Breakthroughs in the way in which we understand the purpose of the amygdala come from identifying peculiarities in behaviour and linking them to areas of the brain where lesions/abnormalities are found. Such is the case when examining Patient S.M. and her diminished exhibition of fear (Adolphs, 1997 & Feinstein et al., 2011). When breaking fear down into it’s simplest physiological properties we can identify it as an increase in heart rate, breathing rate and skin conductance response (Globisch et al., 1999), thus know the autonomic nervous system is involved. With the help of fMRI studies we can measure the spatial location of activated areas of the brain when a subject is presented with a stimuli. In turn, the studies further support the
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How does this compare to those with lesions of the amygdala? A study conducted by Kalin (2004) saw the effects of excitotoxic lesions to the central nucleus of the amygdala in Rhesus monkeys. The study unveiled that those with lesions exhibited a “significant” decrease in “fear related behaviours” when in the presence of a rubber snake, which was used to induce fear; compared to the control group who had no lesions to the amygdala. Furthermore, the study also showed “less freezing behaviours when confronted by a human intruder”, a common indication of fear that was not expressed. The findings in this study are supported by further research conducted …show more content…
Miltner (2004) has since investigated the human ability to detect threatening visual stimuli. Phobics were presented the challenge to identify a mushroom within a picture that also contained a phobia-correlated, fear inducing image, masked amongst a flower distractor. The results showed a delayed recognition, compared to the non-phobic control, of the “neutral image”. It demonstrated how the eyes “fixate” onto the mushroom after initially moving from the “feared distractor”, implying the automatic detection of a feared stimuli from the visual route. Öhman & Soares (1994) found that a large Skin Conductance Reading (SCR) reading was obtained when presenting a brief 30ms image of a spider to an arachnophobe, followed by a 100ms image of something different with similar structure and texture. Globisch et al. (1999) noted an increase in heart rate acceleration when examining students who had viewed a frightening animal. These two physiological changes are associated with fear and are due to the activation of the autonomic nervous system in response to witnessing the visual stimuli. The amygdala is involved amongst this series of events as LeDoux (1996) stated that the visual pathway stemming from the retina travels towards the thalamus and then unto the primary visual cortex, to which information is then passed to the amygdala for “emotional
How does this compare to those with lesions of the amygdala? A study conducted by Kalin (2004) saw the effects of excitotoxic lesions to the central nucleus of the amygdala in Rhesus monkeys. The study unveiled that those with lesions exhibited a “significant” decrease in “fear related behaviours” when in the presence of a rubber snake, which was used to induce fear; compared to the control group who had no lesions to the amygdala. Furthermore, the study also showed “less freezing behaviours when confronted by a human intruder”, a common indication of fear that was not expressed. The findings in this study are supported by further research conducted …show more content…
Miltner (2004) has since investigated the human ability to detect threatening visual stimuli. Phobics were presented the challenge to identify a mushroom within a picture that also contained a phobia-correlated, fear inducing image, masked amongst a flower distractor. The results showed a delayed recognition, compared to the non-phobic control, of the “neutral image”. It demonstrated how the eyes “fixate” onto the mushroom after initially moving from the “feared distractor”, implying the automatic detection of a feared stimuli from the visual route. Öhman & Soares (1994) found that a large Skin Conductance Reading (SCR) reading was obtained when presenting a brief 30ms image of a spider to an arachnophobe, followed by a 100ms image of something different with similar structure and texture. Globisch et al. (1999) noted an increase in heart rate acceleration when examining students who had viewed a frightening animal. These two physiological changes are associated with fear and are due to the activation of the autonomic nervous system in response to witnessing the visual stimuli. The amygdala is involved amongst this series of events as LeDoux (1996) stated that the visual pathway stemming from the retina travels towards the thalamus and then unto the primary visual cortex, to which information is then passed to the amygdala for “emotional