Biological Psychology Final Notes
Chapter 2- Darwin was the first to suggest how evolutionoccurs. Humans belong to the primate family known as hominins. Characteristics that evolved to perform one function but were co-opted to perform another function are called exaptations. Each group of three consecutive nucleotide bases along the strand of messenger RNA is called a codon, which instructs the ribosome to add amino acids to the protein being constructed. Subsequent to the nature-nuture issue, a second line of thought surrounding the biology of behavior is the dualistic physiological-psychological debate.
Courtship displays are thought to be important because they premote the evolution of new species. Amphibians evolved from bony fishes and later into reptiles, the first vertebrates to lay shell-covered eggs and to be covered with dry scales.
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In most species mating is indiscriminate or promiscuous; however, there are some species in which males and females create mating bonds with members of the opposite sex. Genes that contain the information necessary for the synthesis of proteins are enhancer genes. Not all DNA is found in the nucleus of the cell; some is found in mitochondria.
Monoallelic expression occurs when one of the two alleles of a gene is inactivated, due to an unidentified epigenetic mechanism, and the other allele is expressed. Descartes claimed the mind is made up of the soul, body, and spirit. RNA is like DNA except it contains the base uracil instead of thymine. Epigenetic mechanisms are thought to be the mearns by which a small number of genes are able to orchestrate the development of human complexity. The mate-bonding pattern in which bonds are formed between one male and one female is known as monogamy. Evolution is not always adaptive.
Incidental non-adaptive byproducts are called spandrels. Mitochondria are energy generation structures that are located in the cytoplasm of every cell. Each chromosome has double stranded molecules known as DNA and each is a sequence of nucleotide bases. Courtship displays are thought to be important because the premote the evolution of new species. Chapter 3- CNS is made up of the brain and spinal cord. PNS is located outside the skull and spine and serves to bring info to the CNS and carry signals out of the CNS. PNS: Somatic Nervous System – Afferent nerves (sensory) Efferent nerves (motor).
Autonomic Nervous System- Sympathetic and parasympathetic nerves and both nerves are efferent. Sympathetic – thoracic and lumbar, “fight or flight,” second stage neurons are far from the target organ. Parasympathetic – cranial and sacral, “rest and restore,” second stage neurons are near the target organ. All nerves are efferent. Sympathetic and parasympathetic generally have opposite effects. Two stage neural paths, neuron exiting the CNS synapses on a second stage neuron before the target organ. Protective mechanisms of the CNS – bone (brain & spinal cord), meninges (protective membranes), cerebrospinal fluid, and blood brain barrier.
CNS encased in bone and covered by three meninges: dura mater- tough outer membrane, arachnoid membrane – web like, pia mater – adheres to CNS surface. Ventricles & spinal cord – contain spinal fluid, cushion against mechanical shock, delivery of hormones, delivery of nutrients. Cerebral Vascular system – delivery of nutrients (glucose, thiamine), delivery of hormones (communication), thermoregulation (maintain temperature), blood brain barrier. Two Types of Cells in Nervous System: neurons – transmit electrical and chemical signals, different types of neurons.
Glia – different types, different functions. Neurons – specialized cells for the reception, conduction and transmission of electrochemical signals AND many sizes and shapes. Neurons-messengers-release of chemical that forms communication with other neurons. Semi-permeable membranes – uncharged molecules; move freely across membrane, a few charged molecules (sodium, potassium, calcium, and chloride) move through channels, lipids (fat molecules) are key components of the membrane, protein molecules are the key components of ion channels.
Glial cells (forgotten cells): glial cells – support neurons, recent evidence for glial communication and modulatory effects of glia on neuronal communication. Types of glial cells: oligodendrocytes- extensions rich in myelin create myelin sheaths in CNS. Schwann cells- ssimilar to function of oligodendrocytes but in PNS, can guide axonal regeneration. Astrocytes- largest glia, star shaped, many functions. Microglia- involved in response to injury or disease. Radial glia- form temporary network to facilitate neural migration.
Phagocytic microglia in the flat-mounted inner retina of the rat following transection of the optic nerve – the neurons were axotomized and retrogradely labelled with the fluorescent dye, Due to the membranophilic property of the dye, microglial cells became transcellularly stained after phagocytosis of 4Di-10ASP-labelled neuronal debris. Inside the phagocytes, incorporated membranes are accumulated in phagosomes, which are detectable even years after the neuronal injury. Golgi stain – allows for visualization of individual neurons and general shapes.
Nissl stain – selectively stains cell bodies; permits quantification of cell bodies. Electron microscopy – details of neuronal structure. Neuroanatomical Tracing Techniques: Anterograde(forward)- tracing to where axons project away from an area. Retrograde (backward)- tracing from where axons are projecting into an area. Contralateral–opposite side. Ipsilateral – same side. Gray matter – inner component, primarily cell bodies. White matter – outer area, mainly myelinated. Forebrain: Cerebral hemispheres & Cortex, Hippocampus, Basal ganglia, Thalamus, Hypothalamus.
Midbrain: Tectum, Tegmentum, Superior Colliculus, Inferior colliculus, Substantia nigra. Hindbrain: Pons, Cerebellum, Medulla axons. Chapter 4: Membrane potential: difference in electrical charge (charged particles or ions) between inside and outside of cell. Resting membrane potential: Resting membrane potential is about –70 mV, Potential inside of the neuron is 70 mV less than that outside of the neuron, When difference in potential exists, the membrane is said to be polarized (carries a charge). Ions move in/out through ion-specific channels. Potassium (K+) and Chloride (Cl-) pass readily.
Sodium (Na+)-little free movement across membrane. Negatively charged proteins (A-)– Synthesized within the neuron, Found primarily within the neuron, A-don’t move at all, trapped inside. Binding of neurotransmitters to receptors causes changes in the electrical charge. Depolarizations (membrane potential less negative) result in excitatory postsynaptic potentials (EPSPs). Hyperpolarizations (membrane potential more negative) result in inhibitory postsynaptic potentials (IPSPs). Threshold of activation (-65 mV) must be reached near the axon hillock.
Spatial summation : Adding or combining individual signals (PSPs) happening at different places into one overall signal. Temporal summation: Adding or combining individual signals (PSPs) happening at different times into one overall signal. Synthesis, Packaging, and Transport of Neurotransmitter Molecules- The chemical signal: Neurotransmitter molecules — Small; Synthesized in the terminal button and packaged in synaptic vesicles. Large; Assembled in the cell body, packaged in vesicles, and then transported to the axon terminal.
Major Events in Neurotransmission– The arrival of an AP at the terminal opens voltage-activated Ca2+ channels, The entry of Ca2+ causes vesicles to fuse to the presynaptic membrane and be released into the synaptic cleft. Exocytosis – the process of NT release. Glutamate – Most prevalent excitatory neurotransmitter in the CNS. Astrocytes appear to communicate and to modulate neuronal aactivity. Chapter 15: “Addicts” are those who continue to use a drug despite its adverse effects on health and social life . Most addictive drugs target dopamine pathways and other NTs.
Psychoactive drugs – drugs that influence subjective experience and behavior by acting on the nervous system: In order for a psychoactive drug to have an effect, it must get to the brain – it must pass through the blood-brain barrier, Action of most drugs terminated by enzymes in the liver – drug metabolism, Small amounts may also be excreted in urine, sweat, feces, breath, and mother’s milk. Alcohol: A depressant. Marijuana: Cannabis sativa – common hemp plant. Medicinal Uses of Marijuana: Treats nausea, Blocks seizures, Dilates bronchioles of asthmatics, Decreases severity of glaucoma.
Reduces some forms of pain. • Drugs influence availability of neurotransmitters. – Agonist – if drug mimics or enhances NT– Antagonist – if drug inhibits NT aactivity. – Affinity – if drug binds to a receptor. – Efficacy – its tendency to activate the receptor. Relapse – priming doses (prefrontal cortex), drug associated cues (amygdala), and stress (hypothalamic stress circuits). Chapter 5: MRI ? High resolution images. ? Constructed from measurement of waves that hydrogen atoms emit when activated within a magnetic field. PET scan ?
Provides images of brain aactivity ? Scan is an image of levels of radioaactivity in various parts of one horizontal level of the brain ? A radiolabeled substance is administered prior to the scan. Chapter 6: Light enters the eye through the pupil, whose size changes in response to changes in illumination. Sensitivity – the ability to see when light is dim. Acuity – the ability to see details. Lens – focuses light on the retina. Ciliary muscles alter the shape of the lens as needed. Accommodation – the process of adjusting the lens to bring images into focus.
Myopia – nearsightedness – inability to bring distant objects into focus; eyeball too long or cornea too curved; focal point of light falls short of the retina. Hyperopia – farsightedness – inability to focus on near objects; eyeball too short or lens too flat; focal point of light falls beyond the retina. Presbyopia – oldsightedness – lens loses elasticity; unable to refract light; most people over 50. Convergence – eyes must turn slightly inward when objects are close. Binocular disparity – difference between the images on the two retinas.
Light passes through ganglion and bipolar cell to visual receptors and then…? Photoreceptors (rods and cones)? Horizontal cells? Bipolar cells? Amacrine cells? Retinal ganglion cells? Axons of the ganglion cells leave the back of the eye as the optic nerve. Cones: Photopic (daytime) vision. High-acuity and color information in good lighting. Concentrated in the fovea. ? Rods: Scotopic (nighttime) vision. High-sensitivity, allowing for low-acuity vision in dim light, but lacks detail and color information. Found only in the periphery.
Rods: High convergence increased sensitivity, decreased acuity. Cones: Low convergence ? less sensitivity, increased acuity. Fovea: high acuity area at center of retina. Optic nerve is made up of axons of ganglion cells. We continually scan the world with small and quick eye movements – saccades. Transduction – conversion of one form of energy to another. Receptive field: The area of the visual field within which it is possible for a visual stimulus to influence the firing of a given neuron. Most neurons in V1 are either ?
Simple – receptive fields are rectangular with “on” and “off” regions, or all monocular ? Complex – also rectangular, larger receptive fields, respond best to a particular stimulus anywhere in its receptive field and many are binocular. Chapter 7: Primary cortex–input mainly from thalamic relay nuclei • Secondary Cortex – input mainly from primary and secondary cortex within the sensory system • Association Cortex – input from more than one sensory system, usually from secondary sensory cortex. Sensation – detecting a stimulus • Perception – understanding the stimulus.