Limits...
Development and matching of binocular orientation preference in mouse V1.

Bhaumik B, Shah NP - Front Syst Neurosci (2014)

Bottom Line: At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective.The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells.It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

View Article: PubMed Central - PubMed

Affiliation: Electrical Engineering Department, Indian Institute of Technology Delhi New Delhi, India.

ABSTRACT
Eye-specific thalamic inputs converge in the primary visual cortex (V1) and form the basis of binocular vision. For normal binocular perceptions, such as depth and stereopsis, binocularly matched orientation preference between the two eyes is required. A critical period of binocular matching of orientation preference in mice during normal development is reported in literature. Using a reaction diffusion model we present the development of RF and orientation selectivity in mouse V1 and investigate the binocular orientation preference matching during the critical period. At the onset of the critical period the preferred orientations of the modeled cells are mostly mismatched in the two eyes and the mismatch decreases and reaches levels reported in juvenile mouse by the end of the critical period. At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective. In literature around 40% cortical cells are reported as orientation selective in mouse V1. The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells. The absence of near neighbor interaction among cortical cells during the development of thalamo-cortical wiring causes a salt and pepper organization in the orientation preference map in mice. It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

No MeSH data available.


Related in: MedlinePlus

(A) Threshold value (mV) histograms for cortical cells in monocular (histogram on left) and binocular (histogram on right) regions are shown. The y-axis is the percentage of cells and x-axis is the threshold value in mV. (B) This is a scatter plot of observed binocular spike rate on y-axis and predicted binocular spike rate (as linear sum of individual left and right monocular spike rates) on x-axis for cortical cells in binocular region of cortex. The green line has a slope of 45° and the red line is the linear fit to data. The binocular spike rate is less than sum of individual monocular spike rates for higher spike rates. (C) Plots of β function of cells in monocular region (blue) and that in binocular region (red) (y-axis on left) with normalized input activation. β decreases as input activation increases. Plot for the threshold value (green) for all cortical cells with normalized input activation. Threshold value increases as input activation increases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4109519&req=5

Figure 2: (A) Threshold value (mV) histograms for cortical cells in monocular (histogram on left) and binocular (histogram on right) regions are shown. The y-axis is the percentage of cells and x-axis is the threshold value in mV. (B) This is a scatter plot of observed binocular spike rate on y-axis and predicted binocular spike rate (as linear sum of individual left and right monocular spike rates) on x-axis for cortical cells in binocular region of cortex. The green line has a slope of 45° and the red line is the linear fit to data. The binocular spike rate is less than sum of individual monocular spike rates for higher spike rates. (C) Plots of β function of cells in monocular region (blue) and that in binocular region (red) (y-axis on left) with normalized input activation. β decreases as input activation increases. Plot for the threshold value (green) for all cortical cells with normalized input activation. Threshold value increases as input activation increases.

Mentions: We show threshold voltage histograms in Figure 2A for cortical cells in monocular and binocular zones in the model cortex. The threshold histogram for binocular response peaks around −48 mV. This agrees with the experimentally reported threshold values (Tan et al., 2011; Figure 2). The variable threshold when incorporated in the modified SRM, captures the effect of sub-linear addition of spike rates from monocular to binocular experiments as reported in the literature (Longordo et al., 2013). In Figure 2B, the binocular response spike rate is plotted as a function of spike rate from the sum of individual monocular responses. Cell response data used in Figure 2B is the response of the cell at its preferred orientation. Data in Figure 2B is fitted with a linear function (y = 0.64 x + 7.8) and indicated with red line. The fitted linear line (shown in red) has a slope less than unity (shown as green line). At higher spike rates, the difference between the predicted spike rates from sum of monocular responses and the observed binocular spike rate is more noticeable. We also obtain spike rates in the experimentally reported range of spiking under binocular and monocular activations. A plot of β and the threshold voltage as a function of pre-synaptic input activation is shown in Figure 2C.


Development and matching of binocular orientation preference in mouse V1.

Bhaumik B, Shah NP - Front Syst Neurosci (2014)

(A) Threshold value (mV) histograms for cortical cells in monocular (histogram on left) and binocular (histogram on right) regions are shown. The y-axis is the percentage of cells and x-axis is the threshold value in mV. (B) This is a scatter plot of observed binocular spike rate on y-axis and predicted binocular spike rate (as linear sum of individual left and right monocular spike rates) on x-axis for cortical cells in binocular region of cortex. The green line has a slope of 45° and the red line is the linear fit to data. The binocular spike rate is less than sum of individual monocular spike rates for higher spike rates. (C) Plots of β function of cells in monocular region (blue) and that in binocular region (red) (y-axis on left) with normalized input activation. β decreases as input activation increases. Plot for the threshold value (green) for all cortical cells with normalized input activation. Threshold value increases as input activation increases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109519&req=5

Figure 2: (A) Threshold value (mV) histograms for cortical cells in monocular (histogram on left) and binocular (histogram on right) regions are shown. The y-axis is the percentage of cells and x-axis is the threshold value in mV. (B) This is a scatter plot of observed binocular spike rate on y-axis and predicted binocular spike rate (as linear sum of individual left and right monocular spike rates) on x-axis for cortical cells in binocular region of cortex. The green line has a slope of 45° and the red line is the linear fit to data. The binocular spike rate is less than sum of individual monocular spike rates for higher spike rates. (C) Plots of β function of cells in monocular region (blue) and that in binocular region (red) (y-axis on left) with normalized input activation. β decreases as input activation increases. Plot for the threshold value (green) for all cortical cells with normalized input activation. Threshold value increases as input activation increases.
Mentions: We show threshold voltage histograms in Figure 2A for cortical cells in monocular and binocular zones in the model cortex. The threshold histogram for binocular response peaks around −48 mV. This agrees with the experimentally reported threshold values (Tan et al., 2011; Figure 2). The variable threshold when incorporated in the modified SRM, captures the effect of sub-linear addition of spike rates from monocular to binocular experiments as reported in the literature (Longordo et al., 2013). In Figure 2B, the binocular response spike rate is plotted as a function of spike rate from the sum of individual monocular responses. Cell response data used in Figure 2B is the response of the cell at its preferred orientation. Data in Figure 2B is fitted with a linear function (y = 0.64 x + 7.8) and indicated with red line. The fitted linear line (shown in red) has a slope less than unity (shown as green line). At higher spike rates, the difference between the predicted spike rates from sum of monocular responses and the observed binocular spike rate is more noticeable. We also obtain spike rates in the experimentally reported range of spiking under binocular and monocular activations. A plot of β and the threshold voltage as a function of pre-synaptic input activation is shown in Figure 2C.

Bottom Line: At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective.The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells.It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

View Article: PubMed Central - PubMed

Affiliation: Electrical Engineering Department, Indian Institute of Technology Delhi New Delhi, India.

ABSTRACT
Eye-specific thalamic inputs converge in the primary visual cortex (V1) and form the basis of binocular vision. For normal binocular perceptions, such as depth and stereopsis, binocularly matched orientation preference between the two eyes is required. A critical period of binocular matching of orientation preference in mice during normal development is reported in literature. Using a reaction diffusion model we present the development of RF and orientation selectivity in mouse V1 and investigate the binocular orientation preference matching during the critical period. At the onset of the critical period the preferred orientations of the modeled cells are mostly mismatched in the two eyes and the mismatch decreases and reaches levels reported in juvenile mouse by the end of the critical period. At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective. In literature around 40% cortical cells are reported as orientation selective in mouse V1. The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells. The absence of near neighbor interaction among cortical cells during the development of thalamo-cortical wiring causes a salt and pepper organization in the orientation preference map in mice. It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

No MeSH data available.


Related in: MedlinePlus