Lesson 2 Cognitive Neuroscience

Cognitive Neuroscience

Studies how the brain and other aspects of the nervous system are linked to cognitive processing and behavior.

Brain

Is the organ in our bodies that most directly controls our thoughts, emotions, and motivations.

Localization of Function

Refers to the specific areas of the brain that control specific skills or behaviors.

Nervous System

Is the basis for our ability to perceive, adapt to, and interact with the world around us. It includes the brain, spinal cord, and a complex network of nerves.

Forebrain

Is the region of the brain located toward the top and front of the brain. It includes the cerebral cortex, basal ganglia, the limbic system, the thalamus, and the hypothalamus.

Cerebral cortex

Is the outer layer of the cerebral hemisphere. It plays a vital role in our thinking and other mental processes.

Basal Ganglia (Ganglion)

Are collections of neurons critical to motor function.

Limbic system

Is important to emotion, motivation, memory, and learning.

Three Central Interconnected Cerebral Structures

1. Septum

2. Amygdala

3. Hippocampus

Parts of Limbic System

• Formix

• Septum

• Olfactory Bulb (smell)

• Hypothalamus

• Amygdala (basic emotions)

• Entorhinal Cortex (memory)

• Hippocampus

• Thalamus

• Corpus callosum

• Stria Terminalis

Thalamus

Relays in coming sensory information through groups of neurons that project to the appropriate region in the cortex.

Hypothalamus

Regulates behavior related to species survival: fighting, feeding, fleeting, and mating. It also helps regulate emotions and react to stress. It is also important for the functioning of the endocrine system.

Midbrain

Helps to control eye movement and coordination

Superior Colliculi

Involved in vision

Inferior Colliculi

Involved in hearing

Reticular Activating System (RAS)

Is a network of neurons essential to regulating consciousness, including sleep, wakefulness, arousal, attention, and vital functions such as heartbeat and breathing.

Hindbrain

Controls the body's vital functions such as respiration and heart rate. It comprises the medulla oblongata, the pons, and the cerebellum.

Medulla Oblongata

Controls heart activity and largely controls breathing, swallowing, and digestion.

Pons

Contains neural fibers that pass signals from one part of the brain to another.

Cerebellum

Controls bodily coordination, balance, and muscle tone.

Cerebral Cortex

Plays an extremely important role in human cognition.

• It forms a 1–3-millimeter layer that wraps the surface of the brain.

• It forms the outer layer of the two halves of the brain—the left and right cerebral hemispheres.

1. Sulci

2. Fissures

3. Gyri

3 elements of cerebral cortex

Sulci

Small grooves

Fissures

Large grooves

Gyri

Are bulges between adjacent sulci or fissures

Carl Wernicke

• German neurologist who studied language deficient patients who could speak but whose speech made no sense.

• Like Broca, heat raised language ability to the left hemisphere.

• He studied the different precise location, now knowns as Wernicke's area, which contributes to language comprehension

Karl Spencer Lashley

• Often described as the father of neuropsychology.

• He started studying localization in 1915.

• He found that implantations of crudely built electrodes in apparently identical locations in the brain yielded different results.

• Apparently, his research was limited by the technology available to him at the time.

1. Frontal Lobe

2. Temporal Lobe

3. Parietal Lobe

4. Occipital Lobe

5. Projection Areas

Lobes of the cerebral hemispheres

Frontal Lobe

Toward the front of the brain, is associated with motor processing and higher thought processes, such as abstract reasoning, problem solving, planning, and judgment. It contains the primary motor cortex, which specializes in the planning, control, and execution of movement, particularly movement involving any kind of delayed response.

Temporal Lobe

_____________ is located below the parietal lobe, directly under your temples. It is associated with auditory processing and comprehending language. It is also involved in retaining visual memories.

Parietal Lobe

__________ at the upper back portion of the brain, is associated with somatosensory processing. The primary somatosensory cortex receives information from the senses about pressure, texture, temperature, and pain.

Occipital Lobe

____________ is associated with visual processing. It contains numerous visual areas, each specialized to analyze specific aspects of scene, including color, motion, location, and form.

Projection Areas

___________ are the areas in the lobes in which sensory processing occurs. These areas are referred to as projection areas because the nerves contain sensory information going to the thalamus.

• Dorsal (superior)

• Ventral (inferior)

• Caudal (posterior)

• Rostral (anterior)

4 Different Brain Regions

• Soma

• Dendrites

• Axon

• Terminal Buttons

4 Basic Parts of Neurons

Soma (Cell Body)

• contains the nucleus of the cell

• life of the neuron

• produces the proteins for other parts of the neuron

• acts as bridge between the dendrites to the axon

Dendrites

• branch like structures

• receives nerve impulses from other neurons

• collects and stores information

• deliver the signals to the cell body

Axon Hilllock

• located at the end of the soma

• controls the firing of the neuron

Axon

• carry nerve impulses from the cell body to the other neurons

• response to the information through transmitting electrochemical signal

• can connect to sensory neurons, motor neurons, and interneurons

Myelin

connects neurons in somatic nervous systems

Myelin Sheath

the white, fatty substance that surrounds some of the axons of the nervous system

Nodes of Ranvier

Small gaps in the myelin coating along the axon

Unmyelinated Axons

• not covered with myelin sheath

• connects neurons in the automatic nervous system

Terminal Buttons

• small knobs found at the ends of the branches of an axon, below the myelin sheath.

• responsible for sending the signal to the other neurons

Synapse

Serves as a juncture between the terminal buttons of one or more neurons and the dendrites (are sometimes the soma) of one or more other neurons.

Neurotransmitters

• messengers that transmit information across the synaptic gap to the receiving dendrites

• located in the axon terminal, stored within thin-walled socks called synaptic vesicles

• heartbeat and blood pressure

• breathing

• stress response

• senses

• thoughts, memory, learning, and feelings

• muscle movements

Neurotransmitters controls the:

• excitatory neurotransmitters

• inhibitory neurotransmitters

• modulatory neurotransmitters

Neurotransmitters transmits to the target cell:

Excitatory Neurotransmitters

Excites the neuron (i.e., epinephrine and norepinephrine)

Inhibitory Neurotransmitters

Block or prevent the chemical message (i.e., glycine and serotonin)

Modulatory neurotransmitters

Influences the effects of other chemical messengers

• Monoamine Neurotransmitter

• Amino-Acid Neurotransmitters

• Neuropeptides

3 types of chemical substances appear to be involved in neurotransmission

Monoamine Neurotransmitter

Regulate consciousness, cognition, attention, and emotion

Amino-Acid Neurotransmitter

Involved in most function of the nervous system

Neuropeptides

Change of amino acids

Acetylcholine

• a neurotransmitter that plays a role in memory, learning, attention, arousal, and involuntary muscle movement.

• low acetylcholine levels include Alzheimer's disease, Myasthenia Gravis, etc.

Dopamine

• associated with attention, learning, and movement coordination.

• Schizophrenics show high levels of the famine

• Parkinson's disease shows load dopamine levels

Serotonin

• Associated in eating behavior and body weight regulation.

• Also involved in aggression and regulation of impulsivity.

• High serotonin levels play a role in some types of anorexia.

True

T OR F: Postmortem studies and brain dissections have been done for centuries

True

T OR F: In more recent times, postmortem examinations are done on victims of Alzheimer's disease (an illness that causes devastating losses of memory)

True

T OR F: Postmortem examination is limited because it cannot be performed on the living brain.

True

T OR F: Postmortem examinations do not offer insights into more specific physiological processes of the brain

In Vivo

The term ___________ is latin for "within the living". An in vivo technique is a process of a procedure of testing that is conducted on living biological entities instead of the more traditional method of testing extracted tissues or dead (postmortem) organisms.

True

T OR F: The study on the changing activity of a living brain is adapted in vivo techniques which were then only done on animals and not on humans

Selective Lesioning

• In _________, part of the brain is surgically removed or damaged to observe resulting functional deficits.

• Can be done through the administering of drug.

Single Cell Recordings

• Thin electrode is inserted next to a single neuron

• Changes in electrical activity occurring in the cell are then recorded

• Precise

• Cannot be used with humans

Genetic Knockout Procedures

• Generally known as genetic manipulation

• Animals can be created without certain kinds of brain cells or receptors

Record the transmission of brain signals through electrical potentials appear as frequencies and intensities

• Electroencephalogram (EEGS)

• Event Related Potential (ERP)

Electrical Recordings

Electroencephalograms (EEGS)

• Changes in electrical potentials are recorded by electrode attached to scalp

• Relatively non-invasive

• Not precise

Event related potential (ERP)

• Changes in electrical potentials are recorded by electrodes attached to scalp

• Relatively non-invasive

• Does not show actual brain images

• CT scan

• Brain Angiogram

• MRI Scan

Static imaging techniques

CT Scan

• A CT image of a brain uses a series of rotating scans to produce a three-dimensional view of brain structures.

• Consists of several x-ray images of the brain taken from different vantage points that, when combined, result in a three-dimensional image

Brain Angiogram

• A __________ highlights the blood vessels of the brain.

• Allow for the observation of large abnormalities of the brain, such as damage resulting from strokes or tumors. They are limited in their resolution, however, and cannot provide much information about smaller lesions and aberrations.

• Structural MRIs

• Functional MRIs

Types of MRI Scan

Structural MRIs

Provide images of the brain's size and shape.

Functional MRIs

Visualize the parts of the brain that are activated when a person is engaged in a particular task.

Metabolic imaging

________ techniques rely on changes that take place within the brain because of increased consumption of glucose and oxygen in active areas of the brain.

• Subtraction Method

• PET Scan

• Functional Magnetic Resonance Imaging (FMRI)

• Transcranial Magnetic Stimulation (TMS)

Types of Metabolic Method

Subtraction method

• used to pinpoint specialized areas for a task

• involves subtracting activity during the control task from activity during the task of interest.

• involved in a more general or control activity

• engage in the task of interest

Two different measurements of subtraction method

PET Scan

• Still photographs that show different metabolic processes during different activities. _________ permit the study of brain physiology.

• less useful for fast processes.

Functional magnetic resonance imaging (FMRI)

• create a magnetic field that includes changes in the particles of oxygen atoms.

• more active areas draw more oxygenated blood than do less active areas in the brain.

• the differences in the amount of oxygen consumed from the basis for FMRI measurements.

• more precise than pet - uncomfortable

• Pharmacological MRI (PHMRI)

• Diffusion Tensor Imaging (DTI)

Procedures related to FMRI

Pharmacological MRI (PHMRI)

• combines FMRI methods when the study of psychopharmacological agents

• used to examine the role of agonists and antagonists on the same receptor cells.

Diffusion Tensor Imaging (DTI)

• examines the restricted dispersion of water in tissue and in axons.

• measures how far protons have moved in a particular direction within a specific time interval.

Transcranial Magnetic Stimulation (TMS)

• temporarily disrupts normal brain activity to investigate cognitive functioning when particular areas are disrupted.

• potentially dangerous if misused

Brain Tumors

________ are diagnosed via neurological exams, CT scans, MRIs. Treatment often involves surgery, radiation, and chemotherapy.

• Primary

• Secondary

Two types of brain tumor

Primary

_________ starts in the brain (common in childhood).

Secondary

________ originate elsewhere (e.g., lungs)

Benign; Malignant

Tumors can be ____________ or ___________.

Benign

Non-cancerous

Malignant

Cancerous

True

T OR F: benign can be removed, while malignant invade healthy tissue and spread.

Stroke

Vascular disorders stems from strokes, disrupting brain blood flow. Strokes cause cognitive loss based on affected brain area. Symptoms include paralysis, speech loss, impaired movement, and more.

• Ischemic Stroke

• Hemorrhagic Stroke

Types of Stroke

Ischemic Stroke

__________ results from fatty build up breaking of and blocking brain arteries; treatable with clot-busting drugs.

Hemorrhagic Stroke

___________ occurs from sudden brain vessel breakage, causing cell death due to blood spillage. Prognosis depends on damaged type and severity. Stroke symptoms appear immediately.