Biology and Behavior 335

Origins of Physiological Psychology

Biological Roots

Charles Darwin- theory of natural selection

Natural Selection- the process in which advantageous traits increase the likelihood
for survival and become more prevalent in the population.

1) Variation between organisms
2) Some forms of variation are heritable
3) Some forms of variation are better than others
4) Populations grow exponentially
5) Populations can NOT grow exponentially for long

Evolution- Consequence of Natural Selection

Mutation- a change in genetic material which can be passed to an organisms offspring
resulting in genetic variability

Selective Advantages- A characteristic of an organism that permits it to produce more offspring.

Experimental Design

- the process of designing and conducting experiments

Scientific Method

-establish a question
- form hypotheses (Null Hypothesis)
- design experiment
- statistically analyze data and compare results to the Null Hypothesis(HO)
- form conclusion which provides information about universe

Brain Anatomy and Function

Nervous System

Central Nervous System (CNS) - consist primarily of the brain and spinal cord

Peripheral Nervous System (PNS) - nerves and sensory organs

Brain

Cerebral Hemisphere - the two symmetrical halves of the brain, major portion of the brain

Corpus Callosum - large bundle of nerve fibers which connect one side of the brain with the other side

Neurons -nerve cell that process and transmit information throughout the nervous system

Sensory Neurons -neuron that detects changes in the external or internal environment
such as light, sound waves, odors, taste, and contact

Motor Neurons - located within CNS that controls the contractions of a muscle

Interneuron - a neuron located entirely in the CNS responsible for learning, remembering,
deciding and perceiving

View Figure 2.1

4 Structures of the Neuron

Soma -or cell body (where nucleus is located)
Dendrites- information receiver (from terminal buds)
Axon-conveys information from Soma to Terminal Buttons
Terminal Buttons - bud at the end of Axon to communicate with other neurons

Synapse -junction between terminal buttons of an axon and the membrane of another neuron

Nerves -bundles of 1000’s of individual axons wrapped together in a tough protective membrane.

Neurotransmitter -chemical released by terminal buttons

Action Potential - message conducted down axon

Cell Biology

Membrane - defines cell structure, made of double layer lipids (fatlike molecules)

Cytoplasm - the viscous semi liquid substance contained in the interior cell wall

Mitochondrion -power plant of cell (organelle extracts energy from nutrients)

glucose---------->mitochondrion--------------------->converts to ATP

Adenosine triphosphate -important molecule which provides energy throughout cell

Nucleus -information center, contains chromosomes

Chromosomes -contains genetic information made of intertwined strands of DNA

Deoxyribonucleic acid (DNA) -long complex macromolecule consisting of
two interconnected helical strands containing genetic material

View Figure 2.6 page 30

Inhibition- occurs when brain overrides the bodies excitatory response

Glia - support cells of the nervous system protecting and holding nerves together


Blood Brain Barrier
-semipermeable barrier which allows only certain substances to enter the CNS

Diffusion- movement of molecule from regions of a high concentration to regions
of a low concentration (+ -----> - )

Osmosis -movement of a molecule through a semi-permeable membrane from
low to high concentrations (- ------> +)

Hormone -chemical substance released by the endocrine gland affecting the activity of cells.

Description Terms

Rostral - Toward front of organism or anterior

Caudal- Toward back of organism or posterior

Dorsal- Toward back side of organism

Ventral- Toward belly of the organism

Lateral- Toward side of body

What is the benefit of a brain with lobes? Or is there one?

The Forebrain (Telencephalon, diencephalon)

Telencephalon- 2 cerebral hemispheres

Cerebral Cortex- made up of glio cells, dendrites, axons of neurons
wrapped around outside of brain

Primary Visual Cortex- receives visual information

Primary auditory Cortex- receives audio information

Primary Somatosensory Cortex- receives information from body senses

Primary Motor Cortex- motor skills, different muscles

“Rest” of cerebral cortex- perceiving, learning, and remembering

 Diencephalon- second part of Forebrain

Thalamus- Most neural contents, except smell, to thalamus

Hypothalamus- Controls nervous system, endocrine system and organizes
behaviors related to survival (fighting, feeding, fleeing, and mating).
Produce hormones

Mesencephalon-
-Midbrain
-relays signals through visual and auditory
-pain, addictive states

· Metencephalon-
-Hindbrain. Reflex center, equilibrium, motor skills

Cerebellum- (little brain) coordinating movements

Pons- role in sleep and arousal

Medulla Oblongata- Vital functions like heart rate, breathing, and blood pressure

· Peripheral Nervous System- brain and spinal cord

Somatic Nervous System- Consists of cranial nerves and spinal nerves

· Spinal Nerves
-sensory axons into CNS and motor axons out from it
-control muscles and glands

· Cranial Nerves- sensory information
-taste, auditory, balance, visual
-information in and motor axons out

· Autonomic Nervous System- Other branch of peripheral
-smooth muscle, eyes, skin, bladder (automatic functions)
-2 parts

Sympathetic division- controls activities that occur during excitement state

Parasympathetic division - salivation, gastric, and intestinal motility, secretion of digestive juices.
Controls activities during relaxation state

Psychopharmacology - The study of the effects of drugs on the nervous system and on behavior

Drug effect- The changes a drug produces in an organisms physiological processes and behavior

Sites of action- Location of biochemical process in cells from drugs

Pharmacokinetics- movement of drugs through the body

Routes of Administration

Intravenous (IV) injection- inject into vein, very fast, reaches brain in seconds

Intraperitoneol (IP) injection- rapid, through abdominal wall and in peritoneal cavity

Intromuscular (IM) injection- into muscle, butt, arm, thigh, very slow

Subcutaneous (SC) injection- beneath skin, slow, small amounts

Oral administration- pills

Sublinqual administration- under tongue

Inhalation- lungs

Topical administration- cream, patch on skin

Introcerebral administration- inject past blood brain barrier

Tolerance- effects of medications are diminished

Sensitization- drug becomes more and more effective

Withdraw systems- e.g. drug addict

Placebo effect- inert substance used as control in research