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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

The volume of the hippocampus and cortex was significantly reduced in WKY compared to SD rats. In contrast, strain differences were not observed for striatum and corpus callosum.
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Figure 4: The volume of the hippocampus and cortex was significantly reduced in WKY compared to SD rats. In contrast, strain differences were not observed for striatum and corpus callosum.

Mentions: Because SD rats with hippocampal damage mimicked the persistent avoidant behaviors of WKY rats, we investigated whether WKY rats might have an abnormal hippocampus as demonstrated by a smaller hippocampus and impaired hippocampal synaptic plasticity. Hippocampal and cortical volume was reduced in WKY rats compared to SD rats (Figure 4). The volume of the hippocampus, neocortex, corpus callosum, and striatum was estimated using the Cavalieri method. Regional brain volumes in WKY rats differed from SD rats [main effect of strain, Wilks’ Lambda, F(4,5) = 6.348, p < 0.05]. WKY rats had significantly smaller hippocampus [F(1,8) = 25.396, p < 0.01] and cortex [F(1,8) = 9.017, p < 0.05] compared to SD rats (Figure 4). Corpus callosum and striatum were not different between strains.


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)

The volume of the hippocampus and cortex was significantly reduced in WKY compared to SD rats. In contrast, strain differences were not observed for striatum and corpus callosum.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: The volume of the hippocampus and cortex was significantly reduced in WKY compared to SD rats. In contrast, strain differences were not observed for striatum and corpus callosum.
Mentions: Because SD rats with hippocampal damage mimicked the persistent avoidant behaviors of WKY rats, we investigated whether WKY rats might have an abnormal hippocampus as demonstrated by a smaller hippocampus and impaired hippocampal synaptic plasticity. Hippocampal and cortical volume was reduced in WKY rats compared to SD rats (Figure 4). The volume of the hippocampus, neocortex, corpus callosum, and striatum was estimated using the Cavalieri method. Regional brain volumes in WKY rats differed from SD rats [main effect of strain, Wilks’ Lambda, F(4,5) = 6.348, p < 0.05]. WKY rats had significantly smaller hippocampus [F(1,8) = 25.396, p < 0.01] and cortex [F(1,8) = 9.017, p < 0.05] compared to SD rats (Figure 4). Corpus callosum and striatum were not different between strains.

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