Biological basis of behavior(2)

 Prof . Elham Aljammas

MAY2015L18

Organization & Structure The central nervous system has an inherent organization and structure. With an understanding of cellular activity, we then study

this organization . The Central Nervous System comprises the brain and spinal cord.

 The Peripheral Nervous System comprises the

nerves external (peripheral) to the spinal cord . The Autonomic Nervous System is comprised of the Sympathetic and Parasympathetic Nervous Systems. These systems are responsible for activating and de-activating internal states

needed at moments of "fight vs. flight ."

Division of the Lobes of the Cerebral Cortex 

Frontal Lobes :Planning, coordinating, inhibiting actions Supervisory control over cortex

Motor relay station

Temporal Lobes :Primary auditory reception and relay (cortical( Auditory and musical memory

Sense of timing

Parietal Lobes :Primary somatosensory reception and relay

Arithmetic & Language Organization (angular gyrus( Sense of position & direction

Occipital Lobes :

Primary (cortical) visual reception and relay Visual perception Sensory and Motor Areas :

Cortical sensory perception Cortical motors control

 Neuropsychology of Speech :

Broca's Area (expressive) and Wernike's Area (receptive) are crucial to communication .

 

Epilepsy :"Epileptic Seizures result from random electrical activity. This electrical activity spreads from one brain area to many, creating an overload of

synaptic activity . 

"Split-Brain Procedure :"In order to control the electrical activity caused by epileptic seizures, researchers separated the hemispheres of the brain. By cutting the corpus

collosum, which connects the two hemispheres ,

explains the procedure and the resulting cognitive changes.

 I. Neurons: The Messengers 

A. Overview and general structural organization of nervous system

  B. Structure of Neuron

General . Dendrites Cell body

. Axon . Myelin sheath

. A Nerve or Tract is a group of axons bundled together.

  C. Kinds of Neurons:

Sensory (afferent; inward( Motor (efferent; outward(

. Interneurons (between afferent and efferent)

Note: also Glial cells (glia; "housekeeping"(

but they don't transmit impulses)

  D. The Neural Impulse: Transmission within a

neuron Polarization and Resting Potential

.

E. The Synapse: Transmission between neurons

  . The Synapse

  . The Pre-synaptic Anatomy and Activities

a. Terminal Button or Synaptic Knob b. Synaptic Vesicles

c. Neurotransmitters d. Synaptic Cleft or Synaptic Space

  The Post-Synaptic Anatomy and

Activities a. Receptor Sites

b. Reuptake 

. Neurotransmitters a. Acetylcholine

b. Dopamine, c. Serotonin ,

d. Norepinephrine, e. Endorphine

 

   Over 50 different kinds. Fragments of other organic moleculescan simulate neurotransmitters. Some neurotransmitters havemultiple functions (excitatory, inhibitory). Antagonists block orinhibit the normal process. Agonists facilitate it

Acetylcholine (ACh).

Usually excitatory. Attention, arousal ,

motivation, memory, skeletal muscle movement. Skeletal muscles and hippocampus. In muscles,

botulism toxin prevents release of Acetylcholine (Ach). Curareand cobra venom block receptor sites. Venom of black widowspider and certain nerve gases have a destroy Enzyme (AchE) thatdegrades Ach, allowing it to flood the synapse and prolong itsaction, causing convulsions. Possible link to Alzheimer's viareduced production of Ach in brain cells.

Dopamine. General Wide

range of behavior and emotions.

Excess = schizophrenia; shortage = Parkinson's disease.

Chlorpromazine, a tranquilizer, blocks receptor sites in brain .

Cocaine also inhibits reuptake of dopamine. This was theneurotransmitter focused on in the book/movie Awakenings,especially its chemical precursor L-Dopa.

 Serotonin. Generally inhibitory. Most activities, sleep onset,

mood, eating. LSD has similar structure and activates neurons inthe brain that are normally inhibited by that

neurotransmitter .Medications for depression and anxiety such as Prozac, Paxil,

Zoloft, and Luvox are all Selective Serotonin Reuptake Inhibitors

(SSRI.)

Norepinephrine (NE). Generally excitatory. Arousal,

wakefulness, learning, memory, mood. Neurons in brain stem .

Amphetamines, cocaine slow down reuptake and prolong action,

lithium speeds up the reuptake

 Gamma-aminobutyric acid (GABA): Inhibitory.

 Glutamate. Involved in long term potentiation.

 Endorphins : (name composed of endogenous morphine: naturalopiate-like neurotransmitter--or often referred to asneuromodulator—which is linked to pain control

and pleasure  

 II. Central Nervous System 

A. Brain . Hindbrain (central core(

a. medulla - controls breathing, heart rate, and blood pressure.

b. pons -- connects the cerebral cortex at the top of the brain to the cerebellum .

c. cerebellum -- controls certain reflexes, coordinates body movement,

and maintains equilibrium.

Midbrain (limbic system): The region between hindbrain and forebrain which is important for hearing and sight and is one

of the primary places in the brain where pain is registered. Hippocampus and

amygdala.

Forebrain a. Thalamus

b. Hypothalamus c. Cerebrum/Cerebral hemispheres

d. Cerebral Cortex

  B. Cortical areas and their functions .

Occipital: visual information . Temporal: auditory information

. Parietal: somato-sensory . Frontal: voluntary motor movement

  C. Hemispheric specialization

. Corpus callosum . Left Hemisphere

. Right Hemisphere" . Split-brain"" Psychosurgery

  D. Reticular formation: wakefulness,

alertness, arousal. Spread across hindbrain, midbrain, and into forebrain.

 

  E. Limbic system

Memory and emotions Primary structures:

a. Hippocampus b. Amygdala

 

 Cerebral lateralization Left hemisphere right hemisphereMemory for words & numbers Memory for shapes &musicWord recognition Facial recognitionPositive emotion negative emotionResponse to complex commands Response to simple commands 

  F. Spinal cord

Structure . Spinal reflexes

G. Tools for studying nervous system . Microelectrode techniques: inside the

neuron itself Macroelectrode techniques: EEG Alpha,

Beta, Delta and Theta Waves Structural imaging (CAT scan(

4 .Functional imaging (fMRI

  III. Peripheral Nervous System 

A. Somatic nervous system Skeletal (striped) muscles

B. Autonomic nervous system 1 .Smooth muscles.

2 .Sympathetic branch: a. Prepares for emergency or arousal.

b. Fight or Flight 3 .Parasympathetic branch:

a. calms, relaxes body, returns to normal; involved in digestion and

processes which conserve and protect bodily functions.

b. controlled in relaxation work, especially bio-feedback

  A. Function

1 .Release hormones from ductless glands into bloodstream

2 .Organize nervous system and body tissues

3 .Activate behavior 

B. Thyroid 1 .Regulates metabolism

2 .Affects activity level and emotional state. 

C. Parathyroids 

D. Pineal gland: Day-night activity levels 

  E. Pancreas

1 .Insulin/glucagon 2 .Blood sugar regulation

F. Pituitary 1 .Posterior

a. Vasopressin b. Oxytocin

2 .Anterior: "master gland;" a. Linked also to nervous system and

hormones released by hypothalamus b. Produces growth hormone

c. Releases ACTH (stress hormone) and can effect the adrenal glands

  G. Gonads

1 .Males: androgens (testosterone( 2 .Females: estrogens (progesterone(

3 .Sexual/reproductive function. Studies suggest that they have some other

effects, e.g., effects on aggression and on learning

H. Adrenal Gland  V. Behavior Genetics and Our Human Heritage 

A. Genetics 1 .Basic Facts.

2 .Chromosomes and Genes a. Genes

b. Chromosomes c. DNA

d. Dominant and recessive genes e. Sex-linked genes (M > F(

( 1 )color blindness( 2 )hemophilia

f. Blueprints or recipes? 

B. Genetics and Behavior 1 .Animal Behavior Genetics:

a. Heritability of behavioral traits b. Selective brding: Thompson

 

  2 .Human Behavior Genetics:

a. Human Genome Project: Map all 23 sets of human chromosomes.

b. Family Studies c. Twin studies: identical vs fraternal.

Schizophrenia: Identical twins 50%; fraternal 15%

d. Adoption studies 

C. Evolution: 1 .Natural selection: How evolution

occurs and which traits survive.

2 .Can restate Darwin using gene theory. 

  D. Evolutionary Psychology

1 .Environmental influences on gene action 2 .Evolution with its natural selection,

predisposes humans in certain ways, thus is the direct cause of certain

behavioral traits, e.g., aggressiveness and sexuality in men, submission and

nurturance in women. 

E. Social Implications 

F. Environment-Genetic Interaction : 1 .Genes predispose to environmental

influence, environment supplies influence to actually produce behavioral

effect 2 .Examples :

Diabetes <=> overweight Schizophrenia <=> stress

Thank you