Behavioral Neuro 1

behavioral neuroscience

Principles of biology to study the physiological, genetic, and developmental mechanisms of behavior in human and non-human animals

Explains how experience and env modifies brain and behavior

What B.N. uses to understand processes that underlie behavior

brain circuits, nerves, neurotransmitters

Synonyms for Behavioral Neuroscience

biopsychology

Biological Psychology

Physiological psychology

psychobiology

Neuroscience

study of nervous system

Biological Psychology (biopsychology and psychobiology)

same as behavioral neuroscience but more passe (outdated)

Neurobiology

same as neuroscience, more tradition in biology

Neurology

Medicine, studies brain and nervous system and diseases within it

Neuropsychology

similar to biopsychology but involves study of brain lesions to make inferences about function

uses cognitive tests and brain imaging

Psychophysics

not neuroscience at all

investigates relationship between physical stimuli and the sensations and perceptions that they affect

4 Categories of Biological Explanations

descriptive

Evolutionary

developmental

mechanistic

Descriptive

what does behavior look like

ex. features of learning

Evolutionary

how behavior looked earlier (what changed)

ex. how do different species compare in types of learning

Developmental

characteristics over life span

ex. when does learning first appear in life? How does it change over time?

Mechanistic

manipulation to relate a behavior to activity of the brain, circuits, cells, molecules, or genes

ex. chemical changes in brain to hold memory

Reductionism

approach to understanding based upon reducing the nature of complex things to their interactions or fundamental parts

complex system is nothing more than the sum of its parts

Emergentism

property of a system is more than the sum of its parts, cant be understood by combining them together

applies to consciousness (emergent property, at certain levels and in certain spaces)

still dependent on more basic properties, functions more like a parallel view to reductionism

Mind Body Problem

Concerned with reconciling the relationship between mental process and bodily state/processes

Predicament for philosophers

Dualism

different kinda of substance that exist independently (one for consciousness, one for behavior)

rational behind it not so unreasonable

problems with this idea

Monism

universe is only compromised of one type of substance

forms= materialism, mentalism, identity-position

Materialism

form of monism

everything that exists is physical

Mentalism

form of monism

physical and psychological phenomena are mentally constructed, only explicable in terms of the mind

Identity Position

form of monism

mental processes and brain process are the same but described in different terms

solves mind-body problem

Localization Theory

different parts of brain have different functions (relates to reductionism)

structures that look the same/different should have the same/different functions

we use this

Holism

brain function is not localized, function is distributed the same throughout

ex. motor functioning not linked to one area

History of Brain Research

B.C.E- Aristotle, Hippocraes, Pluto- heart, liver, not much role for brain

200 AD= Galen, surgeon, brain but ventricles not gray matter (brain injury= neurological damage)

1500s= Da Vinci and Vesalius, anatomists, stuck in ventricular localization of function

Thomas Wills

Oxford physician

cerebri anatome

proposed= cerebral hemispheres controlled memory, also tied to imagination

brain material implicated in sensation and movement

cerebellum and brain stem involved in vital and involuntary roles

description of brain to brain substance itself (not ventricles)

Rene Descartes

dualist

formulate dualist question in more concrete terms

brain as a reflexive machine (some functions were mechanical)

Bell Magendie Law

1811, 1822

dorsal spinal nerves roots contain only sensory fibers and ventral spinal roots contain only motor fibers

before= sensory and motor signals thought to be mixed

led to the idea that one might have to look at the nervous system in a different way

Franz Joseph Gall

founded phrenology

theory was debunked (along with localization)

holism filled its place

Phrenology

skull features were indicative of brain development, faculties could be detected by surface features

Holism Takes Over

localization fell

Pierre Flourens- opposed Gall , removed parts of birds brains, found that cerebral hemisphere acts as whole, accepted view for 50 years until Broca

Paul Broca

provide definitive proof of cortical localization

examined case of Monsior Leborgne who could not form speech

• died and examined brain

• damage to discrete portion of inferior frontal gyrus (localization) (frontal cortex)

found that language is present in left hemisphere

evidence for motor cortex occurred 9 years later

Neuron Doctrine

scientists thought that branches of nerve cells formed a continuous net (nerve net theory)

Theodore Schwann

Theodore Schwann

first to propose neuron doctrine in1839

Entire body including nervous system was made up of individual cells

Golgi Staining

silver staining procedure, allowed for visualizing occasional cells

proved neuron doctrine

Golgi himself never believed neuron doctrine

Santiago Ramon y Cajal

worked with silver stains and made improvements

Achieve of data describing neuron stricture

Cajals Neuron Doctrine

revealed cells, supported idea that cells were discontinuous (not one network)

provided insight into cell and brain function

most important neuroscientist

Broadmann

mapped cortical areas

still used

localization

Cytoarchieture

cell organization

Connectionism

mental phenomena and behavior can be described in terms of interconnected brain regions subserving different functions

refines localization

William James

the dominant framework for understanding brain function

Neurons

basic elements for connection in brain

spatial relationships very important

distinctive shapes

shape determines its connection with other neurons and its contribution to nervous system

function is related to shape, molecular composition is also important

2 Cells in Nervous System

neurons

glia

many subtypes

brain has 86 billion of each

Components of Neuron

1. dendrites (from synapses)

2. soma (cell body)

3. axon

4. presynaptic terminals (onto synapses)

5. synapse

info flow always goes from 1-5

uses electrical activity to function

dendrites receive info, axon sends info

Synapse

point between neurons (separated by small gap) that transmits/ receives electrical impulses

Replication

one strand of DNA becomes two

Transcription

how DNA becomes RNA

in nucleus, RNA add nre base parts (mRNA)

Translation

mRNA is read and becomes protein

DNA

double stranded, genetic info, in nucleus

RNA

single stranded, coding and decoding

Neurons defined by…

shape and number of poles on cell body (uni, bi, multi polar)

multi polar= stellate, fusiform, pyramid

now classification based more on molecular composition

Sensory Neuron

Specialized at one end to be highly sensitive to a particular type of stimulation (touch,light)

uni polar= one branch

Motor Neuron

soma in spinal cord and receives excitation form other neurons and conducts impulses along axon to a muscle

multi polar

Dendrites

branching fibers lined with synaptic receptors, receive info form other neurons

many have dendritic spines (like pine needles, protuberances providing sites)

highly plastic- rapid changes, easily bendable

Cell Body (soma)

perikayon

contains nucleus, mitochondria, ribsomes, and others

perform regular functions of all cells

Axon

fiber responsible for transmitting nerve impulses toward other neurons, organs, or muscles, neurons have one axon but it may branch many times (bifurcate)

Presynaptic Terminals/ boutons

end point of axon, release of chemicals to communicate with other neurons

one axon may have one or thousands- depends on cell type

Myelin Sheath

part of axon

Insulating material, covers axons, improves its electrical efficiency (makes it fast)

Nodes of Ranvier

part of axon

interruptions in the myelin sheath

Afferent Axons

bringing info toward a structure

arriving to

Efferent Axon

carrying info away from a structure

exiting from

Interneurons

neurons with dendrites and axons that are completely contained within a single structure

Input Zone of Neuron

dendrites (soma, cell body), neurons receive info

Integration Zone of Neuron

axon hilock, all incoming info is combined to determine whether or not to send a signal of its own

Conduction Zone of Neuron

axon, carries neurons own electrical signal away from cell body and toward next neuron

Output Zone of Neuron

axon terminals/boutons, neurons activity is transmitted across synapses to other neurons

Active Zone

region in presynaptic, regulated release of chemicals called neurotransmitters

Synaptic Vesicles

tiny hollow spheres, in presynaptic, contain neurotransmitter molecules

Neurotransmitters

Chemical substances, used to communicate with postsynaptic neuron

Receptors

proteins, capture and react when neurotransmitter binds to them

Postsynaptic Density

protein dense, attached to postsynaptic membrane

ensures all receptors are close to active zone

diversity of proteins, 1000 or more

complexity is what makes synapses modifiable

Methods to View Neurons

light microscopy

electron microscopy

Fluorescence and confocal microscopy

Light Microscopy

show cells and their processes using staining methods

Golgi and Cajal

Electron Microscopy

use staining method, higher resolution bc electrons have shorter wavelengths than light

shows synapses and oraenelles

Florescence and Confocal Microscopy

light based but allows researcher to label cells of interest

Glia

major component of nervous system, exchange chemicals with adjacent neurons

types: astrocytes, microglia, oligodendrocyles and schwann, radial

Astrocytes

type of glia

star shaped, numerous processes that extend in all directions

can attach to neurons and blood vessel to regulate blood flow and provide support

role in synaptic communication, having processes connections nearby to synapses

Involved in formation of synapse during dev

Microglia Cell

type of glia

use fine processes to survey for damage in nervous system

activated in response to injury

can form area of containment around a site of damage

called immune cells of brain

role in normal synapse formation and elimination

Oligodendrocytes and Schwann Cells

type of glia

build myelin sheath that surrounds axons of neurons

Oligodendrocytes in central

Schwann in peripheral

Radial Glia

type of glia

guide migration of neurons and the growth of their axons and dendrites during brain dev

guide neurons during dev

Blood Brain Barrier

Separation between circulating blood and the surrounding extracellular fluid in the brain

provides important layer of defense against invaders (viruses, bacteria, etc)

2 layers- endothelial cells (prevent diffusion in and out of blood vessels) and astrocytes (wrap around and support endothelial cells)

Passive Transport

how chemicals cross

diffusion across can happen freely

ex. oxygen, carbon dioxide, steroid hormones, alcohol, THC

Active Transport

how chemicals cross

energy is needed to move substances across

more tightly regulated

ex, glucose, amino acids

Dorsal

toward back, away from ventral (stomach side)

top part of brain

has this position in four legged animals

Ventral

toward the stomach, away from dorsal (back) side

Anterior/ Rostral

toward the front end

Posterior/ Caudal

toward the rear end

Superior

above another part

Inferior

below another part

Lateral

toward side, away from midline

Medial

toward midline, away from side

Proximal

located close to the point of origin/ attachment

Distal

located more distant from point of origin/attachment

Lpsilateral

on same side of body (two parts on left or two on right)

Contralateral

on opposite side of body (one on left, one on right)

Coronal Plane

a plane that shows brain structures as seen from the front (frontal plane)

Sagittal Plane

a plane that shows brain structures as seen from the side

Horizontal Plane

a plan that shows brain structures as seen from above (transverse plane)

Neuroanatomy

study of the structure/ organization of nervous system

relies on localization/connectionist approach

different levels of analysis from gross (large scales) to cellular level

Peripheral Nervous System Consists of..

somatic and autonomatic NS

Central Nervous System Consists Of…

brain and spinal cord