Textbook Notes (368,788)
Canada (162,165)
Psychology (773)
PSYC 208 (36)
Paul Wehr (21)
Chapter

Ch 2 - The Human Brain.docx

14 Pages
105 Views
Unlock Document

Department
Psychology
Course
PSYC 208
Professor
Paul Wehr
Semester
Fall

Description
Form & Function of the Human Brain 9/24/2012 9:03:00 AM Human Brain  Weight: 1300 – 1400 grams (adult); 350-400 grams (newborn)  Number of total neurons: 100 billion o Send/receive signals, process information (most important part of brain)  Umber of cortical neurons: 20 billion o When studying human type brain/human-like psychology behavior o Outside in cerebrum  Number of synapses in cortex: 150000000000000 o Synapse: interface between two neurons to communicate with each other  Percentage of genes expressed in the brain: 55% o Suggests that brain is primary target of natural selection in human evolution Neural Communication  Two types of neurons o Gray matter: neurons without myelin sheath (processing information) o White matter: neurons with myelin sheath (connect different regions)  Myelin sheath insulates and it accelerates the speed by which info travels  Primarily used to transport information (super highways) o Two neurons don’t touch each other (synaptic cleft) o Information travels only in one direction o Soma: body of the cell (genes are housed there) o Info comes in from dendrites  Presynaptic Neuron – transmitter  Postsynaptic Neuron – receiver  Action Potential: electrical charge indicating a neuron has “fired” o When it sends its message  Two types of messages that can be received o Excitatory  Transmitting telling receiving neuron to fire o Inhibitory  Transmitting telling receiving don’t fire  Plasticity: formation and disintegration of synapses throughout the lifespan o Synaptic pruning: remove synapses that aren’t used anymore Neurotransmitters  Acetylcholine (Ach): synapses with muscle tissue; involved in learning, memory, and emotion o Alzheimer’s: degeneration of Ach neurons  Inappropriate emotional responses, bad memory  Dopamine: involved in voluntary motor activity (move around) o Parkinson’s: degeneration of the substantia nigra  Substantia nigra: factory that produces all dopamine o Schizophrenia: excessive activity in frontal cortex  Epinephrine: mobilizes energy resources  Norepinephrine: regulates sensory arousal and attention o Deficiency can lead to attention deficit/hyperactivity disorder (ADHD), impulsivity, lower pain threshold  Serotonin: sleep, wakefulness, temperature regulation, appetite; aggression, social status and risk taking o Deficiency associated with depression o Excess activity associated with antisocial personality o Deficiency or excess associated with obsessive-compulsitve disorder Amino Acids and Neuropeptides  Amino Acid Neurotransmitters: o Glutamate: primary general excitatory neurotransmitter involved in learning processes and consciousness (brings up activity everywhere in the brain)  Excessive activity associated with psychotic symptoms  Hallucination: hearing voices that obviously aren’t there  Delusion: believe something unreasonable to be true o GABA: primary general inhibitory neurotransmitter  Deficiency associated with epileptic seizure, catatonic syndromes  Seizure: whole brains firing until it runs out of fuel and you pass out to wake up later with no memory  GABA normally puts it out  Neuropeptides: synthesized in the hypothalamus and pituitary gland; modulate neurotransmitter activity o Beta-endorphin: pain relief and relaxed euphoria in response to tissue damage or fearful stimuli  Hand “throbbing” is an illusion, it’s not actually throbbing o Oxytocin: reduces aggression and promotes parental and partner bonding (released during breastfeeding and orgasm); more abundant in females  Kind of opposite from testosterone  The “love drug”  orgasm makes you feel love o Vasopressin: promotes male sexuality and aggression o Neurotrophins: neurogenesis – creation of new neurons, and migration Hierarchy of the Nervous System  Pain from toe travels from somatic nervous system through spinal chord to brain to feel pain  Sympathetic nervous system increases activity, release hormones  Parasympathetic nervous system shuts everything down, stops releasing hormones Organization and Functions of the Brain  Brain  Rhombencephalon (hindbrain) / Mesencephalon (midbrain) / Prosencephalon (forebrain) o Hindbrain: basic physiological functions  E.g. takes care of things like breathing o Midbrain: neurotransmitter production  E.g. dopamine  Forebrain  Diencephalon (thalamus & hypothalamus) / Telecephalon (limbic system & cerebrum) o Thalamus & hypothalamus: sensory information & endocrine system (4 Fs)  Smell is the only sensory info that doesn’t go through the thalamus first  Hypothalamus controls endocrine system  Fighting, fleeing, feeding, mating o Limbic system & cerebrum (emotion & cognitive functioning)  Oldest structures of the brain, shares these three parts with many other species Brainstem  Hindbrain o Cerebellum: fine tunes motor movement; learning repeated motor movement  E.g. ballet, dance, piano…  Classical conditioning  Vocalizing language (precision movements between lips, jaws, tongue) o Pons: sleeping, waking, dreaming o Medulla: involuntary body functions (breathing, heartrate…) o Localization of function: different regions of the brain are specialized to do different, but overlapping tasks  Midbrain o Basal ganglia: action selection (motor) o Substantia Nigra: dopamine production o Integrates sensory information o Reticular Activating System (RAS): monitors background information and arouses higher order processes for events that warrant closer attention  Oh, somebody’s throwing a snowball at me  Oh, he’s really good looking  Wait, what are the kids up to Forebrain  Thalamus o Reroutes sensory information  Hypothalamus o Basic survival & reproduction o Pituitary (master) gland  Limbic System o Amygdala: emotion  Facial expressions, when you experience emotions, evaluation stimulus to decide what’s the proper emotion o Hippocampus: long-term memory  Long-term memory stored in cerebrum, but gateway is hippocampus o Mammilary body: smell & memory  Tags smell to memory o Septal nuclei: pleasure center The Four Lobes of the Cerebrum  Occipital lobe o Visual cortex (info from eyes – color, shading, shapes)  Parietal lobe o Somatosensory cortex (bodily physical senses)  Temporal lobe o Auditory cortex o Wernicke’s Area  Taking sounds and comprehending language (speech, reading)  Frontal lobe o Motor cortex & Broca’s Area  Broca’s Area (production of language) o Prefrontal lobe: personality o Social judgment, planning, rational decision making Lateralization  Right & left hemisphere specialized for different tasks; connected by the corpus callosum  Left-hemisphere specialization: o Control right-side of body o Linear speech: production, grammar, comprehension o First-person perspective  Right hemisphere specialization: o Control left-side of body o Holistic speech: intonation, metaphor, emotional prosody (musical aspect of speech, not monotone) o Spatial tasks o Third-person perspective  Women are less lateralized than men o Female brains are more symmetrical, right and left hemispheres will share tasks Evolution of the Human Brain 9/24/2012 9:03:00 AM Announcements:  Midterm: October 5h  Chapter 1- 3 (no heavy neuroscience content)  All of Ch. 1, except for Genetics  Ch. 2, neurotransmitters – don’t really need to answer questions (class notes only)  Ch. 1, genetics (1.4) will not be tested  Ch. 2, anything to do with brain evolution will be tested o Neuroscience (lateralization, pseudo-architecture of cortex, how it works) Triune Brain  Reptilian: changed little throughout mammalian evolution o Basic vital functioning (temperature, blood, pressure, respiration, sleep); instinctual behavior (classical conditioning)  Palaeomammalian: changed much throughout primate evolution o Limbic system (primary target of natural selection) o Regulation of emotion & motivation of complex behavior (e.g. parental care, exploration)  Neomammalian: significant changes during hominid evolution o Cognition (behavioral flexibility, perception, consciousness, decision making, memory…)  Older parts of the brain operate independently of newer parts of the brain (e.g. breathing vs. perception) Encephalization  Brain size increases with body size but at a slower rate o Rat (400 g):2g (0.5%) o Elephant (5,455,000g):4783g (0.1%) o Human (68,000g):1400g (2%)  Progression Index (PI): brain weight of the species/average brain weight of similarly sized species o Primate brains are 2-3 times larger than expected for a mammal of comparable size o Human brains are about 8 times larger than expected o Humans are most encephalized species  Frontal cortex: where all the uniquely human activities occur  Skull thickness o Human skull isn’t that thick compared to a chimp’s Brain Volume Over Time  Capacity to use tools  explosion of evolution of brain size o Rapid increase in brain size Brain Size and Guts  Bigger brains require extra energy o Brain uses 16% of basal metabolic rate o Digestion uses 15% (get net increase in energy)  Could reduce digestion to give brain more energy, but there’d be a decrease in net energy  Inverse relationship between brain size and stomach size o Reduce digestive tract by eating meat; easier to digest  Meat is easier to digest than the fiber of plants (don’t need digestive tract to be so long) o Humans have small intestine – protein rapidly broken down  Small intestine  evolved for the digestion of meat (chimps don’t have it) o Divert energy surplus to brain  Large brain is very expensive! What forces selected for it? o Social Brain Hypothesis Brain Evolution  Allometric Changes: o Olfactory bulb: PI = 1/40  Sense of smell (gotten smaller) o Neocortex: PI = 156 (chimp PI = 58)  Outer part of brain (uniquely human cognitive functions) o Amygdala: PI = 3.9 o Hippocampus: PI = 4.2  Progression of memory o Enlarged Basal Ganglia  Involved in selection of motor actions o Enlarged Cerebellum and Ne
More Less

Related notes for PSYC 208

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit