Welcome to the APPL601, Biological Bases of Behavior!

Your Host for the Semester Jim McConkey –MS/PMAC Biomedical Engineering from Johns Hopkins Specialties in neuroscience, medical imaging and computer-guided surgery

Tonight Details about the course What are we studying? Organization of the nervous system Anatomy of the nervous system

Development of Psychology Ideopathic model –Spirits, demons, etc. cause pathologies. Mental model –Cognitive defects or faulty thinking cause psychopathologies. Medical (biological) model –Psychopathologies are biologically driven. –They can be treated with drugs. Integrated model –The real world is somewhere in between.

Biological Bases of Behavior aka Biopsychology aka Physiological Psychology The study of behavior and other psychological phenomena in terms of the development, functioning, and pathologies of the nervous system.

Biological Psychology How are behaviors controlled by the brain? What parts of the brain control which behaviors? How much control do humans have? How do psychoactive drugs work?

Neuroanatomy (structure) Neurophysiology (function) Biopsychology (behaviors) Neuropharmacology (drugs) Neuropathology (disease) Neurochemistry Neuroscience

Methods of Biopsychology Historical techniques: dissection, staining Surgical methods Electrical stimulation and measurement Pharmacological methods Genetic engineering Neuropsychological tests Non-invasive imaging techniques

Introduction to the Nervous System

Nervous System –A system of nerves. Cells specialized for the translation and processing of information. Produce electrical and chemical activity. Connects and coordinates all parts of the body. –A collection of specialized subsystems.

Divisions of the Nervous System Central Nervous System –Brain –Spinal Cord Peripheral Nervous System –Everything else

Divisions of the Peripheral NS Somatic –Receives sensory input from periphery –Conscious control of peripheral muscles Autonomic –Receives unconscious sensory input from organs –Unconscious control of movement and organs

Divisions of the Autonomic NS Parasympathetic –Mostly inhibitory –Controls “housekeeping” functions Sympathetic –Mostly excitatory –Controls “fight or flight” responses

Anatomy of the PNS Autonomic nerves –Parasympathetic nerves leave the spinal cord at the cervical and sacral levels. –Sympathetic nerves leave the thoracic and lumbar vertebrae. Somatic nerves –Enter and leave the spinal cord at every vertebra. –Sensory nerves have bodies in the dorsal root ganglia and ascend in the dorsal horns. –Motor nerves descend in the ventral horns.

Recap of NS Organization Nervous System Central NSPeripheral NS ParasympatheticSympathetic Somatic NSAutonomic NS

Organization of Nerves Nerves are organized in a tree-like fashion –Solitary neurons in the outermost periphery, protected by an endoneurium. –Solitary neurons gather in small bundles called fascicles, bound by a perineurium. –Fascicles gather with blood vessels in larger bundles, bound by an epineurium.

Organization of Nerves Endoneurium wraps each neuron w/myelin. Perineurium wraps several neurons into a fascicle. Epineurium wraps a bundle of fascicles plus blood vessels.

Organization of Nerves Collections of neurons, grouped by function –CNS: tracts –PNS: nerves Neuron cell bodies tend to clump together: –CNS: nuclei (nucleus) –PNS: ganglia (ganglion)

Protection of the CNS The CNS is very important and very sensitive and is therefore well protected by: –Thick bones –3 layers of meninges –Cerebrospinal Fluid (CSF) –Blood-Brain Barrier –Circle of Willis – redundant blood supply

Protection of the CNS Skull –Thick, hard bone –Over 1 cm thick in places –Totally surrounds and protects the brain

Protection of the CNS Meninges –Thick, fibrous layers Dura mater –Periosteal –Meningeal Arachnoid mater Pia mater

Protection of the CNS Cerebrospinal Fluid (CSF) –Mostly water –Shock absorber –Produced in choroid plexus

Protection of the CNS Blood-Brain Barrier –Tight junctions pass O 2, CO 2, OH –Carrier-mediated transport of glucose, AAs, ions –Blocks large molecules many drugs and toxins

Organization of the CNS The lower the brain level, the more primitive the more instinctive, and the less brain control. Pure reflexes occur in the spinal cord with no intervention from the brain. The older/lower parts of the brain have 2 layers of neurons. The newer parts of the brain (neocortex) have 6 layers.

Organization of the CNS Myelencephalon –Medulla oblongata (or just medulla) Contains nuclei which are part of the reticular formation and control: –Arousal and attention –Heart rate –Respiration rate –Cardiovascular smooth muscle tone –Skeletal muscle tone

Organization of the CNS Metencephalon –Pons (=“bridge”) Part of reticular formation responsible for sleep and arousal Relay nuclei between cortex and cerebellum –Cerebellum Primarily responsible for coordinated movements Receives all sensory input except olfactory Connected to pons via cerebellar peduncles

Organization of the CNS Mesencephalon –Tectum (=“roof”) Inferior (auditory) and Superior (visual) colliculi Responsible for audiovisual reactions –Tegmentum (=“covering”) Contains nuclei of the reticular formation Controls eye movements Red Nucleus – sends motor info from cortex and cerebelum to spinal cord Substantia Nigra – communicates with caudate and basal ganglia

Organization of the CNS Diencephalon (“2 brains”) –Surrounds the 3 rd ventricle –Thalamus Two lobes Major sensory transfer station Many sensory nuclei –Hypothalamus (=“beneath thalamus”) Autonomic control center, four F’s Hormonal control, direct and thru pituitary

Organization of the CNS Telencephalon –Cerebral cortex Two cerebral hemispheres Lateral ventricles (two) Corpus callosum/ anterior commisure Limbic cortex –Involved in motivation and emotion Basal ganglia –Caudate nucleus, globus pallidus, putamen –Involved in planned movement

Organization of the CNS Cerebral hemispheres –Lateralization, specialization per side –Left Verbal abilities Analysis and serial behaviors –Right Spatial abilities Synthesis Music, arts, emotions

Anatomical Directions Posterior (rear) Anterior (front) Superior (top) Inferior (bottom) Dorsal = back Ventral = front Caudal = tail Rostral = head Lateral = side Medial = center

Anatomical Terminology Brain topography terminology –A gyrus (gyri) is a bump –A sulcus (sulci) is a shallow groove –A fissure (fissures) is a deep groove Gyrus Fissure Sulcus

Anatomy of the Cortex Major anatomical landmarks –Longitudinal Fissure separates hemispheres –Central Sulcus –Lateral (Sylvian) Fissure –Parieto-Occipital Sulcus (internal)

Anatomy of the Cortex Major lobes of the cortex Demarcated by fissures and sulci –Frontal lobe - anterior to central sulcus Thinking, planning, executive function –Parietal lobe - posterior to the central sulcus Association area –Temporal lobe - inferior to the lateral fissure Auditory function –Occipital lobe - posterior of cortex Vision

Anatomy of the Cortex

White Matter – has myelin sheath. Gray Matter – no myelin. Cell bodies are here.

Cranial Nerves - 12 pairs

Spinal Pathways Spinal cord has two gray matter horns which contain cell bodies. The two sides are connected by the gray commissure, and are surrounded by white matter, which carries tracts. Dorsal horns receive sensory afferents. –Afferent somas external in dorsal root ganglia Ventral horns carries somatic motor efferents. –Efferent somas in ventral horns

Sensory Pathway R