Neural substrate of defensive behavior in the midbrain tectum

Brandão, Marcus Lira; Cardoso, Sílvia Helena; Melo, Lauro; Motta, V.; Coimbra, Norberto Cysne

doi:10.1016/0149-7634(94)90047-7

Cited by 162 publications

(96 citation statements)

References 84 publications

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“…Electrical stimulation of the inferior colliculus shares many of the aversive properties of the stimulation of structures classically considered as components of the brain aversion system, such as the dorsal periaqueductal gray matter, deep layers of the superior colliculus, medial hypothalamus and amygdala (4,(14)(15)(16). This is consistent with the demonstration of ana-…”

Section: Discussionsupporting

confidence: 78%

“…Evidence for the involvement of the inferior colliculus in the elaboration of aversive states has been provided by both immunohistochemical and behavioral data (3)(4)(5). C-fos immunoreactivity studies have shown that this structure is also labeled along with the amygdala, hypothalamus and dorsal periaqueductal gray matter following either electrical or chemical stimulation of the latter structure or exposure of the animals to aversive environmental stimulation (3).…”

Section: Introductionmentioning

confidence: 99%

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Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

Troncoso

Cirilo-Júnior

Sandner

et al. 1998

Braz J Med Biol Res

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The inferior colliculus is a primary relay for the processing of auditory information in the brainstem. The inferior colliculus is also part of the so-called brain aversion system as animals learn to switch off the electrical stimulation of this structure. The purpose of the present study was to determine whether associative learning occurs between aversion induced by electrical stimulation of the inferior colliculus and visual and auditory warning stimuli. Rats implanted with electrodes into the central nucleus of the inferior colliculus were placed inside an open-field and thresholds for the escape response to electrical stimulation of the inferior colliculus were determined. The rats were then placed inside a shuttle-box and submitted to a two-way avoidance paradigm. Electrical stimulation of the inferior colliculus at the escape threshold (98.12 ± 6.15 (A, peak-to-peak) was used as negative reinforcement and light or tone as the warning stimulus. Each session consisted of 50 trials and was divided into two segments of 25 trials in order to determine the learning rate of the animals during the sessions. The rats learned to avoid the inferior colliculus stimulation when light was used as the warning stimulus (13.25 ± 0.60 s and 8.63 ± 0.93 s for latencies and 12.5 ± 2.04 and 19.62 ± 1.65 for frequencies in the first and second halves of the sessions, respectively, P<0.01 in both cases). No significant changes in latencies (14.75 ± 1.63 and 12.75 ± 1.44 s) or frequencies of responses (8.75 ± 1.20 and 11.25 ± 1.13) were seen when tone was used as the warning stimulus (P>0.05 in both cases). Taken together, the present results suggest that rats learn to avoid the inferior colliculus stimulation when light is used as the warning stimulus. However, this learning process does not occur when the neutral stimulus used is an acoustic one. Electrical stimulation of the inferior colliculus may disturb the signal transmission of the stimulus to be conditioned from the inferior colliculus to higher brain structures such as amygdala.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

Troncoso

Cirilo-Júnior

Sandner

et al. 1998

Braz J Med Biol Res

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“…Moreover, systemic or local injections of GABA agonists or benzodiazepines into this midbrain structure promptly reduce the aversive consequences of their electrical stimulation (Melo et al, 1992;Pandossio and Brandão, 1999). As GABA receptor antagonists mimic the effects of the electrical stimulation, it has been suggested that the neural substrate of aversion in this midbrain region be under GABAergic tonic inhibitory modulation (Melo et al, 1992;Brandão et al, 1988Brandão et al, , 1993Brandão et al, , 1994Brandão et al, , 1997. Local injections of serotonergic agents known for their antiaversive action when injected in other structures of the brain aversion system also decrease the aversiveness of the exposure of rats to the elevated plus-maze test (Melo and Brandao, 1995).…”

Section: Discussionmentioning

confidence: 99%

Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Troncoso¹,

Osaki²,

Mason³

et al. 2003

Neuropsychopharmacol

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Consistent evidence has shown that learning may be produced in paradigms using electrical stimulation of the inferior colliculus (IC) as unconditioned stimulus (UCS). Recent reports have also demonstrated that aversive stimulation of the IC, at the escape threshold, enhances dopamine (DA) release in the prefrontal cortex. The purpose of the present study was to determine whether dopaminergic mechanisms are involved in the Pavlovian conditioning and latent inhibition using IC stimulation as UCS and light as conditioned stimulus (CS). Rats were placed inside a shuttle box and subjected to a two-way avoidance paradigm. IC aversive electrical stimulation was used as UCS and shuttle box illumination as CS. The rats quickly learned to avoid or interrupt the IC stimulation. Apomorphine injections produced a dose-dependent increase in the number of avoidance responses. On the other hand, chlorpromazine administration promoted a dose-dependent reduction of the avoidance responses. Previous injections of chlorpromazine inhibited the effects of apomorphine. Also, previous exposure to unreinforced light weakened the strength of the conditioning. Apomorphine blocked this latent inhibition effect, which was antagonized by previous injections of chlorpromazine. These findings bring evidence for the involvement of DA in the setting up of adaptive responses to aversive states generated at the IC level, which may underlie stressful situations present in anxiety.

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“…Nos últimos 30 anos, a importância do CI tem sido proposta ir além de processos auditivos, sendo esta estrutura capaz de mediar o também o comportamento emocional (Graeff et al, 1986b;Brandão et al, 1993;Coimbra & Brandão, 1993;Brandão et al, 1994;. O CI tem sido envolvido, assim como outras estruturas do SEA, na mediação de respostas defensivas eliciadas por estímulos de perigo -particularmente os de natureza auditiva -em nível de teto mesencefálico (Brandão et al, 1988;Brandão et al, 1999).…”

Section: Substrato Neural Dos Comportamentos Defensivosunclassified

“…The inferior colliculus (IC) is a primary acoustic structure of the brainstem that also integrates sensory information of an aversive nature. Indeed, chemical and electrical stimulation of the IC causes unconditioned defensive behavior Brandao et al, 1988bBrandao et al, , 1994De Araujo et al, 1999). A circuit that comprises the IC, medial geniculate nucleus, thalamus, and amygdala is involved in the processing of auditory information of an aversive nature, which triggers fear-like behavior (Hoffman and Ison, 1980;Maisonnette et al, 1996;.…”

Section: Introductionmentioning

confidence: 99%

Papel dos mecanismos GABAérgicos do colículo inferior e da substância cinzenta periaquedutal na interface sensoriomotora do medo e ansiedade

Saito¹

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Neural substrate of defensive behavior in the midbrain tectum

Cited by 162 publications

References 84 publications

Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

Apomorphine Enhances Conditioned Responses Induced by Aversive Stimulation of the Inferior Colliculus

Papel dos mecanismos GABAérgicos do colículo inferior e da substância cinzenta periaquedutal na interface sensoriomotora do medo e ansiedade

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