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Central nervous system (CNS) – The brain and the spinal cord
The Spinal Cord connects the brain to the rest of the body through the peripheral nervous system. It is part of the central nervous system.
The Brain
Anatomically, the brain is the part of the central nervous system that fills the upper portion of the skull. It contains billions of interacting cells that integrate information from inside and outside the body.
The cerebral cortex
The cerebral cortex consists of right and left halves, called cerebral hemispheres. Each cerebral hemisphere is divided into four lobes:
The Occipital lobe, the Parietal lobe, the Temporal lobe, and the Frontal lobe
Each lobe has areas that handle particular functions, such as visual processing.
The functions of the prefrontal cortex are something of a mystery, but they may include an executive control system that organizes and directs thought processes.
Left and right hemispheres control opposite sides of the body Stroke on right side can cause damage to the left side of the body:
Spatial Neglect:
Patients pay no attention to specific side of the body
Say do not eat food on left side of the plate (right brain damage).
May not believe left arm is there
Split brains:
Corpus callosum severed
Two different brains letting them what to do
Talk/ be silent, switch lights on/off, walk/ stand still
Neuroanatomy
Neuroanatomy
Most basic building block of the nervous system.
Brain made up of billions of neurons
Neurons link up to form chains and carry information throughout the brain.
Neurons made up of:
Dendrites - Receive incoming messages
Soma - Main cell body that also receives messages
Axon - Fibre that carries information away from the cell body
Axon terminals - Branching fibres at end of axons - link up with dendrites at end of neurons
Myelin sheath - Fatty covering of the axon that speeds up nerve impulses
Ions - Electronically charged molecules inside neurons
Neurons have an electrical charge of minus 70 millivolts
Resting potential - Electrical charge of an inactive neuron
Action potential - Neuron fires off when a message arrives from another neuron - charge raises to minus 50 millivolts (its threshold) and fires off.
Messages are carried at a speed of 200 miles per hour.
Synapse - Microscopic area between neurons
Neurotransmitters:
A chemical released by neurons and carries the message across synapses
Neurotransmitters alter the activity of the neuron’s message in various ways by inhibiting /exciting messages.
Nervous system relays messages from the brain to the rest of the body.
Central Nervous System (spreads messages) to the Peripheral Nervous system (the nervous system outside the brain and spinal cord)
Sides of the Brain
Sides of the Brain
Left side
Language; speaking, writing and understanding
Do math, tell time, keep rhythm
Good at understanding details
Lobes
Occipital: Main function - sight
Parietal: Touch, temperature pressure
Temporal: controls hearing (on sides of brain)
Frontal: higher mental abilities, thinking, movement
Right side:
Picking up patterns, recognizing faces, drawing or figuring out puzzles
Understand irony sarcasm and context
Sees bigger picture
Subcortex
Subcortex
Hindbrain
Medulla - connects brain with spinal cord - regulate vital bodily functions - heart rate, breathing swallowing
Cerebellum - posture, muscle tone and muscular coordination
Midbrain
Of the 12 cranial nerves, two thread directly from the midbrain - the oculomotor and trochlear nerves, responsible for eye and eyelid movement.
Forebrain
Thalamus - relays messages to the cerebral cortex
Hypothalamus - regulates emotional behaviours and motives such as rage, temperature control, eating, drinking and waking up
Limbic system
Amygdala - regulates emotions such as fear
Hippocampus - stores memories
Left hemisphere specialization:
Verbal processing, such as speaking, reading, and writing.
Wernicke’s area, which controls language reception, is located in the left temporal lobe.
Damage to this area can result in problems with language comprehension.
Wernicke’s aphasia results from damage to this and related areas of the brain.
People with Wernicke’s aphasia are characterized by impairment in remembering nouns and verbs and their meaning.
Their language comprehension is impaired and slow, while spontaneous speech is fluent and grammatical but short on meaning.
Broca’s area:
Controls expressive language function, is located in the left frontal lobe.
Damage to this area can result in problems with the production of speech.
Broca’s aphasia results from damage in the left frontal cortex,
characterized by slow, inarticulate language production, including not only speech but
also writing and gesturing. Speech is meaningful, but lacks the prepositions,
conjunctions, and word endings of smooth, grammatical speech.
Almost all right-handed people and about two-thirds of left-handed people show the
specialization of speech function in their left hemisphere.
Most other left-handers show about equal representation of language in both hemispheres.
Only a few people have complete right hemisphere control of language.
Right hemisphere specialization
The right hemisphere is specialized for important roles in nonverbal processing such as spatial tasks and musical and visual recognition (pattern and configuration). Some psychologists characterize the right hemisphere as predisposed to deal with large overall patterns, totalities or organized wholes (gestalten), and diffused representations.
Recent research supports that the right hemisphere is important to perceptions of others’ emotions.
Lateralization of experience and expression of emotions are more complex. Negative emotions seem to activate the right hemisphere, while positive emotions are associated with great activity in the left hemisphere.
In most people, the right hemisphere is apparently critical in understanding the emotional content of speech. People with right hemisphere damage have trouble understanding jokes, sarcasm, irony, tone of voice, and so on.
Research methods
Lesioning – Destroying a piece of the brain
Electrical stimulation of the brain (ESB) – Sending a weak electric current into a brain structure to stimulate (activate) it
CT (computerized tomography) scan – A computer-enhanced X-ray of brain structure
MRI (magnetic resonance imaging) scan – Uses magnetic fields, radio waves, and computerized enhancement to map out brain structure
PET (positron emission tomography) scan – Uses radioactive markers to map chemical activity in the brain over time
Functional magnetic resonance imaging (fMRI) – Variations on MRI technology that monitor blood flow and oxygen consumption in the brain to identify areas of high activity
Neuroplasticity
Neuroplasticity
Aspects of experience can sculpt features of brain structure.
Damage to incoming sensory pathways or the destruction of brain tissue can lead to neural reorganization.
The adult brain can generate new neurons.
Neurogenesis – The formation of new neurons
MCQ Questions (Answers here)
MCQ Questions (Answers here)
In transmitting sensory information to the brain, an electrical signal travels from the _____________ of a single neuron
A Cell body to the axon to the dendrites.
B Dendrites to the axon to the cell body.
C Axon to the cell body to the dendrites.
D Dendrites to the cell body to the axon.
E Axon to the dendrites to the cell body.
The fatty casing that helps speed up the neural transmissions of a neuron is called the
A Medulla
B Myelin sheath
C Cerebrum
D Soma
E Corpus callosum
Which of the following describes what happens when a neuron sends a signal?
A The neuron goes from being positively charged to briefly being negatively charged, and finally returns to being positively charged again. The magnitude of the negative charge is fixed regardless of the strength of the input signal it receives.
B The neuron goes from being negatively charged to briefly being positively charged, and finally returns to being negatively charged again. The magnitude of the negative charge is fixed regardless of the strength of the input signal it receives.
C The neuron goes from being negatively charged to briefly being positively charged, and finally returns to being negatively charged again. The magnitude of the positive charge varies depending on the strength of the input signal it receives.
D The neuron goes from being positively charged to briefly being negatively charged, and finally returns to being positively charged again. The magnitude of the negative charge varies depending on the strength of the input signal it receives.
E The neuron goes from being negatively charged to being positively charged, and then it remains at that level until it fires again. The magnitude of the positive charge varies depending on the strength of the input signal it receives.
In a study mimicking Roger Sperry’s work, Dr. Kornhauser compared the responses of split-brain patients against a control group of neurotypical participants. In his study, participants focused on a dot in the center of a computer screen and objects are presented in either the left or right visual field. After seeing the object, the participants named the object. The results of the experiment are presented on the right.
What is the most appropriate conclusion Dr. Kornhauser can draw from the results?
A Split-brain patients cannot process objects using the right half of their brain and thus are not able to identify the objects in the right visual field.
B Split-brain patients have a much faster reaction time to objects in the right visual field due to having a more direct connection between the visual cortex and their language center.
C Split-brain patients have a much faster reaction time to objects in the right visual field due to having a more direct connection between the visual cortex and their language center.
D Because the connection between the right visual cortex and language center has been severed, split-brain patients are not able to retrieve the name of objects seen in the left visual field.
E Because accuracy in the control group was low, the objects he used were likely too difficult for the participants.
Separating the monkeys into two groups, researchers created a lesion in one area of the brains of the monkeys in one group and a lesion in a different area of the brains of the monkeys in the second group. The researchers then tested the monkeys’ performance on the two tasks. The figures below show the monkeys’ accuracy on the two tasks.
The lesions were most likely performed in the
A Frontal lobe for Group 1 and the occipital lobe for Group 2
B Occipital lobe for Group 1 and the frontal lobe for Group 2
C Temporal lobe for Group 1 and the parietal lobe for Group 2
D Occipital lobe for Group 1 and the parietal lobe for Group 2
E Parietal lobe for Group 1 and the temporal lobe for Group 2
Michael Gazzaniga is best known for
A showing that cats can learn to escape puzzle boxes
B conditioning Little Albert to be fearful of rats
C studying attachment styles in children
D studying false memories
E studying split-brain patients
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