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By Root 895 0

Enlarged ventricles of the brain can be seen in MRIs or at autopsy. The disorder is most likely to express itself during 17- to 25-year age period. Some theorize that mothers were exposed to flu-like viruses during their second trimester and that these factors lie dormant in the brain until late adolescence. Those arguing on the nurture side cite the diathesis stress model and the double-bind situation. According to the double-bind theory, bad parenting makes the child confused about how to perceive the world. Twin studies in which one twin exhibits severe symptoms of schizophrenia and the other milder symptoms or none at all may be a result of environmental factors and stress levels—either real or perceived—that the two experience.

Scoring Rubric for Essay 2

Five points are to be awarded for the sensory and brain issues addressed in a, 2 points for explaining the fight-or-flight theory in b, 1 and point for correctly identifying and explaining a current theory of emotion in c.

Point 1: Eye focusing the image—cornea→pupil→lens→retina

Point 2: Eye transducing energy—rods and cones

are photoreceptors that convert light energy to energy of the electrochemical impulse

Point 3: Transmission of information to the brain—from the retina→optic nerve→thalamus or brain

Points 4 and 5: Mention of at least two brain parts involved in visual processing of the bear: optic chiasma where information from one-half of each eye crosses to opposite hemisphere; thalamus as sensory relay and for color processing; occipital lobes or feature detectors in visual cortex; association areas of the cortex integrate sensory information to enable perception of bear

Point 6: Explanation of the “fight-or-flight” response—sympathetic nervous system increases heart rate, pulse, and blood pressure and slows digestion making energy available to muscles

Point 7: Pituitary signals adrenal glands to secrete adrenaline which gives the extra surge of energy to run faster than ever

Point 8: Description of either Schachter’s two-factor theory or Lazarus’s cognitive appraisal theory or Ekman’s facial feedback system or LeDoux and role of amygdala

Sample Essay

Seeing the brown bear in his backyard obviously caused an alarming sensory experience for John which was quickly translated into quick action thanks to his sympathetic nervous system and the expression of fearful emotion. Light rays bounced off the bear’s brown coat and entered John’s eyes through the cornea which begins the process of focusing. Next the light passes through the pupil controlled by the iris. John’s eyes open very wide! Next the light is focused by the curved lens which changes shape in relation to the distance of the bear and inverts the bear’s image to focus on the retina on the back part of the eye where receptors (rods and cones) are stimulated. The rods and cones transduce the light energy into the electrochemical energy of a neural impulse. The brown color stimulates the cones especially concentrated in the fovea which is where John’s best acuity is. If enough cells fire, the bipolar cells are activated and finally the ganglion cells are activated. The axons of the ganglion cells in each eye form the optic nerves which send the image to the thalamus in the brain (the sensory relay) which then sends it on to the occipital lobes where feature detectors will help John to perceive the dangerous image of the bear.

The “fight-or-flight” reaction is the physiological arousal of the body or sympathetic nervous system in response to a stressor (the bear) that enables John to get away fast. When John perceived the bear, messages were sent to his organs, glands, and muscles. John’s heart rate and blood pressure immediately accelerated and his breathing deepened. The pituitary gland also secreted hormones that commanded the adrenal glands to secrete adrenaline (epinephrine) which helped give him the extra energy to run faster than he had ever done.

There are several contemporary theories which are helpful in explaining why John felt fear and not anger or sadness. Schachter’s two-factor model