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The role of the hippocampus in avoidance learning and anxiety vulnerability.

Cominski TP, Jiao X, Catuzzi JE, Stewart AL, Pang KC - Front Behav Neurosci (2014)

Bottom Line: In the current study, we examined the effect of hippocampal damage in avoidance learning, as avoidance is a core symptom of all anxiety disorders.The WKY rat is an animal model of behavioral inhibition, a risk factor for anxiety, and demonstrates abnormal avoidance learning, marked by facilitated avoidance acquisition and resistance to extinction.These results suggest that hippocampal dysfunction enhances the development of persistent avoidance responding and, thus, may confer vulnerability to the development of anxiety disorders and PTSD.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Neurosciences, Rutgers - New Jersey Medical School, Rutgers, The State University of New Jersey , Newark, NJ , USA.

ABSTRACT
The hippocampus has been implicated in anxiety disorders and post-traumatic stress disorder (PTSD); human studies suggest that a dysfunctional hippocampus may be a vulnerability factor for the development of PTSD. In the current study, we examined the effect of hippocampal damage in avoidance learning, as avoidance is a core symptom of all anxiety disorders. First, the effect of hippocampal damage on avoidance learning was investigated in outbred Sprague Dawley (SD) rats. Second, the function of the hippocampus in Wistar-Kyoto (WKY) rats was compared to SD rats. The WKY rat is an animal model of behavioral inhibition, a risk factor for anxiety, and demonstrates abnormal avoidance learning, marked by facilitated avoidance acquisition and resistance to extinction. The results of the current study indicate that hippocampal damage in SD rats leads to impaired extinction of avoidance learning similar to WKY rats. Furthermore, WKY rats have reduced hippocampal volume and impaired hippocampal synaptic plasticity as compared to SD rats. These results suggest that hippocampal dysfunction enhances the development of persistent avoidance responding and, thus, may confer vulnerability to the development of anxiety disorders and PTSD.

No MeSH data available.


Related in: MedlinePlus

Avoidance acquisition and extinction following hippocampal and entorhinal cortex lesion and in WKY rats. Hippocampal and entorhinal cortex lesions did not alter avoidance acquisition (A). Rats with hippocampal lesions were impaired in extinction learning compared to sham controls (A). Acquisition of avoidance in WKY rats did not differ from SD rats (B). WKY rats exhibited a trend toward impaired extinction of avoidant responding (B). Although all six groups were statistically analyzed together, lesion (A) and unoperated (B) groups are displayed separately for clarity.
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Figure 2: Avoidance acquisition and extinction following hippocampal and entorhinal cortex lesion and in WKY rats. Hippocampal and entorhinal cortex lesions did not alter avoidance acquisition (A). Rats with hippocampal lesions were impaired in extinction learning compared to sham controls (A). Acquisition of avoidance in WKY rats did not differ from SD rats (B). WKY rats exhibited a trend toward impaired extinction of avoidant responding (B). Although all six groups were statistically analyzed together, lesion (A) and unoperated (B) groups are displayed separately for clarity.

Mentions: Hippocampal and entorhinal cortex lesions did not alter acquisition of avoidance (Figure 2A). Similarly, acquisition of avoidance in WKY rats did not differ from SD rats (Figure 2B). Rats from all groups increased avoidance responding with training [Figure 2; main effect of session: F(11,495) = 30.55, p < 0.001]. Acquisition of avoidance did not differ between lesion groups nor between strains [main effect of lesion/strain, F(5,45) = 1.91, p = 0.111; session × lesion/strain interaction, F(55,495) = 1.14, p = 0.237] (Figures 2A,B).


The role of the hippocampus in avoidance learning and anxiety vulnerability.

Cominski TP, Jiao X, Catuzzi JE, Stewart AL, Pang KC - Front Behav Neurosci (2014)

Avoidance acquisition and extinction following hippocampal and entorhinal cortex lesion and in WKY rats. Hippocampal and entorhinal cortex lesions did not alter avoidance acquisition (A). Rats with hippocampal lesions were impaired in extinction learning compared to sham controls (A). Acquisition of avoidance in WKY rats did not differ from SD rats (B). WKY rats exhibited a trend toward impaired extinction of avoidant responding (B). Although all six groups were statistically analyzed together, lesion (A) and unoperated (B) groups are displayed separately for clarity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4125878&req=5

Figure 2: Avoidance acquisition and extinction following hippocampal and entorhinal cortex lesion and in WKY rats. Hippocampal and entorhinal cortex lesions did not alter avoidance acquisition (A). Rats with hippocampal lesions were impaired in extinction learning compared to sham controls (A). Acquisition of avoidance in WKY rats did not differ from SD rats (B). WKY rats exhibited a trend toward impaired extinction of avoidant responding (B). Although all six groups were statistically analyzed together, lesion (A) and unoperated (B) groups are displayed separately for clarity.
Mentions: Hippocampal and entorhinal cortex lesions did not alter acquisition of avoidance (Figure 2A). Similarly, acquisition of avoidance in WKY rats did not differ from SD rats (Figure 2B). Rats from all groups increased avoidance responding with training [Figure 2; main effect of session: F(11,495) = 30.55, p < 0.001]. Acquisition of avoidance did not differ between lesion groups nor between strains [main effect of lesion/strain, F(5,45) = 1.91, p = 0.111; session × lesion/strain interaction, F(55,495) = 1.14, p = 0.237] (Figures 2A,B).

Bottom Line: In the current study, we examined the effect of hippocampal damage in avoidance learning, as avoidance is a core symptom of all anxiety disorders.The WKY rat is an animal model of behavioral inhibition, a risk factor for anxiety, and demonstrates abnormal avoidance learning, marked by facilitated avoidance acquisition and resistance to extinction.These results suggest that hippocampal dysfunction enhances the development of persistent avoidance responding and, thus, may confer vulnerability to the development of anxiety disorders and PTSD.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Neurosciences, Rutgers - New Jersey Medical School, Rutgers, The State University of New Jersey , Newark, NJ , USA.

ABSTRACT
The hippocampus has been implicated in anxiety disorders and post-traumatic stress disorder (PTSD); human studies suggest that a dysfunctional hippocampus may be a vulnerability factor for the development of PTSD. In the current study, we examined the effect of hippocampal damage in avoidance learning, as avoidance is a core symptom of all anxiety disorders. First, the effect of hippocampal damage on avoidance learning was investigated in outbred Sprague Dawley (SD) rats. Second, the function of the hippocampus in Wistar-Kyoto (WKY) rats was compared to SD rats. The WKY rat is an animal model of behavioral inhibition, a risk factor for anxiety, and demonstrates abnormal avoidance learning, marked by facilitated avoidance acquisition and resistance to extinction. The results of the current study indicate that hippocampal damage in SD rats leads to impaired extinction of avoidance learning similar to WKY rats. Furthermore, WKY rats have reduced hippocampal volume and impaired hippocampal synaptic plasticity as compared to SD rats. These results suggest that hippocampal dysfunction enhances the development of persistent avoidance responding and, thus, may confer vulnerability to the development of anxiety disorders and PTSD.

No MeSH data available.


Related in: MedlinePlus