General Psychology 2301

1
General Psychology 2301

• The Brain and Behavior

2
Nervous System Basics

• Central nervous system (CNS)
• Brain and spinal cord
• Spinal reflexes
• Peripheral nervous system (PNS)
• Sensory and motor nerves
• Somatic (skeletal) and autonomic subsystems
• Autonomic subsystem composed of sympathetic and
  parasympathetic mechanisms

3
Basic Units Nerve Cells

• Neurons (green) ? primary communication devices
  estimated to be 100 billion
• Glial cells (red) ? 90 of brains cells,
  multi-function support for neurons
• Brain structure, nourishment, plasticity,
  protection from toxins

4
Neuron Structure

• Cell body
• Keeps neuron alive
• Triggers send signals
• Axon
• Transmits messages away from the cell body
• Most neurons have one
• Myelinated and unmyelinated
• Dendrites
• Receive messages from other neurons
• May be as many as 10K

5
How Neurons Talk

• Synapse ? site where axon terminal meets a
  receiving dendrite
• Axons can have thousands of terminals
• Synapses grow exponentially early in life
  (plasticity)

6
The Mechanism

• An action potential occurs when neuron is
  stimulated (must reach threshold)
• Impulse travels down the axon (speed depends on
  myelination)
• Synaptic vesicles open, releasing chemicals
  (neurotransmitters)
• Neurotransmitters bind to receptors on dendrites
  (excitatory or inhibitory)
• Signal is carried to next set of neurons

7
Important Biochemicals Neurotransmitters

• Neurotransmitters ? chemicals that exist in
  nervous tissue and certain glands
• Serotonin sleep, appetite, mood, pain
• Dopamine movement, learning/memory, reward
• Acetylcholine muscles, emotion, memory
• Norepinephrine stress reactions, sleep, emotion
• GABA major inhibitory transmitter
• Glutamate major excitatory transmitter

8
Biochemistry Endorphins and Hormones

• Endorphins are opioid peptides thus, they blunt
  pain and promote pleasure
• Hormones are produced in glands and are released
  into the bloodstream
• Melatonin ? biological rhythms
• Oxytocin ? uterine contractions, lactation
• Adrenal hormones ? cortisol, epinephrine and
  norepinephrine
• Androgens and estrogens
• Insulin ? blood sugar regulation and fat storage

9
Measuring the Brain

• Electroencephalogram (EEG) ? contacts on the skin
  detect electrical impulses
• Position emission tomography (PET) ? radioactive
  glucose injected and monitored
• Magnetic resonance imaging (MRI) ? magnetic
  fields disrupt atoms, energy discharge recorded

10
Measuring the Brain

• PET scans

MRI image
11
How the Brain Is Put Together

• Roughly divided into three parts
• Brain stem or lower brain
• Limbic system and midbrain
• Cerebral cortex

12
How the Brain Is Put Together

• Medulla
• Respiration, heartbeat
• Pons
• Sleep cycles, arousal
• Reticular activating system (RAS)

13
How the Brain Is Put Together

• Cerebellum
• Vestibular sense, some cognition
• Thalamus
• Relay station
• All senses pass through except smell

14
How the Brain Is Put Together

• Hypothalamus
• Energy intake, reproduction, body regulation
• Medial forebrain bundle
• Pituitary gland

15
How the Brain Is Put Together

• Amygdala
• Fear, anxiety, aggression
• Hippocampus
• Memory index, threat detector
• Hypothalamus, amygdala and hippocampus included
  in the limbic system

16
How the Brain Is Put Together

• Cerebrum
• Higher-order functions
• Corpus callosum
• Bridge between brain hemispheres

17
Lobes of the Cortex

• Occipital lobes - vision
• Parietal lobes sensation, attention

18
Lobes of the Cortex

• Temporal lobes audition, language
• Frontal lobes reasoning, movement, speech

19
The Brain in Two

• Brain is cross-wired
• If corpus callosum is severed, the brains cant
  talk
• May be severed to treat epilepsy

20
Split-Brain Experiments

• Note the exact questioning required to show the
  effect

21
His and Hers Brains?

• Primary differences in language comprehension
  activation
• Males ? left only
• Females ? left and right
• Lets not get carried away
• Gender differences are usually quite small
  practically speaking
• Patterns of activity do not necessarily translate
  into performance differences
• Brain may reflect differences in experiences, not
  vice versa