Stimulus contrast modulates burst activity in the lateral geniculate nucleus
Burst activity is a ubiquitous feature of thalamic neurons and is well documented for visual neurons in the lateral geniculate nucleus (LGN). Although bursts are often associated with states of drowsiness, they are also known to convey visual information to cortex and are particularly effective in e...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2023-01-01
|
| Series: | Current Research in Neurobiology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2665945X23000244 |
| _version_ | 1797799929447448576 |
|---|---|
| author | Alyssa N. Sanchez Henry J. Alitto Daniel L. Rathbun Tucker G. Fisher W. Martin Usrey |
| author_facet | Alyssa N. Sanchez Henry J. Alitto Daniel L. Rathbun Tucker G. Fisher W. Martin Usrey |
| author_sort | Alyssa N. Sanchez |
| collection | DOAJ |
| description | Burst activity is a ubiquitous feature of thalamic neurons and is well documented for visual neurons in the lateral geniculate nucleus (LGN). Although bursts are often associated with states of drowsiness, they are also known to convey visual information to cortex and are particularly effective in evoking cortical responses. The occurrence of thalamic bursts depends on (1) the inactivation gate of T-type Ca2+ channels (T-channels), which become de-inactivated following periods of increased membrane hyperpolarization, and (2) the opening of the T-channel activation gate, which has voltage-threshold and rate-of-change (δv/δt) requirements. Given the time/voltage relationship for the generation of Ca2+ potentials that underlie burst events, it is reasonable to predict that geniculate bursts are influenced by the luminance contrast of drifting grating stimuli, with the null phase of higher contrast stimuli evoking greater hyperpolarization followed by a larger dv/dt than the null phase of lower contrast stimuli. To determine the relationship between stimulus contrast and burst activity, we recorded the spiking activity of cat LGN neurons while presenting drifting sine-wave gratings that varied in luminance contrast. Results show that burst rate, reliability, and timing precision are significantly greater with higher contrast stimuli compared with lower contrast stimuli. Additional analysis from simultaneous recordings of synaptically connected retinal ganglion cells and LGN neurons further reveals the time/voltage dynamics underlying burst activity. Together, these results support the hypothesis that stimulus contrast and the biophysical properties underlying the state of T-type Ca2+ channels interact to influence burst activity, presumably to facilitate thalamocortical communication and stimulus detection. |
| first_indexed | 2024-03-13T04:27:24Z |
| format | Article |
| id | doaj.art-e5cd7c0b57084287975a92687863d57d |
| institution | Directory Open Access Journal |
| issn | 2665-945X |
| language | English |
| last_indexed | 2024-03-13T04:27:24Z |
| publishDate | 2023-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Current Research in Neurobiology |
| spelling | doaj.art-e5cd7c0b57084287975a92687863d57d2023-06-20T04:20:48ZengElsevierCurrent Research in Neurobiology2665-945X2023-01-014100096Stimulus contrast modulates burst activity in the lateral geniculate nucleusAlyssa N. Sanchez0Henry J. Alitto1Daniel L. Rathbun2Tucker G. Fisher3W. Martin Usrey4Center for Neuroscience, University of California Davis, 95618, USACenter for Neuroscience, University of California Davis, 95618, USADept. of Ophthalmology, Detroit Inst. of Ophthalmology, Henry Ford Health System, Detroit, MI, 48202, USADepartment of Neurobiology, Stanford University, CA, 94305, USACenter for Neuroscience, University of California Davis, 95618, USA; Corresponding author. Center for Neuroscience, University of California, 1544 Newton Court, Davis, CA 95618, USA.Burst activity is a ubiquitous feature of thalamic neurons and is well documented for visual neurons in the lateral geniculate nucleus (LGN). Although bursts are often associated with states of drowsiness, they are also known to convey visual information to cortex and are particularly effective in evoking cortical responses. The occurrence of thalamic bursts depends on (1) the inactivation gate of T-type Ca2+ channels (T-channels), which become de-inactivated following periods of increased membrane hyperpolarization, and (2) the opening of the T-channel activation gate, which has voltage-threshold and rate-of-change (δv/δt) requirements. Given the time/voltage relationship for the generation of Ca2+ potentials that underlie burst events, it is reasonable to predict that geniculate bursts are influenced by the luminance contrast of drifting grating stimuli, with the null phase of higher contrast stimuli evoking greater hyperpolarization followed by a larger dv/dt than the null phase of lower contrast stimuli. To determine the relationship between stimulus contrast and burst activity, we recorded the spiking activity of cat LGN neurons while presenting drifting sine-wave gratings that varied in luminance contrast. Results show that burst rate, reliability, and timing precision are significantly greater with higher contrast stimuli compared with lower contrast stimuli. Additional analysis from simultaneous recordings of synaptically connected retinal ganglion cells and LGN neurons further reveals the time/voltage dynamics underlying burst activity. Together, these results support the hypothesis that stimulus contrast and the biophysical properties underlying the state of T-type Ca2+ channels interact to influence burst activity, presumably to facilitate thalamocortical communication and stimulus detection.http://www.sciencedirect.com/science/article/pii/S2665945X23000244ThalamusLGNCatRetinaCortexCoding |
| spellingShingle | Alyssa N. Sanchez Henry J. Alitto Daniel L. Rathbun Tucker G. Fisher W. Martin Usrey Stimulus contrast modulates burst activity in the lateral geniculate nucleus Current Research in Neurobiology Thalamus LGN Cat Retina Cortex Coding |
| title | Stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| title_full | Stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| title_fullStr | Stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| title_full_unstemmed | Stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| title_short | Stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| title_sort | stimulus contrast modulates burst activity in the lateral geniculate nucleus |
| topic | Thalamus LGN Cat Retina Cortex Coding |
| url | http://www.sciencedirect.com/science/article/pii/S2665945X23000244 |
| work_keys_str_mv | AT alyssansanchez stimuluscontrastmodulatesburstactivityinthelateralgeniculatenucleus AT henryjalitto stimuluscontrastmodulatesburstactivityinthelateralgeniculatenucleus AT daniellrathbun stimuluscontrastmodulatesburstactivityinthelateralgeniculatenucleus AT tuckergfisher stimuluscontrastmodulatesburstactivityinthelateralgeniculatenucleus AT wmartinusrey stimuluscontrastmodulatesburstactivityinthelateralgeniculatenucleus |