Introduction
Emotions form an integral part of human life. Consequently, this paper will examine emotions and the theories related to them. The theories include James-Lange Theory, Cannon-Bard Theory, Darwin Theory and the Limbic System. It looks at the mechanisms of addiction and how it works. Lastly, cerebral laterizations and the four methods of studying them. It looks at how these relate to functionality in the right and left hemisphere of the brain.
Emotions
Emotions are the defined in three-fold: The subjective experience, the expressive or behavioral responses and the nervous response. They encompass the feelings, perceptions and cognitive processes in the interaction with certain stimuli. These include: joy, anger, hatred et cetera.
Theories of Emotion
Darwin’s Theory
Mainly speaks of facial expressions as emotional expressions to communicate a certain message. For example, a smile or flashing of the eyebrows may show joy or a way of saying hello to some people.
James- Lange Theory
Posits that when we perceive a threatening stimulus or any impulse, the perception of this causes an autonomic nervous system response. The brain receives the impulse and causes the increase in internal processes like heart rate and breathing after assessing the type of stimuli. For example, when we see a lion before us, a message is sent to the brain to increase our level of anxiety and cause an initial response of increased heart rate. The brain then tells us to fear the lion. The cingulated gyrus receives messages from the hippocampus from the hypothalamus that it projects to the cortex for emotional expression and subsequent physiological response (Encyclopedia Britannica, 2010).
Cannon-Bard Theory
The initial response to stimuli is simultaneous to perception. The impulse sent to the brain in response to the stimuli is sent to two different parts of the brain: cortex and thalamus. The thalamus receives the message from the mamillary bodies (while the cortex receives messages from the cingulated gyrus) and responds to elicit an emotion with manifestation in increased breathing or facial expressions. When we see the lion we will be fearful then we will prompt ourselves to have an increased heart rate then we will flee or, we will see an old friend, be glad then smile (LOL to Good Health, n.d).
Limbic System
Limbic System refers to the cerebral area of the brain connected to the hypothalamus and its closely related parts like the hippocampus, pituitary gland, thalamus among others. It comprises the paleopallium (intermediate brain). It determines affective functions such as maternal instinct or playful moods. According to Papez, the hypothalamus is primarily responsible for emotional responses. It receives relays from the cingulated gyrus, which sends them to hippocampus. The hypothalamus sends the impulses to the cortex (Do Amaral & de Oliviera, n.d.).
The effects of drug taking can be devastating since it becomes a conditioned response due to conditioned stimulus of regular drug in take. It therefore leads to drug tolerance. According to Pinel (2007, p.488), the D2 theory of schizophrenia is defective in that it does not account for development of tolerance to neuroleptics. It states that a schizophrenic may develop a conditioned response to the drug such that they become less therapeutic or effective in managing schizophrenia. This explains why a drug abuser would need higher doses to get high with frequency of drug intake. The addict develops an anticipatory effect of drug antagonists to deal with the introduction of the pathogen. If one regularly takes drugs these defenses are up it becomes easier for the taker to protect from overdosing (Jim). However, Jack died because his body had not been classically conditioned to take such amounts of heroine with no anticipatory body effect (Pinel, 2007).
Cerebral Lateralization & Functionality
Cerebral laterization is the division of the brain into two distinct parts: right and left hemispheres. Based on these divisions the brain and these two symmetries or these two parts can be used to study the functionality of each hemisphere and how they contribute to overall brain functions. Insight into the working of the hemispheres and their contribution to emotions, moods, memory and handedness is a key aspect of psychology especially in the psychology of emotions. Some of these methods of studying the hemisphere are listed below:
The sodium amytal test for cerebral laterization entails injecting sodium amytal into the carotid artery. It anesthetizes that hemisphere so that the other part with language capacity can be assessed.
Dichotic listening involves whispering a sequence of digits through earphones in the left and right ear simultaneously and the digits are to be repeated. The right ear hears better so the left hemisphere is more dominant.
Functional brain imaging the brain activity is monitored through the PET (Positron emission tomography) and the functional magnetic resonance imaging (fMRI).
Relation between handedness and laterization shows dominance in left hemisphere for dextral (right handed) and majority of the sinestrals (left-handed) and tend to be more variable in languages (Pinel, 2007).
Reference
Encyclopedia Britannica. (2010). Limbic System. Web.
Do Amaral, J., R., & DeOliviera, J., M. (n.d.) Limbic System: The Center of Emotions. 2010. Web.
LOL to Good Health. (n.d.).Early Theories of Emotions. 2010. Web.
Pinel, J., J. (2007). Basics of Biopsychology. Boston.MA: Allyn & Bacon.