Biological Psychology n Study of influences of biological systems on behavior n Primary focus on CNS n Behavior - anything involving action in response to a stimulus n Early controversy centered around mind/body problem

Historical Origins n Early controversy centered around mind/body problem n Aristotle thought mind resided in the heart n Hippocrates identified the brain as source of human actions n n Descartes envisioned the nervous system as a hydraulic model n n Galvani refuted Descartes' theory n n Flourens used experimental method to demonstrate brain function

Reflex n Descartes thought stimulus was reflected by the muscles n Whytt (1751) thought spinal cord controlled reflexes n Charles Bell (1811) identified the sensory and motor roots n Magendie (1822) identified the dorsal root as sensory, ventral root as motor. u Bell-Magendie law n Müller (1838) - doctrine of specific nerve energies

Localization of Function n Gall ( ) developed phrenology u Thought mental functions divided into different faculties u Different faculties related to specific brain areas (localization) u Greater ability relates to that area being larger u Larger area would produce bump on skull u First 3 assumptions were correct - not the last u His did not use the experimental method u Experimental physiologists eventually refuted his popular thinking u Localization of function for some cognitive processes n Fritsch & Hitzig - mapped the motor area n Ferrier & Munk demonstrated specific sensory areas

Localization of Language n Language very complex, but localized n Bouilland (1825) discovered expressive language in left frontal lobe

n Broca (1861) first to confirm anatomically that the 3rd convolution of the left frontal lobe is concerned with motor sequencing Lesion produces expressive aphasia Wernicke identified receptive language area Posterior 1/3 of the left superior temporal lobe Near the auditory projection area Lesion produces receptive aphasia

The Neuron n Golgi used silver stain u Stained only a few selective cells u Under microscope individual cells could be viewed n Demonstrated that the neuron was the basic unit of the nervous system

The Synapse n Sherrington labeled the junction between neurons as synapse u Studied spinal reflexes in dogs (sensory, connecting, motor neuron) u Demonstrated that there is a time delay in transmission across synapse n Loewi demonstrated the delay due to chemical transmission across synapse u Demonstrated chemical effects by stimulating frog hearts u While most synapses are chemical some in the heart are electrical

Mass Action & Equipotentiality n Lashley discovered data which tended to refute localization n Found size of damage more predictive of effect than specific location n Mass Action - Specific function is shared by all neurons in association cortex n Equipotentiality - All neurons within a sensory area share equally in determining function

Current Approaches to Biological Psychology n Neuroscience - Study of the nervous system n Physiological Psychology - Study primarily non-human brain/behavior relationships n Psychophysiology - Study of physiology/behavior relationships n Psychopharmacology - Study of the effect of drugs on behavior n Neuropsychology -Use psychological tests to assess functional consequences of brain damage n Comparative Psychology - Study of the effects of genetics & evolution on behavior

The Genetic Basis of Behavior n Each cell contains our genetic code in chromosomes n Genes are segments of DNA located on chromosomes n DNA is active compound of each chromosome

Chromosomes n 46 chromosomes (23 pairs) n Sperm & egg are gametes - each containing only 23 chromosomes n Upon fertilization - 2 combine & cell has 46 n Gametes formed by meiosis u During this process crossing over can occur u Responsible for individual differences

Individual Characteristics n Dominant gene - expression will dominate n Recessive gene - expression only if both pairs are recessive n Huntington's disease - example of a dominant gene u Onset is between ages 30 to 40 u Can be determined by investigating chromosome 4

Evolution of the Nervous System n Single celled organisms have no nervous system n As multicellular organisms increased in size there was a problem of communication

…Evolution of the Nervous System u Jellyfish - specialized nerve cells but no nervous system

…Evolution of the Nervous System n Flatworm - two ganglia

…Evolution of the Nervous System u Roundworm - simple ring of nerves

…Evolution of the Nervous System u Earthworm - brain with segmented nervous system

…Evolution of the Nervous System u Insects - more complex nervous system

Vertebrate Nervous System n Has bony coverings over the nervous system n Contralateral representation n Major brain divisions u Hindbrain u Midbrain u Forebrain

Mammalian Nervous System n Forebrain greatly developed u Cortex becomes deeply folded u 2/3 of cortex hidden in grooves u Human cortex equivalent to 2.5 sq feet n Brain increases in size due to increase in neurons and connections

Ethics in Human Research n Ethics committee must approve proposal n All must be informed by written agreement n Must participate of their own free will n Subject must be informed as to the results of the study

Ethics in Nonhuman Research n Animal subjects provide better control n Animal Care & Use Committee must approve n The research must be justified and animals must be properly cared for n Animal research has led to significant understanding & treatment