Volumetric Analysis of Amygdala, Hippocampus, and Prefrontal Cortex in Therapy-Naive PTSD Participants

Abstract

Objective. In our study we have hypothesized that volume changes of amygdala, hippocampus, and prefrontal cortex are more pronounced in male posttraumatic stress disorder participants. Material and Methods. We have conducted a study of 79 male participants who underwent MRI brain scanning. PTSD diagnosis was confirmed in 49 participants. After MRI was taken all scans were software based volume computed and statistically processed. Results. We found that left amygdala is the most significant parameter for distinction between PTSD participants and participants without PTSD. There were no significant differences in volumes of hippocampi and prefrontal cortices. Roc curve method outlined left amygdala AUC = 0.898 (95% CI = 0.830–0.967) and right amygdala AUC = 0.882 (95% CI = 0.810–0.954) in the group of PTSD participants which makes both variables highly statistically significant. Conclusion. The present investigation revealed significant volume decrease of left amygdala in PTSD patients. Concerning important functions of the amygdala and her neuroanatomical connections with other brain structures, we need to increase number of participants to clarify the correlation between impared amygdala and possible other different brain structures in participants with PTSD.

Nociception, Pain, Negative Moods, and Behavior Selection

“…Moreover, medial prefrontal cortex connectivity to the nucleus accumbens has become a primary neurosurgical stimulation target for treating intractable depression (Mayberg et al, 2005; Ressler and Mayberg, 2007) with the intention of modulating properties of the corticostriatal circuit. Decreases in hippocampus and amygdala volumes have also been described in post-traumatic stress (PTSD) (Chao et al, 2013; Chao et al, 2014; Gilbertson et al, 2002; Starcevic et al, 2014), and white matter microstructural predispositions in PTSD indicate that such structural differences reflect long-term vulnerability (Sekiguchi et al, 2014), as also observed for chronic back pain (Mansour et al, 2013). In humans, amygdala response properties seem to indicate risk for developing PTSD (McLaughlin et al, 2014), and in rodents, susceptibility to stress response is dependent on hippocampal volume and functional processing (Nalloor et al, 2014; Tse et al, 2014).…”

Structural Brain Changes in PTSD

“…Various MRI techniques are available for clinical use such as fast spin echo, high-performance gradients, echo planar, and diffusion weighted imaging. In a study of male therapy-naïve participants with PTSD, Starcevic et al [12] performed the scanning using a 3.0 T whole-body scanner (Philips Medical Systems, Best, The Netherlands). After the scanning, all the participants were coded in order to blind the volumetric evaluation team, and sent for the subsequent volumetric analysis.…”

“…The exposure to a traumatic event results in autonomic activation, after which the amygdala evaluates information and, depending on that assessment, determines the emotional significance of the entrance and triggers a structure such as hypothalamus, hippocampus, and basal prosencephalon, which then determines the behavioral, autonomic and neurohormonal function and its manifestation. In a study conducted on forty-nine male patients, Starcevic et al [12], found that both left and right amygdala volumes were statistically significantly different between individuals with PTSD and individuals without PTSD, with the emphasis on the volume of the left amygdala as more significant. LeDoux [21] discovered the crucial role of the amygdala in the emotional brain, which he called neural alarm, which can take control over behavior even when the prefrontal cortex is still at the stage of selecting an equal reaction to external stimulation.…”

Psychotherapy for PTSD: Neuroimaging of Recovery Processes

“…44 Other studies, including some in combat veterans, have not found volume differences in this structure. 11,37,39,[45][46][47] A challenge in this area of research has been to distinguish whether a smaller hippocampus is a risk factor for PTSD or is acquired after trauma. The inverse correlation noted above between PTSD duration and hippocampal volume could indicate an effect of PTSD or could indicate a risk factor for development of persistent symptoms.…”