BCS 282 Lecture 18

Brain Functioning

• Regions associated with fear conditioning and extinction (e.g. increased amygdala activation and decreased medial prefrontal cortex activation)

• Both amygdala and MPC are connected to the hippocampus, which is closely associated with conditioned fear and associative learning

• “HPA axis” - hippocampus + pituitary gland + adrenal gland: implicated in stress reaction and regulation of emotions

Three primary brain regions affected by PTSD and their functions

• Prefrontal cortex

• Amygdala

• Hippocampus

Cortisol and the HPA Axis

The HPA Axis

• Neuroendocrine system that plays a significant role is stress response

• Overactivation of the HPA axis for prolonged period of time can lead to impairments in cortisol production

  • Hypo vs hyperactivation → changes in individual’s response stress

• Findings about how exposure to trauma impacts the HPA Axis are inconsistent

  • Many cases where exposure to trauma results in less cortisol

Psychosocial Models - Classical Conditioning and Extinction

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The Dose-Dependent Response/Stress-Dose Model

• Severity, duration, and proximity to a traumatic event, or “dose” of trauma exposure, determines who will and who will not develop PTSD

Impaired Fear Extinction Hypothesis

• Individuals who develop chronic PTSD have impairments in learning new inhibitory associations to trauma-related reminders

• Seen the the failure of natural recovery after trauma response

Memory Processing Models

• Memory processing: how we encode, store, and later retrieve memories

  • In PTSD, recall of traumatic events may occur via two pathways: (1) contextual representations (consciously accessible) and (2) Sensory representations (inflexible, involuntary, disintegrated from broader memory, connected to amygdala and insula)

  • Therapy, from this POV, involved an integration of these two domains

  • Empirical validation for memory fragmentation in PTSD is weak

Cognitive Models

• Maladaptive beliefs about the traumatic event, the broader world, and self causal in the PTSD

• One has to make sense of the event, drawing from one’s “autobiographical” knowledge; however, one can focus on the details of the experience (e.g. sensory cues) without appreciation of broader context. Memories can be intrusive and threatening, so one engages in rumination, thought suppression, and avoidance are helpful in short-term but prevent adaptation

Perceptual Priming

Blurred picture paradigm: participants w/PTSD recognized trauma-related, blurred pictures more readily than neutral pictures, relative to controls

Attention

• Emotional stroop test - persons with PTSD take longer to respond to items related to threats

• Working memory impaired in PTSD

  • Participants take longer to read out negative words (like hate or depressed) than normal words like exam or sky

Emotional Processing Models

• One view - inability to integrate traumatic event into existing cognitive schema

• Pathological “fear structures” (e.g. responses that are not amenable to modification)

  • Fear structure: associative networks for escaping danger; includes information about the stimulus, responses, and their meanings

  • Avoidance behaviors thought to prevent individuals from accessing the fear structure and learning information that would correct the abnormal, pathological elements of the network

• Interventionists recognize that the client may have belief that world is unrealistically dangerous and/or that he/she is overly incompetent

Complex PTSD

• Repeated exposure to traumatic events (e.g., domestic violence, human trafficking) disrupts normal developmental attachment, cognition, attachment to others

• Empirical record is mixed as to whether this stands as a unique disorder

  • Consider: 300,000 to 450,000 unaccompanied minors were encountered at the Southern Border between 2021-2023. Many of these children experienced repeated exploitation, enroute and after arrival

Treatment of PTSD

• CBT - e.g. exposure and cognitive restructuring

• Conversely, treatments that do not focus on trauma/reaction to trauma not particularly effective (relaxation, counseling)

• Exposure therapy - in vivo and imaginal - “revisiting” and reinterpreting events

• Eye movement desensitization and reprocessing (EMDR) - appears to be a helpful adjunct, thought underlying mechanism is poorly understood

• Narrative exposure therapy - repeated exposure to memories and created of a written narrative that may be shared

Clear demonstration of potential of effectiveness

Moderator variables of interest

• Younger people have more success than older adults

• Lack of substance abuse of psychiatric medication

• Civilians are more likely to benefit substantially compared to military

• Natural disaster/transportation trauma vs other types of trauma

• Individual vs group therapy

Schizophrenia Spectrum and Other Psychotic Disorders

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Schizophrenia

• Onset typically during youth adulthood (i.e., about 25)

• About 1% of population around the world

• Etiology is complex and appears varied across individuals

• Conceptualized as a brain disease with genetic/environmental factors at play

• Brain maturational processes play a role in emergence of disorders

Brief Historical Notes

• Mid-29th century - “psychosis” - symptoms consistent with schizophrenia and mood disorders with psychotic features

• Syphilis - infection of brain CNS and treated with antibiotics

• Emil Kraepelin - “dementia praecox”(i.e., “dementia of the young”; included “hebephrenia”, “paranoia”, and “catatonia”

“Schizophrenia”

• “Schizo” - tear or split

• “Phren” - one’s intellect

  • Literally, a tearing of one’s mind and emotional stability

Bluelar’s Fundamental Symptoms of Schizophrenia

• Disturbance of association (loose, illogical thought processes)

• Disturbances of affect (indifference, apathy, or inappropriateness)

• Ambivalence (conflicting thoughts, emotions, or impulses which are present simultaneously or in rapid succession)

• Autism (detachment from social life with inner preoccupation)

• Abulia (lack of drive or motivation)

• Dementia (irreversible change in personality)

Belular's "Accessory Symptoms”

• Allocations

• Movement disturbances

• Somatic symptoms

• Manic and melancholic states

• Delusions 

  • Fixed false beliefs cannot be coerced by logic and are not consistent with culture and education of the patient

• Hallucination

  • False sensory perception experienced without real external stimulus. They are usual experiences as originated in the outside world not within the mind as imagination

• Illusions

  • Misperception of real external stimulus. Most likely to occur when general level of sensory stimulation is reduced