Download Biological and Psychology Why are psychologists concerned about

Biological and Psychology
Why are psychologists concerned about human biology?
 The nervous system and body chemistry play a vital role in our behavior and mental
processes
 Many of the important questions that psychologists ask are related to biology and the
brain
 Questions
o Are the two halves of the brain specialized to perform different functions?
o How do mood altering drugs work?
o What happens inside the body when you feel a strong emotion?
o Are some mental disorders the result of chemical imbalances in the brain?
Biological Psychology - Branch of psychology concerned with the links between biology and
behavior
Some biological psychologists call themselves behavioral neuroscientists, neuropsychologists,
behavior geneticists, physiological psychologists, or biopsychologists
Key: Understanding Neurons and the Nervous system
The Nervous System
 the body’s speedy, electrochemical communication system
 consists of all the nerve cells of the peripheral and central nervous systems
 Billions of interconnected cells
The Nervous System: Divisions
o Central nervous system (CNS) - Brain and spinal cord
o Peripheral nervous system (PNS)
o Somatic nervous system - Sensory nerves and muscular activity
o Autonomic nervous system – internal organs
 Sympathetic nervous system – arouses
 Parasympathetic nervous system – calms
The Nervous System: Pathways
 Interneurons – neurons of the spinal cord and brain which process information
 Afferent Nerves (sensory nerves) - Carry information to the spinal cord and brain
 Efferent Nerves (motor nerves) - Carry information to the muscles
Neurons are individual cells in the nervous system that receive, integrate, and transmit
information.
 Approximately 100 billion neurons and 10 trillion connections
 Speeds up to 330 miles per hour
 Glia Cells: Provide support and nutrition
 Over 200 types of neurons and glia cells
Common Features of Neurons
 Dendrites
 Cell body or soma
 Axon
 Myelin sheath
 Terminal buttons
Synapse - a junction between the axon tip of the sending neuron and the dendrite or cell body
of the receiving neuron. This tiny gap is called the synaptic gap or cleft.
Neurotransmitters – chemicals that transmit information from one neuron to another.
 Stored in small sacs within the terminal buttons
 Nerve impulse triggers their release
 Over 50 have been identified
 Major ones are described in the text
Drugs and Neurotransmitters
 Agonist – mimics or enhances NT effects
 Antagonist – blocks effects of NT
Brain and its Structures
Brain: 3 Main divisions
 Hindbrain – vital functions – medulla, pons, and cerebellum
 Midbrain – sensory functions –reticular activating system
 Forebrain – emotion, complex thought – thalamus, hypothalamus, limbic system,
cerebrum, cerebral cortex
Hindbrain - Most primitive part of the brain – basic life sustaining functions
 Brain Stem - Alertness, breathing, heart rate, blood pressure
 Medulla – control breathing, regulate reflexes
 Cerebellum – movement, motor coordination
 Pons – governs sleep and arousal
Midbrain
Relay between hindbrain and forebrain
Integrating sensory info.
Reticular Formation - Regulates arousal, attention, sleep/wakefulness, pain perception
Forebrain - Largest and most complex regions of the brain
(Thalamus, hypothalamus, limbic system, cerebrum, or cerebral cortex)
Thalamus - Relay station for much sensory information
Hypothalamus - Eating, drinking, sexual behaviors
It directs several maintenance activities like eating, drinking, body temperature, and control of
emotions.
It helps govern the endocrine system via the pituitary gland.
Limbic System – memory, motivation and emotions
 Amygdala - Emotional awareness and expression
 Hippocampus - Formation and storage of memories
Damage to the Hippocampus – The case of Clive Wearing
Forebrain: Cerebrum
Largest and most complex part of the brain
The cerebral cortex is the convoluted outer layer of the cerebrum
Cerebral Cortex
 Occipital Lobe – Vision
 Temporal Lobe – Hearing, language processing, memory
 Frontal Lobe – Intelligence, personality, voluntary muscles
 Parietal Lobe - Spatial location, attention, motor control
Functions of the Cortex
 The Motor Cortex is the area at the rear of the frontal lobes that control voluntary
movements.
 The Sensory Cortex (parietal cortex) receives information from skin surface and sense
organs.
Association Cortex - Region of the cortex in which the highest intellectual functions occur
75% of the cortex
Damage does not lead to specific loss of function
e.g., Phineas Gage Video
More intelligent animals have increased “uncommitted” or association areas of the cortex.
Cerebral Hemispheres
The cerebral cortex is divided into 2 hemispheres (left and right) connected by the corpus
callosum.
Research has shown the some lateralization of the hemispheres exist
Lateralization is the specialization of one the hemispheres to handle a particular function
The left brain control the right side of the body and the right brain controls the left side of the
body
Left hemisphere – verbal processing: language, speech, reading, writing
Right hemisphere – nonverbal processing: spatial, musical, visual recognition
Handedness
90% of world’s population is right handed
In 95% of right-handers and about 62% of left-handers, the left hemisphere handles most of the
language functions (Hellige, 1990) Including: speaking, writing, reading, and understanding the
spoken word
Paul Broca in 1861 noticed that damage to the left hemisphere led to aphasia
Aphasia is an impairment of language, usually caused by left hemisphere damage either to
Broca’s area (impaired speaking) or to Wernicke’s area (impaired understanding).
Damage to the right brain often had an effect of stopping spatial recognition of faces and
objects
Right Hemisphere - Generally considered to be the hemisphere more adept at visual spatial
abilities and at interpreting nonverbal behavior.
Specializations not as evident in young children. Why?
The brain is sculpted by our genes but also by our experiences.
Plasticity refers to the brain’s ability to modify itself after some type of injury or illness.
Split-Brain Research
Splitting the Brain -A procedure in which the two hemispheres of the brain are isolated by
cutting the connecting fibers (mainly those of the corpus callosum) between them.
Research by Roger Sperry and Michael Gazzaniga
Non-Split Brains - People with intact brains also show left-right hemispheric differences in
mental abilities.
A number of brain scan studies show normal individuals engage their right brain when
completing a perceptual task and their left brain when carrying out a linguistic task.