Biology subjects

Demirayak, P.

Publications and source records attributed to Demirayak, P..

3 recordsLinked to original sources

bioRxiv2025

Increased attentive use leads to more idiosyncratic functional connections

Experience is thought to modify neural connections to adapt the network to be more optimal for the environment. Given the brains complexity, multiple network changes could each move the system toward optimality. Standard methods ignore this multiplicity and examine each connection independently; these studies have often shown considerable inter-individual variability and modest effects (1). Here, we take a different strategy, determining how a whole-brain connection pattern differs from the typical pattern, that is, how idiosyncratic the pattern is. We examined how the idiosyncrasy of whole brain connection patterns varies with frequency of the use of that part of cortex for attention-demanding tasks, focusing on central versus peripheral vision in healthy individuals (where individuals use central vision more frequently for attention-demanding tasks). We found that the whole-brain pattern of functional connections to the cortical representations of central vision is idiosyncratic, whereas patterns of connections to representations of peripheral vision were very similar person-to-person. In a second set of analyses, we examined the brains of people with central vision loss who use a portion of peripheral vision (called the preferred retinal locus) more frequently for attention-demanding tasks in their daily lives. The cortical representation of the preferred retinal locus exhibits more idiosyncratic connections, compared to a control brain region, or compared to the same brain region in matched control participants with healthy vision. These results are consistent with the hypothesis that increased attentive use of a brain area results in idiosyncratic patterns of whole brain connections. Significance StatementWe found that increased attentive use of a brain region results in more idiosyncratic patterns of connections of that region to the rest of the brain. Our findings support the view that V1 retains the capacity for plasticity well beyond the critical period and that these adaptations are idiosyncratic to the individuals experiences. This approach suggests that tailoring personalized rehabilitation plans for individuals with retinal diseases may be more effective than a one size fits all approach. More generally, it offers a promising framework for investigating brain plasticity in both typical and clinical populations, especially in the context of sensory loss and compensatory adaptation.

neuroscience↗

bioRxiv2024

Impact of deprivation and preferential usage on functional connectivity between early visual cortex and category-selective visual regions

Human behavior can be remarkably shaped by experience, such as the removal of sensory input. Many studies of conditions such as stroke, limb amputation, and vision loss have examined how the removal of input changes brain function. However, an important question has yet to be answered: when input is lost, does the brain change its connectivity to preferentially use some remaining inputs over others? In individuals with healthy vision, the central portion of the retina is preferentially used for everyday visual tasks, due to its ability to discriminate fine details. However, when central vision is lost in conditions like macular degeneration, peripheral vision must be relied upon for those everyday tasks, with certain portions receiving "preferential" usage over others. Using resting-state fMRI collected during total darkness, we examined how deprivation and preferential usage influence the intrinsic functional connectivity of sensory cortex by studying individuals with selective vision loss due to late stages of macular degeneration. We found that cortical regions representing spared portions of the peripheral retina, regardless of whether they are preferentially used, exhibit plasticity of intrinsic functional connectivity in macular degeneration. Cortical representations of spared peripheral retinal locations showed stronger connectivity to MT, a region involved in processing motion. These results suggest that long-term loss of central vision can produce widespread effects throughout spared representations in early visual cortex, regardless of whether those representations are preferentially used. These findings support the idea that connections to visual cortex maintain the capacity for change well after critical periods of visual development. HighlightsO_LIPortions of early visual cortex representing central vs. peripheral vision exhibit different patterns of connectivity to category-selective visual regions. C_LIO_LIWhen central vision is lost, cortical representations of peripheral vision display stronger functional connections to MT than central representations. C_LIO_LIWhen central vision is lost, connectivity to regions selective for tasks that involve central vision (FFA and PHA) are not significantly altered. C_LIO_LIThese effects do not depend on which locations of peripheral vision are used more. C_LI

neuroscience↗

bioRxiv2020

The fronto-parietal network connects more strongly to central than peripheral V1

The functionality of central vision is different from peripheral vision. Central vision is used for fixation and has higher acuity that makes it useful for everyday activities such as reading and object identification. The central and peripheral representations in primary visual cortex (V1) also differ in how higher-order processing areas modulate their responses. For example, attention and expectation are top-down processes (i.e., high-order cognitive functions) that influence visual information processing during behavioral tasks. This top-down control is different for central vs. peripheral vision. Since functional networks can influence visual information processing in different ways, networks (such as the Fronto-Parietal (FPN), Default Mode (DMN), and Cingulo-Opercular (CON)) likely differ in how they connect to representations of the visual field across V1. Prior work indicated the central representing portion of V1 was more functionally connected to regions belonging to the FPN, and the far-peripheral representing portion of V1 was more functionally connected to regions belonging to the DMN. Our goals were 1) Assess the reproducibility and generalizability of retinotopic effects on functional connections between V1 and functional networks. 2) Extend this work to understand structural connections of central vs. peripheral representations in V1. 3) Examine the overlapping eccentricity differences in functional and structural connections of V1. We used resting-state BOLD fMRI and DWI to examine whether portions of V1 that represent different visual eccentricities differ in their functional and structural connectivity to functional networks. All data were acquired and minimally preprocessed by the Human Connectome Project. We identified central and far-peripheral representing regions from a retinotopic template. Functional connectivity was measured by correlated activity between V1 and functional networks, and structural connectivity was measured by probabilistic tractography and converted to track probability. In both modalities, differences between V1 eccentricity segment connections were compared by paired, two-tailed t-test. Dice Coefficients were used to determine spatial overlap between modalities. We found 1) Centrally representing portions of V1 are more strongly functionally connected to frontal regions than are peripherally representing portions of V1, 2) Structural connections also show stronger connections between central V1 and frontal regions, 3) Patterns of structural and functional connections overlaps in the lateral frontal cortex. In summary, the works main contribution is a greater understanding of higher-order functional networks connectivity to V1. There are stronger structural connections to central representations in V1, particularly for lateral frontal regions, implying that the functional relationship between central V1 and frontal regions is built upon direct, long-distance connections. Overlapping structural and functional connections reflect differences in V1 eccentricities, with central V1 preferentially connected to attention-associated regions. Understanding how V1 is functionally and structurally connected to higher-order brain areas contributes to our understanding of how the human brain processes visual information and forms a baseline for understanding any modifications in processing that might occur with training or experience.

neuroscience↗