correcting the relationship between tonic and burst firing modes in dopamine neurons may help normalise stimulus-reinforcement gradients and contingent behaviour in attention-deficit/hyperactivity disorder (adhd) children. but appropriate evaluations of stimuli for developing adaptive plans and controlling impulsivity will not occur without moderating the gain-like functions of serotonin. the “dynamic theory” correctly highlights the need to account for variability in adhd. the dysmaturation of pre-executive information processing is proposed as an explanation.

at the core of the article by sagvolden and colleagues there is a set of data that throws light on an aspect of the adhd phenomenon. but one asks if the authors are a measure too brave to generalise so broadly from the unusually steep reinforcement gradients reported for the human condition and an animal model to the syndrome as a whole.

Context, connection, and coordination (CCC) describe well where the problems that apply to thought-disordered patients with schizophrenia lie. But they may be part of the experience of those with other symptom constellations. Switching is an important mechanism to allow context to be applied appropriately to changing circumstances. In some cases, NMDA-voltage modulations may be central, but gain and shift are also functions that monoaminergic systems express in CCC.

The integration of perceived events with appropriate action usually requires more flexibility to result in adaptive responses than Hommel et al. report in their selective review. The need for hierarchies of function that can intervene and the existence of diverse mediating brain mechanisms can be illustrated by the non-adaptive expression in psychiatric illness of negative priming, blocking, and affective responses.

The boundaries, the influences on, and consequences of a short-term memory (STM) capacity of 4 leads us to consider global versus local processing. We argue that in schizophrenia cognitive problems can lie partly in pre-conscious automatic selective attention and partly with the speed of processing in later controlled processes (including compound STM). The influence of automatic attentional mechanisms may be under-estimated in normal psychology and explain the loss of the magic 4 in schizophrenia.

Sensitivity to incentive motivation has a formative influence on extraversion. Mesoamygdaloid dopamine (DA) activity may, at one level, act as a micro-gate permitting an incentive to influence behavioral organization – “Go/No-Go” in this scheme. Data on function elsewhere in the mesocorticolimbic DA system are taken to support this particular function. At another level of analysis, the data in Depue & Collins's review, along with those on the rest of the ventral tegmental area (VTA) system, may fit better with a “switching” function in information processing. This link is supported by correlations between measures of extraversion, learned inattention, and overall DA activity. The point is extended to the novelty-seeking feature of the extraverted personality.