Changes in the synaptic filtering at the lateral PP
It has been hypothesized that low-pass filtering of synaptic inputs to the DG underlies the encoding information of auditory, olfactory, and visual cues (Scullin and Partridge, 2012; Madar et al., 2019). In this regard, frequency-dependent synaptic filtering of the LPP has been thoroughly characterized in adult mice (Quintanilla et al., 2022). We first confirmed that juvenile rats possess this physiological property; then, we demonstrated that synaptic filtering in the LPP is drastically altered in slices from MK-801-treated animals. Our experimental findings and multiple theoretical models (Chance et al., 1998; Quintanilla et al., 2022) imply that the diminished filtering capacity of the LPP synapse may result from a decreased presynaptic release. The impaired low-pass filtering capability of the LPP could represent the cellular substrate that explains the abnormal processing of sensory information conveyed by the LPP, which is excessively amplified in the DG of schizophrenic individuals (Arnold, 1999; Prasad et al., 2004; Behrendt, 2016) instead of being properly filtered. Although appealing, this idea requires experimental examination.