What is it about?

The acoustic startle response and prepulse inhibition (PPI) of startle are measures related to information processing, which is impaired in schizophrenia. Some studies have provided inconclusive patterns of association between both measures in rodents. We assessed the influence of baseline startle response on PPI in large samples of Roman high-(RHA) and low-avoidance (RLA) rat strains and in genetically heterogeneous stock (HS) rats. Results show that RHAs exhibit a PPI deficit compared to RLA rats, which is present regardless of the startle response levels. HS rats were stratified in two sub-samples according to their high or low PPI (HS-HighPPI or HS-LowPPI, respectively) scores, and then they were grouped by their differential baseline startle amplitude (high reactivity –HR- or low reactivity –LR-) within each sub-sample. Differences between high- and low-PPI-stratified HS rats remained regardless of their high or low startle amplitude scores. Thus, the impairments in %PPI found in both RHA and HS-LowPPI rats are present irrespective of the relatively high or low levels of startle amplitude in pulse-alone trials. Another objective of the present study was to evaluate whether habituation to the startling stimulus (i.e., pulse) depends on the initial baseline startle response. RLA rats habituated to the startling stimulus more effectively than RHAs regardless of their baseline startle responses. Conversely, there were no differences in startle habituation in the HS rats grouped by their extreme scores of baseline startle. Altogether, these findings suggest a deficit in information processing in RHA rats, which along with evidence indicating that this strain displays other attentional/cognitive impairments, strengthens the validity of the RHA strain as a putative model of schizophrenia-relevant features.

Featured Image

Why is it important?

Prepulse inhibition (PPI) is important because it serves as a robust measure of information processing and sensorimotor gating deficits, which are core features of schizophrenia. PPI deficits are consistently observed in patients with schizophrenia and can be used as a translational tool across species to study the neurobiology of the disorder and to evaluate potential treatments. Additionally, PPI is heritable and can act as a biomarker or endophenotype in genetic and pharmacological research related to schizophrenia.

Perspectives

From a research perspective, prepulse inhibition (PPI) offers a valuable bridge between basic neuroscience and clinical psychiatry, especially in understanding schizophrenia. Its consistent deficits in both patients and animal models make it a powerful tool for studying the underlying mechanisms of information processing abnormalities. Looking ahead, PPI can aid in identifying novel therapeutic targets and refining animal models that closely mimic human cognitive symptoms. However, while PPI is a robust research measure, its clinical applications remain limited, emphasizing the need for further studies to fully realize its potential in guiding treatment strategies and understanding the complexity of schizophrenia.

Carles Tapias Espinosa

Read the Original

This page is a summary of: Prepulse inhibition deficits in inbred and outbred rats and between-strain differences in startle habituation do not depend on startle reactivity levels, Behavioural Processes, April 2022, Elsevier,
DOI: 10.1016/j.beproc.2022.104618.
You can read the full text:

Read

Contributors

The following have contributed to this page