PsychoBIO Unit 1

psychobiology

study of the bidirectional relationship between the brain and behavior

Brain and spinal cord

Central nervous system CNS

Everything else like your neurons and nerve processes, the network of nerves that connects your brain and spinal cord to the rest of your body

Peripheral nervous system PNS

Aristotle and Mentalism

-Human Behavior is produced by the psyche

-role of mind is large

-role of brain is nothing

Descartes and Dualism

-Mind and body separate but connected

-role of mind medium

-role of brain medium

Darwin and Materialism

-Behavior is the function of the nervous system and mind is not important

-relative to today

-role of mind none

-role of brain large

Mentalism

explanation of behavior as a function of the mind, it is independent from the body

Aristotle believed…..

the brain cooled the blood and it had no role in producing behavior, also the mind was separate from the brain

Dualism

both the mind and brain contribute to behavior

Descartes believed……

mind interacts with the body to produce movement, working through the pineal gland at brain’s center

-brain and mind equally as important

Materialism

behavior can be explained as a function of the nervous system alone

-no mind, only brain

Darwin believed…..

evolution by natural selection explains how new species evolve and existing species change over time and also differential success in the reproduction of characteristics (phenotypes) results from the interaction of organisms with their environment

Natural selection

theory explaining how new species evolve and how existing species change over time

Phenotype

set of individual characteristics that can be seen or measured

ex: hair color, eye color

Genotype

particular genetic makeup of an individual

ex: DNA

Epigenetics

“beyond genes”

differences in gene expression related to the environment and experience, turned on or off

-switch genes

-do not change genes

-can persist throughout a lifetime

Contemporary brain theory is

materialistic

-objective, measurable descriptions of behavior that can be referenced to brain activity

-there is no role for the mind

Nerve Net

simple nervous system with no center; consists of neurons that receive sensory information and connect directly to other neurons that move muscles

-humans do not have

Bilateral symmetry

the nervous system on one side of the animal mirrors that on the other side

-humans have

Segmentation

the vertebrae (in humans) contain the repeating nervous system segments of the spinal cord

-broken in parts

Ganglia

resemble primitive brains and function somewhat like them in that they are comman centers

Spinal cord

a single nervous system pathway connects the brain with sensory receptors and muscles

Brain

the phylum chordata (amphibians, reptiles, birds, and mammals) display the greatest degree of encephalization; chordates have a true brain

Features of the chordate brain

-a brainstem, but birds and mammals have a large forebrain and cerebellum

-bilateral symmetry of the nervous system

-segmentation of the nervous system

-spinal cord and brain that are encased in bone

Encephalization Quotient EQ

Quantitative measure of brain size obtained from the ratio of actual to expected brain size, according to the principle of proper mass, for an animal of a particular body size

brain to body size

ex: human brain has the largest size relative to body weight

Estimates of brain size and behavioral complexity line up better…..

if cell counts are compared

The cognitive abilities of humans are best explained by

the number of cerebral neurons, we have a lot more neurons in our cerebral cortex

how many neurons in human brain

86 billion

the brain’s primary function is to produce

behavior (movement)

the brain is plastic meaning

-it changes overtime and neural tissue has the capacity to adapt to the world by constantly changing how its functions are organized

Afferent

information comes into the CNS→incoming

Efferent

information leaves the CNS→outgoing information

Somatic nervous system (SNS)

somatic=body

-monitored and controlled by the CNS

-cranial nerves by the brain

-spinal nerves by the spinal cord segments

SNS does…

it receives sensory information from the body, sensory receptors and nerves→afferent

sends motor information to the body, controls muscles→efferent

Autonomic Nervous system includes

-sympathetic nervous system

-parasympathetic nervous system

Sympathetic nervous system

portion of autonomic nervous system that controls functions that accompany arousal and expenditure of energy

fight or flight

Parasympathetic nervous system

portion of autonomic nervous system that controls functions that occur during relaxed state

rest and digest

Enteric nervous system (ENS)

network of neurons embedded in the lining of the gastrointestinal tract

-brain and ENS connect extensively through the autonomic nervous system via the vagus nerve

Anterior

toward the front

Posterior

toward the back

Dorsal and Superior

toward the top

Ventral and inferior

toward the bottom

Medial

toward the middle

Lateral

toward the outside

Sagittal cut

Cuts the brain right down the center, making a left and right side

Horizontal cut

Horizontal slice parallel to the ground

Splits the body or organ into upper (superior) and lower (inferior) parts

Coronal cut

Vertical slice that runs side-to-side

Splits the body or organ into front (anterior) and back (posterior) sections

Meninges

three layers of protective tissue that encases the brain and spinal cord

-like wrapping paper for the brain

Cerebrospinal fluid (CSF)

-cushions the brain

-circulates regularly and gets cleaned regularly

-brain sits in fluid, acts as another protective shield

Cerebral cortex

outer part of the brain; extensive folding in humans

-two nearly symmetrical left and right hemispheres

-each hemisphere is divided into four lobes

Frontal lobe

motor and executive functions

primary motor cortex

Parietal lobe

sensory integration and tactile somatosensory functions (some visual)

Primary somatosensory cortex-body senses

Temporal lobe

auditory, taste, smell, memory and gustatory functions

Primary auditory cortex

Occipital lobe

visual functions

Primary visual cortex

Cerebrum

major structure of the forebrain, consisting of two virtually identical left and right hemispheres

Cerebellum (little brain)

involved in coordination of motor and possibly other mental processes

Gyrus or Gyri

A small protrusion or bump formed by the folding of the cerebral cortex

Sulcus or Sulci

a groove in brain matter, usually found in the neocortex or cerebellum

-little grooves in between the bumps

Fissure

a very deep sulcus

Brainstem

central structures of the brain, including hindbrain, midbrain, thalamus, hypothalamus, responsible for most unconscious behavior

Stroke occurs

with blockage or break in cerebral artery

Ischemic

blocked blood vessel

hemorrhagic

burst blood vessel, leaking

Gray matter

areas of the nervous system predominantly composed of cell bodies and blood vessels

White matter

areas of the nervous system rich in fat-sheathed neural axons

-fat parts of brain

Corpus callosum

fiber system connecting the two cerebral hemispheres

Lateral ventricles (holes)

winged-shaped cavities filled with CSF made by a network of interconnected blood vessels

Neurons are connected to one another by

fibers known as axons

Tract

collection of nerve fibers in brain and spinal cord

Nerve

bundle of fibers outside the CNS

Spinal Cord

controls most body movements and can act independently of the brain

Spinal reflex

automatic movement

hard to prevent (brain cannot inhibit)

ex: knee-jerk reflex

In order from bottom to top

goes spinal cord to brainstem which includes hindbrain (lower brainstem) and midbrain (upper brainstem) then to diencephalon

Where does the brainstem begin?

begins where the spinal cord enters the skull

Hindbrain

-oldest part of the brain

-closet to spinal cord

-includes cerebellum, reticular formation, pons, and medulla

Cerebellum

plays a role in coordinating movement and in cognitive function

Reticular formation (also called reticular activating system)

stimulates the forebrain; regulation of sleep-wake behavior and behavioral arousal

Pons

controls important movements of the body

medulla

vital functions; control of breathing and heart rate

Midbrain

structures in this part of the brain are critical for producing orienting movements, species-specific behaviors, and pain perception

-includes the tectum and tegmentum

Tectum

is the roof of the midbrain

Tegmentum

is the floor of the midbrain

Diencephalon

this is the between brain, which integrates sensory and motor information on its way to the cerebral cortex

-is part of the forebrain

-includes hypothalamus and thalamus

Hypothalamus

contains many nuclei associated with temperature regulation, eating, drinking, and sexual behavior

feeding, fighting, fleeing, and fornication/mating

Thalamus

which information from all sensory systems is organized, integrated, and projected into the appropriate region of the neocortex

It processes and routes all incoming sensory signals—such as sight, sound, touch, and taste—to the correct areas of the cerebral cortex

central information relay station

Forebrain

-contains the four lobes, neocortex (cerebral cortex), allocortex (hippocampus, amygdala, cingulate cortex, and basal ganglia

-large

-the major internal and external structures integrate sensation, motivation, emotion, and memory to enable such advanced cognitive functions as thinking, planning, and using language

Amygdala (Allocortex)

anxiety and fear

body’s danger alarm

Cingulate Cortex (Allocortex)

emotion formation and processing, learning, memory, linking behavior to motivation

Hippocampus (Allocortex)

plays a role in spatial navigation, learning, and memory

Basal Ganglia

controls voluntary and involuntary movement

-structures include caudate nucleus, putamen, and globus pallidus

the cortex has….

layers

Behavioral neuroscience/psychobiology

-study of the biological bases of behavior

-includes the study of both humans and laboratory animals

-major challenge is to develop methods for studying both normal and abnormal behavior

Animals

-rodents are most commonly used

-some disorders are easy to model like stroke, but behavioral disorders like ADHD is harder for them to model

-use IACUC for animals and IRB for humans

-Animal Welfare Act

Humans

-IRB

-neuropsychological testing, designed tasks to measure brain functions known to be linked to a particular brain structure or pathway

Electrical stimulation

-first used to stimulate the cerebral cortex of humans during neurosurgery

-the stimulation affects a neural circuit involving both eating and pleasure

-rats would keep pushing lever to keep having the electrical self-stimulation

Deep brain stimulation DBS

-involves surgery

-involves electrodes implanted in the brain stimulate a targeted area with a low-voltage electrical current to facilitate behavior

Transcranial magnetic stimulation TMS

-no surgery

-procedure is which a magnetic coil is placed over the skull to stimulate the underlying brain

-used either to induce behavior or disrupt ongoing behavior

-used for depression

-looks like figure 8

Single-cell recording (Activity)

measuring single-neuron action potentials with fine electrodes

Electroencephalography EEG (Activity)

measures the summed graded potentials from many thousands of neurons

Event-related potentials ERPs (Activity)

-graded potentials on dendrites that a sensory stimulus triggers

-related in time to a specific event

-in response to something/event