Psychology Biological Basis of Behavior

 “DNA, by itself, does nothing at all” Denis Noble, Genes and Causation  The expression of genotype is completely dependent on molecular, physiological, behavioral, and environmental conditions.  The gene is not an infallible unit of heredity, but rather part of an extremely complex, reciprocally-determined developmental system

Biological Basis of Behavior  Heredity and Behavior Darwin’s Theory of natural selection has been applied to the development of species-typical behaviors  Certain behaviors, that would serve to the survival and reproduction of the organism would become genetically- determined over many generations  This theory, while appealing, is generally frowned upon by developmental scientists The development of species-typical behavior is determined by the organism’s ontogenetic niche: a complex system of hierarchically-organized environmental and biological constraints that an organism would typically “inherit”  The ontogenetic niche includes genes, epigenetics, physical forces (gravity, temperature) and social experience.

Biological Basis of Behavior  Genotype: the genetic structure an organism inherits; DNA  Phenotype: The individual organism’s characteristics, resulting from the interaction between genetics and environment  Epigenenome: a series of molecular mechanisms (methyl groups and histones) that alter the expression of the genome as a result of environmental stimuli MZ or identical twins, who share 100% DNA, can have vastly different epigenomes, based on experience, and therefore can have vastly different developmental outcomes Epigenetic tags can be inherited  Your behavior can effect your epigenome and the epigenome of your children/grandchildren.

Neurology  Central Nervous System (CNS): Brain and spinal cord Communication Reflexes  Peripheral Nervous System (PNS): the nerve fibers that connect the CNS to the rest of the body. The peripheral nervous system is composed of two subsystems: Autonomic Nervous System: regulates basic life processes and survival; unconscious; responds to threats (fight or flight)  Sympathetic division: EMERGENCY!!  Parasympathetic: routine, homeostasis Somatic Nervous System: regulates conscious actions of skeletal muscle

Neurology  Sensory Neuron: carry messages from sense receptor cells toward the CNS There are different kinds of sensory neurons specializing in different senses  Photoreceptors  Chemoreceptors  Nociceptors  Ect…  Motor Neuron: carry messages from the CNS to muscles and glands  Interneuron: part of the intermediate network between sensory, motor, and other interneurons.  Mirror Neurons*: a neuron that responds when an individual observes another performing a motor action or experiencing a sensation, has implications for social imitation and empathy; only observed in non- human primates.  Glia cell: “support cells” or scaffolding for neurons

Neurology  Plasticity: The malleability of neural structures in response to experience.

Neurology

Neurology

 Neurotransmitters: chemical messengers from one neuron to the next Influenced by stimuli, behavior, and drugs Problems occur when there is too much or too little

Neurology Common Neurotransmitters Acetylcholine: skeletal muscles, attention, memory Dopamine: voluntary movement, “reward system” Norepinephrine: mood and arousal Serotonin: sleep & wake cycle, aggression GABA:regulation of anxiety Glutamate: learning and memory Endorphins*: pain relief and stress response Oxytocin*: social bonding

Brain Imaging  PET (positron emission tomography)  CAT or CT (computerized axial tomography)  EEG (electroencephalogram)  MRI (magnetic resonance imaging)  fMRI (functional magnetic resonance imaging)

Brain Imaging: Your Professor’s Brain!

Neuroanatomy: Brain Stem  Medulla: regulates breathing, blood pressure, and heartbeat  Pons: “bridge” between spinal cord and brain; regulates sleep  Thalamus: relays sensory information

Neuroanatomy: Limbic System  Hippocampus: explicit memory  Amygdala: emotion, aggression, fear, and related memories  Hypothalamus: motivated behavior and homeostasis  Olfactory Bulb: smells

Neuroanatomy: The BRAINS (Cortex)!!

Neuroanatomy: BRAINS!!  Cerebrum: the region of the brain that controls higher cognitive and emotional processes (the brain-looking part). Divided into left and right hemispheres: Left and right hemispheres are connected by the corpus collosum, anterior and posterior commissures. Cerebral cortex: the outer surface of the brain  Sulci: the trenches in the cortex  Gyri: the folds of the cortex  Cerebellum: attached to the brainstem and controls motor coordination, posture, and balance

More BRAINS!!

 The sensory and motor cortex strips are bilateral, with the left hemisphere controlling the right side of the body, and the right hemisphere controlling the left side of the body  The sensory and motor cortex strips allocate space based on complexity and sensitivity

“Split Brain” Patients 

Endocrine System & Behavior  The endocrine system uses hormones to supplement the work of the nervous system The endocrine system regulates metabolism, and influences body growth, mood, and sexual characteristics  Pituitary: the “Master Gland” in the brain that regulates the endocrine system Endocrine glands include:  Thyroid  Adrenals  Pancreas  Ovaries  Testes

Take Away  The brain is super complicated! No one spot is “in charge” of any process; it’s all about the connections and interactions between areas  Experience effects neurology and neurology effects experience Either chemical (drugs) or environmental (behavior) can break and change the entire cycle