Chapter 3: Neuroscience and Behavior 3.4-3.6 Flashcards
Networks
Consists of interacting and interdependent regions of the brain that work together to support complex psychological functions
What are the three main divisions of the brain?
From bottom to top (simpler functions to more complex), hindbrain, midbrain, and forebrain
Hindbrain
Area of the brain the coordinates information coming into and out of the spinal cord (continuous with one another)
What functions do the hindbrain control?
The most basic functions of life: respiration, wakefulness, heart rate, sleep
What structures make up the hindbrain?
Medulla, reticular formation, cerebellum, and pons
Medulla
An extension of the spinal cord into the skull that coordinates heart rate, circulation, and respiration
Reticular formation
Small cluster of neurons that begins inside the medulla and extends upward, and regulates sleep, wakefulness, and levels of arousal
Cerebellum
Controls fine motor skills i.e. fine-tunes the execution of our actions (not initiating), Latin for “little brain”
Pons
Relays information from the cerebellum to the rest of the brain, Latin for “bridge”
What are the two main structures of the midbrain?
The tectum and the tegmentum
Tectum
Orients an organism in the environment through receiving a stimulus from the eyes, ears, and skin and moving the organism in a coordinated way towards the stimulus
Tegmentum
Involved in movement and arousal, and also helps orient an organism towards sensory stimuli
Midbrain
Central location of neurotransmitters involved in arousal, mood, motivation, and the brain structures that rely on them
Forebrain
Controls complex cognitive, emotional, sensory, and motor functions
What are the two main sections of the forebrain?
The cerebral cortex and the subcortical structures
Cerebral cortex
Outermost layer of the brain, visible to the naked eye, and divided into two hemispheres that are connected by the corpus callosum
Subcortical structures
Areas of the forebrain housed under the cerebral cortex near the center of the brain
What are the six subcortical structures?
Thalamus, three components of the limbic system (hypothalamus, hippocampus, and amygdala), basal ganglia, and pituitary gland (part of the endocrine system)
Thalamus
Relays and filters information from the senses (except for smell which has direct connections) to the cerebral cortex, closes pathways of incoming sensory information during sleep
Hypothalamus
Located under (hypo in Greek) the thalamus, regulates body temperature, hunger, thirst, food intake
Limbic system
Group of forebrain structures including the hypothalamus, hippocampus, and amygdala that are involved in motivation, emotion, learning, and memory; where the subcortical structures meet the cerebral cortex
Hippocampus
Creating new memories and integrating them into a network of knowledge for indefinite storage in other parts of the cerebral cortex
Amygdala
Located at the tip of each horn of the hippocampus, plays a central role in many emotional processes e.g. formation of emotional memories; encoding events as fearful
Basal ganglia
Set of subcortical structures that directs intentional movements e.g. striatum for the control of posture and movement
Pituitary gland
Releases hormones that direct the functions of many other glands in the body
Gyri (gyrus for singular) and Sulci (sulcus for singular)
Gyri are the raised part and Sulci are the indentations or fissures
Contralateral control
Right cerebral hemisphere perceives stimuli from and controls movements from the left side of the body and vice versa
Commissures
Bundles of axons that connect cerebral hemispheres and allow them to communicate
Corpus callosum
Largest commissure; connects large areas of the cerebral cortex on each side of the brain and supports communication of information across the hemispheres
What are the four lobes in each hemisphere?
From back to front, occipital lobe, parietal lobe, temporal lobe, frontal lobe
Occipital lobe
Processes visual information
Parietal lobe
Carries out functions that include processing information about touch, contains the somatosensory cortex
Somatosensory cortex
Strip of brain tissue running from the top of the brain down to the sides; represents skin areas on the contralateral surface of the body
Homunculus
Distorted figure that shows how much of the somatosensory cortex is devoted to each body part e.g. tongue and hands are more sensitive/controllable
Motor cortex
Strip of brain tissue in the frontal lobe right in front of the somatosensory cortex that initiates voluntary movements and sends messages to the basal ganglia, cerebellum, and spinal cord
Temporal lobe
Responsible for hearing and language
Primary auditory cortex
Receives sensory information from the ears based on the frequencies of sounds
Frontal lobe
Has specialized areas for movement, abstract thinking, planning, memory, and judgement
Association areas
in the cerebral cortex, composed of neurons that help provide sense and meaning to information registered in primary areas by integrating them
Mirror neurons
Found in the frontal lobe and parietal lobe; are active when people watch someone perform a behavior and recognizes its goal and outcome
Brain plasticity
Brain’s ability to be changed; functions that were assigned to certain areas of the brain may be capable of being reassigned to other areas of the brain to accommodate changing input from the environment.
Phantom limb syndrome
Amputees continue to experience sensation where a missing limb would be
Degree of relatedness
The probability of sharing genes
Epigenetics
The study of environmental influences that determine the expression of genes without altering basic DNA sequences that constitute the genes themselves
Epigenetic marks
Chemical modifications to DNA that turn genes on or off e.g. DNA methylation and Histone modification
Heritability
Measure of the variability of behavioral traits among individuals that can be accounted for by genetic factors; calculated as a proportion with an index ranging from 0-1
What are four important points about heritability?
Heritability is an abstract concept, a population concept, dependent on the environment, not fate
Split brain procedure
An operation that severs the corpus callosum to alleviate the severity of seizures
What is the behavior of people with split brains?
The information on the right hemisphere is unable to travel to the left hemisphere, which controls the production of speech, and vice versa.
Electroencephalograph (EEG)
Device used to record electrical activity in the brain; amplifies the electrical signals in synapses and action potentials from electrodes placed on the outside of the head
Feature detectors
Neurons in the visual cortex that selectively respond to certain aspects of a visual image
Structural brain imaging
Provides information about the basic structure of the brain and allows clinicians/researchers to see abnormalities in brain structure
Functional brain imaging
Provides information about the activity of the brain while people perform various cognitive or motor tasks
Computerized axial tomography (CT) scan
Scanner rotates a device around a person’s head and takes a series of X-ray photographs from different angles; shows different densities of tissue in the brain and locates lesions or tumors (darker, less dense)
Magnetic resonance imaging (MRI)
Strong magnetic field lines up nuclei of specific molecules of brain tissue and pulses of radio waves cause nuclei to rotate out of alignment then snap back in line, releasing unique energy signatures; reveals brain structures with unique molecular compositions in better resolution that a CT scan to localize brain damage
Diffusion tensor imaging (DTI)
type of MRI that is used to visualize white matter pathways, which are fiber bundles that connect nearby and distant brain regions to one another, by measuring the rate and direction of diffusion or movement of water molecules
Positron emission tomography (PET)
Harmless radioactive substance is injected into bloodstream, brain is scanned by radiation detectors as person performs perceptual or cognitive tasks, level of radioactivity in each region is recorded producing a computerized image of activated areas
Functional magnetic resonance imaging (fMRI)
Detects the difference between oxygenated hemoglobin and deoxygenated hemoglobin when exposed to magnetic pulses to provide a picture of the level of activation in each brain area
Hemoglobin
Molecule in the blood that carries oxygen to our tissues, including the brain
Advantages of fMRI over PET
Doesn’t require exposure to radioactive substance, can localize changes in brain activity over briefer periods, design experiments that more closely resemble those carried out in psychology laboratory
Resting state functional connectivity
Does not require patients to perform a task while fMRI measures the extent to which spontaneous activity in different brain regions is correlated over time to identify brain networks
Default networks
Group of interconnected regions in the frontal, temporal, and parietal lobes involved in internally focused cognitive activities
Transcranial magnetic stimulation (TMS)
Activates and deactivates regions of the brain with a magnetic pulse, temporarily mimicking brain damage; enables scientists to perform experiments that establish causal relationships
What are the three main methods to understand how the brain affects behavior?
Studying people with brain damage, studying the brain’s electrical activity, and using brain imaging to study brain structure and watch the brain in action
Spinal reflexes
Mediated by connections between sensory inputs and motor neurons in the spinal cord
Reflex arc
neural pathway that controls reflex actions
Mirror therapy
Movement of intact hand in front of a mirror tricks the brain by letting the person perceive that the missing hand is moving as well, reducing the phantom pain
Stroke damages right hemisphere
Only local processing
Stroke damages left hemisphere
Only global processing
Magnetoencephalography (MEG)
Records magnetic fields generated by brain’s electric activity
Single neuron recording
Hubel and Wiesel inserted electrodes into brains of anesthetized cats and discovered feature detectors: neurons in the visual cortex responded to different line orientations or angles
