Modulation of Spontaneous and Light-Induced Activity in the Rat Dorsal Lateral Geniculate Nucleus by General Brain State Alterations under Urethane Anesthesia
“…Interestingly, however, there were some differences in the proportion of different types of cells between structures, most probably reflecting different retinal input and/or structure function (Brown et al, 2010;Do, 2019;Román Rosón et al, 2019). In the case of the dLGN and OPN, our results are in agreement with previously published data showing the majority of recorded cells as transient (dLGN) and sustained (OPN) (Trejo and Cicerone, 1984;Brown et al, 2010Brown et al, , 2011Allen et al, 2011;Szkudlarek et al, 2012;Jeczmien-Lazur et al, 2019;Román Rosón et al, 2019). However, our data reveal some differences in the SCN, as we have found mostly transient neurons.…”
Section: Light Responsive Cells In the Pigmented Rat Dlgn Scn And Opnsupporting
confidence: 91%
“…For the black hooded rat there is one published study investigating the OPN (Trejo and Cicerone, 1984) and one for the SCN (Aggelopoulos and Meissl, 2000). In contrast, rich literature exists covering light responsive cells in the dLGN of different species [mouse: (Brown et al, 2010(Brown et al, , 2012Piscopo et al, 2013;Denman et al, 2017;Stabio et al, 2018;Román Rosón et al, 2019); black hooded rats: (Sriram et al, 2016;Jeczmien-Lazur et al, 2019)].…”
Section: Light Responsive Cells In the Pigmented Rat Dlgn Scn And Opnmentioning
The amount and spectral composition of light changes considerably during the day, with dawn and dusk being the most crucial moments when light is within the mesopic range and short wavelength enriched. It was recently shown that animals use both cues to adjust their internal circadian clock, thereby their behavior and physiology, with the solar cycle. The role of blue light in circadian processes and neuronal responses is well established, however, an unanswered question remains: how do changes in the spectral composition of light (short wavelengths blocking) influence neuronal activity? In this study we addressed this question by performing electrophysiological recordings in image (dorsal lateral geniculate nucleus; dLGN) and non-image (the olivary pretectal nucleus; OPN, the suprachiasmatic nucleus; SCN) visual structures to determine neuronal responses to spectrally varied light stimuli. We found that removing short-wavelength from the polychromatic light (cut off at 525 nm) attenuates the most transient ON and sustained cells in the dLGN and OPN, respectively. Moreover, we compared the ability of different types of sustained OPN neurons (either changing or not their response profile to filtered polychromatic light) to irradiance coding, and show that both groups achieve it with equal efficacy. On the other hand, even very dim monochromatic UV light (360 nm; log 9.95 photons/cm2/s) evokes neuronal responses in the dLGN and SCN. To our knowledge, this is the first electrophysiological experiment supporting previous behavioral findings showing visual and circadian functions disruptions under short wavelength blocking environment. The current results confirm that neuronal activity in response to polychromatic light in retinorecipient structures is affected by removing short wavelengths, however, with type and structure – specific action. Moreover, they show that rats are sensitive to even very dim UV light.
“…Interestingly, however, there were some differences in the proportion of different types of cells between structures, most probably reflecting different retinal input and/or structure function (Brown et al, 2010;Do, 2019;Román Rosón et al, 2019). In the case of the dLGN and OPN, our results are in agreement with previously published data showing the majority of recorded cells as transient (dLGN) and sustained (OPN) (Trejo and Cicerone, 1984;Brown et al, 2010Brown et al, , 2011Allen et al, 2011;Szkudlarek et al, 2012;Jeczmien-Lazur et al, 2019;Román Rosón et al, 2019). However, our data reveal some differences in the SCN, as we have found mostly transient neurons.…”
Section: Light Responsive Cells In the Pigmented Rat Dlgn Scn And Opnsupporting
confidence: 91%
“…For the black hooded rat there is one published study investigating the OPN (Trejo and Cicerone, 1984) and one for the SCN (Aggelopoulos and Meissl, 2000). In contrast, rich literature exists covering light responsive cells in the dLGN of different species [mouse: (Brown et al, 2010(Brown et al, , 2012Piscopo et al, 2013;Denman et al, 2017;Stabio et al, 2018;Román Rosón et al, 2019); black hooded rats: (Sriram et al, 2016;Jeczmien-Lazur et al, 2019)].…”
Section: Light Responsive Cells In the Pigmented Rat Dlgn Scn And Opnmentioning
The amount and spectral composition of light changes considerably during the day, with dawn and dusk being the most crucial moments when light is within the mesopic range and short wavelength enriched. It was recently shown that animals use both cues to adjust their internal circadian clock, thereby their behavior and physiology, with the solar cycle. The role of blue light in circadian processes and neuronal responses is well established, however, an unanswered question remains: how do changes in the spectral composition of light (short wavelengths blocking) influence neuronal activity? In this study we addressed this question by performing electrophysiological recordings in image (dorsal lateral geniculate nucleus; dLGN) and non-image (the olivary pretectal nucleus; OPN, the suprachiasmatic nucleus; SCN) visual structures to determine neuronal responses to spectrally varied light stimuli. We found that removing short-wavelength from the polychromatic light (cut off at 525 nm) attenuates the most transient ON and sustained cells in the dLGN and OPN, respectively. Moreover, we compared the ability of different types of sustained OPN neurons (either changing or not their response profile to filtered polychromatic light) to irradiance coding, and show that both groups achieve it with equal efficacy. On the other hand, even very dim monochromatic UV light (360 nm; log 9.95 photons/cm2/s) evokes neuronal responses in the dLGN and SCN. To our knowledge, this is the first electrophysiological experiment supporting previous behavioral findings showing visual and circadian functions disruptions under short wavelength blocking environment. The current results confirm that neuronal activity in response to polychromatic light in retinorecipient structures is affected by removing short wavelengths, however, with type and structure – specific action. Moreover, they show that rats are sensitive to even very dim UV light.
“…Thus, the majority of recorded neurons were tested for light responsiveness. Quite recently it has been showed that neuronal activity within the dLGN is modulated by the general brain state 30,31 , accordingly, we aimed to describe OXA-responsive neurons also regarding this particular property. A subpopulation of dLGN cells was previously found to express infra-slow oscillatory activity 32–34 ; hence, we verified whether such neurons are influenced by OXA.Figure 1Experimental design.…”
Section: Resultsmentioning
confidence: 99%
“…The relationship between the firing rate of a single dLGN neuron and ECoG changes was established as in 31 . Briefly, a cross-correlation coefficient (CC) analysis was performed on delta power band derived from ECoG signals containing both activated and SWA phases (at least one alteration in ECoG) and simultaneously recorded FR of the dLGN neurons.…”
Section: Methodsmentioning
confidence: 99%
“…Therefore, this sensory modality has been suggested to be modulated by arousal and a circadian factor, both of which are related to orexins 27 . Certainly, visual processing in the dLGN differs according to vigilance state 28,29 , and the neuronal activity of the dLGN has recently been reported to be influenced by the general state of the brain under different types of anaesthesia 30,31 .…”
Orexins (OXA, OXB) are hypothalamic peptides playing crucial roles in arousal, feeding, social and reward-related behaviours. A recent study on juvenile rats suggested their involvement in vision modulation due to their direct action on dorsal lateral geniculate (dLGN) neurons. The present study aimed to verify whether a similar action of OXA can be observed in adulthood. Thus, in vivo and in vitro electrophysiological recordings on adult Wistar rats across light-dark and cortical cycles were conducted under urethane anaesthesia. OXA influenced ~28% of dLGN neurons recorded in vivo by either excitation or suppression of neuronal firing. OXA-responsive neurons did not show any spatial distribution nor represent a coherent group of dLGN cells, and responded to OXA similarly across the light–dark cycle. Interestingly, some OXA-responsive neurons worked in a cortical state-dependent manner, especially during the dark phase, and ‘preferred’ cortical activation over slow-wave activity induced by urethane. The corresponding patch clamp study confirmed these results by showing that < 20% of dLGN neurons were excited by OXA under both light regimes. The results suggest that OXA is involved in the development of the visual system rather than in visual processes and further implicate OXA in the mediation of circadian and arousal-related activity.
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