What is Biopsychology?
How the brain affects behavior
Neuroscience
study of the brain. Bio focus on brain and behavior
Physiological Psychology
Examines the neural mechanisms of behavior via direct surgical, electrical, and chemical manipulation of the brain in controlled experiments with laboratory animals
Effect of ventromedial hypothalamic lesions
Rats grows two to three times their normal size. This is were hungry and eating behavior comes from
Psychopharmacology
Same as physiological psychology but focuses on manipulation of neural activity and behavior with drugs
Neuropsychology
Examines the psychological effects of brain damage in human patients
Damage due to stroke or injury
Psychophysiology
Studies the relationship between brain activity and psychological processes in humans typically using non-invasive imaging techniques
Comparative Psychology
Compares behavior of different species with a focus on genetics and evolution
Craniotomy or Trephination
Dates back 10,000 yrs
Early man putting holes in the brain
Egyptians
Edwin Smith Surgical Papyrus
Importance of heart not the brain
The brain was removed by carefully inserting special hooked instruments up through the nostrils, in order to pull out bits of brain tissue.
They left the heart in place.
Hippocrates (460-377 BC) Greeks
Brain as the seat of the soul
Humoral theory
Believe that different fluids controlled our behavior. Black and Yellow vile
Aristotle (384-322 BC)
Extensive animal dissections
Cardiocentric Theory- believe our heart was where our soul was not in the brain.
Brain acted as a refrigerator for the blood.
Galen (129-199 AD)
Animal spirits housed in ventricles of the brain.
Highly Influential ideas (1500yrs)
Andreas Vesalius (1514-1564)
Performed human brain dissections
Question Galen's Humoral theory
Found over 200 errors in Galen theory
Thomas Willis (1621)
Accomplished Anatomist
Localization of abilities
to brain tissues
He believed memory was
Held on the side of our
Brain because people would
Rub their temples trying to
Remember things.
Phrenology
Idea that pro-locolization that certain parts of your brain will be bigger or smaller depending on how big that part of the brain is.
Aggregate field View
Conducted lesion experiments on animals
"All perceptions, all volitions occupy the same seat in these (cerebral) organs"; the faculty of perceiving, of conceiving, of willing merely constitutes therefore a faculty which is essentially one
Pierre Paul Broca (1824-1880)
Clinical support for localization
Tan's brain and Broca's area
Gustav Fritsch and Eduard Hitzig
Experimental support for localization (1870)
Electrical stimulation of dog brain
Wilder Penfield (1891-1976)
Electrical brain stimulation of human subjects
animism
Gradually abandoned in favor for physical phenomena, but not for mental phenomena
Each of us are aware of our own existence-we think, act, and feel as though there is something in side us thinking, acting and feeling
What is the role of the brain in conscious experience
Rene Descartes (1596-1650)
French Philosopher
Views influenced by Galen
Role of the pineal gland
Mind and body are separate entities but interact
Dualism
separate but interact
Monism
the brain and mind are the same
epigenetics
Experience can change the brain by chemically coating DNA
Instead of altering the genetic code, this chemical coating alters gene expression increasing or decreasing protein expression
Major types of cells in the brain?
Neurons and glia
Number of neurons (nerve cells)?
Approximately 100 billion
Cell body (Soma)
Contains the nucleus, mitochondria, ribosomes, and other structures found in other cells.
Responsible for the metabolic work of the neuron.
Dendrites
branching fibers with a surface lined with synaptic receptors responsible for bringing in information from other neurons.
dendritic spines
that further branch out and increase the surface area of the dendrite.
Axon
thin fiber of a neuron responsible for transmitting nerve impulses away to other neurons, glands, or muscles
Presynaptic nerve terminals
refer to the end points of an axon responsible for releasing chemicals (neurotransmitters) to communicate with other neurons.
sensory neuron
is specialized at one end to be highly sensitive to a particular type of stimulation (touch, temperature, odor etc.)
motor neuron
has its soma in the spinal cord and receives excitation from other neurons and conducts impulses along it axon to a muscle
Selectively Permeable
O2, CO2, and small uncharged fat soluble molecules can cross readily
Glucose and some large amino acids cross via energy dependent active transport mechanisms
Circumventricular organ
Areas where blood brain barrier is weakened
Pineal body
Secretes melatonin and neuroactive peptieds associated with circadian rhythms
neurons nourishment
Primarily use glucose in a metabolic pathway with O2
Glucose comes from diet and conversion of other fuels
Thiamine (vitamin B1) also required for glucose utilization
Korsakoff's syndrome
in ability to make new memories due to lack of vitamin B1
Neuroplasticity
Brain is not a static deteriorating organ
Brain is highly plastic and constantly changing
What are neural stem cells?
Undifferentiated cells found in the interior of the brain that generate "daughter cells" which can transform into glia or neurons
Discovery (Rizzolatti et al. 1996)- Italian researcher
Areas of the brain ( premotor cortex) active when monkeys clutched food were also active when they watched people handle food.
Resting Potential
Electrical Potential Across the cell membrane when the neuron is not sending a message
electrical polarization
inside is slightly negative compared to the outside) due to the differential distribution of ions (charged particles) across the membrane. This electrical potential is known as the resting potential
Important Ions
Sodium (Na+)
Potassium (K+)
Large proteins- intracellular anions
Passive ion channels
Always open
Voltaged gated (dependent) Ion channels
Open when the membrane potential changes to a specific membrane potential
Chemically (Neurotransmitter) gated ion channels
To be discussed late
Sodium (Na+)
Much higher concentration out side neuron (inward gradient)
Potassium (K+)
higher concentration inside neuron (outward gradient)
Large Intracellular
negatively charges ions (anions) trapped inside neurons contributed to electrical polarization
Sodium-Potassium pump (Na+/K+ Pump)
Membrane bound protein complex that transports Na+ out of the cell and K+ into the cell
3 Na+ molecules pumped out for every 2K+ pumped in
Net movement of positively charged ions out of the cell
Pump requites energy (40% of neurons energy)
Na+ accumulates outside cell and cannot reentre
Electrical Gradient
Gradient that develops because of the difference in charge across the membrane
Opposite charges attract and like charges repel
Charles Scott Sherrington (1906)
Early evidence for the existence
of synapses based on behavioral
data from reflex arc
Reflexes slower than conduction
of action potentials along axons suggesting delay of neurotransmission at synapse
Graded potentials
they fade over time and space
Excitatory postsynaptic potentials (EPSP)
Graded depolarizations (makes membrane more positive)
Inhibitory postsynaptic potentials (IPSP)
Graded hyperpolarizations
Sherrington's experiment
Sherrington observed that repeated stimuli over a short period of time produced a stronger response.
Temporal summation
Repeated stimuli occurring within a brief time can have a cumulative effect and can produce a verve impulse with a single stimuli is too weak
Spatial summation
Several synaptic inputs originating from separate locations can have a cumulative effect on a neuron
Greater number of EPSP's
greater probability of an action potential (because of charge)
Greater number of IPSP's
lower probability of an action potential