The effect of periaqueductal gray lesions on responses to age-specific threats in infant rats

Wiedenmayer, Christoph P.; Goodwin, Gregory A.; Barr, Gordon A.

doi:10.1016/s0165-3806(00)00009-2

Cited by 35 publications

(29 citation statements)

References 36 publications

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“…In rat pups, different columns of the midbrain periaqueductal gray (PAG) mediate different behavior patterns. Whereas both the ventrolateral and lateral columns mediate isolation-induced USVs in 12-day-old rats, only the ventrolateral PAG seems to mediate male-induced immobility in 14-day-old pups (Wiedenmayer, Goodwin, & Barr, 2000). Male exposure seems to have affected the two pathways differently as vocalization, but not immobility, was altered after the exposure.…”

Section: Discussionmentioning

confidence: 88%

Rat pups reduce ultrasonic vocalization after exposure to an adult male rat

Wiedenmayer

Lyo

Barr

2003

Developmental Psychobiology

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We examined how the experience of a threatening stimulus alters subsequent behavior in a situation where the immediate threat is absent. A small huddle of 12-day-old rats was exposed to a potentially infanticidal adult male rat for 5 min. During male exposure, pups were significantly more immobile than control pups. Thirty, 60, and 180 min after male exposure, the pups were isolated for 5 min from litter and dam in an unfamiliar environment. When isolated, pups that had been previously exposed to the male emitted significantly fewer ultrasonic vocalizations than controls, but did not differ in immobility. Low levels of vocalization were apparent 30 and 60 min after male exposure and were not evident at 180 min. The pups seemed to have adjusted their behavior to a potential male threat in a different context for a limited period of time. ß

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Section: Discussionmentioning

confidence: 88%

Rat pups reduce ultrasonic vocalization after exposure to an adult male rat

Wiedenmayer

Lyo

Barr

2003

Developmental Psychobiology

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“…One such area that controls defensive behavior and receives amygdala projections is the periaqueductal gray in the midbrain (Bandler and Shipley, 1994). We have demonstrated previously that maleinduced levels of c-fos expression in the periaqueductal gray correlate with freezing and that periaqueductal gray lesion decreased levels of freezing on P14 (Wiedenmayer et al, 2000;Wiedenmayer and Barr, 2001b).…”

Section: Discussionmentioning

confidence: 92%

The Role of the Amygdala and Olfaction in Unconditioned Fear in Developing Rats

Chen¹,

Shemyakin²,

Wiedenmayer³

2006

J. Neurosci.

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Early in ontogeny, young rats must be able to detect dangerous stimuli and to exhibit appropriate defensive behaviors. Different nuclei of the amygdala mediate unconditioned and conditioned fear responses to threat in adult rats. The aim of this study was to determine the role of the amygdala in unlearned fear behavior in young rats. When exposed to an unfamiliar adult male rat, preweaning rat pups freeze, with peak levels on postnatal day 14 and declining levels on day 18. Pups were made anosmic to block olfactory input to the amygdala, and amygdala activation was assessed by quantifying the neuronal marker c-fos. Anosmic pups did not freeze in the presence of the male rat and had decreased c-fos expression in the medial amygdala on day 14 and in the medial and lateral amygdala on day 18. However, the decrease in freezing between days 14 and 18 was not associated with a decrease in c-fos expression in the medial amygdala. The medial and lateral amygdala were then inactivated by local muscimol infusion on day 14. Muscimol infusion into the medial amygdala decreased freezing to the male rat but not to a loud noise, whereas infusion into the lateral amygdala blocked freezing to a loud noise but not to the male. These findings indicate that different nuclei of the amygdala process sensory information of different modalities, mediate unconditioned freezing, and may be involved in developmental changes in the fear response in young rats.

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“…For example, interpretation of isolation-induced vocalizing as a measure of crying has prompted many researchers to use USV as a dependent measure in animal models of anxiety (e.g., Kehoe & Harris, 1989;Olivier et al, 1998;Zimmerberg, Brunelli, & Hofer, 1994). Within these models, USVs have been used to measure the effects of various prenatal stressors (e.g., Morgan, Thayer, & Frye, 1999;Takahashi, Baker, & Kalin, 1990), to measure the effects of pharmacological agents (e.g., Carden et al, 1994;Kehne, Coverdale, McCloskey, Hoffman, & Cassella, 2000;Kehoe, Callahan, Daigle, Mallinson, & Brudzynski, 2001), and to measure responsivity to threatening stimuli (e.g., Takahashi, 1994;Wiedenmayer, Goodwin, & Barr, 2000). Many of these studies restrict their assessments to pups 2 weeks of age or younger given the prevalent belief that USV decreases with age.…”

Section: Assessing the Ontogeny Of Usvs: Implications For Research Mementioning

confidence: 99%

Developmental differences in temporal patterns and potentiation of isolation‐induced ultrasonic vocalizations: Influence of temperature variables

Kraebel

Brasser

Campbell

et al. 2002

Developmental Psychobiology

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The present study examined the relationship between the thermal environment and core body temperature in producing age-related patterns of ultrasonic vocalizations (USVs). Implanted telemetry devices allowed on-line measurement of core body temperature during an extended period of isolation and after maternal contact, both as a function of age and thermal environment. At 12 or 17 days of age, rat pups were isolated for 30 min in either a cool or a warm environment, returned home for 5 min, and then re-isolated for 10 min. Number of USVs, body temperature, and behavioral activity were measured. During initial isolation in a cool environment, 12-day-olds displayed relatively stable patterns of ultrasounding and body temperature across time whereas older animals showed a time-dependent increase in USV calling and in core temperature. During re-isolation, 12-day-olds potentiated their USV calling at both ambient temperatures while 17-day-olds did not. The overall results suggest a strong dependence between USV calling, core body temperature, and ambient temperature during initial isolation at both ages-a finding in agreement with interpretations of USVs as an acoustic by-product of thermal challenge. In contrast, during re-isolation, USV calls, core body temperature, and ambient temperature functioned independently-a finding in agreement with interpretations of USVs as a representation of an emotional state.

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The effect of periaqueductal gray lesions on responses to age-specific threats in infant rats

Cited by 35 publications

References 36 publications

Rat pups reduce ultrasonic vocalization after exposure to an adult male rat

Rat pups reduce ultrasonic vocalization after exposure to an adult male rat

The Role of the Amygdala and Olfaction in Unconditioned Fear in Developing Rats

Developmental differences in temporal patterns and potentiation of isolation‐induced ultrasonic vocalizations: Influence of temperature variables

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