Recomendación psicoterapéutica Terapia familiar

is considered to reflect response inhibition (Nakata, Inui, Wasaka, Tamura, et al., 2006;

J. L. Smith, Johnstone, & Barry, 2008) or conflict monitoring (Nieuwenhuis, Yeung, van

den Wildenberg, & Ridderinkhof, 2003; Rueda, Posner, Rothbart, & Davis-Stober, 2004; van Veen & Carter, 2002a; Yeung, Botvinick, & Cohen, 2004). The N2 typically occurs ap-

proximately 200–400 ms (for adults) after the onset of the inhibitory (no-go) stimulus, yet

before the behavioral response. The N2 occurs over frontocentral electrodes, and has been localized to several neural generators, most commonly the ACC in both children (Jonkman,

Sniedt, & Kemner, 2007; Lamm, Zelazo, & Lewis, 2006; Stieben, Lewis, Granic, Zelazo,

Segalowitz, & Pepler, 2007) and adults (Bekker, Kenemans, & Verbaten, 2005; Bokura, Yamaguchi, & Kobayashi, 2001; Jonkman, Sniedt, et al., 2007; Ladouceur, Dahl, & Carter,

2007; Mathalon, Whitfield, & Ford, 2003; van Veen & Carter, 2002b)—particularly the dor-

sal ACC (Stieben et al., 2007; van Veen & Carter, 2002b)—but also the right OFC (Bokura et al., 2001; Lamm et al., 2006) and the lateral PFC, including the VLPFC (particularly the

2004; Nakata, Inui, Wasaka, Akatsuka, & Kakigi, 2005) and DLPFC (Lavric et al., 2004; Mathalon et al., 2003).

The N2 has been found to be larger on trials requiring inhibition of a prepotent response

than on trials that do not require inhibition, leading some researchers to argue that the no- go (or stop) N2 may index response inhibition (Band & van Boxtel, 1999). Alternatively,

other researchers have suggested that the N2 reflects conflict monitoring and not inhibition

(e.g., Nieuwenhuis et al., 2003). In the following review, we review studies that examined whether the N2 reflects response inhibition.

There is some evidence that the N2 in tasks requiring inhibition may index response

inhibition (for a review, see Band & van Boxtel, 1999). First, the N2 has been associated with behavioral performance during inhibition trials in both go/no-go and stop-signal tasks

(e.g., van Boxtel, van der Molen, Jennings, & Brunia, 2001). Moreover, the N2 amplitude

is influenced by the degree of inhibition required to overcome the prepotent response, as shown by larger N2 amplitudes on trials with greater inhibition difficulty by manipulating

the time allowed to respond (Jodo & Kayama, 1992). Interestingly, a no-go ERP potential

has been identified in monkeys that is considered equivalent to the no-go N2 (Band & van Boxtel, 1999), whose neural source in the PFC, when stimulated, results in successfully

inhibited responses (Sasaki, Gemba, & Tsujimoto, 1989).

In addition, the N2 has also been associated with success or failure of inhibition. Larger no-go N2 amplitudes, larger N2 amplitude effects (no-go N2 amplitude minus go N2 am-

plitude), and shorter N2 latencies are typically associated with better response inhibition.

inhibition, which may enable better inhibitory control. Shorter N2 latencies may reflect faster inhibitory processing. In the horse-race model, there are two ongoing and compet-

ing processes during action evaluation and execution: (1) an execution process and (2) an

inhibitory process (Logan & Cowan, 1984). The process that completes first “wins the race,” and determines whether a behavioral response occurs. Shorter N2 latencies may

reflect faster inhibitory processing and, therefore, a greater likelihood of successful response

inhibition. Consistent with these models of the N2 as reflecting response inhibition, pre- vious studies have found larger N2 amplitudes and shorter N2 latencies in better response

inhibition performance.

In a study with 4–5-year-old children, larger N2 amplitudes were associated with faster response inhibition on a go/no-go task (Lahat, Todd, Mahy, Lau, & Zelazo, 2010). In a

go/no-go study with 7- and 9-year-olds, larger N2 amplitudes were associated with better

inhibition performance on the no-go trials for the 7-year-olds, although the authors found no association among the 9-year-olds (Cragg et al., 2009). In addition, in a go/no-go study

with adults, larger no-go N2 amplitudes and shorter no-go N2 latencies were associated

with better response inhibition in the task (Falkenstein, Hoormann, & Hohnsbein, 1999). In a go/no-go study with 5-year-old children, Chevalier, Kelsey, Wiebe, and Espy (2014)

observed a frontal negativity around 350–650 ms, with shorter latencies associated with

better inhibition performance.

In summary, there is evidence that the no-go N2 or N2 effect may reflect response

inhibition, as measured by go/no-go tasks. In particular, larger no-go N2 amplitudes and N2

amplitude effects along with shorter N2 latencies on go/no-go tasks are typically associated with better response inhibition. Consistent with this interpretation of the N2 as reflecting

response inhibition, behavior problems characterized by deficits in response inhibition such as ADHD and externalizing problems typically show smaller N2 amplitudes and longer N2

latencies, as we review later.

Similar to the go/no-go task, the stop-signal task elicits larger N2 amplitudes to stop (equivalent to no-go trials) than to go trials (Kok, Ramautar, Ruiter, Band, & Ridderinkhof,

2004). As such, studies have investigated the relation of the stop N2 to response inhibition.

For example, in a stop-signal study with adults, the stop N2 was larger for successful inhibi- tion trials compared to failed inhibition trials (Schmajuk, Liotti, Busse, & Woldorff, 2006).

Moreover, adults with more efficient response inhibition on the stop-signal task (i.e., faster

reaction times) have shown larger stop N2 amplitudes (van Boxtel et al., 2001). In contrast, other stop-signal studies with adults have found that stop N2 amplitudes were larger for

failed than for successful inhibition trials (Dimoska, Johnstone, & Barry, 2006; Kok et al.,

2004; Ramautar, Kok, & Ridderinkhof, 2004; Ramautar, Kok, & Ridderinkhof, 2006). In addition, Ramautar, Kok, and Ridderinkhof (2004, 2006) found that stop N2 latencies were

longer for failed than for successful inhibition trials among adults. In summary, there are

inconsistencies in the direction of association between the stop N2 and response inhibition performance. Whereas some stop-signal studies support the typical finding in go/no-go

studies that larger N2 amplitudes and shorter N2 latencies are associated with better re-

sponse inhibition, other stop-signal studies suggest that smaller N2 amplitudes may reflect

better response inhibition. Differences between findings from go/no-go and stop-signal

paradigms may reflect that the tasks may induce different types of conflict, recruit differ- ent neural resources, and therefore may reflect different cognitive constructs (Swick et al.,

the stop N2 in inhibitory processing.

In addition to response inhibition, the N2 has been examined in relation to other self- regulatory phenotypes, as well. Grabell (2014) found that smaller no-go N2 amplitudes were

associated with poorer emotional dysregulation in 3 1_{/2–5-year-old children, as reported by} parents. A study by Wiersema and Roeyers (2009) found that larger no-go N2 amplitudes

were associated with better effortful control in 8–13-year-old children, as measured by self-

reports of the executive attention ability to shift attention. A study by Espinet, Anderson, and Zelazo (2012) examined the relations of the N2 amplitude to executive functioning,

another form of behavioral regulation requiring response inhibition, among 35–54-month-

old children in the context of the Dimensional Change Card Sort task that requires sorting cards by one dimension and then sorting by a second dimension. The authors found that

children with better executive functioning who passed the task had smaller N2 amplitudes

than did children who did not. There are several possible reasons for the discrepancy in findings in comparison to other findings of children with better response inhibition showing

larger N2 amplitudes. First, the study involved a different type of outcome measure that

involves relatively more cognitive flexibility than response inhibition. Second, the relation between the N2 and social functioning may depend on the range of behavior problems in

the sample, as described later. Thus, the findings in a normative sample may differ from

those of a clinical sample.

In summary, although there are some inconsistencies in the directions of the association

between the N2 and response inhibition, findings typically suggest that larger N2 amplitudes

and shorter N2 latencies are associated with better response inhibition. Future studies should examine the role of the N2 in inhibitory processing versus conflict monitoring to

specify the functional role of the no-go and stop N2 in order to clarify the meaning of its relation to behavioral phenotypes.