Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “sensorimotor behavior”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed2005

Corticotrophin-releasing hormone decreases synaptic transmission in rat sensorimotor cortex in vivo.

Corticotrophin-releasing hormone is a key regulator of the mammalian stress response. Although its actions on behavior are well documented, the actions of corticotrophin-releasing hormone in cortical neuronal systems are poorly understood. In the present experiments, adult male Sprague-Dawley rats were anesthetized and field excitatory post-synaptic potential recordings were made from sensorimotor cortex layer II/III and layer V cells. Infusions of corticotrophin-releasing hormone (100 ng/nl) directly into the sensorimotor cortex produced a significant depression of the initial excitatory component of evoked responses that could be prevented by prior administration of a corticotrophin-releasing hormone antagonist. Although requiring the activation of corticotrophin-releasing hormone receptors, the depression was also dependent upon N-methyl-D-aspartate receptor activity and could be blocked by the competitive N-methyl-D-aspartate antagonist -3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate. These findings demonstrate that corticotrophin-releasing hormone has a novel depressant-like action in sensorimotor cortex in vivo that may play a role in modulating motor activity during periods of stress.

Animals↗
PubMed1997

Analyzing Neuronal Processing Locus in Stimulus-Response Association Tasks

If a neuron is being recorded while a trained animal performs a 2x2 stimulus-response association task, how can we decide whether it is related more to the encoding and analysis of the sensory stimulus, to the preparation and execution of the motor response, or to the animal's decision that associates the two? The difficulty arises because, within a single task, stimulus and response are intrinsically confounded per task instruction; it is only through proper analysis of errors in performance (behavioral noise) and variance in recorded neural activity (neuronal noise) that one can identify the sensorimotor significance of such activity. A quantitative technique is proposed here, based on the framework of signal detection theory, to determine the sensorimotor "locus" of a neural process when recorded simultaneously with the animal's performance on a trial-by-trial basis. The premise is that a pure sensory process should be influenced only by the nature of the sensory stimulus regardless of the nature of the behavioral response, and vice versa for a pure motor process. From the recorded neural activity, we calculate the prediction or discriminability (by an ideal operator) for the stimulus categories and for the response categories. These discriminability values are then compared with each other to infer whether the neural process is more related to stimulus or to response. An index is derived that quantitatively specifies the processing locus of a given neural process along the sensorimotor continuum, with pure sensory and pure motor processes at the two extremes. In between lies the locus of decision-related processes whose activities allow equal (but not chance) prediction for stimulus and response categories. The technique is applied to single-unit activities recorded in monkey primary motor cortex (MI) while the monkey performed a simple go/nogo task involving visual stimulus and hand/wrist movement. We find that sensorimotor indices of MI neurons are widely distributed, with a preponderance of motor-related units (that better predict go/nogo response than go/nogo stimulus) but also sensory-related ones (with predictabilities reversed). Copyright 1997 Academic Press

Journal Article↗
PubMed1998

Adrenergic alpha2C-receptors modulate the acoustic startle reflex, prepulse inhibition, and aggression in mice.

Studies on animal models of stress, anxiety, aggression, and sensorimotor gating have linked specific monoamine neurotransmitter abnormalities to the cognitive and behavioral disturbances associated with many affective neuropsychiatric disorders. Although alpha2-adrenoceptors (alpha2-ARs) have been suggested to have a modulatory role in these disorders, the specific roles of each alpha2-AR subtype (alpha2A, alpha2B, and alpha2C) are largely unknown. The restricted availability of relevant animal models and the lack of subtype-selective alpha2-AR drugs have precluded detailed studies in this area. Therefore, transgenic mice were used to study the possible role of the alpha2C-AR subtype in two well established behavioral paradigms: prepulse inhibition (PPI) of the startle reflex and isolation-induced aggression. The alpha2C-AR-altered mice appear grossly normal, but subtle changes have been observed in their brain dopamine (DA) and serotonin (5-HT) metabolism. In this study, the mice with targeted inactivation of the gene encoding alpha2C-ARs (alpha2C-KO) had enhanced startle responses, diminished PPI, and shortened attack latency in the isolation-aggression test, whereas tissue-specific overexpression of alpha2C-ARs (alpha2C-OE) was associated with opposite effects. Correlation analyses suggested that both the magnitude of the startle response and its relative PPI (PPI%) were modulated by the mutations. In addition, the differences in PPI, observed between drug-naive alpha2C-OE mice and their wild-type controls, were abolished by treatment with a subtype nonselective alpha2-agonist and antagonist. Thus, drugs acting via alpha2C-ARs might have therapeutic value in disorders associated with enhanced startle responses and sensorimotor gating deficits, such as schizophrenia, attention deficit disorder, post-traumatic stress disorder, and drug withdrawal.

Adrenergic Uptake Inhibitors↗
PubMed2001

Effect of the serotonin agonist 8-OH-DPAT on the sensorimotor system of the rat.

8-Hydroxy-2-(di-n-propylamino)-tetralin hydrobromide (8-OH-DPAT, 2 mg/kg) is used to induce perseverative behavior in rats in a T-maze as a model for obsessive-compulsive disorder (OCD). Using the open-field test, radiant heat test, and the test with von Frey filaments, we examined whether alterations in sensorimotor functioning could contribute to the perseverative tendencies in this model by measuring differences in left versus right hind paw reactions after 8-OH-DPAT administration (2 mg/kg, sc). Also, the effect of repeated 8-OH-DPAT administration on sensorimotor functioning was tested every third day. 8-OH-DPAT administration induced a significantly decreased sensorimotor performance in the open-field test, an increased threshold for noxious thermal stimulation (increased withdrawal latency, WL, and decreased elevation time, ET) in the radiant heat test, and a decreased nociceptive threshold for mechanical stimulation in the test with von Frey filaments. All changes in sensorimotor functioning were similar for left and right hind paws suggesting that, these changes as measured with the tests in the present study, are not likely to contribute to the perseverative behavior of rats in a T-maze. Further, repeated administration of 8-OH-DPAT had no effect in the radiant heat test and the test with the Frey filaments, but produced a tolerance effect in the open-field test.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Effects of daily dermal application of DEET and epermethrin, alone and in combination, on sensorimotor performance, blood-brain barrier, and blood-testis barrier in rats.

DEET and permethrin were implicated in the development of illnesses in some veterans of the Persian Gulf War. This study was designed to investigate the effects of daily dermal application of these chemicals, alone or in combination, on the permeability of the blood-brain barrier (BBB) and blood-testes barrier (BTB) and on sensorimotor performance in male Sprague-Dawley rats. Groups of five rats were treated with a dermal daily dose of 4, 40, or 400 mg/kg DEET in ethanol or 0.013, 0.13, or 1.3 mg/kg permethrin in ethanol for 60 d. A group of 10 rats received a daily dermal dose of ethanol and served as controls. BBB permeability was assessed by injection of an iv dose of the quaternary ammonium compound [3H]hexamethonium iodide. While permethrin produced no effect on BBB permeability, DEET alone caused a decrease in BBB permeability in brainstem. A combination of DEET and permethrin significantly decreased the BBB permeability in the cortex. BTB permeability was decreased by treatment with DEET alone and in combination with permethrin. The same animals underwent a battery of functional behavior tests 30, 45, and 60 d after exposure to evaluate their sensorimotor abilities. All treatments caused a significant decline in sensorimotor performance in a dose- and time-dependent manner. These results show that daily dermal exposure to DEET, alone or in combination with permethrin, decreased BBB permeability in certain brain regions, and impaired sensorimotor performance.

Administration, Topical↗
PubMed2001

Identified nerve cells and insect behavior.

Studies of insect identified neurons over the past 25 years have provided some of the very best data on sensorimotor integration; tracing information flow from sensory to motor networks. General principles have emerged that have increased the sophistication with which we now understand both sensory processing and motor control. Two overarching themes have emerged from studies of identified sensory interneurons. First, within a species, there are profound differences in neuronal organization associated with both the sex and the social experience of the individual. Second, single neurons exhibit some surprisingly rich examples of computational sophistication in terms of (a) temporal dynamics (coding superimposed upon circadian and shorter-term rhythms), and also (b) what Kenneth Roeder called "neural parsimony": that optimal information can be encoded, and complex acts of sensorimotor coordination can be mediated, by small ensembles of cells. Insect motor systems have proven to be relatively complex, and so studies of their organization typically have not yielded completely defined circuits as are known from some other invertebrates. However, several important findings have emerged. Analysis of neuronal oscillators for rhythmic behavior have delineated a profound influence of sensory feedback on interneuronal circuits: they are not only modulated by feedback, but may be substantially reconfigured. Additionally, insect motor circuits provide potent examples of neuronal restructuring during an organism's lifetime, as well as insights on how circuits have been modified across evolutionary time. Several areas where future advances seem likely to occur include: molecular genetic analyses, neuroecological syntheses, and neuroinformatics--the use of digital resources to organize databases with information on identified nerve cells and behavior.

Animals↗
PubMed1996

Organization of afferent and efferent projections of the nucleus basalis prosencephali in a passerine, Taeniopygia guttata.

The connections of nucleus basalis (NB) of the rostral forebrain of the zebra finch were investigated electrophysiologically and with anterograde and retrograde tracing methods to determine their functional organization, the sources of their pontine afferents, and the targets of their telencephalic efferents. The nucleus was found to be partitioned into three major components, a rostral lingual part that received a hypoglossal projection via a lateral subnucleus of the principal sensory trigeminal nucleus (PrV), a middle beak part that received a trigeminal projection via a medial subnucleus of PrV, and a caudal auditory part that received a short latency auditory projection via the intermediate nucleus of the lateral lemniscus. Beak NB also received a projection from a paralateral lemniscal nucleus, and the dorsocaudal part of auditory NB and the medially adjacent neostriatum also received a projection from a lateral subnucleus of the superior vestibular nucleus (VS). The efferent projections of each of the three major parts of NB were mainly to the adjacent neostriatum frontale (NF), which then provided projections to the lobus parolfactorius (exclusive of area X), the lateral archistriatum intermedium (Ail), and the lateral neostriatum caudale (NCl). Ail received a projection from NCl and provided terminal fields to the contralateral NCl and the NF. The major projections of Ail, however, descended bilaterally through the brainstem via the occipitomesencephalic tracts, with dense terminations in the medial spiriform nucleus and with extensive bilateral terminations throughout the lateral reticular formation of the pons and medulla. For the most part, jaw, tongue, and tracheosyringeal motor nuclei did not receive terminations. The results suggest that NB in zebra finch, like NB in pigeon and duck, is likely to be a major component of trigeminal sensorimotor circuitry involved in feeding and in other oral-manipulative behaviors. Results also show that the auditory component of NB is not directly linked to the vocal control system at telencephalic levels, but the possibility remains that the lingual, beak, and auditory parts of NB play a role in vocalization by multisynaptic influences on cranial nerve motor nuclei innervating various parts of the vocal tract.

Afferent Pathways↗
PubMedDate not supplied

Neural sites and pathways regulating food intake in birds: a comparative analysis to mammalian systems.

The paper reviews hypotheses explaining the regulation of food intake in mammals that have addressed specific anatomical structures in the brain. An hypothesis, poikilostasis, is introduced to describe multiple, homeostatic states whereby the regulation of metabolism and feeding occur in birds. Examples are given for both wild and domestic avian species, illustrating dynamic shifts in homeostasis responsible for the changes in body weights that are seen during the course of an annual cycle or by a particular strain of bird. The following neural structures are reviewed as each has been shown to affect food intake in birds or in mammals: ventromedial hypothalamic nucleus (n.), lateral hypothalamic area, paraventricular hypothalamic n., n. tractus solitarius and area postrema, amygdala, parabrachial n., arcuate n. and bed n. of the stria terminalis. Two neural pathways are described which have been proposed to regulate feeding. The trigeminal sensorimotor pathway is the most complete neural pathway characterized for this behavior and encompasses the mechanics of pecking, grasping and mandibulating food particles from the tip of the bill to the back of the buccal cavity. A second pathway, the visceral forebrain system (VFS), affects feeding by regulating metabolism and the balance of the autonomic nervous system. Wild, migratory birds are shown to exhibit marked changes in body weight which are hypothesized to occur due to shifts in balance between the sympathetic and parasympathetic nervous systems. Domestic avian species, selected for a rapid growth rate, are shown to display a dominance of the parasympathetic nervous system. The VFS is the neural system proposed to effect poikilostasis by altering the steady state of the autonomic nervous system in aves and perhaps is applicable to other classes of vertebrates as well.

Animals↗
PubMed1994

Mapping of globus pallidus and ventral pallidum lesions that produce hyperkinetic treading.

The purpose of this study was to identify sites where striatopallidal lesions produce two distinct sensory-triggered hyperkinetic syndromes: (1) exaggerated forelimb treading alone to oral taste infusions and (2) sensorimotor exaggerated treading plus enhanced aversive reactions to taste infusions. The behavioral characteristics of these syndromes have been described previously (Berridge, K.C. and Cromwell, H.C., Behav. Neurosci., 104 (1990) 778-795). Bilateral excitotoxin lesions were made using quinolinic acid (10 micrograms in 1 microliter) in the caudate/putamen, nucleus accumbens, globus pallidus or ventral pallidum/substantia innominata. In order to identify the precise center, borders, severity and size of lesion sites that caused these hyperkinetic treading syndromes, neuron counts (modified fractionator technique) and glial fibrillary acidic protein immunoreactivity (GFAP-IR) densitometry were used in a stereological mapping analysis. The site of lesions that produced the hyperkinetic treading syndrome without enhanced aversion was found to be restricted to the globus pallidus (GP). Damage exceeding 60% neuron loss bilaterally within a 0.8 x 1.0 x 1.0 mm subregion of the ventromedial GP produced this syndrome. The site of lesions that produced the combined syndrome of hyperkinetic treading and aversive enhancement was ventral to the globus pallidus, within the ventral pallidum/substantia innominata (VP/SI). Damage exceeding 70% neuron loss bilaterally within a 1.0 x 0.5 x 1.0 mm diameter subregion of the ventromedial ventral pallidum/substantia innominata produced this syndrome. This subterritory was located immediately lateral to the border of the lateral hypothalamus. Bilateral lesions to the caudate/putamen or nucleus accumbens did not produce either hyperkinetic treading syndrome. These results are discussed in terms of the connectivity of the ventral pallidal/substantia innominata and globus pallidus regions and in terms of neuropathological models of hyperkinetic disorders.

Animals↗
PubMed2004

Beta oscillations in a large-scale sensorimotor cortical network: directional influences revealed by Granger causality.

Previous studies have shown that synchronized beta frequency (14-30 Hz) oscillations in the primary motor cortex are involved in maintaining steady contractions of contralateral arm and hand muscles. However, little is known about the role of postcentral cortical areas in motor maintenance and their patterns of interaction with motor cortex. We investigated the functional relations of beta-synchronized neuronal assemblies in pre- and postcentral areas of two monkeys as they pressed a hand lever during the wait period of a visual discrimination task. By using power and coherence spectral analysis, we identified a beta-synchronized large-scale network linking pre- and postcentral areas. We then used Granger causality spectra to measure directional influences among recording sites. In both monkeys, strong Granger causal influences were observed from primary somatosensory cortex to both motor cortex and inferior posterior parietal cortex, with the latter area also exerting Granger causal influences on motor cortex. Granger causal influences from motor cortex to postcentral sites, however, were weak in one monkey and not observed in the other. These results are the first, to our knowledge, to demonstrate in awake monkeys that synchronized beta oscillations bind multiple sensorimotor areas into a large-scale network during motor maintenance behavior and carry Granger causal influences from primary somatosensory and inferior posterior parietal cortices to motor cortex.

Animals↗
PubMed1984

Relationship between the home environment and sensorimotor development of Down syndrome and nonretarded infants.

Thirteen Down syndrome and 19 nonretarded infants participated in a prospective, longitudinal study designed to investigate the effect of the home environment on sensorimotor development as assessed by infant tests and direct observation of behavior. The present paper is concerned with the age span from 6.5 to 24 months. The two groups did not differ on measures of the social environment obtained at 6.5 months but differed on such measures at 17 months. At 6.5 months, the amount of tactile stimulation, encouragement of postural control, and level of social stimulation were all related to concurrent test performance in both groups; characteristics of the inanimate environment were of longer-term predictive significance among the Down syndrome babies. At 17 months, mothers' referential speech was related to the developmental pattern from 6.5 to 24 months for the Down syndrome children. The Down syndrome children tended to explore objects as a solitary activity, whereas exploration was done within the interactional situation by the nonretarded subjects. An attempt at multiple prediction demonstrated the usefulness of an interactional approach, showing the joint predictive value of language behavior and mothers' referential speech. Of special concern was how slowness of development among Down syndrome children may be a factor producing changes in maternal behavior.

Adolescent↗
PubMed1980

A lesson on negativism in the toddler. Preceded by some considerations on the teaching of general pediatrics.

This study presents observations about certain preliminary conditions necessary for the practicing physician's teaching ambulatory pediatrics. The author's practical experience is cited in the transcription of a lesson about 'negativism in the toddler', and a sensorimotor psychodynamic concept is proposed to explain the child's oppositional behavior: the unusual energy potential at this age, the immediacy of an act, an object concept different from that of the adult. The pediatrician's role as 'health counselor' is evoked in the therapeutic considerations.

Child Behavior↗
PubMed1983

Chronic lithium administration alters behavioral recovery from nigrostriatal injury: effects on neostriatal [3H]spiroperidol binding sites.

Unilateral damage to the mesotelencephalic dopaminergic projection of the rat produces impairments in sensorimotor functions, including an inability to localize contralateral somatosensory stimuli. Many rats with 6 hydroxydopamine injections along this pathway show a gradual improvement in somatosensory localization during the first post-operative month. One mechanism that may contribute to this behavioral recovery is the proliferation of dopamine receptor sites in the affected neostriatum. The role of these binding site changes in the recovery was tested by chronic administration of lithium to rats. Rats given lithium in their drinking water for 4 weeks after the 6-hydroxydopamine injection showed a greatly attenuated recovery of sensorimotor functions, compared to brain-damaged rats drinking unadulterated water. When rats that were given lithium for the first four postoperative weeks were subsequently given unadulterated water to drink, they recovered normally. Lithium treatment did not prevent the augmentation of [3H]spiroperidol binding in the neostriatum ipsilateral to the lesion, relative to the contralateral control neostriatum, at 4 or 8 weeks post-operatively. Thus, lithium treatment dissociates behavioral recovery after nigrostriatal injury from the lesion-induced relative proliferation of neostriatal [3H]spiroperidol binding sites. However, the lithium treatment decreased the absolute amount of specific [3H]spiroperidol binding to both the ipsilateral and contralateral neostriata. The significance of these findings for the neural mechanism underlying this recovery sequence is discussed.

Animals↗
PubMed1984

[Relearning and critical postoperative period in the restoration of nerve function. Example of vestibular compensation and clinical implications].

The role of sensorimotor activity in the recovery process after unilateral vestibular neurectomy was studied on cats and monkeys using behavioral and electrophysiological methods. It was analyzed by comparing the time-course of the recovery of posture, locomotion and equilibrium function in animals which remained free after surgery in their usual environment (unrestrained group) to others which were submitted to a postoperative sensorimotor restriction (restrained group). This sensorimotor restriction was applied at different postoperative times; the effects of short and long-lasting restrictions were also studied. Results showed that the functional recovery develops in active animals only, i.e. when they can use all available information elicited by an active sensorimotor exploration. It is blocked and delayed in the restrained group, the postoperative disorders being reduced much later when a long-lasting restriction is used. It is also demonstrated that the functional recovery is better and faster in animals having an early sensorimotor activity. It is concluded that vestibular compensation resembles a sensorimotor relearning process requiring the activity of the subject, and that a postoperative critical period may exist in functional recovery which may be crucial for achieving well-or maladapted behavior. The clinical implications of these findings are presented in the discussion as some general principles able to stimulate reflexions and improve the postoperative training methods.

Animals↗
PubMed2003

[Altered behavioral response to centrally acting drugs in mice lacking PACAP].

Mice lacking PACAP (PACAP-KO) exhibits altered psychomotor behaviors, including impaired habituation to a novel environment and perseverative jumping, with a slightly reduced levels of the serotonin metabolite, 5-HIAA, in the brain. We have recently demonstrated that PACAP-KO exhibits abnormalities in sensorimotor gating as measured by prepulse inhibition (PPI) of the acoustic startle. In the present study, behavioral responses to centrally acting drugs (amphetamine, haloperidol, risperidone, fluoxetine, and 8-OH-DPAT) were examined in PACAP-KO. Surprisingly, a psychostimulant amphetamine effectively normalized the deficit in PPI as well as hyperactivity and jumping behavior. These results implied phenotypic and pharmacological similarity between PACAP-KO and attention deficit hyperactivity disorder (ADHD). Although a potent dopamine D2-like receptor antagonist, haloperidol, ameliorated the hyperactivity and jumping behavior, it had no effect on the deficit in PPI. In contrast, a prototype of serotonin-dopamine antagonist (SDA), risperidone, effectively normalized the deficit in PPI as well as hyperactivity, and jumping behavior. A selective serotonin reuptake inhibitor (SSRI), fluoxetine, also suppressed the hyperactivity and jumping behavior. A 5-HT1A receptor agonist, 8-OH-DPAT, significantly lowered rectal temperature in wild-type mice, while it had only a small effect in PACAP-KO. These results suggest the involvement of dopaminergic and serotonergic dysfunction in phenotypic changes observed in PACAP-KO.

Amphetamine↗
PubMed1988

Lateralized wall-facing versus turning as measures of behavioral asymmetries and recovery of function after injection of 6-hydroxydopamine into the substantia nigra.

The tendency of a rat to approach the wall of an open-field and to travel along the perimeter of the field (termed as "peritaxis" or "wall-facing") is affected by unilateral removal of the vibrissae. Peritaxis is lateralized by hemivibrissotomy. The finding that the dopamine agonist apomorphine reversed the direction of wall-facing asymmetry after 10 days of vibrissae removal suggested a link between this sensorimotor asymmetry and dopamine transmission. The present experiment examined the influence of a unilateral injection of 6-hydroxydopamine into the substantia nigra on peritaxis and compared this behavioral measure with turning behavior as an index of lesion-induced sensorimotor asymmetries and of recovery of function. The lesion of the substantia nigra reduced wall-facing with the side contralateral to the lesion to near-zero values. During the first week after the injection animals with incomplete dopamine depletion recovered from this asymmetry. The changes in wall-facing behavior were paralleled by turning asymmetries. Wall-facing was at least as sensitive to application of amphetamine and apomorphine as turning behavior. We concluded that lateralized wall-facing, or peritaxis, can serve as a useful index of dysfunction in the nigrostriatal dopamine system and the influence of catecholaminergic drugs. Wall-facing can also serve as a measure of recovery of function.

Animals↗
PubMed1997

Three models of song learning: evidence from behavior.

Research on avian song learning has traditionally been based on an instructional model, as exemplified by the sensorimotor model of song development. Several large-scale, species-wide field studies of learned birdsongs have revealed that variation is narrowly restricted to certain aspects of song structure. Other aspects are sufficiently stereotyped and so widely shared by species' members that they qualify as species-specific universals. The limitations on natural song variation are difficult to reconcile with a fully open, instructive model of song learning. An alternative model based on memorization by selection postulates a system of innate neural templates that facilitate the recognition and rapid memorization of conspecific song patterns. Behavioral evidence compatible with this model includes learning preferences, rapid conspecific song learning, and widespread ocurrence of species-specific song universals that are recognized innately but fail to develop in songs of social isolates. A third model combines instruction, in the memorization phase, with selection during song production. An overproduced repertoire of plastic songs previously memorized by instruction is winnowed by selection imposed during social interactions at the time of adult song crystallization. Selection during production is well established as a factor in the song development of several species, in the form of action-based learning. The possible role of selective processes in song memorization merits further neurobiological investigation.

Animals↗
PubMed2002

Control over location-based response activation in the Simon task: behavioral and electrophysiological evidence.

In 4 Simon experiments the authors examined control over 2 routes of sensorimotor processing: response priming in the unconditional route and response selection via the conditional route. The Simon effect diminished as the frequency of noncorresponding trials increased. Location-based response priming was observed only when the stimulus followed a corresponding event but not after a noncorresponding trial. Therefore, the unconditional route appears to be suppressed whenever the task context indicates priming as potentially disadvantageous. Moreover, the task-irrelevant stimulus location was used for response selection as a function of correspondence probability. Although exact repetitions of stimulus-response sequences caused a marked speed-up of responses, this 3rd mechanism is independent of unconditional route suppression and frequency-based adjustments in the conditional route.

Adult↗