Franz Gill formulated the theory, phrenology: claimed that bumps on the scull
could reveal our mental abilities and character traits.
Phrenology correctly focused attention on the idea that various brain regions have
Two discoveries: body is composed of cells
Neurons conduct electricity and communicate with each other
using chemical messages.
Biological psychology: Abranch of psychology that deals with links between biology and
We, humans, are bio psychosocial systems, meaning that we are a combination of
biological, psychological and social-cultural systems.
Neurons are the nerve cells
Sensory Neurons: Carry messages from tissues and organs to the brain and the spinal
cord, for processing.
Motor Neurons: Carry messages from the brain and spinal cord to the tissues and organs.
Interneurons: Neurons within the brain and spinal cord that communicate internally.
Myelin Sheath insulates the axon of some neurons and help speed their impulses. If it
degenerates, it results in multiple sclerosis and the communication to muscle slows, with
eventual loss of muscle control.
Action Potential:Abrief electrical charge that travels down its axon.
The fluid inside the interior of a resting axon contains negative ions whereas the fluid
outside the axon membrane is positively charged.
During depolarization, the specific area of the interior becomes positively charged due to
the influx of sodium ions.
During refractory period, neuron pumps the positively charged sodium ions back outside. Threshold: The level of stimulation required to trigger a neural impulse.
The reaction of a stimulus depends on the number of neurons fired and how often the
neurons are being fired.
Charles Sherrington discovered synapse, a meeting point between neurons.
Synapse: The junction between the axon of the sending neuron and the dendrite of the
receiving neuron and the tiny gap at this junction is called synaptic gap or synaptic cleft.
Reuptake is the process of absorbing excess neurotransmitter by the sending neuron.
Learn table 4.1
Endorphins: It is a neurotransmitter that is linked to pain control and to pleasure. These
are the natural pain killers in the body.
If the body is flooded with artificial opiates such as heroin or morphine, the brain may
stop producing its own neurotransmitter production.
Agonist:Amolecule which is similar enough to a neurotransmitter to mimic its effects or
it may block the neurotransmitter’s activity.
Too much of acetylcholine at the synapses, for example, in the case of black widow
spider venom, can lead to excess muscle contraction , convulsions and possible death.
Antagonists: Molecules that block a neurotransmitter’s functioning. Eg- Botulin, a poison
in improper canned food can cause paralysis by blockingAch release.
Curare, used for hunting processes, blocks the receptors forAch,
leaving the neurotransmitter unable to affect the muscles and the
animal becomes paralyzed.
The CNS consists of brain and the spinal cord.
The PNS consists of the sensory and motor neurons that connect the CNS to the rest of
PNS contains the somatic system and the autonomic nervous
Somatic nervous system controls the voluntary actions and
enables voluntary control of our skeletal muscles.
Autonomic nervous system controls our glands and muscles of
our internal organs. Usually, the system operates on its own. Autonomic nervous system has 2 divisions: parasympathetic:
conserves energy by decreasing heartbeat, lowering blood
sugar and sympathetic: arouses and expends energy by
increasing heart beat and raising blood sugar.
Endocrine glands secrete hormones which travel through bloodstream.
Pituitary gland is the master gland whose master is hypothalamus.
Lesion: Tissue destruction. Abrain lesion is naturally or experimentally caused destruction of
Electrical activity in the brain’s billions of neurons sweeps in regular waves across its
Electroencephalogram (EEG) is an amplified read -out of such waves. Stimulus
is presented repeatedly and having a computer filter out the brain activity
unrelated to the stimulus, one can identify the electrical wave evoked by the
These waves are measured by electrodes placed on the scalp.
PET, Positron emission tomography: Depicts brain activity by showing each area’s
consumption of its chemical fuel, glucose.
Active neurons consume a lot of glucose.
When the person receives temporarily radioactive glucose, the PET scans detects
where this glucose goes in the brain by locating the radioactivity.
The PET scan brain areas which are most active as the brain performs mathematical
calculations, looks at images of faces or daydreams.
MRI scan, Magnetic resonance imaging: The head is put in a strong magnetic field, which
aligns the spinning atoms of brain molecules. Then a radio wave pulse momentarily disorients the atoms. When the atoms return
to their normal spin, they release signals that provide a detailed picture of the
brain’s soft tissue.
It is revealed that there is an enlarged fluid-filled brain area in some patients who
fMRI, functional MRI can reveal the brain’s functioning and its structure.
Blood flows in the area where the blood is especially active. By comparing the MRI
scans taken less than second apart, researchers can see the brain “light-up” (with
increased oxygen-laden bloddflow).
The brain’s oldest and the innermost region is the brainstem. It begins where the spinal cord
swells slightly after entering the skull. The swollen site is called medulla.
Medulla controls out breathing and heartbeat.
Pons helps to coordinate movements.
Inside the brainstem, lies the reticular formation. Reticular formation:Anerve network in the
brainstem that plays an important role in controlling arousal.
The reticular formation passes through both medulla and pons.
It filters incoming stimuli and filter important information to other areas of the brain.
Thalamus receives information from all senses except smell and routes it to the higher brain
regions that deal with seeing, hearing, tasting and touching.
The function of cerebellum is to :
Enable one type of non-verbal learning and memory.
It helps to judge time, modulate emotions and discriminate sounds and textures.
It coordinates voluntary movement.
The limbic system lies between the older parts and its cerebral hemispheres.
The component of limbic system, the hippocampus, processes memory.
Limbic system’s amygdala, influence aggression and fear.
Some neural clusters in the hypothalamus influence hunger; others regulate thirst, body
temperature, sexual behavior and helps keep the internal environment, steady. Eg- Thinking about sex: stimulation of hypothalamus to secrete hormones which
in turn triggers the “master gland” to influence hormones released by other
Reward deficiency syndrome:Agenetically disposed deficiency in the natural brain
systems for pleasure and well-being.
This leads people to crave whatever provides that missing pleasure.
Cerebral cortex is the brain’s ultimate control and information processing center.
The larger cerebral cortex in mammals offers increased capacities for learning and
thinking, and enables us to be more adaptable.
Glial cells: cells in the nervous system that support nourish and protect neurons. They
provide nutrients and insulating myelin.
4 portions of cerebral cortex:
Frontal lobes: It is involved in speaking and muscle movements and in making
plans and judgments.
Parietal lobes: It receives sensory input for touch and body position.
Occipital lobes: Receives information from the visual fields.
Temporal lobes: includes the auditory areas and receives information primarily
from the opposite ear.
Motor Cortex: An area at the rear of the frontal lobes that controls voluntary
The brain devotes more tissue to sensitive areas and to areas requiring precise control.
Sensory Cortex:An area at the front of the parietal lobes that registers and processes
body touch and movement sensations.
AssociationAreas: Involved in higher mental functions such as learning, remembering,
thinking and speaking.
Association areas are found in all four lobes. In frontal lobe: It enables judgment, planning, and processing of new
o Frontal lobe damage can alter personality.
In parietal lobes: Enable mathematical and spatial reasoning.
In temporal lobe: Enables us to recognize faces.
Plasticity: The brain’s ability to change, especially during childhood, by reorganizing
after damage or by building new pathways based on experience.
Constraint-induced therapy: Rewire brains by restraining a fully functioning limb and
forcing use of the “bad hand” or uncooperative leg.
Accidents, strokes and tumors in the left hemisphere can impair reading, writing,
speaking, arithmetic reasoning and understanding.
Corpus callosum: It is a large band of neural fibers that connects the two brain
Split brains: Acondition resulting from surgery that isolates the brain’s two hemispheres
by cutting the fibers connecting them.
Either genes or some prenatal factors influence handedness.
DNA: Acomplex molecule that contains the genetic information that makes up the
Chromosomes: Are thread like structures made up of DNAmolecules that contain the
Gene: Asegment of DNAthat is capable of synthesizing a protein.
Identical twins develop from a single fertilized egg that splits in two and are genetically
• Identical twins have the same genes but not the same number of copies of
• They share a same placenta but sometimes they have two different placentas
and thus one may receive better nourishment which may contribute to identical
twin differences. Behavior geneticists: The study of the relative power and limits of genetic and
environmental influences on behavior.
Fraternal twins develop from separate fertilized eggs.
On extraversion (outgoingness) and neuroticism (emotional instability), identical twins
are much more similar than fraternal twins.
Genetic relatives: Biological parents and siblings ; Environment relatives:Adoptive
parents and siblings
Temperament: Aperson’s characteristic emotional reactivity and intensity
• Difficult babies: more irritable, intense and unpredictable
• Easy babies: Cheerful, relaxed and predictable
• Slow-to-warm up: Resist or withdraw from new people and situations.
Heritability: The proportion of variation among individuals that we can attribute to
People with identical genes but differing experience have similar though not identical
Interaction: The interplay that occurs when the effect of one factor (such as
environment) depends on another factor (such as heredity).
Molecular genetics: The subfield of biology that studies the molecular structure and
function of genes.
Evolutionary psychologists: The study of the evolution of the behavior and the mind,
using the principles of natural selection.
Sensation: The process by which our sensory receptors and nervous system receive and
represent stimulus energies from our environment.
Perception: The process of organizing and interpreting sensory information, enabling us
to recognize meaningful objects and events.
Psychophysics: The study of relationship between the physical characteristics of stimuli,
such as intensity, and our psychological experience of them. Absolute Threshold: The minimum stimulation needed to detect a particular stimulus
50% of the time.
Subliminal: Below one’s absolute threshold for conscious awareness.
Priming: The activation, often unconsciously, of certain associations, thus predisposing
one’s perception, memory, or response.
The difference threshold: The minimum difference a person can detect bet