Biology subjects

Rathbun, D. L.

Publications and source records attributed to Rathbun, D. L..

3 recordsLinked to original sources

bioRxiv2025

Adaptation of visual responses in degenerating rd10 and healthy mouse retinas during ongoing electrical stimulation.

ObjectiveVisual adaptation is a physiological and perceptual process by which the visual system adjusts to changes in the environment or visual stimuli. This process is fundamental to how we perceive the world around us and allows our visual system to efficiently encode and process visual information. The retina incorporates adaptaion with its dozens of functionally distinct retinal ganglion cell types. Meanwhile, the field of retinal prostheses is increasing its understanding of electrical adaptation and cell-specific stimulation. However, very little is known about the interaction of visual and electrical stimulation on the adaptation of retinal ganglion cell types. Methods/ApproachRecording with a microelectrode array (MEA), we presented an ON and OFF full-field, visual stimulus to characterize various visual response parameters in healthy and degenerating rd10 mouse retinas. We then evaluated visual response changes before and after blocks of monophasic voltage-controlled electrical pulse stimulation. Main ResultsA history of electrical stimulation strengthened visual responses in WT retina, even when changes attributable to in vitro visual adaptation were taken into account. In rd10 retinas, electrical adaptation counteracted the baseline in vitro visual adaptation. In all cases, adaptation often affected the ON and OFF visual response components differentially. Consequently, the ON/OFF classification of indiviual cells changed as a result of adaptation. SignificanceElectrical stimulation-induced changes in the retina should be considered in the encoding of visual stimuli by retinal prosthetic devices. In vitro investigations for bionic vision should strive to probe electrical responsiveness after adaptation to ongoing electrical stimulation has achieved a steady-state.

neuroscience↗

bioRxiv2023

Neural extracellular matrix regulates visual sensory motor integration

Visual processing depends on sensitive and balanced synaptic neurotransmission. Extracellular matrix proteins in the environment of cells are key modulators in synaptogenesis and synaptic plasticity. In the present study, we provide evidence that the combined loss of the four extracellular matrix components brevican, neurocan, tenascin-C and tenascin-R in quadruple knockout mice leads to severe retinal dysfunction and diminished visual motion processing in vivo. Remarkably, impaired visual motion processing was accompanied by a developmental loss of cholinergic direction-selective starburst amacrine cells. Additionally, we noted imbalance of inhibitory and excitatory synaptic signaling in the quadruple knockout retina. Collectively, the study offers novel insights into the functional importance of four key extracellular matrix proteins for retinal function, visual motion processing and synaptic integrity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=73 SRC="FIGDIR/small/537074v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@eec571org.highwire.dtl.DTLVardef@1e4b282org.highwire.dtl.DTLVardef@18398a7org.highwire.dtl.DTLVardef@9b113b_HPS_FORMAT_FIGEXP M_FIG C_FIG In briefIn their study, Reinhard et al. show that the combined loss of the extracellular matrix components brevican, neurocan, tenascin-C and tenascin-R in quadruple knockout mice leads to retinal dysfunction, diminished visual motion processing, developmental loss of cholinergic direction-selective starburst amacrine cells and imbalance of inhibitory and excitatory synaptic integrity. HighlightsO_LICombined loss of the four extracellular matrix molecules brevican, neurocan, tenascin-C and tenascin-R causes retinal dysfunction C_LIO_LIImpaired visual motion processing in quadruple, tenascin-C and tenascin-R knockout mice C_LIO_LILoss of cholinergic direction-selective starburst amacrine cells in the quadruple knockout retina C_LIO_LIThe matrisome influences inhibitory and excitatory synaptic balance C_LI

neuroscience↗

bioRxiv2018

The augmentation of retinogeniculate communication during thalamic burst mode

Retinal signals are transmitted to cortex via neurons in the lateral geniculate nucleus (LGN), where they are processed in burst or tonic response mode. Burst mode occurs when LGN neurons are sufficiently hyperpolarized for T-Type Ca2+ channels to de-inactivate, allowing them to open in response to a depolarization which can trigger a high-frequency sequence of Na+-based spikes (i.e. burst). In contrast, T-type channels are inactivated during tonic mode and do not contribute to spiking. Although burst mode is commonly associated with sleep and the disruption of retinogeniculate communication, bursts can also be triggered by visual stimulation, thereby transforming the retinal signals relayed to the cortex.\n\nTo determine how burst mode affects retinogeniculate communication, we made recordings from monosynaptically connected retinal ganglion cells and LGN neurons in the cat during visual stimulation. Our results reveal a robust augmentation of retinal signals within the LGN during burst mode. Specifically, retinal spikes were more effective and often triggered multiple LGN spikes during periods likely to have increased T-Type Ca2+ activity. Consistent with the biophysical properties of T-Type Ca2+ channels, analysis revealed that effect magnitude was correlated with the duration of the preceding thalamic interspike interval and occurred even in the absence of classically defined bursts. Importantly, the augmentation of geniculate responses to retinal input was not associated with a degradation of visual signals. Together, these results indicate a graded nature of response mode and suggest that, under certain conditions, bursts facilitate the transmission of visual information to the cortex by amplifying retinal signals.\n\nSignificanceThe thalamus is the gateway for retinal information traveling to the cortex. The lateral geniculate nucleus (LGN), like all thalamic nuclei, has two classically defined categories of spikes--tonic and burst--that differ in their underlying cellular mechanisms. Here we compare retinogeniculate communication during burst and tonic response modes. Our results show that retinogeniculate communication is enhanced during burst mode and visually evoked thalamic bursts, thereby augmenting retinal signals transmitted to cortex. Further, our results demonstrate that the influence of burst mode on retinogeniculate communication is graded and can be measured even in the absence of classically defined thalamic bursts.

neuroscience↗