Kofler M, Valls-Solé J, Thurner M, Pucks-Faes E, Versace V. In the spotlight: How the brainstem modulates information flow.
Clin Neurophysiol 2023;
148:52-64. [PMID:
36801494 DOI:
10.1016/j.clinph.2023.01.013]
[Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/25/2023] [Accepted: 01/29/2023] [Indexed: 02/08/2023]
Abstract
OBJECTIVE
The blink reflex (BR) to supraorbital nerve (SON) stimulation is reduced by either a low-intensity prepulse stimulus to digital nerves (prepulse inhibition, PPI) or a conditioning SON stimulus (SON-1) of the same intensity as the test (SON-2) stimulus (paired-pulse paradigm). We studied how PPI affects BR excitability recovery (BRER) to paired SON stimulation.
METHODS
Electrical prepulses were applied to the index finger 100 ms before SON-1, which was followed by SON-2 at interstimulus intervals (ISI) of 100, 300, or 500 ms.
RESULTS
BRs to SON-1 showed PPI proportional to prepulse intensity, but this did not affect BRER at any ISI. PPI was observed on the BR to SON-2 only when additional prepulses were applied 100 ms before SON-2, regardless of the size of BRs to SON-1.
CONCLUSIONS
In BR paired-pulse paradigms, the size of the response to SON-2 is not determined by the size of the response to SON-1. PPI does not leave any trace of inhibitory activity after it is enacted.
SIGNIFICANCE
Our data demonstrate that BR response size to SON-2 depends on SON-1 stimulus intensity and not SON-1 response size, an observation that calls for further physiological studies and cautions against unanimous clinical applicability of BRER curves.
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