Memory Synthesis Essay

Maren S. Seeking a spotless mind: extinction, deconsolidation, and erasure of fear memory. Neuron. 2011;70(5):830-845.

Neurobiological studies show that both suppression and recall and the creation of false memories are possible. (Kandel, 1994) In this paper both sides of the debate will be analyzed and evaluated.

The hippocampus is a component of the brain that is used for memory. Neuroscientist now know this because of a patient who received surgery on his hippocampus and it caused his memory to be altered. The study of the patient led to many new discoveries of human memory and how it is specifically related to the hippocampus. The patient known as H.M. had surgery on his brain.

training. Mice infused with anisomycin (n= 12) immediately after conditioning showed impairment in contextual fear memory compared with vehicle-infused animals (saline, n=18) when tested 24 hours after CFC training (DF=28, F=7.19, t-test: p< 0.05) (Figure 2A).

Little Albert was exposed, briefly and for the first time, to a white rabbit, a rat, a dog, a monkey, masks (with and without hair), cotton, wool, burning newspapers, and other stimuli. Initially, Albert showed no apparent fear towards the stimuli. Later, Albert was placed with the white rat (to whom he exhibited no fear) and simultaneously Watson and Rayner created a loud noise behind Albert by striking a suspended steel bar with a hammer - to which Albert responded with fear and crying. After just two replications of this, the child begin crying at the placement of the rat alone. Thus Watson and Rayner had successfully developed the rat into a conditioned stimulus to which Albert reacted with fear, the conditioned response.

Arguably, an organism is better described as an information seeker, forming relations amongst events from information provided by a stimulus. For example, Rescorla suggests that contiguity is an insufficient example of Pavlovian Conditioning. As shown in simple CS/US parings, learning was determined by how the two stimuli differ, not in what they share, showing that contiguity is not a necessity, (Rescorla, 1988). Furthermore, systematic fear conditioning scenarios imply the base rate of US occurrence against a CS/US contiguity is also sensitive to conditioning. Evidence for this can be found in previous work that validates the current conclusion. Rescorla (1968, p. 1), argues that contingency over contiguity is an important determinant of fear conditioning, and refers to contingency as the “relative probability of occurrence of US in the presence of a CS as contrasted with its probability in the absence of CS.” Rescorla’s (1988) adaptation of these results measures asymptotic fear levels, (where each curve shows conditioning as an increasing function of the likelihood of receiving a shock during the tone), supporting the continued importance of perceived fear in associations. Furthermore, results from studies on Blocking, Conditioned Inhibition and Auto-shaping in pigeons suggest that the simplistic notion of previous theory

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

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,

Following the sound test, the authors had means to test several important factors. These factors were 1. Conditioning fear of an animal, and if they could establish a conditioned emotional response, 2. Would there be a transference to other animals/objects. Thirdly, they wanted to determine the effect time had on the conditioned emotional response. Finally, if an emotional response did not die out, what methods could be used to remove

safer space to engage in my challenge. That being said, the downside to this approach is the fact that I lack the technology to actually engage in such method and the technology is quite pricey for me to go out and buy. In addition to the exposure therapy approaches, another counterconditioning approach I could attempt to use is systemic desensitization. This approach requires an individual to gradually think about more troubling situations that they may encounter related to their fear (Chance, 2014). In the same way, I can use this to correct my behavioral challenge. To apply this method, I could first think about pulling out of my parking spot, then I can picture driving around the block, next I could imagine driving to the grocery store

To assess functional connectivity between distinct brain regions in relation to levels of processing, the researchers used psychophysiological interaction analysis (Schott et al., 2013). To assess the correlation between levels of processing and later memory performance, the researchers computed a two-way ANOVA (Schott et al., 2013). The main findings of the results are deep and shallow study processing engaged extensive distinct (although with some overlap) cortical networks, but they both elicited pronounced activation in the bilateral hippocampus (although for deep level processing, this was greater) (Schott et al., 2013). In both study conditions, successful encoding was associated with significant activations in the bilateral hippocampus in addition to the dorsolateral and ventrolateral prefrontal cortex (Schott et al., 2013). These activations were more pronounced during deep processing verses shallow processing (Schott et al., 2013). The results of this study are consistent with recent brain research by showing that successful encoding for later episodic memory is associated with increased neural connectivity, which is the precondition during successful retrieval (Schott et al., 2013). Memory traces reside in neocortical areas, coordinated by the hippocampus (Schott et al., 2013). This hippo-campal-cortical connectivity increases during successful encoding and we can see that this

Another part of Experiment 5, examined whether pre-shock induced enhancement of conditional fear can be displayed in a new environment in which animals never received shock. This was done by giving rats either 0 or 15 shocks in Context A, as done in previous experiments. In Context B, some rats received a tone paired with a single shock. Rats were then tested in another distinct context, Context C. If rats showed an enhanced freezing response to the tone, unique information is provided regarding how this effect is transferred because the rats were tested in a completely new environment. The data collected for this part of Experiment 5 make it unclear whether the increase in tone and post-tone freezing is due to enhanced fear learning or generalization of fear between Context A and Context C (Rau et al., 2005). To address this issue, a follow-up experiment was conducted, Experiment 5B.

However, Rosensweig and Bennet (1972) definitely showed some indication of the presence of positive effect of enriched environment full with stimulus may lead to brain development. Following this study, Maguire (2000) studied the effects of hippocampus on memory by using MRI scans. He studied 50 normal men and 50 London taxi drivers and scanned each of their brain. As he analyzed the volume of the hippocampus using pixel counting, Maguire found out that the taxi drivers had larger posterior hippocampus compared to the control. More importantly, he observed that as the experience of the taxi drivers were longer, the larger the volume of posterior hippocampus. This findings, thus, supported the conclusion offered by Rosenzweig and Bennet (1972)

Previous research have demonstrated that avoidance responding is influenced by shock intensity and duration (Leander, 1973; de Souza et al., 1984; Badia et al., 1973). Powell (1970) investigated the effect of two shock intensities in single and multiple avoidance schedules and found that the higher shock intensity was generally more effective in producing avoidance responding. Leander (1973) investigated the effects of shock intensity and duration on free-operant avoidance. The results indicated that shock intensity and shock duration combine in a multiplicative fashion to determine the avoidance performance. The relation between shock intensity and shock duration suggested that longer shock durations can be substituted with lower shock intensities (Leander, 1973). The increased strength and magnitude of shock predicted higher rates of avoidance responding.