Biology subjects

Schriver, K. E.

Publications and source records attributed to Schriver, K. E..

5 recordsLinked to original sources

bioRxiv2026

INS-fMRI: a novel method for mapping mesoscale connectome networks in vivo in nonhuman primates

Mapping brain connections is paramount in neuroscience. Lacking has been a method that can systematically map mesoscale (<1mm) connections in the brain in vivo at brainwide scale. Mesoscale mapping is particularly important for NHPs in which information is represented in submillimeter clusters (e.g. cortical columns, striosomes, thalamic rods). Here, we present a method called INS-fMRI, which comprises optical stimulation of single sites in the brain using pulsed Infrared Neural Stimulation (INS), coupled with mapping of functionally connected sites in the brain using ultrahigh field fMRI. It is the only method available for mapping mesoscale connections rapidly (multiple networks mapped within single MRI sessions), systematically (allowing comparison of networks within single individuals), in vivo (no animal sacrifice needed), at whole brain scale, and without viral transfection. This method has broad applicability to a wide range of neuroscience questions. It can be used at any brain site, on different animal models, and on different MRI platforms. The ability to probe circuits repeatedly within single individuals also opens doors for studying changes in mesoscale circuits over time (e.g. for development, aging, disease studies). In addition, as this method circumvents the need for viral transfection, there is exciting potential for human clinical application.

neuroscience↗

bioRxiv2024

A novel interface for cortical columnar neuromodulation with multi-point infrared neural stimulation

Cutting edge advances in electrical visual cortical prosthetics have evoked perception of shapes, motion, and letters in the blind. Here, we present an alternative optical approach using pulsed infrared neural stimulation. To interface with dense arrays of cortical columns with submillimeter spatial precision, both linear array and 100-fiber bundle array optical fiber interfaces were devised. We delivered infrared stimulation through these arrays in anesthetized cat visual cortex and monitored effects by optical imaging in contralateral visual cortex. INS modulation of response to ongoing visual oriented gratings produced enhanced responses in orientation-matched domains and suppressed responses in non-matched domains, consistent with a known higher order integration mediated by callosal inputs. Controls included dynamically applied speeds, directions and patterns of multipoint stimulation. This provides groundwork for a distinct type of prosthetic targeted to maps of visual cortical columns.

neuroscience↗

bioRxiv2023

Unveiling interactions of spatial-temporal information in tactile motion perception

The intricate interplay of spatial and temporal information in tactile-motion perception remains elusive. Despite strides in decoding neural signals for direction, speed and texture in tactile perception, nuanced interactions persist as challenges. Addressing this, we investigated direction and speed tactile perception, exploring the intricate spatial-temporal dynamics. Psychophysical experiments manipulated direction and speed parameters using a laboratory-designed fingerpad ball-stimulator. A pivotal discovery includes quadrant-dependent anisotropic distortion in perceived motion direction, expanding the well-known notion of a specific preferred orientation. Spatial features primarily influence inherent responses, while temporal features impact stimulus-specific responses, shedding light on dynamic directional perception. The introduction of a psychometric function improved the modeling of tactile-motion speed perception, incorporating both linear and nonlinear components for a more accurate representation. This study provides intriguing insights into the neural mechanisms in tactile-motion perception, with potential applications for somatosensation in brain-machine interfaces. TeaserThis study unveils the intricate interplay of perceiving tactile motion, shedding light on the mysteries of tactile sensations.

neuroscience↗

bioRxiv2022

Spatial frequency representation in V2 and V4 of macaque monkey

Spatial frequency (SF) is an important attribute in the visual scene and is a defining feature of visual processing channels. However there remains many unsolved questions about how primate visual cortex, in particular extrastriate areas V2 and V4, codes this fundamental information. Here, using intrinsic signal optical imaging in visual cortex of Macaque monkeys, we quantify the relationship between spatial frequency maps and (1) visual topography, (2) color and orientation maps, and (3) across visual areas V1, V2, and V4. We find that in orientation regions, low to high spatial frequency is mapped orthogonally to orientation; however, in color regions, which is reported to contain orthogonal axes of color and lightness, only low spatial frequencies are represented without a gradient of SF representation. This produces the first observation of a population spatial frequency fluctuation related to the repeating color/orientation organizations. These findings support a generalized hypercolumn model across cortical areas, comprised of two orthogonal parameters with additional parameters.

neuroscience↗

bioRxiv2021

Selective Corticofugal Modulation on Sound Processing in Auditory Thalamus of Awake Marmosets

Cortical feedback has long been considered crucial for modulation of sensory processing. In the mammalian auditory system, studies have suggested that corticofugal feedback can have excitatory, inhibitory, or both effects on the response of subcortical neurons, leading to controversies regarding the role of corticothalamic influence. This has been further complicated by studies conducted under different brain states. In the current study, we used cryo-inactivation in the primary auditory cortex (A1) to examine the role of corticothalamic feedback on medial geniculate body (MGB) neurons in awake marmosets. The primary effects of A1 inactivation were a frequency-specific decrease in the auditory response of MGB neurons coupled with an increased spontaneous firing rate, which together resulted in a decrease in the signal-to-noise ratio. In addition, we report for the first-time that A1 robustly modulated the long-lasting sustained response of MGB neurons which changed the frequency tuning after A1 inactivation, e.g., neurons with sharp tuning increased tuning bandwidth whereas those with broad tuning decreased tuning bandwidth. Taken together, our results demonstrate that corticothalamic modulation in awake marmosets serves to enhance sensory processing in a way similar to center-surround models proposed in visual and somatosensory systems, a finding which supports common principles of corticothalamic processing across sensory systems.

neuroscience↗