Biology subjects

Chrobak, J. J.

Publications and source records attributed to Chrobak, J. J..

4 recordsLinked to original sources

bioRxiv2026

Decoding instrumental lever pressing from prefrontal, accumbens, and hippocampal local field potentials: conservation across sex, task, and dopamine depletion

During operant behavior, oscillatory activity is coordinated across multiple brain regions and can change under different task conditions. In this study, we use a decoding approach to characterize these patterns and predict lever pressing behavior in rats from local field potentials (LFP) recorded bilaterally in the hippocampus, nucleus accumbens, and prefrontal cortex. We extract LFP features for band power and peak frequency and predict behavior across animals and conditions with a Poisson Generalized Linear Model (GLM). We use data from both male and female rats performing either fixed-ratio (FR40) or progressive (PROG) operant lever-pressing tasks, under vehicle (VEH) or tetrabenazine (TBZ), a vesicular monoamine transport (VMAT-2) inhibitor that depletes dopamine and induces depressive-like motivation dysfunction. We find that we can accurately predict lever pressing from multi-region LFP within-animals on a timescale of seconds with >30% variance explained. Although within-animal and within-condition predictions are highest, we also find, interestingly, that these decoders generalize across animals and across drug, sex, and task conditions, suggesting a stable association between LFP and behavior. We then evaluate whether LFP features can be used to decode long-term task variables, such as the number of presses since or until the next reinforcer. We find that LFP features can predict these long-term task variables, but that decoding relies on different LFP features for prediction than those used for immediate lever pressing. Altogether these results suggest that there are robust distributed patterns of LFP associated with lever-pressing behavior under multiple drug, task, and sex conditions.

neuroscience↗

bioRxiv2026

Comparison scanning generalized eigendecomposition separates temporal dynamics of alpha oscillations during inhibition of spatialized acoustic distractors.

Lateralized alpha-band oscillations are thought to reflect distractor inhibition through suppression of cortical regions processing spatially-localized distracting stimuli. Standard lateralization indices (LI) quantify hemispheric asymmetries in spectral power over large time windows, while characterizations of the time-varying dynamics of alpha-mediated distractor inhibition are lacking. Here we evaluate comparison scanning generalized eigendecomposition (csGED), a multivariate signal processing technique, for its efficacy in addressing questions related to alpha-mediated distractor inhibition using a simulation of same-frequency sources at symmetric cortical locations adapted from Zuure and Cohen (2021). We show that while LI accurately captures topographic power asymmetries, csGED is effective at recovering source-projections for bilateral, same-frequency activity across a wide range of signal-to-noise ratios (SNRs). We further extend these models to a pilot sample (N = 11) performing a speech-in-noise task using spatialized naturalistic distractors through individualized head-related transfer functions (HRTFs). Our results demonstrate the efficacy of GED to characterize source projections during spatialized distractors, and provide preliminary evidence for shifts in oscillatory activity in both the alpha (7 - 13 Hz) and beta frequency ranges (15 - 25 Hz) during spatialized speech-in-noise tasks. Together, these results demonstrate the feasibility of csGED for investigating temporal dynamics of lateralized distractor inhibition and motivate larger confirmatory studies.

neuroscience↗

bioRxiv2022

Correlations across timing cues in natural vocalizations predict judging synthetic sound burst durations.

It is well known that animals rely on multiple sources of information in order to successfully identify sounds in natural environments, to make decisions that are optimal for their survival. For example, rats use duration and pitch cues to respond appropriately to prosocial and distress vocalizations (Saito et al., 2019). Vocalization duration cues are known to co-vary with other temporal cues (Khatami et al., 2018), yet little is known about whether animals rely upon such co-variations to successfully discriminate sounds. In the current study, we find natural alarm vocalizations in rats have onset and offset slopes that are correlated with their duration. Accordingly, vocalizations with faster onset slopes are more likely to have shorter durations. Given that vocalization slopes begin and end within milliseconds, they could provide rapid perceptual cues for predicting and discriminating vocalization duration. To examine this possibility, we train rodents to discriminate duration differences in sequences of synthetic vocalizations and examine how artificially changing the slope impacts duration judgments. We find animals are biased to misjudge a range of synthetic vocalizations as being shorter in duration when the onset and offset slopes are artificially fast. Moreover, this bias is reduced when rats are exposed to multiple synthetic vocalization bursts. The observed perceptual bias is accurately captured by a Bayesian decision-theoretic model that utilizes the empirical joint distribution of duration and onset slopes in natural vocalizations as a prior during duration judgements of synthetic vocalizations. This model also explains why the bias is reduced when more evidence is accumulated across multiple bursts, reducing the priors influence. These results support the theory that animals are sensitive to fine-grained statistical co-variations in auditory timing cues and integrate this information optimally with incoming sensory evidence to guide their decisions.

animal behavior and cognition↗

bioRxiv2018

Parvalbumin loss following chronic sub-anesthetic NMDA antagonist treatment is age-dependent in the hippocampus: Implications for modeling NMDA hypofunction

A marked decrease in parvalbumin (PV), a calcium-binding protein specific to a subset of GABAergic neurons, is a consistent finding in postmortem schizophrenic brain tissue. This reduction is selective to PV and is regionally specific: occurring primarily in the prefrontal cortex and hippocampus (HPC) of patients. Rodent models of NMDA receptor hypofunction utilizing NMDA antagonist treatments - e.g. ketamine (KET) - show schizophrenia-like cognitive and behavioral impairments with parallel changes in PV. While decreased PV is considered a hallmark of neuropathology in schizophrenia, previous work elucidating the effects of KET administration on PV are contradictory, with findings suggesting decreased, increased, or no change in PV expression. Upon close examination of the procedures used across studies, there are two primary inconsistencies, including: 1) the age of animals used; and 2) the timeline of post-treatment tissue collection. To better understand whether these key differences impact observed PV changes, the present study investigated the impact of age and time of sacrifice on chronic KET-induced PV changes in the neocortex and HPC. Our findings suggest an effect of age, but not sacrifice timeline, on PV cell count following 14 days of sub-anesthetic KET treatment. We provide evidence that 1-month-old rats exhibit significant KET-induced HPC PV decreases, while adult rats show a modest increase in HPC PV following chronic KET. Taken together, we propose that PV is a dynamic marker, and that changes in cell counts - and their interpretation - following NDMA antagonist treatment should be considered in the context of age.

neuroscience↗