Reduced Prefrontal Short—Latency Afferent Inhibition in Older Adults and Its Relation to Executive Function: A TMS-EEG Study

Abstract

Combining transcranial magnetic stimulation (TMS) with electroencephalography (EEG) allows for the assessment of various neurophysiological processes in the human cortex. One of these paradigms, short-latency afferent inhibition (SAI), is thought to be a sensitive measure of cholinergic activity. In a previous study, we demonstrated the temporal pattern of this paradigm from both the motor (M1) and dorsolateral prefrontal cortex (DLPFC) using simultaneous TMS–EEG recording. The SAI paradigm led to marked modulations at N100. In this study, we aimed to investigate the age-related effects on TMS-evoked potentials (TEPs) with the SAI from M1 and the DLPFC in younger (18–59 years old) and older (≥60 years old) participants. Older participants showed significantly lower N100 modulation in M1–SAI as well as DLPFC–SAI compared to the younger participants. Furthermore, the modulation of N100 by DLPFC–SAI in the older participants correlated with executive function as measured with the Trail making test. This paradigm has the potential to non-invasively identify cholinergic changes in cortical regions related to cognition in older participants.

The effects of individualised intermittent theta burst stimulation in the prefrontal cortex: A TMS‐EEG study

“…Studies have reported N100 to be associated with GABA B -mediated inhibitory mechanisms in both motor (Bonnard et al, 2009;Farzan et al, 2013;Premoli, Rivolta, et al, 2014b;Rogasch, Daskalakis, et al, 2013a) and prefrontal cortex (Chung et al, 2017;Rogasch et al, 2015). The amplitude of N100 increased following SAI both in motor and prefrontal cortex (Noda et al, 2016;Noda, Zomorrodi, Backhouse, et al, 2017c), but decreased following cerebellar iTBS (Casula, Pellicciari, Ponzo, et al, 2016b), which are in line with the change observed in N100 following Ind iTBS. However, our previous studies showed increased N100 following prefrontal iTBS (50 Hz at 5 Hz) (Chung et al, 2017;Chung, Rogasch, Hoy, & Fitzgerald, 2018a;Chung, Rogasch, Hoy, Sullivan, et al, 2018b), and the discrepancy of the outcome…”

“…A growing body of evidence suggests P60 may provide a marker of cortical excitability. In the prefrontal cortex, SAI resulted in a reduction of this component (Noda, Zomorrodi, Backhouse, et al, 2017c). a Not adding up to 100% due to 1 subject having no differences in score change (Δ = 0).…”

“…Due to the implications of P60 and N100 in cortical plasticity mentioned above and the frequent observation of the change in the amplitude of these peaks following neuromodulatory paradigms over the left prefrontal cortex (Chung, Rogasch, Hoy, Sullivan, et al, 2018b;Hill et al, 2017;Noda, Zomorrodi, Backhouse, et al, 2017c), we hypothesised that individualised iTBS would produce the strongest change in these components. We also measured mood on a visual analogue scale (VAS) and working memory performance via 3-back task following iTBS to investigate relationship between the neurobiological effects of iTBS and the change in behaviour.…”

Decline of prefrontal cortical-mediated executive functions but attenuated delay discounting in aged Fischer 344 × brown Norway hybrid rats

“…Deficits in working memory and other cognitive functions supported by the dlPFC are widely reported in older adults (Alexander et al, 2012; Daigneault and Braun, 1993; Langley and Madden, 2000; MacPherson et al, 2002; Noda et al, 2017). In stark contrast to the associations between working memory impairment and intertemporal choice described above, however, advanced age is accompanied by an increased ability to forgo immediate gratification in favor of delayed rewards (Green et al, 1999, 1996; Jimura et al, 2013; Samanez-Larkin et al, 2011; Simon et al, 2010).…”

The Current and Future Potential of Transcranial Magnetic Stimulation With Electroencephalography in Psychiatry

“…In the reviewed studies, only two explored the relation between cognition and TMS‐EEG, linking deficits in working memory and executive functions with GABAergic and cholinergic impairments, respectively. This relationship is also poorly explored in healthy controls, with only a handful of studies linking TMS‐EEG measures in the DLPFC with cognitive functions, such as LICI and working memory, and SAI and executive functions . TMS‐EEG can be a powerful method allowing measurement of the involvement of several neurotransmitter systems in specific cognitive domains in psychiatry, and future studies should definitively explore this extensively.…”