Long-Term Potentiation-Like Visual Synaptic Plasticity Is Negatively Associated With Self-Reported Symptoms of Depression and Stress in Healthy Adults

Abstract

Long-term potentiation (LTP) is one of the most extensively studied forms of neuroplasticity and is considered the strongest candidate mechanism for memory and learning. The use of event-related potentials and sensory stimulation paradigms has allowed for the translation from animal studies to non-invasive studies of LTP-like synaptic plasticity in humans. Accumulating evidence suggests that synaptic plasticity as measured by stimulus-specific response modulation is reduced in neuropsychiatric disorders such as major depressive disorder (MDD), bipolar disorders and schizophrenia, suggesting that impaired synaptic plasticity plays a part in the underlying pathophysiology of these disorders. This is in line with the neuroplasticity hypothesis of depression, which postulate that deficits in neuroplasticity might be a common pathway underlying depressive disorders. The current study aims to replicate and confirm earlier reports that visual stimulus-specific response modulation is a viable probe into LTP-like synaptic plasticity in a large sample of healthy adults (n = 111). Further, this study explores whether impairments in LTP-like synaptic plasticity is associated with self-reported subclinical depressive symptoms and stress in a healthy population. Consistent with prior research, the current study replicated and confirmed reports demonstrating significant modulation of visual evoked potentials (VEP) following visual high-frequency stimulation. Current results further indicate that reduced LTP-like synaptic plasticity is associated with higher levels of self-reported symptoms of depression and perceived stress. This indicate that LTP-like plasticity is sensitive to sub-clinical levels of psychological distress, and might represent a vulnerability marker for the development of depressive symptoms.

Investigating causal effects of pupil size on visual discrimination and visually evoked potentials in a Snellen eye chart task

“…Three time windows were arbitrarily selected to capture the peak for each component (C1: 90-110 ms, P1:130-160 ms, N1: 180-205 ms). Latencies and topographical distributions of different VEP components were qualitatively similar to those observed in previous research 41,42 .…”

“…Visually-evoked event related potential (ERP) components were specifically used to examine the relationship between pupil size and visually evoked activity, because VEPs are modulated by stimulus contrast [32][33][34][35][36][37] , as one of the most primitive components of saliency [38][39][40] , allowing us to compare the effects of pupil size with those of stimulus contrast. Similar to previous research 41,42 , we focused on three components: C1, P1, and N1, and these VEPs were measured using data of electrodes in the occipital scalp, including the O1, Oz, and O2. Three time windows were arbitrarily selected to capture the peak for each component (C1: 90-110 ms, P1:130-160 ms, N1: 180-205 ms).…”

Rapidly repeated visual stimulation induces long-term potentiation of VEPs and increased content of membrane AMPA and NMDA receptors in the V1 cortex of cats

“…Statistical comparisons show that repeated LFS had no significant effect on VEPs in the V1 cortex, whereas repeated HFS could significantly increase N1P1 and P1N2 amplitude of VEPs in response to visual stimuli with both SO and NSO, but the effect was faster, stronger and lasted longer at SO than at NSO. Our results suggest that repeated HFS but not LFS can induce a long-lasting increase of VEPs in V1 cortex, which is similar to the classic LTP ( Bliss and Lomo, 1973 ; Sarvey et al, 1989 ; Kirkwood and Bear, 1994 ; Volianskis and Jensen, 2003 ) and sensory stimulation-evoked LTP-like response improvement reported in human subjects ( Sanders et al, 2018 ; Valstad et al, 2020 ; Rygvold et al, 2021 , 2022 ). Nevertheless, our results indicate that HFS-induced VEP-amplitude improvement shows a less specificity to stimulus orientation and can partially generalize to visual stimuli at the other orientations, which differs from LTP-like neural response potentiation observed in human studies ( McNair et al, 2006 ; Ross et al, 2008 ; Kirk et al, 2010 ; Clapp et al, 2012 ; Valstad et al, 2021 ) and is also unlike the perceptual learning effect with high specificity to trained stimulus parameters ( Hua et al, 2010 ; Lu et al, 2011 ; Seitz, 2011 ; Li, 2016 ; Yan et al, 2018 ; Yang et al, 2020 ; Jing et al, 2021 ; Astorga et al, 2022 ).…”

BIDS-structured resting-state electroencephalography (EEG) data extracted from an experimental paradigm

“…The EEG recordings were conducted by experienced operators and provide data of high quality. In two previous studies, our group analysed event-related data from the same recordings and reported the results [10 , 13] . In these investigations, in addition to visual expert assessment, a preprocessing and cleaning pipeline similar to the one included with the dataset was utilised.…”