Acceso usuarios
Jorge Andrés Pinto Pinto
La disminución progresiva de los potenciales relacionados a eventos o ERPs (Event-Related Potentials), como consecuencia de la estimulación repetida, ha sido comúnmente interpretada como habituación. Sin embargo, para establecer con certeza que esta es habituación genuina, debería cumplir con las características conductuales propuestas por Thompson y Spencer (1966) y Rankin et al. (2009). Por ello, en este estudio se revisaron las características conductuales examinadas en los estudios de habituación de ERPs en humanos a través de la metodología PRISMA. Se evaluó la elegibilidad de 206 artículos y se incluyeron 83. La mayoría se centra en la habituación intrasesión de N1, N2, P2 y P3 y es escasa la evidencia de especificidad del estímulo y deshabituación, las cuales son las características más críticas para descartar otros procesos no asociados al aprendizaje. Se concluye que la evidencia aún es insuficiente para establecer con seguridad el mecanismo que subyace a la disminución en ERPs.
It has been proposed that habituation, defined as a decrease in response to a repeating stimulus, functions as a first "filter" that would allow animals to ignore irrelevant stimuli and would thus be critical for the efficient regulation of several cognitive functions that are critical for adaptation (Kepler et al., 2020). This view is consistent with reports of impaired habituation in disorders characterized by marked deficits in attention, such as schizophrenia (Blackford et al., 2015) and attention deficit hyperactivity disorder (ADHD) (Lloyd et al., 2014).
Unfortunately, behavioral habituation studies with humans in both typical and atypical behavior Interdisciplinaria, 2025, 42(1) Características de la habituación en ERPs populations face several limitations, which explain, in part, why there is no consistent translational evidence in the literature (McDiarmid et al., 2017).
A common limitation of behavioral studies with humans is that by relying on a manipulation of the input (stimulus) to observe its effect on the output (response), the mechanisms mediating these two events are only inferred. An alternative is to explore the electrophysiology underlying the stimulus-response circuit through event-related potentials (ERPs). Thanks to their temporal resolution, ERPs provide a continuous measure of the processing that occurs in the stimulus-response period (Luck, 2014), where a change in the mnemic representation of the stimulus likely occurs because of repeated stimulation (Groves & Thompson, 1970; Sokolov, 1960; Wagner, 1981), allowing to identify potential mechanisms according to their temporal dynamics. In electroencephalography (EEG), brain electrical activity is recorded from the summation of tiny electric fields produced by assemblies of pyramidal neurons located in the cerebral cortex (Luck, 2014). During an experimental session, participants receive a sequence of stimuli (events) while voltage changes are recorded at various electrodes located on the scalp. The windows of recordings around these stimulus presentations are then averaged, and characteristic waveforms representing the average neural response to each type of stimulus are obtained. These waveforms, consisting of several positive and negative deflections, occurring at specific latencies, and representing activation at different phases of cortical processing, are known as event-related potentials (ERPs).
The typical result of repeated stimulation in studies of ERPs is the observation of a progressive decrease in the amplitude of their components or habituation (Budd et al., 1998;
Megela & Teyler, 1979). While these findings coupled with the recent development of methodologies such as principal component analysis have allowed researchers to focus on homologizing habituation procedures with behavioral and electrophysiological measures (MacDonald & Barry, 2020), there is still controversy about the nature of that decrease (Roemer et al., 1984; Rosburg & Sörös, 2016). Therefore, to establish with certainty that this decrease is genuine habituation, it should meet the behavioral characteristics proposed by Thompson and Spencer (1966) and Rankin et al. (2009). Consequently, this review sought to examine the behavioural characteristics of habituation in ERP studies in humans through the PRISMA methodology. A total of 206 articles were evaluated for eligibility and 83 were included. Most of the studies focus on intra-session habituation in components such as N1, N2, P2 and P3 with little evidence of long-term phenomena and features such as stimulus specificity and dishabituation, which are the most critical parameters to rule out other processes not associated with learning. This study concludes that the evidence is still insufficient to establish with certainty the mechanism underlying the decrease in ERPs in early components, although there is promising evidence regarding later components. Specifically, each of the components of the Late Positive Complex or LPC (P3a, P3b, nP3, SW) has differential sensitivity to habituation, Interdisciplinaria, 2025, 42(1) Características de la habituación en ERPs with nP3 (novelty P3) mostly reflecting the effects of the loss of stimulus novelty resulting from stimulus repetition (Barry et al., 2020; MacDonald & Barry, 2020).
