6-hydroxydopamine and avoidance: Possible role of response suppression

Lenard, Lane G.; Beer, Bernard

doi:10.1016/0091-3057(75)90120-3

Cited by 30 publications

(7 citation statements)

References 15 publications

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“…Dopamine depletion impairs active behaviors such as escape, while enhancing passive aversive behaviors such as freezing (Lenard and Beer, 1975). To examine whether the RMTg also modulates these types of aversive behaviors, we made fiber-sparing lesions of the RMTg region using the excitotoxin ibotenic acid, and then tested lesioned and unlesioned rats on three measures of anxiety and fear: auditory conditioned freezing, freezing to the predator odor trimethylthiazoline (TMT), and elevated plus maze arm avoidance.…”

Section: Resultsmentioning

confidence: 99%

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The Rostromedial Tegmental Nucleus (RMTg), a GABAergic Afferent to Midbrain Dopamine Neurons, Encodes Aversive Stimuli and Inhibits Motor Responses

Jhou

Fields

Baxter

et al. 2009

Neuron

576

670

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Summary Separate studies have implicated the lateral habenula (LHb) or amygdala-related regions in processing aversive stimuli, but their relationships to each other and to appetitive motivational systems are poorly understood. We show that neurons in the recently identified GABAergic rostromedial tegmental nucleus (RMTg), which receive a major LHb input, project heavily to midbrain dopamine neurons, and show phasic activations and/or Fos induction after aversive stimuli (footshocks, shock-predictive cues, food deprivation, or reward omission) and inhibitions after rewards or reward-predictive stimuli. RMTg lesions markedly reduce passive fear behaviors (freezing, open-arm avoidance) dependent on the extended amygdala, periaqueductal gray, or septum, all regions that project directly to the RMTg. In contrast, RMTg lesions spare or enhance active fear responses (treading, escape) in these same paradigms. These findings suggest that aversive inputs from widespread brain regions and stimulus modalities converge onto the RMTg, which opposes reward and motor-activating functions of midbrain dopamine neurons

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Section: Resultsmentioning

confidence: 99%

“…Furthermore, the RMTg plays these roles over a remarkably wide range of stimulus modalities and behavioral paradigms. These roles are inverse to those of DA depletion, which enhances freezing responses to fearful stimuli at the expense of escape responses (Lenard and Beer, 1975). …”

Section: Discussionmentioning

confidence: 99%

The Rostromedial Tegmental Nucleus (RMTg), a GABAergic Afferent to Midbrain Dopamine Neurons, Encodes Aversive Stimuli and Inhibits Motor Responses

Jhou

Fields

Baxter

et al. 2009

Neuron

576

670

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“…Although Jhou et al (2009a) did not detect significant increases in baseline locomotion compared with control following such lesions, their results support strong RMTg effects on specific types of locomotor-related responding in fear-eliciting circumstances. Moreover, their results show that the effects of RMTg lesions oppose those associated with dopamine depletion, which impairs active, but enhances passive, fear behaviors (Lenard and Beer, 1975;Jhou et al, 2009a).…”

Section: Discussionmentioning

confidence: 99%

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

Lavezzi

Parsley

Zahm

2014

Neuropsychopharmacol

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The rostromedial tegmental nucleus (RMTg) is a strong inhibitor of dopamine neurons in the ventral tegmental area (VTA) reported to influence neurobiological and behavioral responses to reward omission, aversive and fear-eliciting stimuli, and certain drugs of abuse. Insofar as previous studies implicate ventral mesencephalic dopamine neurons as an essential component of locomotor activation, we hypothesized that the RMTg also should modulate locomotion activation. We observed that bilateral infusions into the RMTg of the gamma-aminobutyric acid A (GABA A ) agonist, muscimol, indeed activate locomotion. Alternatively, bilateral RMTg infusions of the GABA A receptor antagonist, bicuculline, suppress robust activations of locomotion elicited in two distinct ways: (1) by disinhibitory stimulation of neurons in the lateral preoptic area and (2) by return of rats to an environment previously paired with amphetamine administration. The possibility that suppressive locomotor effects of RMTg bicuculline infusions were due to unintended spread of drug to the nearby VTA was falsified by a control experiment showing that bilateral infusions of bicuculline into the VTA produce activation rather than suppression of locomotion. These results objectively implicate the RMTg in the regulation of locomotor activation. The effect is important because much evidence reported in the literature suggests that locomotor activation can be an involuntary behavioral expression of expectation and/or want without which the willingness to execute adaptive behaviors is impaired.

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“…These results are inverse relative to those observed following dopamine depletion, which produces impairment of active fear-elicited behaviors and enhances passive fear-elicited behaviors [78]. Insofar as lesions of the ventrolateral periaqueductal gray (PAG) produce behavioral effects similar to those observed following lesions of the RMTg [79-80] and the PAG receives input from both the central nucleus of the amygdala [81] and the bed nucleus of stria terminalis [82], Jhou et al [36] have speculated that these structures activate RMTg neurons in fear-arousing circumstances.…”

Section: Rmtg Neuronal Function and Reward-related Stimulimentioning

confidence: 80%

The mesopontine rostromedial tegmental nucleus: An integrative modulator of the reward system

Lavezzi

Zahm

2011

Basal Ganglia

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The mesopontine rostromedial tegmental nucleus (RMTg) is a newly discovered brain structure thought to profoundly influence reward-related pathways. The RMTg is prominently GABAergic, receives dense projections from the lateral habenula and projects strongly to the midbrain ventral tegmental area and substantia nigra compacta. It receives additional afferent connections from widespread brain structures and sends additional strong efferent connections to a number of non-dopaminergic brainstem structures and, to a lesser extent, the forebrain. Projection neurons of the RMTg have been shown to express Fos in response to aversive stimuli and/or reward omission and psychostimulant drug administration. This review will first recount how the RMTg was discovered and then describe in greater detail what is known about its neuroanatomical relationships, including afferent and efferent connections, neurotransmitters, and receptors. Finally, we will focus on what has been reported about its function.

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6-hydroxydopamine and avoidance: Possible role of response suppression

Cited by 30 publications

References 15 publications

The Rostromedial Tegmental Nucleus (RMTg), a GABAergic Afferent to Midbrain Dopamine Neurons, Encodes Aversive Stimuli and Inhibits Motor Responses

The Rostromedial Tegmental Nucleus (RMTg), a GABAergic Afferent to Midbrain Dopamine Neurons, Encodes Aversive Stimuli and Inhibits Motor Responses

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

The mesopontine rostromedial tegmental nucleus: An integrative modulator of the reward system

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