Biopsychology The Biological Basis of Behavior Neurons Structure

Biopsychology The Biological Basis of Behavior

Neurons: Structure Dendrites ü Cell Body ü Axon ü Myelin Sheath ü Nodes of Ranvier ü Terminal Buttons ü p. 45

Normally Functioning Nerves

The Synapse Synaptic Vesicles ü Synaptic Cleft ü Receptor Sites ü Presynaptic membrane ü Postsynaptic membrane ü Neurotransmitters ü p. 47

Neurotransmission 1. 2. 3. 4. 5. Resting Potential (-70 millivolts) Threshold ( greater than -70 mv) Action Potential ( positive) Hyperpolerization (less than – 70 mv) Resting Potential (-70 mv)

All or None Response Action Potential Threshold Resting Potential Graded Potential Hyperpolarization

Effects of Neurotransmitters n Excitatory n Inhibitory

Types of Neurotransmitters w w w Acetylcholine: ACh Norephinephrine: NE Dopamine: DA Serotonin: 5 -HT Gamma-amino-butyric acid: GABA

Acetylcholine (ACh): v v v found through out the central nervous system, autonomic nervous system, and all neuromuscular junctions. Excitatory Involved in muscle action, attention, learning, and memory Too much: spasms Too little: paralysis

Norephinephrine: NE o o Synonymous with Adrenalin Found in ANS Excitatory Responsible for getting “pumped up” • o Fight or Flight Response Eating behavior • Carbo-craving

Dopamine: DA Ø Ø Reward system Produced by neurons located in a region of the brain called the substantia nigra. Involved in pleasure, movement, attention, and learning. Degeneration of dopamine-producing neurons has been linked with Parkinson’s Disease. Too much dopamine is implicated in schizophrenia and Tourette’s.

Serotonin: 5 -HT n n n Found in the brain and spinal cord. Inhibitory Plays a role in the regulation of mood and is control of eating, sleep and arousal. Has also been implicated in the regulation of pain and dreaming. Destroyed by MAO SSRI’s (Prozac, Zoloft)

Gamma-amino-butyric acid: GABA n n n Found through out the brain and spinal cord, in very high concentrations compared to other Neurotransmitters. Inhibitory Is the major inhibitory neurotransmitter in the brain. Abnormal levels of GABA have been linked to eating and sleeping disorders.

Nervous System n Central N. S. Peripheral Central Brain & Spinal Cord n Peripheral Somatic Autonomic Somatic ? ? ? Autonomic Parasympathetic Sympathetic Para. Symp p. 51

Autonomic Nervous System Sympathetic n Fight or Flight 1. 2. 3. 4. Eyes open Wide Mouth Goes Dry Hr Increase Start to Sweat Parasympathetic n Maintenance & Refuel 1. 2. 3. 4. Eyes constrict Mouth Waters Digestion Blood away from muscles

The Endocrine System The Brain Stem What is the difference between a neurotransmitter and a hormone? Where are the seats of consciousness?

Motivation & Emotion in the Brain n Hypothalamus n Limbic System n Thalamus

Cortex o Parietal Lobe o Temporal Lobe o Occipital Lobe o Frontal Lobe

Brain Lateralization n Right Hemisphere n n Left side of the body Creativity Math & Spatial tasks Nonverbal - Emotion n Left Hemisphere n n Right side of the body Language n Wernike & Broca

Q: What is the cause of ambidexterity? A: Handedness (the preference to use one hand over the other) is speciesspecific. In humans, about 90% prefer to use their right hand. What does this mean? Recall that the human brain is divided into a right and a left hemisphere. Typically, the left hemisphere in humans is dominant. We're not really sure why the left rather than the right (or both) becomes dominant, but probably it reflects the early fetal environment, particularly hormonal factors. Since the left hemisphere controls the right side of the body, people with left hemisphere dominance will be right-handed. For lefthanders and for those who are ambidextrous (can use both hands with the same level of skill), the right hemisphere tends to be dominant. Interestingly, language, which typically is the province of the dominant hemisphere, is equally likely to reside in either the left or right hemisphere for non-righthanded people. Those who are left-handed or ambidextrous also tend to have a thicker corpus callosum (the bundle of fibers joining the two hemispheres).

Genetics n Structure and Function n Gene therapy n Nature vs. Nurture