Consequences of ptsd and memory processing
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The hypothesis of testing consequences of trauma on cellular level in brain ; either it deteriorates connectivity, dendritic extensions and synaptogenesis !
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Consequences of ptsd and memory processing
- 1. Consequences of PTSD and Memory Processing on Neural Structures: Can Psychotherapy Influence Dendritic Reformation? Dr Hena Jawaid Waliyah Mughis
- 2. Disclosure The purpose of our research is to explore all the possibilities and potential of psychotherapy on a molecular level. The aim is not to discourage or diminish the importance of medication, but to further discover other avenues that can be used in conjunction with SSRIs and other medications.
- 3. Session outline • Understanding neural structures • Understanding hippocampal function in trauma processing • The role of psychotherapeutic interventions at a molecular level • Study aims and objectives • Hypothesis • Discussion on neuroimaging
- 4. The neuron Dendritic spine dynamics (Kasai et al, 2010)
- 5. The hippocampus in trauma The hippocampus is involved in explicit memory processing (Tsien et al, 2013) and contextual retrieval of fear-related memories (Corcoran & Maren, 2001; Corcoran et al, 2005).
- 6. PTSD and the hippocampus • Reduction in size of hippocampal neurons? Glucocorticoids Energy utilization • Reduction in size of hippocampal neurons? Glucocorticoids Energy utilization
- 7. PTSD and the amygdala • Processing of fear • Hyper vigilance • Negative appraisal • Processing of fear • Hyper vigilance • Negative appraisal
- 8. PTSD and the mPFC • Hyporesponsive • Regulates extinction of fear conditioning • Hyporesponsive • Regulates extinction of fear conditioning
- 10. Role of psychotherapy in emotional reprocessing • Cognitive processing therapy and prolonged exposure • Regulates emotions through memory channelization • Modes used: reading, writing, recounting events to themselves or to their therapists • Retrieval, reprocessing, reimagination, reinforcement, rehearsal • Facilitating reprocessing: Critical incident stress debriefing, CBT, exposure, eye movement desensitization, reprocessing therapy
- 11. Our hypothesis • Can emotional/memory reprocessing help with – Dendritic reformation – Cell body growth – Synaptogenesis in the hippocampus • Through retrieval, reimagination, exposure • With emotionally charged memories being appropriately processed & discharged, can dendritic connections be reformed?
- 12. Abstract Traumatic events such as assault, abuse, war and violence can impact the human brain both structurally and functionally. Dendrites in the hippocampus are among some of the affected structures, as emotionally charged memories are stored in them before due processing in the cell bodies. If these memories are not appropriately processed in the hippocampus, individuals suffering from post-traumatic stress disorder experience intrusive thoughts, flashbacks and high stress levels as a result of the high emotional charge of such memories. In this paper we postulate that if trauma-related emotions can be discharged through psychotherapeutic techniques such as exposure and memory reprocessing, would there also be a structural or anatomical change in hippocampal neurons, such as reformation of aberrant dendritic extensions, followed by an improvement in synaptic conductance between neurons?
- 13. Feedback Neuroimaging – how to look at it •What kind of neuroimaging modalities can measure cell body growth and dendritic structures?
- 14. mMRI Molecular MRI of a mouse brain presenting acute inflammation in the right hemisphere.
- 15. mMRI • Proposed method: molecular MRI • Hengerer & Grimm, 2006: mMRI comprises the contrast agent-mediated alteration of tissue relaxation times for the detection and localisation of – molecular disease markers (such as cell surface receptors, enzymes or signaling molecules), – cells (e.g. lymphocytes, stem cells) or – therapeutic drugs (e.g. liposomes, viral particles)
- 16. References • Kasai et al, 2010, Structural dynamics of dendritic spines in memory and cognition. • Tsien et al, 2013, On initial brain activity mapping of episodic and semantic memory code in the hippocampus. • Corcoran et al, 2005, Hippocampal inactivation disrupts the acquisition and contextual encoding of fear extinction. • Corcoran & Maren, 2001, Hippocampal inactivation disrupts contextual retrieval of fear memory after extinction. • Mechanic, 1998, A comparison of normal forgetting, psychopathology, and information-processing models of reported amnesia for recent sexual trauma • Shin et al, 2006, Amygdala, medial prefrontal cortex and hippocampal function in PTSD. • Sadeh et al, 2014, Aberrant Neural Connectivity during Emotional Processing Associated with Posttraumatic Stress. • Van der Kolk et al, 1996, A general approach to treatment of posttraumatic stress disorder
Notes de l'éditeur
- Recent studies show that dendritic spines are dynamic structures. Their rapid creation, destruction and shape-changing are essential for short- and long-term plasticity at excitatory synapses on pyramidal neurons in the cerebral cortex. The onset of long-term potentiation, spine-volume growth and an increase in receptor trafficking are coincident, enabling a ‘functional readout’ of spine structure that links the age, size, strength and lifetime of a synapse. Spine dynamics are also implicated in long-term memory and cognition: intrinsic fluctuations in volume can explain synapse maintenance over long periods, and rapid, activity-triggered plasticity can relate directly to cognitive processes. Thus, spine dynamics are cellular phenomena with important implications for cognition and memory. Furthermore, impaired spine dynamics can cause psychiatric and neurodevelopmental disorders.
- It has been widely recognized that the understanding of the brain code would require large-scale recording and decoding of brain activity patterns. In 2007 with support from Georgia Research Alliance, we have launched the Brain Decoding Project Initiative with the basic idea which is now similarly advocated by BRAIN project or Brain Activity Map proposal. As the planning of the BRAIN project is currently underway, we share our insights and lessons from our efforts in mapping real-time episodic memory traces in the hippocampus of freely behaving mice. We show that appropriate large-scale statistical methods are essential to decipher and measure real-time memory traces and neural dynamics. We also provide an example of how the carefully designed, sometime thinking-outside-the-box, behavioral paradigms can be highly instrumental to the unraveling of memory-coding cell assembly organizing principle in the hippocampus. Our observations to date have led us to conclude that the specific-to-general categorical and combinatorial feature-coding cell assembly mechanism represents an emergent property for enabling the neural networks to generate and organize not only episodic memory, but also semantic knowledge and imagination.
- Robert M. Sapolsky (1986); GCs endanger hippocampal neurons by impairing their energy metabolism. Diminished volumes, neuronal integrity, and functional integrity of the hippocampus in PTSD (Shin et al, 2006). Ehlers 2004: Distressing and intrusive reexperiencing of the trauma is a hallmark symptom of posttraumatic stress disorder (PTSD; American Psychiatric Association, 1994). However, unwanted memories of trauma are not a sign of pathology per se. In the initial weeks after a traumatic experience, intrusive memories are common. For most trauma survivors, intrusions become less frequent and distressing over time. A central question for understanding and treating patients with PTSD is therefore what maintains distressing intrusive reexperiencing in these people. Three factors appear to be important: (1) memory processes responsible for the easy triggering of intrusive memories, (2) the individuals’ interpretations of their trauma memories, and (3) their cognitive and behavioral responses to trauma memories. Bremner, 1995 - Monkeys exposed to the extreme stress of improper caging have shown increased glucocorticoid release as well as damage to the CA2 and CA3 subfields of the hippocampus (10). Studies in a variety of animal species suggest that direct glucocorticoid exposure results in a loss of neurons and a decrease in dendritic branching in the hippocampus (11, 12) with associated deficits in memory function (13). The mechanism of action of glucocorticoid toxicity is probably through an increase in the vulnerability of neurons to the toxicity of excitatory amino acids (14–16).
- The amygdala’s function in the assessment of threat-based stimuli relates to the processing of fear conditioning. Due to the hyper-responsivity of the amygdala in PTSD cases, people tend to be hypervigilant and negatively appraise events or potential threats in their environment (Höistad et al, 2008).
- When the mPFC becomes hyporesponsive or traumatised or damaged, individuals suffering from trauma struggle to appropriately express and extinguish their fear responses to daily life stimuli (Hanson et al, 2015)
- A variety of the psychtherapeutic approaches to PTSD, all involving some form of exposure and trauma processing have been shown to be effective – exposure, stress inoculation training, cognitive processing therapy, EMDR, CPT, specifically designed for the treatment of PTSD resulting from sexual assault, consists of two integrated components: cognitive therapy and exposure in the form of writing and reading about the traumatic event (Resick, 1992; Resick & Schnicke, 1992, 1993). Resick et al 2002: exposure component consists of having clients write detailed accounts of the most traumatic incident(s) that they read to themselves and to the therapists. Clients are encouraged to experience their emotions while writing and reading
- Molecular magnetic resonance imaging A Hengerer, PhD1,* and J Grimm, MD2
- Molecular magnetic resonance imaging A Hengerer, PhD1,* and J Grimm, MD2