Essay Lab 8: Dorsal Periaqueductal Gray

The parabrachial nucleus is a center for regulation of physiologic manifestations of fear avoidance and anxiety 83. These connections develop information about whole body rotation and position with respect to gravity. This information is linked to threat assessment pathways via connections between parabrachial nucleus and the central nucleus of the amygdala 85. Connections between amygdala and superior colliculi and between amygdala and thalamus link visual and somatosensory inputs to threat assessment pathways 86. Sensory inputs and assessment of threat converge in the hippocampus, dorsolateral prefrontal cortex, the insula, and anterior cingulate. These four structures are components of both the limbic and the vestibular cortex 87. Vestibuloparabrachial network and amygdala-locus coeruleus outputs

In addition, heart rates vary according to exercise, physical needs, age, gender, air temperature, etc. In this experiment the dependent variable

Many studies have shown us that a specific area of the brain called the amygdala is responsible for instinctual reactions. These reactions include fear and aggressive behaviour. These instinctual reactions area

The group consisted of a male (n=116) and female cohort (n=122). They tested the monkeys in a setting where they were placed in a cage for 30 minutes and allowed to act freely. It is at this point that a human would enter the room, stand (2.5 meters away from the cage) and face the monkey, but make no eye contact (NEC). This test is indicative of a possible threatening situation for the monkey and those who have AT would exhibit more freezing behaviour, decreased communication and higher blood cortisol levels. Prior to procedure, the monkeys were injected with F-deoxyglucose (FDG). Blood was drawn immediately after testing. FDG is an analog for glucose, with becomes trapped in cells which are metabolically active and consequently can be used as a radiotracer. After blood was drawn, the monkeys were anaesthetized and placed in a microPET which allowed the visualizing of the FDG cells within the brain in response to the experimental

Each subject was allowed this resting period of two minutes; after the two minutes were finished, we recorded their heart rate for five seconds. This EKG graph acted as the subject’s baseline or resting heart rate. After recording the baseline, the subjects were presented three different tests. The first test was a light, “About Me” questionnaire in which the subject was asked to fill in basic information about themselves such as, their favorite color, their nickname, etc. The subject was given two minutes to complete the questionnaire and heart rate was recorded immediately after. The subject was allowed two minutes to rest to allow their heart rate to return to baseline. The second test, a “Minute Math” worksheet was given. The subjects had the same amount of time, two minutes, to answer the addition problems on the worksheet and heart rate was recorded immediately after. The subject was again allowed to rest before the third test, a 1040A tax form was given. The subject again had two minutes to complete a 1040A (with information from a provided, fake W2 form) and heart rate was recorded

The following experiment was preformed by Marieke Soeter and Merel Kindt. Their research tested if the disruption of reconsolidation of memories also lowers fear in an individual who has an ongoing fear of spiders in their everyday life. Studies over the past years have found that retrieving previously consolidated memories may signal a process known as reconsolidation (restabilization due to proteins). In the lab setting, a process known as Pavlovian fear conditioning can be used to train the mind to fear a stimulus. This conditioned fear can then easily be used to test the neurobiology of associative fear learning and memory. Fear conditioning is also a great method to be used in studying new treatments for anxiety disorders focused around

Condition suppression technique was a new way for studying learned fear. According to (William K Estes, Biography, American Psychology, Britannica.com), rats were repeatedly given food after pressing the lever. An electric shock was applied immediately after the food was given. That caused the lever pressing to be suppressed. This allowed Estes to conduct trial by trial in the changes in the learned response. This Paradigm became one of the most widely used techniques for studying animal behavior, and still is used today, according to (Smith, 2014, para.

In the addition to the hormone testosterone, other biological factors such as brain structures contribute to the behaviour of aggression. The amygdala is a part of the limbic system which is located in the frontal lobe of the brain. The amygdala is considered to function or mediate the expression of rage and fear. Research was conducted of rhesus Monkeys to determine if the amygdala was responsible for the behaviour of rage (Harry Harlow,1955). Researchers removed this region to determine the effect on the aggressive monkeys. The removal of the amygdala caused the monkeys to act lethargic and docile and inability to respond or to recognise possible threats. This research displayed the function of the amygdala in determining the fight or flight response in dangerous situations, contributing to when a human or animal should display aggressive behaviour. Therefore the amygdala’s role in regulating

According to the article by Schaffhausen, the brain has two basic requirements to learn a fear. The first one is the sensory systems, such as the visual system for a light or the tactile system for a shock. The second area is the amygdala as a critical region for fear conditioning. “The amygdala is a small, almond-shaped cluster of nuclei set deep in the temporal lobe that seems ideally positioned as the locus of fear learning. It receives input through its lateral nucleus from cortical areas and the thalamus, which is a key sensory relay station within the brain, and it sends output via its central nucleus to a variety of brain regions that are known to mediate fear responses, such as the hypothalamus.” (Schaffhausen.2005). The crucial role for the amygdala in fear conditioning that if it is destroyed, it will still show a fear response but fail to learn the association between the sensory systems, such as the light and the brain regions that are known to control fear responses. Consequently, the amygdala is a key structure for fear

Current study focuses on the understanding of Molecular Mechanism of Pavlovian conditioning (PC). Pavlovian conditioning is the reference paradigm for the study of associative learning based on the programmed relation of two stimuli, the conditioned stimulus (CS), a tone, and the unconditioned stimulus (US), sucrose-water. Previous research in rodents has revealed that the limbic circuits (or BLA), play an important role in Pavlovian reward learning. We hypothesize that PC acquisition produces a different memory from PC extinction in the BLA. In this study some of the markers analyzed and measured include: atypical Protein Kinase M ζ (PKMζ), Protein Kinase C ι/λ (PKC ι/λ), AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor subunits glutamate A1 (GluA1), GluA2 and GluA3.These markers are important for consolidation and retrieval of memory.

A team of neuroscientists from the University of Cambridge found a way of unconsciously removing a fear memory from the brain (a specific fear). Fear related disorders affect around one in 14 people and are currently treatmented through aversion therapy. Aversion therapy is a treatment in which they confront their fear by being exposed to it. However, this treatment is not very pleasant, and typically not continued. This new technique created by the team of neuroscientists could lead to a new way of treating patients with these conditions or fears. They neuroscientists first developed a method to read and identify a fear memory using a new technique called 'Decoded Neurofeedback'.Decoded Neurofeedback is the technique used for brain scanning to monitor activity in the brain, and identify complex patterns of activity that resembled a specific fear memory. They then administered a brief shook when they saw a certain computer image creating a fear memory was created in 17 healthy volunteers. When they detected the pattern the researchers began to overwrite the fear memory by giving their experimental subjects a reward. The team continued this procedure multiple times and at the end of their studies that concluded that they had and could reduce the fear memory without the volunteers ever consciously experiencing the fear memory in the process. Although this study was small it could lead to major advances in treatment of fears, PTSD,

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.

Did you know that 75% of people suffer from glossophobia. There are usually 5 kids in every grade who suffer from it. Glossophobia is very common, especially in a school or at a job. It is more common in adults than children. You may experience glossophobia before a performance or speech. When we first sense fear our sensory organs gather information and send it to the thalamus to get processed. The information then gets sent to the amygdala. The amygdala activates our brain stem. It triggers our bodies freeze response. The amygdala also signals nerves that control facial muscles. The amygdala also signals the hypothalamus. Starting our fight or flight response. Our heart rate increases, blood pressure, and sweat.

The fearfulness and screams exhibited by the victims will not be processed by the offender, proving diminished ability to know right from wrong (DeLisi et al., 2009). This example demonstrates an offender’s inability to interpret the emotion of fear in others, potentially leading to sadistic crime. Other emotions which when misjudged, can lead to sadistic crime are aggression and sexual emotions (DeLisi et al., 2009). These emotions may be the case in crimes of rape and murder. Further to this, a study conducted by Raine et al. (1997) shows the murderer test subjects of having decreased relative glucose in the left, and increased relative glucose in the right of the amygdala when compared to controls, proving amygdala dysfunction. As a result, there is an obvious link between sadistic crime and the amygdala as shown through perspectives conducted by neuropsychological

Pavlovian Conditioning paradigms (PC) is a learning process used to model the emergent behavioral, neural and cognitive associations that form as a result of presentation of two types of stimuli: the conditioned stimulus (CS), which is a stimulus without inherent rewarding properties, and the unconditioned stimulus (US), a stimulus with inherent rewarding properties1. Previous studies in rats have revealed that PC can activate the limbic and prefrontal cortex regions in the brain2-4. In addition, the amygdala and nucleus accumbens, which form part of the limbic circuits, play an important role in Pavlovian reward learning2-5. Interestingly, the PC model offers a way to eliminate associations through extinction, whereby the presentation of the