The limbic system, or motivational system, includes: Amygdaloid body- Basal nucleus that acts as an interface between the limbic system, cerebrum, and sensory systems. Plays role in regulation of heart rate, control of “fight/flight” response, and linking emotions with specific memories. Cingulated gyrus- Sits superior to the corpus callosum. NOTE: (pl.: gyri; prominent fold or ridge or neural cortex on the surface of the cerebral hemispheres). Dentate and parahippocampal gyri- Form the posterior and inferior portions of the limbic lobe. Hippocampus- Region, beneath the floor of a lateral ventricle, involved with emotional states and the conversion of short-term to long-term memories.

The limbic system, continue: -Fornix: An arching tract that connects the hippocampus with the mamillary bodies. - Functions of the limbic system involved emotions and behavioral drives

Figure 14.13 The Limbic System

Figure 14.14 The Brain in Section Figure 14.14a

Figure 14.14 The Brain in Section Figure 14.14b

The cerebral cortex Surface contains gyri and sulci (fissures) Longitudinal fissure separates two cerebral hemispheres Central sulcus separates frontal and parietal lobes Temporal and occipital lobes also bounded by sulci

White matter of the cerebrum Contains: Association fibers- Interconnect areas of neural cortex within a single cerebral hemisphere. Shorter association fibers are called arcuate fibers as they curve in an arc to pass from one gyrus to another. Commissural fibers- Interconnect and permit communication between the cerebral hemispheres. Bands of commissural fibers linking the hemispheres include the corpus collasum and anterior commissure. Projection fibers-Link the cerebral cortex to the diencephalon, brain stem, cerebellum, and spinal cord.

Figure 14.15 The White Matter of the Cerebrum

The basal nuclei Basal Nuclei- Masses of gray matter that lie within each hemisphere deep to the floor of the lateral ventricle. Are embedded in the white matter of the cerebrum. Radiating projection fibers and commissural fibers travel around or between these nuclei. Caudate nucleus- One of the basal nuclei involved with the subconscious control of skeletal muscular activity. Lentiform- Consists of the medial globus pallidus and lateral putamen (Control muscle tone and coordinate learned movement patterns).

Motor and sensory areas of the cortex Primary motor cortex of the precentral gyrus directs voluntary movements Primary sensory cortex of the postcentral gyrus receives somatic sensory information Touch Pressure Pain Taste Temperature

Figure 14.17 The Cerebral Hemispheres PLAY Figure 14.17

Association areas Control our ability to understand sensory information and coordinate a response Somatic sensory association area- Monitors activity in the primary sensory cortex. Allows one to recognize a touch as light as a mosquito landing on one’s arm. Visual association area- Monitors pattern of activity in visual cortex and interprets the result. Ex.: interprets c, a, r as c+a+r or car. Somatic motor association area (premotor cortex)- Responsible for coordination of learned movements.

general interpretive and speech areas General interpretive area Receives information from all sensory areas Present only in left hemisphere Speech center Regulates patterns of breathing and vocalization

cortex functions and hemispheric differences Prefrontal cortex Coordinates information from secondary and special association areas Performs abstract intellectual functions Hemispheric differences Left hemisphere typically contains general interpretive and speech centers and is responsible for language based skills Right hemisphere is typically responsible for spatial relationships and analyses

Figure 14.18 Hemispheric Lateralization PLAY Figure 14.18

Electroencephalogram (EEG) Measures brain activity Alpha waves = healthy resting adult Beta waves = concentrating adult Theta waves = normal children Delta waves = normal during sleep

Figure 14.19 Brain Waves PLAY Figure 14.19a-d

Focus: Cranial Nerves 12 pairs of cranial nerves Each attaches to the ventrolateral surface of the brainstem near the associated sensory or motor nuclei

Figure 14.20 Origins of the Cranial Nerves PLAY Figure 14.20a

Figure 14.20 Origins of the Cranial Nerves PLAY Figure 14.20b

Figure 14.20 Origins of the Cranial Nerves PLAY Figure 14.20c