Amygdala-Lesion Case Study

Due to its primary role in processing memory and emotional reactions, over the last decade and a half psychologists have been linking the amygdala to psychopathy. It is involved in aversive conditioning and instrumental learning and is thus involved in all the processes that, when impaired, produce the same functional impairments displayed by psychopaths. Two famous studies conducted by Tiihonen and Kiehl respectively have confirmed this. Tiihonen used a volumetric MRI to test and confirm the positive correlation between low amygdaloid volume and a high degree of psychopathy in violent criminals (measured by the Hare checklist-revised) while Kiehl used a functional MRI to prove reduced amygdala response during an emotional memory task in individuals who scored high on the Hare checklist-revised. However, both these studies along with numerous others were conducted using violent offenders as subjects rather than individuals with psychopathy. Although many psychopaths do exhibit violent tendencies, not all violent offenders are necessarily psychopaths. A study conducted by Raine is one of the few that did focus only on individuals exhibiting psychopathy. In his study Raine was able to show reduced prefrontal grey matter in his test subjects. Unfortunately though, he was unable to differentiate between grey matter in different regions of the prefrontal cortex. It is however clear that there is one region of the frontal cortex that could be

In Chapter 8 “Where the Wild Things Are,” the author Le Doux looked at the how our brain regions and systems functioned during the development of anxiety disorders. He introduced many researchers’ ideas and theories such as Pavlovian conditioning and instrumental conditioning; then, he listed the brain regions that were associated with anxiety and fear conditioning such as hippocampus, amygdala, sympathetic nervous system, and various brain cortexes. He also explained how our brain became conditioned for different anxiety disorders.

Because of Patient SM’s condition, she has been harmed, held at gunpoint, and has even had history of being involved in domestic violence. She does not have the capability to learn from the situations she has been through. The amygdala is very important and it is also the reason why we connect fearful stimuli to a particular situation. Therefore, Patient SM lacks the ability to connect the stimulus and memories she has obtained through these situations.

The amygdala specializes in threat detection, fear, excitement, and arousal, hippocampus helps format long-term declarative memories and spatial reasoning. The anterior cingulate cortex influences autonomic function, decision making, error detection and emotion while the posterior has a role in spatial annotations memory. The septal area produces pleasurable feeling,

The amygdala of psychopaths have has been found to be hypoactive during fear conditioning (Birbaumer et al., 2005), moral decision-making (Glenn, Raine, & Schug, 2009), and social cooperation (Rilling et al., 2007). As expected, studies have also found the amygdala to be hypoactive in response to fearful faces or other affect-related activity (e.g. Carré et al., 2013; Kiehl et al., 2001). Nevertheless, Müller et al. (2003) found that psychopaths had increased activation in the amygdala (in addition to increased prefrontal activation) when viewing negative content (e.g. pictures of threatening animals, wounded people) which they interpreted as reflecting abnormal prefrontal – amygdala communication.” (Umbach et al., 2015,

The term ‘amygdala’ was first used by Burdach (1819) and referred to a set of nuclei in the brain (Aggleton & Saunders, 2000). In 1939, researchers Klüver & Bucy inflicted bilateral lesions of the inferior temporal lobe of monkeys in a laboratory in an attempt to reduce aggression. These lesions affected the cortical areas, amygdala, and the hippocampus. Later this became known as Klüver-Bucy syndrome, and consisted of symptoms such as psychic blindness, hypermetamorphsis, oral tendencies, and changes in emotional and sexual behaviors. Lesions of the amygdala made monkeys fearless of e.g. humans or snakes, and affectively flat, tame. This research brought recognition to the notion that the amygdala plays a significant role in the

There are three different theories that are used when talking about how we react to stress through the physiological aspect or the psychological aspect. The first is part of the physiological aspect of stress called the Cannon Fight or Flight theory which was proposed in 1914. Fight or Flight response is a physiological stress response that evolved to help organisms to survive immediate danger. The theory states that when an organism, human being or animal, faces imminent danger (acute stressor) the body arouses quickly and is ready to act via two different systems. They are the sympathetic nervous system and the endocrine system. The sympathetic nervous system stimulates the adrenal medulla which is part of the endocrine system and is the region that produces the hormones such as adrenaline and noradrenaline. These hormones increase heart rate, blood flow, and glucose levels to prepare the body for an emergency. This response from the body suggests that the body knows how to protect itself and reach homeostasis. These two systems work together to either fight against the danger or flight away from the danger. Lord, King and Pfister in 1976 studied the Fight or Flight response in animals through a very unethical study. They administered chemicals on male hooded Wistar rats which inhibited the neurotransmitters from functioning normally. This made it very difficult for the rats to escape an electric shock. The results of the study suggest that the Flight or Fight response

Throughout the course of this semester we have examined numerous issues which have all had different implications for the brain = behavior argument. Some who have been skeptical of the validity of this idea have been swayed by observations that processes and behaviors they originally thought to have a cloudy neurobiological basis in fact have a sound biological and physiological underpinning. One such phenomenon which can help elucidate the ongoing brain = behavior debate is Post-Traumatic Stress disorder, or PTSD. Most people are familiar in some sense with the phenomenon of PTSD. This phenomenon has been renamed, reworked, and redefined numerous times over the past

Studying parts of the brain that are involved in dealing with fear and stress also helps researchers understand possible causes of PTSD to begin formulating a plan to treat PTSD. The amygdala is known for its role in emotion, learning, and memory. The amygdala appears active in learning to fear an event as well as in the early stages of fear extinction. In storing extinction memories and dampening an existing fear the prefrontal cortex, which is involved in problem solving, decision making, and judgement, is seemingly

On the brain of a mammal, once external stimuli affects a person, pressure is put on the paraventricular nucleus of the thalamus. The paraventricular thalamus (PVT) is a stress sensor that is activated once influenced by physical and psychological stressors. Studies show that the paraventricular nucleus of the thalamus controls a part of the amygdala, and the interaction between the neurons of the central amygdala and the paraventricular nucleus of the thalamus is a step towards modulation of fear as it forms a stable foundation of fear memory and manifestation of response to fear.

Two structures in the brain work independently and with each other to impact memory and emotions: the amygdala and the hippocampus. The amygdala is linked to fear-conditioning, while the hippocampus is linked to episodic memories, which are those memories that a person can recall whenever wanted [1]. An experiment was performed to demonstrate the independence of the two structures from each other which involved patients with lesions in the amygdala and patients with lesions in the hippocampus. Researchers designed a fear-condition wherein a blue patch applied to the wrist initiated a shock. They found that patients with lesions in the amygdala had no physiological response to the conditioned stimulus (the blue patch) [2], whereas patients with lesions in the hippocampus demonstrated appropriate

Amygdala hypo-responsiveness tends to indicate a limbic structure dysfunction leading to reduced responsiveness to fearful faces. This often manifests as a lack of empathy and failure to control aggressive behavior owing to impairment in recognition of distress cues from others.

The importance of the amygdala in social cognitions has been examined in both primate and human studies. Use of primates to study the social brain suggests that the amygdala contributes to social cognition. Kluver and Bucy made large bilateral lesions in monkey brains made across the amygdala, temporal neocortex, and surrounding structure. After the lesion, the animals engaged in hypersexual behaviors, unusual tameness, and a lack of knowledge about emotional stimuli. Lesions exclusively targeting the monkey’s amygdala resulted in similar, but more subtle impairments. This suggest that the amygdala may play a role in emotions elicited by social cues. Studies of the amygdala’s role in human social cognition suggest that the temporal lobes process socially relevant facial information from humans. Emotions from facial expressions, in particular fear are projected to the amygdala. Studies using FMRI to examine typical subjects and subjects with amygdala damage support this theory. Individuals with amygdala damage have difficulty recognizing facial expressions, specifically negative emotions such as fear.

When I first began to read this article the first thing that popped in my head was the movie “Minority Report.” In this movie people were incarcerated for crimes that they did not yet commit because people believed that three individuals could foresee the future. Which to some extent I believe that brain pathology and neurocriminology. Yes, there have been studies where some criminal’s brains function differently than a normal individuals. However, there needs to be a lot more research done because not everyone who may have these same disorders are going to make the same decision on becoming a criminal. In the article they say that there are many different factors that could influence an individual into a life of crime such as environment,

The amygdala is responsible for our emotional memories. Damage to the amygdala could impact us negatively causing us to misinterpret our memories and our emotions related to those memories. What should cause fear and anger could be diminished to a point that could cost you significantly if the amygdala is damaged. For example, if you don’t remember a negative emotion with a certain action in a memory of the past that has impacted you negatively, you might continue to make the same mistakes over and over again. By taking the same actions without causing you any fear and anxiety of loss or damage could cause you major negative effects in your