PSY 2012 General PsychologyChapter 2: Biopsychology

Samuel R. Mathews, Ph.D.Associate Professor

The Department of PsychologyThe University of West Florida

Biological Psychology: Core Concepts

• At the species level there are unique characteristics that are explained within biological and psychological sciences from the Evolutionary Perspective

• At the individual level unique characteristics are influenced by one’s Genotype (inherited genetic make-up from biological parents) and Phenotype (the way the genotype is expressed)

Evolutionary Perspective• All species have a common origin;

• Individual organisms with attributes that allowed them to survive and breed, were more likely to pass on the genetic structure to offspring who themselves had a higher likelihood of surviving;

Biological Psychology: Core Concepts• Evolutionary Perspective—

– Based on a scientific approach of prediction, data collection, analysis, interpretation, questioning and further prediction with testing and revision.

– Other perspectives based on authority or belief that disallow analysis of empirical data in favor of belief are not the purview of science. They are grounded in philosophical or theological perspectives

Biological Psychology: Core Concepts

• At the individual level, Genetic Codes play a role in the unique individual characteristics

• Genotype—unique genetic code inherited by the individual from biological parents

Biological Psychology: Core Concepts

• Phenotype—expression of the genotype in physical and psychological characteristics– Impacted by biological and environmental

forces• Biological forces: disease, toxins, injury• Environmental forces: access to health care,

access to stimulation from the environment

How Natural Selection Works

Environmental pressureEnvironmental pressure(changes in the environment)(changes in the environment)

CompetitionCompetition(for resources)(for resources)

Selection of fittest phenotypeSelection of fittest phenotype(from among a variety of phenotypes)(from among a variety of phenotypes)

Reproductive successReproductive success(genotype corresponding to fittest (genotype corresponding to fittest

phenotypes passed to next generation)phenotypes passed to next generation)

Frequency of that genotype increasesFrequency of that genotype increases(in next generation)(in next generation)

The Individual: Chromosomes, Genes, and Inherited DNA

• Why are some people shorter than others?

• Why are some babies unable to digest protein?

• Why are some children born with Down’s syndrome?

• Why did Sam’s hair fall out?

The Individual: Chromosomes, Genes, and Inherited DNA

Chromosomes— the structure that carries the genetic material (DNA) 23 pairs— half contributed by the biological mother

and half by the biological father

• Chromosomes are made up of genes—with specific DNA codes. – Each gene is responsible for some characteristic of

the organism and work in concert with others to yield the whole organism

The Individual: Chromosomes, Genes, and Inherited DNA

• One pair of chromosomes determines our biological sex– The biological mother contributes the X– The biological father contributes either

another X or a Y chromosome.• XX= female (more female fetuses survive than

males)• XY=male

The Individual: Chromosomes, Genes, and Inherited DNA

• Relationship between genotype and characteristics and behaviors is complex;– Inheriting a genotype linked to some

psychopathology does not mean individuals will experience that pathology (e.g. schizophrenia).

– Impact of the pathology is frequently minimized by alterations in the environment (e.g. corrective lenses).

Hot Issues in Genetics

• Cloning

• Choosing the sex of your child

• Diagnosis of genetic fetal abnormalities

• Choosing your mate

• Social engineering

The Central Nervous System

The Homer Brain

The Human Brain

Brain Structures and Functions

• Brain stem (reptilian brain)– First to evolve– Life-sustaining systems: breathing, pulse rate– Similar to brains of reptiles

• Cerebellum– Coordination of “automatic” movements

(walking, dancing)– Processing other temporal (time related)

stimuli (e.g. music)

Brain Structures and Functions

Limbic system– Emotion, memories, desires– Functions to help us remember highly emotional

experiences– Contains the hypothalamus—control center for many

functions

• Cerebral cortex– Last to evolve– Linked to higher mental processes– Different areas or “lobes” control different functions

Cerebral Cortex: Higher Mental Functions

Frontal Lobe

• “Executive functions”—Planning, controlling, recognize future outcomes from current actions etc.,

• Broca’s area of the frontal lobe—production of complex language

• Motor functions—controls voluntary muscle groups• Matures later—late adolescence into young adulthood• Issues focus on culpability for crimes among early and

middle adolescents• Alcohol likely decreases the functioning of this part of the

brain related to impulse control (Amen, 1999)

Parietal Lobe

• Receives input from senses• Distributes sensory information to other

parts of the brain• Spatial information is processed—location

of limbs in space, location of sounds, etc.,• Supports selective attention to particular

sensory information• With parietal lobe damage, attention may

be disrupted (Vecera & Flevaris, 2004)

Occipital Lobe

Visual information—color, brightness, motion, etc., Specialized areas for human face recognition Infants, at birth, orient to human face in lieu of other

stimuli

Temporal Lobe

• Left temporal lobe (Werneke’s area) language comprehension, naming, etc.

• Auditory sense is processed

Peripheral Nervous System

• Somatic Nervous System—links with senses and voluntary muscles

– Sensory Nervous System—brings information FROM the senses to the central nervous system

– Motor Nervous System—carries information from the central nervous system TO the muscles for action

Peripheral Nervous System

• Autonomic Nervous System—links internal glands and organs– Sympathetic Division—arouses our systems when the need

arises (e.g. startling stimulus, anxiety producing stimulus, sexual arousal)

– Parasympathetic Division—inhibits our systems or reduces the arousal (reduces salivation, inhibits digestive juices in our stomachs)

Putting it all together: Puberty

• The experience of puberty is one in which we can examine the relationship among species-specific and individual differences, among the CNS and endocrine system, and social factors.

Puberty Process• Hypothalamus (part of the brain that controls much of the

endocrine system) Gonadotropin Releasing Hormones (GRH)Pituitary Gland

• Pituitary gland GonadotropinGonads (ovaries/testes)

• Gonadsstimulate release of sex hormones (estrogens/androgens) that stimulate secondary sex characteristics

Puberty Process:• Process begins approximately 2 years prior to initial

secondary sex characteristic changes;

• Timing of puberty, particularly for females, is related to timing of maternal puberty but environmental factors also have a major impact;

• Hypothalamus secretions typically increase during deep sleep;

• Males and females produce both estrogens and androgens but in different proportions;

Puberty Process: Physical Changes

• Secondary sex characteristics (Phenotype)– Body/pubic hair (males and females)– Breast enlargement (most obvious in females)– Increase in growth rate (females and males)– Changes in voice (most obvious in males)– For females, increase in fat to muscle cell

ratio (increase in fat cells relative to muscle cells)

Puberty Process: Physical Changes• For females: as level of estrogen increases, the

hypothalamus produces Gonadotropin Inhibiting Hormones (GIH). This inhibits the production of estrogen by the ovaries;

• The periodic cycle of increases and decreases in estrogen controls the ovulation cycle.

• Estrogen is stored in fat cells so the increase in fat cells relative to muscle cells allows the critical level of estrogen necessary for ovulation.

Neurological Changes

• Myelinization– Fatty tissue surrounding nerve cells in the

brain– Increases the efficiency of transmission of

signals across the synaptic junctions in the brain

– Made up of cholesterol and proteins– Rapid increase of myelinization during and

after puberty through adolescence

Neurological Changes

• Elaboration of synaptic connections– Neurons form new connections based on

experience throughout the lifespan;– Plasticity still a major force—brain responds to

stimulation

Neurological Changes

• Frontal cortex major area of development across adolescence– Maturation of neurological systems that allow:

• Planning• Regulation of emotion• Monitoring

– Prediction based on this is that across adolescence, ability to forecast, anticipate long-term outcomes and recognize risk is limited

Health Practices and Puberty Process

• Nutrition—balanced diet including appropriate levels of carbohydrates (myelinization)

• Sleep—reasonable opportunities for deep sleep (supports initiation and maintenance of puberty process)

• Limited alcohol consumption—some evidence that alcohol interferes with hormonal balance of pubescent females