Biology subjects

Karagoz, A. B.

Publications and source records attributed to Karagoz, A. B..

3 recordsLinked to original sources

bioRxiv2026

LLM-powered automatic scoring tools for memory recall

Free recall of naturalistic stimuli, such as films and stories, reveals what people remember and how they organize it. Scoring such recall requires matching each recalled utterance to the encoded stimulus, and doing this manually often makes large studies impractical. Existing automated methods mostly return similarity or aggregate scores rather than explicit matches between recalled and stimulus content. Here we introduce an open-source, model-agnostic pipeline that uses a large language model (LLM) to divide the stimulus and the recall into information units and to match units between the two texts. The output is a table of unit-to-unit matches with accuracy labels, from which standard analysis scripts compute recall measures. We validated the pipeline with four LLMs (Claude Sonnet 4.5, GPT 5.4, Gemini 2.5 Pro, and Gemini 2.5 Flash) on three datasets. On typed recall of four short stories, agreement between each model and two trained raters ({phi} = .73-.79) was close to the agreement between the raters themselves ({phi} = .77). A second run reproduced each model's matches ({phi} = .91-.97) more closely than the raters agreed with each other. On spoken recall of 10 films, every model attributed recall to the correct film with high agreement. On uncorrected speech-to-text recall of a television episode, agreement varied more across models. The median cost was under $1 per participant for every model. These results suggest that the pipeline can serve as a reliable, low-cost alternative to manual scoring of free recall.

neuroscience↗

bioRxiv2026

Age Differences in Hippocampal Neural Timescales During Movie-Viewing

Episodic memory requires integrating information across multiple scales, a process theorized to be supported by a gradient of neural timescales along the anterior-posterior axis of the hippocampus that enables both coarse-and fine-grained representations. Aging is associated with changes in hippocampal function and declines in fine-grained episodic memory, but whether this impacts the gradient organization of the hippocampus is unknown. Additionally, the relationship between the neural timescales of the hippocampus and memory specificity remains unclear. Here, we analyzed the length of timescales of individual voxels in the hippocampus during movie-viewing, along with subsequent recall data, in a sample of young and older participants. Younger adults showed the expected anterior-to-posterior timescale gradient, replicating prior work. In contrast, older adults exhibited a reversal of the expected gradient. Older adults recall was coarser and more gist-like than that of younger adults. In younger adults, longer neural timescales were associated with less specific, more gist-like recall; this was seen predominantly in the posterior-lateral hippocampus. In contrast, no relationship between neural timescales and recall were observed in older adults. An exploratory analysis revealed a similar relationship between neural timescales and memory specificity in cortical regions, in younger but not older adults. These findings suggest that aging alters the organization of neural activity throughout the hippocampus and that neural timescales in the hippocampus and cortex are related to the specificity of memory. Significance statementAs people age, episodic memories become more gist-like and less detailed. The hippocampus, which supports both gist and detailed memory, exhibits a neural timescale gradient--from slow-changing activity (longer timescales) to fast-changing activity (shorter timescales). This organization is theorized to support coarse-and fine-grained memory, respectively, yet a direct link to the age-related shift towards gist-like memory remains unestablished. Here, we identify an age-related shift in the hippocampal timescale gradient that parallels a decline in memory specificity. Furthermore, longer timescales in the hippocampus and cortical regions correlated with decreased memory specificity in younger adults. These findings demonstrate that aging is associated with a reorganization of hippocampal activity and that cortical timescales during encoding may relate to the specificity of memory.

neuroscience↗

bioRxiv2024

Evidence for shallow cognitive maps in schizophrenia

Individuals with schizophrenia can have marked deficits in goal-directed decision making. Prominent theories differ in whether schizophrenia (SZ) affects the ability to exert cognitive control, or the motivation to exert control. An alternative explanation is that schizophrenia negatively impacts the formation of cognitive maps, the internal representations of the way the world is structured, necessary for the formation of effective action plans. That is, deficits in decision-making could also arise when goal-directed control and motivation are intact, but used to plan over ill-formed maps. Here, we test the hypothesis that individuals with SZ are impaired in the construction of cognitive maps. We combine a behavioral representational similarity analysis technique with a sequential decision-making task. This enables us to examine how relationships between choice options change when individuals with SZ and healthy age-matched controls build a cognitive map of the task structure. Our results indicate that SZ affects how people represent the structure of the task, focusing more on simpler visual features and less on abstract, higher-order, planning-relevant features. At the same time, we find that SZ were able to display similar performance on this task compared to controls, emphasizing the need for a distinction between cognitive map formation and changes in goal-directed control in understanding cognitive deficits in schizophrenia.

neuroscience↗