Basolateral Amygdala Essay

The Role of the Frontal Lobes Table of Contents 1 Introduction_ 3 2 The Structure and Functional Anatomy of the Frontal Lobes 3 2.1 Figure 1. A diagrammatic representation of the brain_ 5 3 Luria’s Model of Brain Function_ 5 4 The Complex Function of Frontal Lobes 6 5 No Longer En-Gage-ing; What Happens When The Frontal Lobes Go Wrong?

Fear is just an Illusion; One that most innocent people can not control. Fear comes to a person when the person does not know what to do and is in an helpless position or in other words insecure. Unfortunately according to many sources a lot of human fear is based on social anxieties and threats. When someone puts one in a situation the person receiving the situation can not control it triggers hyperactivity in the amygdala which causes them to think irrationally. Without knowing what to do these innocent souls end up making the wrong decision and possibly ruin their lives.

Psychiatrists hypothesis that hippocampal dysfunctioning showed the anatomic basis for alteration in memory like fragmentation and delayed recall of traumatic memories of childhood abuse. 3 Based on a research made by David de Wied, the anterior pituitary gland is the primary site of action for glucocorticoid dexamethasone: a potent synthetic glucocorticoid, a blocking substance or suppressor of stress-induced ACTH. And the medial basal hypothalamus is the site for both synthetic and natural occurring glucocorticoid (corticosterone and aldosterone; stress inducers). Corticosterone acts more than hypothalamus in the brain, and there are different modes of actions of dexamethasone and Corticosterone in the brain. The accumulation of dexamethasone in the pituitary cotrophs determine the hyperactive and the dysfunctioning of the hypothalamus- pituitary-adrenal axis commonly found in depressive patients.

The brain develops in such a way that it leaves itself vulnerable to these negative influences. The prenatal brain develops an overabundance of neurons, some of which are then carefully eliminated before age 4 (5). In a process similar to this, the amount of synapses between neurons is built up during early childhood and then pruned back for the next 30 years of life (5). These two processes are both disturbed by elevated levels of stress hormones (5). The two centers of the brain with the most postnatal changes, including the growth of new neurons after birth, are the hippocampus, which is part of the limbic system, and the cerebellar vermis (6). The hippocampus is in charge of creating and retrieving memories, working together with the other parts of the limbic system, such as the amygdala, which records the emotions for each memory. The vermis controls the production and release of two of the catecholamine neurotransmitters, dopamine and norepinephrine (6). Both the vermis and the limbic system have higher concentrations of receptors for the stress hormone cortisol than anywhere else in the brain (6). Due to this fact, these still-developing areas are the most vulnerable to the damage done by elevated levels of stress hormones.

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.

Damage done from trauma on the neurological functioning of the brain can be widespread, but can be found to interfere with functioning of the hippocampus and the limbic system to a greater extent. Randall (2011) explained that when a large amount of stress is continually placed on the brain from ongoing trauma, cortisol, a fight or flight response chemical, can fail to stop firing when the stressor that ignited the cortisol is no longer present. This excess of cortisol impairs the brains ability to function properly (Randall, 2011). Andersen, Tomada, Vincow, Valente, Polcari, Teicher (2008) found that women who had experienced sexual abuse during childhood actually had a difference in the volume of their hippocampus (as cited in Pechtel and Pizzagalli, 2011). The region which controls memory and emotional regulation was found to be smaller in the women who had been sexually abused in early childhood in comparison to

The amygdala is the name of the collection of nuclei found in the frontal portions of the temporal lobes in the brains of all primates (the term Amygdala derives from the Greek word, αμύγδαλο or amýgdalo meaning almond). This collection of nuclei is a small almond shaped structure located on either side of the thalamus at the lower end of the hippocampus in the limbic system which is located in the frontal portion of the temporal lobe. Considering the human brain is bilaterally symmetrical, there are two amygdalae, both located in relatively the same place, but one in the left side of the brain, and one in the right side of the brain. Although this structure is merely as big as an almond, there are vast amounts of functions that begin and travel

They were then tested on the morris water maze and found the distance taken to travel and find the platform decreased from first trials to second trials indicating better short term spatial learning while the measurement in long term spatial learning the socially stressed rats were swimming longer distances to get to the platform between first and second sessions. Which suggests that long term spatial memory in the morris water maze was impaired. This experiments indicate that exposure to social insabilty stress only impaired long term spatial memory and not short term spatial memory in the morris water maze. This current study after rats were exposed to the stress were placed back into their housing with another rat that was also exposed to the stress procedure but exposure the rat may be some sort of coping mechanism for the rats and that might be as to why the stress didn’t effect short term spatial memory in the morris water maze. As well this study is focusing on social stress by isolating the rats but by exposing them to another rat in the same housing they were before exposure to the stress may make the rats bond as they both were exposed to the stress which could mitigate the prior stress exposure. In addition short term memory might not have been effected due to stresses ability to effect distinct memory systems

The adult brain is described as the brain to think by feeling. We are feeling machines that think. Hardships that effect the brain can be post-traumatic stress disorder (PTSD), depression, and stroke. The brain reacts in different ways, especially in the adult brain. When the brain encounters a stroke, it cannot process emotions because there are no neurons functioning. Generally, when the brain encounters an emotional event, the amygdala is the first brain structure to respond. The role of the amygdala and the brain stem when responding to an emotional event is working together to get a response through the body. The nerve impulse travels from the amygdala down the brain stem; without each other, the body would not function right. Although

For example, Faraji et al (2008) proposes that the hippocampus is substantial to spatial learning and memory. In this study, rats with widespread hippocampus damage have their spatial learning memory tested through the use of spatial cues which navigate them to a food reward. Findings show the storage of spatial- location memory was poorer in those with hippocampus damage, contrary to healthy controls. This meant that the affected rats took more time to locate the food when given spatial cues compared to the healthy rats. Whereas, without cues- trial by trial- it took the duration of ten days to locate food. This suggests that spatial-location is remarkably dependent on the health of the

“The ‘stress hormone’ cortisol is believed to create a domino effect that hard-wires pathways between the hippocampus and amygdala in a way that might create a vicious cycle by creating a brain that becomes predisposed to be in a constant state of fight-or-flight” (Bergland, 2014).

The hypothalamus is a section of the brain that is responsible for the production of the body’s hormones and chemical substances that help control different cells and organs. The hormone from the hypothalamus control the functions like regulation of the temperature causing cold and hot flashes, thirst, hunger, sleep, mood, sex drive, and the release of other hormones within the body.

Therefore, some previous studies hypothesized that these brain regions, especially within the emotional corticolimbic system, acted as the bridge of pain modulation and stress regulation5.

The Amygdala is apart of the Limbic system its primary function is that it influences our emotional control, motivation, fear response and interpretations of nonverbal emotional expressions (facial and bodily expressions) (Ciccarelli & White, 2014). For some reason, explained by many but I'm going off of the book and one other source with two differing opinions on how the amygdala is involved with fear and the memory of (Ciccarelli & White, 2014).