More Like this

1. Left digit bias in children’s and adults’ paper-and-pencil number line estimation

   https://doi.org/10.3758/s13421-025-01707-y  

   Barth, Hilary; Rutkowski, Bethany; Vaidya, Leah; Kim, Erin; Bourassa, Cameron; Fabian, Annie; Eisen, Sierra; Zax, Alexandra; Williams, Katherine; Patalano, Andrea L (April 2025, Memory & Cognition)

   Number line estimation tasks are frequently used to learn about numerical thinking, learning, and development. These tasks are often interpreted as though estimates are determined by overall magnitudes of target numerals, rather than specific instantiating digits. Yet estimates are strongly biased by leftmost digits. For example, numbers like “698” are placed too far to the left of numbers like “701” on a 0–1,000 line. This “left digit effect” or “left digit bias” has been investigated little in children, and only on electronic tasks. Here, we ask whether left digit bias appears in paper-and-pencil estimates, and whether it differs for paper-based versus computer-based tasks. In Study 1, 5- to 8-year-old children completed a 0–100 number line task on paper. In Study 2, 7- to 11-year-olds completed a 0–1,000 paper task. In Study 3, adults completed tasks on paper in both ranges. Large left digit effects were observed for children aged 8 years or older and adults, but we did not find evidence for left digit bias in younger children. Study 4 compared paper and computer tasks for adults and children aged 9–12 years. Strong left digit bias was observed in all conditions, with a larger effect for the paper-based task in children. Large left digit effects in number line estimation emerge regardless of task format, with a developmental trajectory broadly consistent with other studies. For children in the age range that reliably exhibits left digit bias (but not adults), paper-and-pencil number line estimation tasks elicit even greater bias than computer-based tasks. 

   more » « less
2. Shared Numerosity Representations Across Formats and Tasks Revealed with 7 Tesla fMRI: Decoding, Generalization, and Individual Differences in Behavior

   https://doi.org/10.1093/texcom/tgaa038  

   Wilkey, Eric D; Conrad, Benjamin N; Yeo, Darren J; Price, Gavin R (January 2020, Cerebral Cortex Communications)

   null (Ed.)

   Abstract Debate continues on whether encoding of symbolic number is grounded in nonsymbolic numerical magnitudes. Nevertheless, fluency of perceiving both number formats, and translating between them, predicts math skills across the life span. Therefore, this study asked if numbers share cortical activation patterns across formats and tasks, and whether neural response to number predicts math-related behaviors. We analyzed patterns of neural activation using 7 Tesla functional magnetic resonance imaging in a sample of 39 healthy adults. Discrimination was successful between numerosities 2, 4, 6, and 8 dots and generalized to activation patterns of the same numerosities represented as Arabic digits in the bilateral parietal lobes and left inferior frontal gyrus (IFG) (and vice versa). This indicates that numerosity-specific neural resources are shared between formats. Generalization was also successful across tasks where participants either identified or compared numerosities in bilateral parietal lobes and IFG. Individual differences in decoding did not relate to performance on a number comparison task completed outside of the scanner, but generalization between formats and across tasks negatively related to math achievement in the parietal lobes. Together, these findings suggest that individual differences in representational specificity within format and task contexts relate to mathematical expertise. 

   more » « less
3. Dynamical latent state computation in the male macaque posterior parietal cortex

   https://doi.org/10.1038/s41467-023-37400-4  

   Lakshminarasimhan, Kaushik J.; Avila, Eric; Pitkow, Xaq; Angelaki, Dora E. (April 2023, Nature Communications)

   Abstract Success in many real-world tasks depends on our ability to dynamically track hidden states of the world. We hypothesized that neural populations estimate these states by processing sensory history through recurrent interactions which reflect the internal model of the world. To test this, we recorded brain activity in posterior parietal cortex (PPC) of monkeys navigating by optic flow to a hidden target location within a virtual environment, without explicit position cues. In addition to sequential neural dynamics and strong interneuronal interactions, we found that the hidden state - monkey’s displacement from the goal - was encoded in single neurons, and could be dynamically decoded from population activity. The decoded estimates predicted navigation performance on individual trials. Task manipulations that perturbed the world model induced substantial changes in neural interactions, and modified the neural representation of the hidden state, while representations of sensory and motor variables remained stable. The findings were recapitulated by a task-optimized recurrent neural network model, suggesting that task demands shape the neural interactions in PPC, leading them to embody a world model that consolidates information and tracks task-relevant hidden states. 

   more » « less
4. Functional Differentiation of Dorsal and Ventral Posterior Parietal Cortex of the Rat: Implications for Controlled and Stimulus-Driven Attention

   https://doi.org/10.1093/cercor/bhab308  

   Yang, Fang-Chi; Dokovna, Lisa B; Burwell, Rebecca D (September 2021, Cerebral Cortex)

   Abstract The posterior parietal cortex (PPC) is important for visuospatial attention. The primate PPC shows functional differentiation such that dorsal areas are implicated in top–down, controlled attention, and ventral areas are implicated in bottom–up, stimulus-driven attention. Whether the rat PPC also shows such functional differentiation is unknown. Here, we address this open question using functional neuroanatomy and in vivo electrophysiology. Using conventional tract-tracing methods, we examined connectivity with other structures implicated in visuospatial attention including the lateral posterior nucleus of the thalamus (LPn) and the postrhinal cortex (POR). We showed that the LPn projects to the entire PPC, preferentially targeting more ventral areas. All parts of the PPC and POR are reciprocally connected with the strongest connections evident between ventral PPC and caudal POR. Next, we simultaneously recorded neuronal activity in dorsal and ventral PPC as rats performed a visuospatial attention (VSA ) task that engages in both bottom–up and top–down attention. Previously, we provided evidence that the dorsal PPC is engaged in multiple cognitive process including controlled attention (Yang et al. 2017). Here, we further showed that ventral PPC cells respond to stimulus onset more rapidly than dorsal PPC cells, providing evidence for a role in stimulus-driven, bottom–up attention. 

   more » « less
5. Neuronal Activity in the Rat Pulvinar Correlates with Multiple Higher-Order Cognitive Functions

   https://doi.org/10.3390/vision4010015  

   Yang, Fang-Chi; Burwell, Rebecca D. (March 2020, Vision)

   The pulvinar, also called the lateral posterior nucleus of the thalamus in rodents, is one of the higher-order thalamic relays and the main visual extrageniculate thalamic nucleus in rodents and primates. Although primate studies report the pulvinar is engaged under attentional demands, there are open questions about the detailed role of the pulvinar in visuospatial attention. The pulvinar provides the primary thalamic input to the posterior parietal cortex (PPC). Both the pulvinar and the PPC are known to be important for visuospatial attention. Our previous work showed that neuronal activity in the PPC correlated with multiple phases of a visuospatial attention (VSA) task, including onset of the visual stimuli, decision-making, task-relevant locations, and behavioral outcomes. Here, we hypothesized that the pulvinar, as the major thalamic input to the PPC, is involved in visuospatial attention as well as in other cognitive functions related to the processing of visual information. We recorded the neuronal activity of the pulvinar in rats during their performance on the VSA task. The task was designed to engage goal-directed, top–down attention as well as stimulus-driven, bottom–up attention. Rats monitored three possible locations for the brief appearance of a target stimulus. An approach to the correct target location was followed by a liquid reward. For analysis, each trial was divided into behavioral epochs demarcated by stimulus onset, selection behavior, and approach to reward. We found that neurons in the pulvinar signaled stimulus onset and selection behavior consistent with the interpretation that the pulvinar is engaged in both bottom–up and top–down visuospatial attention. Our results also suggested that pulvinar cells responded to allocentric and egocentric task-relevant locations. 

   more » « less