Cerebral Hemispheres Corpus Callosum The cerebrum is the largest and most complex part of the human brain. It includes the brain areas that are responsible for our most complex mental activities, including learning, remembering, thinking, and consciousness itself. The cerebrum is divided into right and left halves, called cerebral hemispheres. If we pry apart the two halves of the brain, we see that this fissure descends to a structure called the corpus callosum. Corpus Callosum Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Parietal Frontal Occipital Temporal Each cerebral hemisphere is divided by deep fissures into four parts called lobes. To some extent, each of these lobes is dedicated to specific purposes. The occipital lobe includes the cortical area where most visual signals are sent and visual processing is begun - the primary visual cortex. The parietal lobe includes the area that registers the sense of touch - the primary somatosensory cortex. The temporal lobe contains an area devoted to auditory processing, the primary auditory cortex. Occipital Temporal Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Production of Speech Broca’s Area In recent decades, an exciting flurry of research has focused on cerebral lateralization—the degree to which the left or right hemisphere handles various cognitive and behavioral functions. However, hints of cerebral specialization were found as early as the late 1800s. In 1861, Paul Broca, a French surgeon, performed an autopsy on a patient who had been unable to speak. The autopsy revealed a lesion on the left side of the man’s frontal lobe. Since then, many similar cases have shown that this area of the brain—which came to be known as Broca’s area—plays an important role in the production of speech Broca’s Area Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Comprehension of Language In 1874, Paul Wernicke discovered that damage to a portion of the temporal lobe of the left hemisphere leads to problems with the comprehension of language. Patients with damage in Wernicke’s area can speak normally but have difficulty understanding others. Wernicke’s Area Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Stimulus in Left Half of Visual Field Stimulus in Right Half of Visual Field Fixation Point Left Eye Right Eye Right Hemisphere (Control of Light Hand) Left Hemisphere (Control of Right Hand) Each hemisphere’s primary sensory and motor connections are to the opposite side of the body - the left hemisphere controls and communicates with the right hand, arm, etc. and the right hemisphere controls and communicates with the left side. Vision is more complex. Stimuli in the right half of the visual field are registered by receptors on the left side of each eye that send signals to the left hemisphere. Similarly, stimuli in the left half of the visual field are registered by receptors on the right side of each eye that send signals to the right hemisphere. Severed Corpus Callosum Optic Nerves Information Delivered to Left Visual Processing Area Information Delivered to Right Visual Processing Area Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Roger Sperry and his colleagues found that the ability of split-brain subjects to name and describe objects depended on which side of the visual field the image was flashed in. When pictures of common objects were flashed in the right visual field and thus sent to the left hemisphere, the split-brain subjects were able to name and describe the objects depicted Roger Sperry Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

In another experimental procedure, split-brain subjects were asked to reach under a screen to hold various objects. When objects were placed in the split-brain subjects’ right hand, which communicates most directly with the left hemisphere, the subjects had no problem naming the objects. When the objects were placed in the subjects’ left hand, which communicates most directly with the right hemisphere, the subjects had difficulty naming the objects. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Verbal Processing Nonverbal Processing Research with split-brain subjects provided the first compelling evidence that the right hemisphere has its own special talents. Based on this research, investigators concluded that the left hemisphere usually handles verbal processing, whereas the right hemisphere usually handles nonverbal processing, such as that required by visual-spatial and musical tasks. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Eventually, researchers wondered whether it was safe to generalize from split-brain subjects to normal individuals whose corpus callosum was intact. One method of studying cerebral specialization in an intact brain is by looking at perceptual asymmetries - left-right imbalances between the cerebral hemispheres in the speed of visual or auditory processing. Subtle differences in the abilities of the two hemispheres can be detected by precisely measuring how long it takes participants to recognize different types of stimuli. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Placenta (in Female During Pregnancy) Pineal Gland Hypothalamus Pituitary Glands Parathyroid Glands Thyroid Gland Thymus Placenta (in Female During Pregnancy) Ovary (in Female) Testis (in Male) Liver Adrenal Gland Pancreas Kidney The endocrine system consists of glands that secrete chemicals - known as hormones - into the bloodstream that help control bodily functioning. Some hormones are released in response to changing conditions in the body and act to regulate those conditions. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Placenta (in Female During Pregnancy) Pineal Gland Hypothalamus Pituitary Glands Parathyroid Glands Thyroid Gland Thymus Placenta (in Female During Pregnancy) Ovary (in Female) Testis (in Male) Liver Adrenal Gland Pancreas Kidney Hormones are secreted by the endocrine glands in a pulsatile manner – that is, several times per day in brief bursts or pulses. The levels of many hormones increase to a certain level, then signals are sent to the hypothalamus or other endocrine glands to stop secretion of that hormone – a negative feedback system. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Hypothalamus Pituitary Glands Pineal Gland Parathyroid Glands Liver Thymus Placenta (in Female During Pregnancy) Ovary (in Female) Testis (in Male) Liver Adrenal Gland Pancreas Kidney Much of the endocrine system is controlled by the nervous system through the hypothalamus, which also connects with the pituitary gland. The pituitary gland stimulates actions in the other endocrine glands. For example, in the fight or flight response, the hypothalamus sends signals through the pituitary gland and autonomic nervous system to the adrenal glands, which then secrete stress hormones. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Genetic Material Nucleus Cell Chromosomes DNA Every cell in your body contains information from your parents, found on the chromosomes that lie within the nucleus of each cell. Each chromosome contains thousands of genes, which also occur in pairs. Sometimes a member of a pair has a louder voice, always expressing itself and masking the other member of the pair - this is a dominant gene. A recessive gene is one that is masked when the paired genes are different. When a person has two genes in a specific pair that are the same, the person is homozygous for that trait. If the genes are different, they are heterozygous. Cell Chromosomes DNA Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Twin Research Family studies, twin studies, and adoption studies are assess the impact of heredity on behavior. Family studies and twin studies focus on genetic relatedness and how it affects various traits in order to study the influence of nature on behavior. Adoption studies are able to assess the influences of both nature and nurture, as adopted children’s traits can be evaluated in relation to both their biological and adoptive parents. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior

Charles Darwin The field of evolutionary psychology is based on the work of Charles Darwin and the ideas of natural selection and reproductive fitness. Evolutionary theorists study adaptations, or inherited characteristics, that increase in a population because they help solve a problem of survival or reproduction during the time they emerge. Communication in the Nervous System Postsynaptic Potentials and Reuptake Postsynaptic Potentials and Reuptake Organization of the Nervous System The Brain and Behavior Cerebral Laterality The Endocrine System Heredity and Behavior