chapter 2 psych 1 online stud 1199299912883466 2[1]
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Behavioral Neuroscience
Chapter 2
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Biology and Behavior
• The term behavioral neuroscience describes the work of scientists from several disciplines who work to understand how the nervous system is related to behavior.
• Concerned with:
SensingProcessingResponding
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The Evolutionary Perspective
• The evolutionary perspective > role of physiological structures & behaviors; adaptation to the environment
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Natural Selection
• Natural selection = the most fit organisms survive; they adapt best to the environment; pass on genes
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The Nervous System
• We use the processes of sensing, processing, and responding to interact with the environment.
• The nervous system is divided into two parts: – central nervous system (CNS-brain and spinal
cord)– peripheral nervous system (PNS-all parts of
the nervous system outside the CNS)
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The CNS
• The spinal cord is composed of sensory (afferent or ascending) and motor (efferent or descending) nerves.
• Interneurons may connect sensory and motor neurons.
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CNS Nerves
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CNS Nerves
• A reflex arc occurs in less than 1/1000 of a second• A typical “fast” response that uses brain pathways takes
about 1/10th of a second
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CNS NervesThe Cranial Nerves
•Olfactory•Optic•Oculomotor•Trochlear•Trigeminal•Abducens•Facial•Auditory-vestibular•Glossopharyngeal•Vagus•Spinal Accessory•Hypoglossal
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The PNS
• PNS > the somatic division and the autonomic division.
• Somatic division > sensory nerves run from receptors to the brain; motor nerves run to the glands and muscles.
• Autonomic division > sympathetic division, which mobilizes body's resources, and the parasympathetic division which returns body to homeostasis.
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Divisions of the Nervous SystemCentral Nervous
System– Brain– Spinal cord
Peripheral Nervous System–Somatic –Autonomic
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Neurons: The Basic Cells
• The cells that make up the nervous system are called neurons.
• Neurons are composed of:– dendrites > receive signals from adjacent neurons – cell body or soma – axon > transmits signals – terminal buttons > contain
neurotransmitters.
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Structure of a Neuron
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Structure of a Neuron
Bipolar > interneurons or association neurons
Unipolar > usually sensory neurons
Multipolar > tend to be motor neurons
All neurons carry impulses in only one direction
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The Synapse
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Key Neurotransmitters
• Acetylcholine (ACh)
• Dopamine
• Serotonin
• Endorphins
• Norepinephrine
• Gamma amino butryic acid (GABA)
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Refractory Period
• Neurotransmitters must be removed from the synapse before another signal can be transmitted.
Removal is accomplished either by breakdown or by reuptake.
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Agonists and Antagonists
• Agonists > drugs that promote the action of a neurotransmitter.
• Antagonists > drugs that inhibit the action of a neurotransmitter.
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Neuromodulators
• Neuromodulators have more widespread and indirect effects than neurotransmitters.
• Neuromodulators also influence transmission between cells.
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The Action Potential
The reversal in electrical charge is known as the action potential.
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The Brain: A Closer Look
• Phrenology is not a science. Popularized in the 1800s by Franz Joseph Gall
• Gall > skills and characteristics determined by id’ing bumps on the skull.
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The Brain: A Closer Look
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The Brain: A Closer Look
Early studies stimulated or
removed portions of the cortex.
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The Brain
• The brain is divided into the hindbrain, the midbrain, and the forebrain.
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The Hindbrain
• The most primitive of the three main divisions.
• Major structures > medulla, pons, and cerebellum.
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The Brain
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Balance and
movement
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The Midbrain
The midbrain, pons, and medulla lie on top of the spinal cord. Together they make up the brain stem.
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The Forebrain
The forebrain consists of subcortical structures and the two hemispheres of the cerebral cortex
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The Corpus Callosum
• Millions of myelinated axons connecting the brain’s hemispheres
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Subcortical Structures Thalamus
Like a relay station to areas of the cortex
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Subcortical Structures Thalamus
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Subcortical Structures Hypothalamus
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The Cortex
• The cerebral cortex covers the forebrain and is divided into four lobes: – frontal– parietal– temporal– and occipital
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Occipital lobe
Visual center
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Parietal lobe
Includes somatosensory cortex (input from environment)
Helps process perceptions
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Temporal lobe
•Hearing•Understanding language•Memory
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Frontal lobe
You are who you are because of this lobe. •Personality•Emotions•Controlling judgment•Impulses •Sexual behavior•Using Language •Movement
Motor Cortex
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Somatosensory and Motor Cortexes
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More About the Brain
• Aphasia
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More About the Brain
AphasiaCAT Scan
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More About the Brain
Apraxia of lid opening
(blepharospasm)
ApraxiaLoss or impairment of the ability to execute complex, coordinated movements without impairment of the muscles or senses.
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Split-Brain and Lateralization
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Split-Brain Experiment
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The Endocrine System
• Endocrine system:– Ductless glands that
regulate growth, reproduction, metabolism, mood, and some behavior
• Hormones: – Chemical messengers
secreted into the bloodstream
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The Endocrine System
• Cortisol:
• CortiSlim?
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The Endocrine System• “Cortisol is the body's main
stress hormone, and is required for many vital purposes -- proper glucose metabolism, blood pressure, immune function and inflammatory response are a few. In times of stress, either mental or physical, the body can produce an excessive amount of cortisol. At these high levels, cortisol is a nasty little number indeed. It can negatively affect cognitive performance, suppress thyroid function, foster blood sugar imbalances and the subsequent deposition of body fat, decrease bone density, as well as other things. Athletes don't like cortisol, as it is catabolic -- i.e., muscle-wasting, rather than anabolic -- i.e., muscle building.”
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