Unit 1: Biological Base of Behavior

Nature vs. Nurture

• Nature: Genetics and heredity

• Nurture: The influence of environmental factors, including experiences, upbringing, and culture, on individual development and behavior.

Twin studies

• Used to study nature vs. nurture

• Identical twins living different lives (same nature, different nurture)

Evolutionary perspective

How natural selection effects the expression of thoughts and behavior to increase survival and reproduction.

• Keywords: species, instinct, needs for survival

Epigenetics

The on/off expression of genes (like a light switch)

• Ex. smoking can affect your genes

Peripheral nervous system

• nerves

• relay signals for movement, sensory perception, and automatic body functions.

Somatic peripheral nervous system

voluntary

• sensory (afferent)

  • input

  • carries information from the skin, sensory organs, and muscles to your brain and spinal chord.

• motor (efferent)

  • output

  • sends command signals from the central nervous system to your skeletal muscles to make voluntary movements happy

Autonomic peripheral nervous system

involuntary

• sympathetic

  • “fight or flight”

  • heart rate increases

  • blood supply goes to muscles

  • digestion is inhibited

  • the bronchi (lungs) dilate

  • saliva production decreases

• parasympathetic

  • “rest and digest”

  • heart rate decreases

  • blood supply goes to digestive organs

  • digestion is stimulated

  • bronchi constricts

  • pupils constrict

  • salvia production increases

  • conserves energy needed when in sympathetic

Central nervous system

• Brain and spinal cord

• The main command center for the body, processing sensory input and coordinating all actions

Cerebral cortex (cerebrum)

• Ultimate command center for the human body, processing your experiences and how you react

• Made up of lobes, aka “cortical structures”

• The parietal, temporal, and occipital lobes all receive and process sensory data

Frontal lobe

• Higher mental functions (planning, judging, emotional decisions

• Part that separates us from animals

• Contains the motor cortex (responsible for voluntary movement)

Parietal lobe

• Contains the somatic-sensory cortex

• From the skin (touch)

  • Ex. temperature and pressure

Temporal lobe

Auditory information (hearing)

Occipital lobe

• Vision

• Contains the visual cortex

Thalamus

• Relay center of the brain

• All sensory info must pass through the thalamus before going to its proper lobe (except smell)

• Language = left side of brain

Broca’s area (thalamus)

• Left side of the frontal lobe

• Language production

• Broca’s aphasia: damaged Broca’s → you know what you want to say, but you can’t say it

Wernicke’s area (thalamus)

• Left side of the temporal lobe

• Language comprehension

• Wernicke’s aphasia: damaged Wernicke’s → you can speak, but not comprehensively and cannot understand what others are saying

Subcortical structures

Limbic system: emotions

• hypothalamus:

  • Regulates body temperature (sweating, shivering)

  • Center for drives (hunger, thirst, sex)

  • Controls the pituitary gland

  • Helps maintain homeostasis

• hippocampus

  • Learning and memory (where all of your memories are)

• amygdala

  • Fear and rage response

  • Threat detection center (helps respond to danger before we know what’s going on)

  • Interpreting non-verbal expression

  • Sensory info has to pass the amygdala before it gets to the frontal lobe

Brainstem

• Pons

  • Superior (above)

  • Influences sleep

• Medulla

  • Inferior (lower)

  • Controls heartbeat, breathing, swallowing (vital life functions)

  • Damage to the medulla leads to death

Reticular formation

• Keeps you awake and alert

• Damage leads to coma

• Allows you to ignore unchanging information and become alert to when it changes

• Part of survival

Cerebellum

• Posterior (in the back, under the lobes)

• Controls balance and coordination (walking straight, standing up, upright posture)

• Allows you to have smooth movements (typing, writing, instruments)

• Muscle memory

• Rapid, successive, and fine (small) motor skills

Endocrine system

Creates hormones

Pineal gland (endocrine system)

• Secrete melatonin (affected by light)

• Melatonin regulates a sleep-wake cycle

Pituitary gland (endocrine system)

• Secretes oxytocin (“love hormone”)

• Stimulates uterus contractions during childbirth

• Controlled by the hypothalamus

Pancreas (endocrine system)

• Insulin and glucagon

• Insulin decreases blood glucose levels

• Glucagon increases blood glucose levels

Adrenal gland (endocrine system)

• Kidney

• Secrete adrenaline (epinephrine)

  • Stimulates sympathetic arousal

  • Keeps your nervous system going

Gonads (endocrine system)

• Ovaries secrete estrogen and progesterone

• Testes secrete testosterone

Neurons

A specialized nerve cell that transmits electrical and chemical information throughout the body's nervous system

• Dendrites: Receives chemical messages from other cells and send them toward the cell body

• Axon: Carries electrical impulses away from the cell body towards other neurons

Myelin

Protects the axon and speeds up the rate of the electrical impulse

• Like rubber around a wire

Multiple sclerosis (MS)

A condition when the body attacks the myelin and it deteriorates, exposing the neuron and leaving it unprotected

Neuroplasticity

The nervous system’s ability to change in response to experiences

• Whenever you learn something new, the brain changes

• When the brain changes, more neurons are communicating with more neurons/more synapses are made

Neurotransmitters

• Chemical messengers that float in the synapse

• Lock-and-key mechanism

• Drug effects:

  • Agonist: increases effect

  • Antagonist: decrease/block effect