Chapter 1: The Science of Cognition Flashcards
Frontal lobe
Book definition: “The region at the front of the cerebral cortex that includes the motor cortex and the prefrontal cortex. (p. 15)”.
Separated from the parietal lobe by the central sulcus and from the temporal lobe by the lateral sulcus, the frontal lobe plays a key role in the ability to project consequences from actions, choose between “good” and “bad” (i.e. conscience) and override or suppress socially unacceptable responses. It is not fully developed until the late 20s, which in part explains the behavior of children and teenagers.
Also contains the primary motor cortex, which regulates bodily movement, as well as most of the dopamine-sensitive neurons in the cortex, which are associated with reward, attention, short-term memory, planning and motivation.
Electroencephalography (EEG)
Book definition: “Measurement of electrical activity of the brain, measured by electrodes on the scalp. (p. 20)”
This technique has limited spatial resolution due to skull and brain tissue distorting the electrical field, but high temporal resolution and ability to provide a continuous measure of activity in the millisecond range.
Introspection
Book definition: “A methodology much practiced at the turn of the 20th century in Germany that attempted to analyze thought into its components through self-analysis. (p. 4)”
Commonly attributed to the German philosopher Wilhelm Wundt, introspection is, in essence, the examination of one’s own conscious thoughts and feelings.
Basal ganglia
Book definition: “Subcortical structures that play a critical role in the control of motor movement and complex cognition. (p. 16)”
The greatest source of insight into the functions of the basal ganglia come from the studying of two neurological disorders that affect the area - Parkinson’s disease and Huntington’s disease - both of which involve impaired motor control.
In addition, the basal ganglia have been linked to both eye movement and motivation, where things such as food, sex and drugs elicit a response in a local dopamine system. Damage to this particular subarea can produce a state of apathy.
Axon
Book definition: “The part of a neuron that carries information from one region of the brain to another. (p. 12)”
Axons connect, or synapse, to the tree-like dendrites of other neurons. Axons can be myelinated, meaning they become surrounded by a layer of fat that functions as electrical insulation, making the electrical impulses passing through them faster.
Cognitive neuroscience
Book definition: “The study of the neural basis of cognition. (p. 10)”
Cognitive neuroscience was coined by George Miller and Michael Gazzaniga toward the end of the 1970’s. It emerged as an interdisciplinary study of mainly neuroscience, psychology and computer science, with a focus on the scientific study of the biological processes and neuronal connections that underlie cognition and mental processes.
Aphasia
Book definition: “An impairment of speech that results from a brain injury. (p. 17)”
Examples: Fluent aphasia (also known as Wernicke’s aphasia), is caused by damage to Wernicke’s area and results in problems understanding and producing meaning (semantics) in written and spoken language, but with an otherwise intact grammar and prosody (syntax). Non-fluent aphasia (also known as Broca’s aphasia), is caused by damage to Broca’s area and results in problems creating fluent and syntactically correct sentences (so-called ‘telegraphic speech’).
Topographic organization
Book definition: “A principle of neural organization in which adjacent areas of the cortex process information from adjacent parts of the sensory field. (p. 18)”
Excitatory synapse
Book definition: “A synapse in which the neurotransmitters decrease the potential difference across the membrane of the neuron. (p. 12)”
Blood oxygen level dependent (BOLD) response
Book definition: “A measure obtained in fMRI studies of the amount of oxygen in the blood. (p. 24)”
As neurons consume oxygen, they convert oxyhaemoglobin to deoxyhaemoglobin, which in turn distorts the magnetic field of the brain. By measuring this distortion, the amount of oxygen in the blood (and thereby the activity of the neurons) can be inferred.
Haemodynamic response
Book definition: “The increased flow of oxygenated blood to a region of the brain that has greater activity – the basis of fMRIbrain imaging. (p. 21)”
As neurons consume oxygen, they convert oxyhaemoglobin to deoxyhaemoglobin, which in turn distorts the magnetic field of the brain. By measuring this distortion using fMRI, the amount of oxygen in the blood (and thereby the activity-level of the neurons) can be inferred.
Functional magnetic resonance imaging (fMRI)
Book definition: “A method for determining metabolic activity by measuring the magnetic field produced by the iron in oxygenated blood. (p. 21)”
When neurons consume oxygen, oxyhaemoglobin is converted to deoxyhaemoglobin, which produces distortions in the magnetic field. By assessing this distortion, the concentration of oxygen in the brain (also called the BOLD-response) can be measured. High spatial resolution at about 1 millimeter and medium temporal resolution, detecting changes after about 2-3 seconds. Limitations include patients feeling claustrophobic or being disturbed by the noisy MRI-scanner, while small movements (like answering a question) can distort the BOLD-signal.
Synapse
Empiricism
Book definition: “The position that all knowledge comes from experience in the world. Compare nativism. (p. 4)”
Also known as the ‘blank slate view’. This is in contrast to the opposing nativism view, which suggests that humans are born with certain knowledge about language already encoded in our genes.
Myelin
Book definition: “ – ”
An insulating layer of fat around some axons (called ‘myelinated axons’) which functions as electrical insulation, making the electrical signal – or action potential – move faster through the axon.
Myelination is essential to the proper functioning of the nervous system, and the loss of this layer through demyelination is the hallmark of several neurodegenerative autoimmune diseases such as multiple sclerosis.
Cell body (also called soma)
Event-related potential (ERP)
Book definition: “Measurement of changes in electrical activity at the scalp in response to an external event. (p. 21)”
This brain imaging technique uses several scalp electrodes, like in EEG, to record the pattern of electrical brain activity during a repeated presentation of the same stimulus. This produces a single waveform, which allows working out the timing of various cognitive processes. Limited spatial resolution due to skull and brain tissue distorting the electrical field, but high temporal resolution and ability to provide a continuous measure of activity in the millisecond range.
Temporal lobe
Book definition: “The region at the side of the cerebral cortex that contains the primary auditory areas and controls the recognition of objects. (p. 15)”
Separated from the frontal lobe by the lateral sulcus, the temporal lobe holds the primary audio cortex (involved in auditory perception and semantics-processing) the hippocampus (involved in memory storage) and Wernicke’s area (involved in the comprehension of written and spoken language). It also shares the fusiform gyrus (involved in facial recognition) with the frontal lobe.
Split-brain patient
Book definition: “A patient who has had surgery to sever the corpus callosum, which connects left and right hemispheres. (p. 17)”
The procedure, known as a “corpus callosotomy,” severs the connection between the left and right brain hemispheres. This is used as a last resort to alleviate powerful epileptic seizures caused by sporadic electrical storms in the brain.
Prefrontal cortex
Book definition: “The region at the front of the frontal cortex that controls planning and other higher level cognition. (p. 15)”
The prefrontal cortex is heavily involved with top-down processing – i.e. behavior guided by internal states or intentions, such as with personality expression, decision making and moderating social behavior. Functions carried out by the prefrontal cortex are called executive functions and include the abilities to differentiate among conflicting thoughts, considering consequence from current actions, predicting outcomes and suppressing socially unacceptable urges.
Artificial intelligence (AI)
Book definition: “A field of computer science that attempts to develop programs that will enable machines to display intelligent behavior. (p. 1)”
Broca’s area
Book definition: “A region in the left frontal cortex that is important for processing language, particularly syntaxin speech. (p. 17)”
Damage to this area can lead to non-fluent aphasia, which results in an inability to create fluent phrases out of otherwise meaningful words (so-called ‘telegraphic speech’) – e.g. this actual patient quote: “The woman… wants to… The girl wants to… the flowers and the woman.”
See also Wernicke’s area and fluent aphasia.
Dendrite
Hippocampus
Book definition: “A structure within the temporal lobe that plays a critical role in the formation of permanent memories. (p. 16)”
Situated under the cerebral cortex in the medial temporal lobe, it consists of two parts, one on each side of the brain. The hippocampus is responsible for the consolidation of information from short-term memory to long-term memory as well as spatial navigation.
Alzheimer’s disease damages this area, resulting in memory loss and disorientation, while bilateral hippocampal damage may result in anterograde amnesia – i.e. the inability to form and retain new memories.
Spatial resolution
Book definition: “ – ”
Term for the “resolution” of a given brain imaging technique in terms of space. The visibility of a recording can extend to the brain as a whole (low spatial resolution) or single neurons and synapses (high spatial resolution). A low resolution, like in fMRI, is useful for studying the overall activity of the brain, while a high resolution, like in single-unit recording, can study activity in very specific areas.
Magnetoencephalography (MEG)
Book definition: “Measurement of magnetic fields produced by electrical activity in the brain. (p. 21)”.
This brain imaging technique uses a Superconducting Quantum Interference Device (or “SQUID”) to measure magnetic fields produced by brain activity.
It has high spatial resolution and very high temporal resolution at the millisecond level, but is limited by the costs of operation, as SQUIDs must be kept very cool by means of liquid helium and recordings must be made under magnetically shielded conditions.
It also looks totally fucking ridiculous.
Thalamus
Book definition: “ – ”
Core part of the brain considered the cerebral ‘information hub’. Situated between the cerebral cortex and the midbrain, the thalamus receives information from all the senses except the olfactory system (smell) and then relays it to the appropriate cortical areas. The visual system, for instance, sends input from the retina to the lateral geniculate nucleus located in the thalamus, which in turn relays it to the occipital lobe.
The thalamus is also responsible for the regulation of consciousness, sleep, alertness and arousal levels. Damage to this area can lead to permanent coma.
Sulcus (plural: sulci)
Book definition: “An inward crease of the brain. Contrast with gyrus. (p. 15)”
Sulci are essentially the ‘wrinkles’ of the brain, and often separate two functionally different brain areas - such as the central sulcus, which separates the frontal lobe from the parietal lobe, or the lateral sulcus, which separates the temporal lobe from both the frontal and parietal lobe.
Neuron
Book definition: “A cell in the nervous system responsible for information processing. Neurons accumulate and transmit electrical activity. (p. 11)”
A neuron consists of a cell body (also called soma), a cable-like axon that carries information to other neurons, and tree-shaped (or ‘arborized’) dendrites that the axons of other neurons connect to.
Occipital lobe
Book definition: “The region at the back of the cerebral cortex that controls vision. (p. 15)”
Situated below the parietal lobe and behind the temporal lobe, the occipital lobe is the main visual processing center of the brain, containing the entire visual cortex. Damage to this part of the brain can result in partial or complete blindness.
Transcranial Magnetic Stimulation (TMS)
Book definition: “A magnetic field is applied to the surface of the head to disrupt the neural processing in that region of the brain. (p. 22)”
This brain imaging technique studies the effects of brain damage using artificial magnetic fields to temporarily create “lesions” in a specific brain area. By placing a magnetic coil in the shape of a figure-eight close to a participant’s head and running a brief (>1 ms) pulse of current through it, a magnetic field is produced, affecting a nearby brain area of about 1 cm3. By measuring the participant’s performance of a task, it is possible to conclude if the affected brain area is necessary for the performance.
Several limitations, such as loud noise and twitching of muscles affecting performance, as well as difficulty in establishing a precise area of effect.
Positron emission tomography (PET)
Book definition: “A method for measuring metabolic activity in different regions of the brain with the use of a radioactive tracer. (p. 21)”
This brain imaging technique detects positrons emitted from the decay of radioactive substances in a tracer injected into the participant’s body. PET has moderate spatial resolution, being able to locate active brain areas to within 5-10 millimeters, but poor temporal resolution and is only able to indicate brain-activity over a period of 30-60 seconds.
In addition, the invasiveness of injecting radioactively labelled water may rule out potential participants.
Parietal lobe
Book definition: “The region at the top of the cerebral cortex concerned with attention and higher level sensory functions. (p. 15)”
Separated from the frontal lobe by the central sulcus, the parietal lobe holds the somatosensory cortex (responsible for the sense of touch) and the dorsal stream (or ‘Where’-pathway) of the visual system. It also receives sensory input from the skin relayed through the thalamus.
Corpus callosum
Book definition: “A broad band of fibers that enables communication between the left and right hemispheres of the brain. (p. 17)”
In a drastic procedure known as “corpus callosotomy,” this band is surgically severed as a last-ditch effort to alleviate powerful epileptic seizures, resulting in so-called split-brain patients.
Cognitive psychology
Book definition: “The scientific study of cognition. (p. 1)”
Coined by German-American psychologist Ulric Neisser in 1967, cognitive psychology is the study of mental processes such as attention, language use, memory, perception, problem solving, creativity and cognition.
Temporal resolution
Book definition: “ – ”
Term for the “resolution” of a given brain imaging technique in terms of time. The duration of a recording can vary from milliseconds (high temporal resolution) to seconds, minutes or several hours (low temporal resolution). A low resolution, like in fMRI, is useful for studying changes in the brain over a longer time, while a high resolution, like in MEG, is needed to pinpoint exactly when a specific activity occurs.
Wernicke’s area
Book definition: “A region of the left temporal lobe important to language, particularly the semantic content of speech. (p. 17)”
Damage to this area can lead to fluent aphasia (also called Wernicke’s aphasia), which impairs the semantic processing of language – i.e. the ability to grasp the meaning of spoken words and sentences as well as create meaningful phrases (out of otherwise fluently connected words). For instance, this actual patient quote: “Poomer, near the fortunate, porpunate tamppo, all around the fourth of martz.”
See also Broca’s area and non-fluent aphasia.
Neurotransmitter
Gyrus (plural: gyri)
Book definition: “An outward bulge on the brain. Contrast with sulcus. (p. 15)”
