The Biology of Behavior Unit 2: Biopsychology

The Nervous System Central nervous system  consists of the brain and the spinal cord Brain  an organ of soft nervous tissue contained in the skull; functions as the coordinating center of sensation, intellect, and nervous activity Spinal Cord  cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine; connects nearly all parts of the body to brain Peripheral nervous system  made up of nerve cells that send messages between the central nervous system and all of the other parts of the body

Spinal Cord

Spinal cord

Spinal cord anatomy

Neurons Neurons  nerve cells that run through the whole body and communicate with each other. 30,000 neurons can fit on a pinhead Each neuron contains: Cell body with nucleus Dendrites : fibers that receive messages from other neurons Axons : fibers that send messages to other neurons Neurons do NOT touch; there is a gap between them called a synapse Messages are sent across the synapses by special chemicals called neurotransmitters

Communication Between Neurons The use of neurotransmitters causes an electrical current There is enough electrical current in the brain to power a flashlight

Major Neurotransmitters Serotonin Dopamine Achetylcholine Norephinephrine Endorphins

Peripheral Nervous System Nerves : visible bundles of axons and dendrites that extend from the brain and spinal cord to all other parts of the body Responsibilities: Sensory nerves - carry messages from body to brain (pain, pressure, temperature) Motor nerves – carry messages from brain to body to respond

Somatic Nervous System Voluntary Actions!!! Transmits sensory messages to the central nervous system It is activated by touch, pain, changes in temperature, and changes in body position The somatic nervous system allows the body to move or change position It also sends messages to the muscles and the glands and helps to maintain posture and balance

Automatic Nervous System Involuntary Actions!!! Regulates the body’s vital functions, such as heartbeat, breathing, digestion, and blood pressure We generally do not have to think about these activities – they occur automatically and are essential for keeping us alive Two divisions: Sympathetic  activated when a person is going into action (“fight or flight”) Parasympathetic  restores the body’s reserves of energy after an action has occurred

Anatomy of the Brain The Hindbrain: Medulla  involved in vital functions such as heart rate, blood pressure, and breathing Pons  located in front of the medulla; involved in regulating body movement, attention, sleep, and alertness Cerebellum  rests under the larger part of the brain (cerebrum); involved in balance and coordination

Anatomy of the Brain The Midbrain: Located between the hindbrain and the forebrain Involved in vision and hearing Reticular activating system  begins in the hindbrain, rises through the midbrain, continues into the lower part of the forebrain Important for attention, sleep, and arousal

Anatomy of the Brain The Forebrain: Thalamus  serves as a relay point for sensory stimulation; most of the messages coming from the sense organs go through the thalamus on the way to the higher levels of the brain Hypothalamus  located below the thalamus; vital to regulation of body temperature, storage of nutrients, and various aspects of motivation and emotion

Anatomy of the Brain The Forebrain: Limbic system  forms a fringe along the inner edge of the cerebrum; involved in learning and memory, emotion, hunger, sex, and aggression Hippocampus  involved in memory processing Amygdala  involved in aggressive and fear based responses (fight or flight)

Anatomy of the Brain The Forebrain: Cerebrum  accounts for 70% of the weight of the human brain; surface is wrinkled with ridges and valleys, known as the cerebral cortex Cerebral cortex is involved with thinking, memory, language, emotions, complex motor functions, perception, and more

Lobes of the Brain (4) Frontal Parietal Occipital Temporal

Lobes of the Brain - Frontal The Frontal Lobe of the brain is located deep to the Frontal Bone of the skull. It plays an integral role in the following functions/actions: - Memory Formation - Emotions - Decision Making/Reasoning - Personality

Lobes of the Brain - Parietal Lobe It plays a major role in the following functions/actions: - Senses and integrates sensation(s) Spatial awareness and perception

Lobes of the Brain – Occipital Lobe The Occipital Lobe of the Brain is located at the back of the head Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Lobes of the Brain – Temporal Lobe The Temporal Lobes are located on the sides of the brain They play an integral role in the following functions: Hearing Organization/Comprehension of language