Chapter 36 Animal Brain Organization and Function Chapter 36

CENTRAL NERVOUS SYSTEM  2 components  Brain  White matter: inner region  Gray matter: outer region  Spinal cord  White matter: outer region  Gray matter: inner region  Both covered by 3 protective layers of connective tissue called meninges  Dura mater: outer  Arachnoid: middle  Pia mater: inner

MAJOR BRAIN REGIONS

FOREBRAIN  Cerebrum (Cerebral Cortex): Also called Cerebral Hemispheres  4 lobes in 2 hemispheres connected by corpus callosum  Most complex integrating system in CNS  “The Boss”’; controls conscious perception, thought, voluntary motor activity; can override most other systems  Frontal lobe: personality defects, speech, aggression, motor  Parietal lobe: speech, taste, reading, somatosensory  Occipital lobe: vision  Temporal lobe: hearing  Thalamus: relay station for sensory info to cerebrum  Responsible for sensations like pain, body temperature, touch  Hypothalamus  Regulates pituitary glands; homeostasis, endocrine function  Thirst, body temperature, water balance, hormones  Limbic System: inner component that controls instincts, emotions, motivation, physiological drives (pleasure, pain,etc)  Hippocampus: posterior portion of limbic system; controls long term memory

LIMBIC SYSTEM Limbic System: inner component that controls instincts, emotions, motivation, physiological drives (pleasure, pain,etc) Hippocampus: posterior portion of limbic system; controls long term memory

HUMAN BRAIN ORGANIZATION

MOTOR AND SOMATOSENSORY CORTICES Central sulcus: separates primary motor cortex of frontal lobe from primary somatosensory cortex Motor cortex: controls skeletal muscle movements Somatosensory cortex: takes tactile info and sends to motor cortex Right cortex controls left side of body and vice versa

TOPOGRAPHIC MAPS Represent different body regions of the primary motor cortex and somatosensory cortex

MIDBRAIN  Is part of brainstem  Integrates sensory information  Pupillary and visual reflexes  Auditory pathways  Coordination of movement  Primitive functions  “pupils are fixed and dilated”…..brain death

HINDBRAIN  3 parts  Cerebellum: balance, muscular coordination  Pons (part of brainstem): reflex center; controls respiration  Medulla oblongata (part of brainstem): junction of brain and spinal cord  Heart rate, BP; vomiting, swallowing, digestion, coughing, sneezing  NOTE: The brainstem is made up of the midbrain, pons, and medulla. It connects the spinal cord to the brain and is responsible for many essential/primitive functions. Damage to the brainstem often causes death, therefore, it is now used to test for “brain death” (a more accurate assessment than heart stopping). Damage to relatively large parts of cerebrum or cerebellum may be damaged without being life-threatening (social/higher functioning skills)

SYNAPTIC PLASTICITY

IMAGING OF BRAIN FUNCTION