Mind, Brain & Behavior Wednesday January 22, 2003

Discussion of Term Paper  The goal is to integrate information about brain and behavior with real-world controversies.  Be sure to cover pros and cons, as well as your own opinions.  Give credit to all sources and do not copy from anyone.  Language use counts, but any format is OK.

The Nervous System Chapter 4

Imaging Techniques  Looking at brain structure: CAT scan – computer-assisted tomography  Absorption of radiation MRI – magnetic resonance imaging  Looking at brain functioning: PET scan – positron emission tomography  Emission of radiation from sites absorbing an isotope changing with metabolism fMRI – functional MRI

Parts of the Nervous System  Central Nervous System (CNS) – brain and spinal cord  Peripheral Nervous System (PNS) – ganglia and peripheral nerves outside the brain and spinal cord.  Anatomically separate but functionally interconnected – they work together.

Parts of the PNS  Somatic – provides CNS with sensory information.  Autonomic – the motor system for the viscera, the smooth muscles, and the exocrine glands. Sympathetic – helps the body respond to stress. Parasympathetic – restores the body to a resting state Enteric – controls the smooth muscle of the gut

Seven Main Parts of the CNS  Spinal cord  Medulla – regulates blood pressure and breathing  Pons – helps medulla  Cerebellum – planning, timing of movement  Midbrain – control of eye movement, relay  Diencephalon – thalamus & hypothalamus  Cerebral hemispheres – perception, cognition

Spinal Cord  Receives sensory information and contains neurons for voluntary and reflex muscle movement. 31 pairs of spinal nerves Dorsal roots carry sensory information Ventral roots carry outgoing motor axons and axons of the sympathetic and parasympathetic ANS Ascending and descending pathways to brain.

Brain Stem  Contains the medulla, pons and midbrain. Receives sensory information and controls muscles of head, neck, face. Involved with hearing, taste, balance. Reticular formation mediates alertness and attention. Ascending and descending pathways to higher brain regions.

Cerebral Cortex  Outer layers of cortex – gray matter  Underlying myelinated axons and glial cells – white matter  Clusters of related neurons – called nuclei: Basal ganglia Hippocampus Amygdala  Two hemispheres

Four Functional Lobes  Frontal  Parietal  Temporal  Occipital  Two other areas: Insular cortex – inside the lateral sulcus Limbic lobe – inside the four lobes overlying the brain stem and diencephalon

Deep-Lying Structures  Basal Ganglia – regulation of movement, cognition. Receive input from all four lobes and communicate to the frontal cortex via thalamus.  Hippocampus – forms memories  Amygdala – coordinates emotion, autonomic and endocrine systems via hypothalamus. Hippocampus & amygdala are parts of limbic system.

Four Organizational Principles  Each system contains relay centers (nuclei). Relay nuclei contain local interneurons and projection interneurons. Thalamus – processes almost all sensory info  Each system has several distinct pathways.  Pathways are topographically organized.  Most pathways cross to the opposite side. Decussation

Systems Interact  Textbook example: physical actions involve sensory, motor and limbic (motivational) systems. When systems interact, they must be interconnected (see Figure 5-9) Different senses have their own pathways operating in parallel. Information is combined (integrated) at some point -- how this happens is an open question.