250 Questions
What is the primary function of neurons in the nervous system?
To transmit information throughout the nervous system
What is the term for the gap between the terminal end of one neuron and the beginning of another?
Synapse
What is the term for the part of the neuron that carries electrical signals away from the cell body?
Axon
What is the term for the process by which an electrical signal is transmitted from one neuron to another?
Neurotransmission
What is the term for the voltage difference across the neuronal membrane during rest?
Resting Membrane Potential
What is the term for the ion channels that open and close rapidly to change the membrane potential?
Voltage-Gated Ion Channels
What is the term for the cells that provide support and maintenance functions for neurons?
Glial Cells
What is the term for the process by which the electrical gradient is generated in a neuron?
Asymmetrical Ion Distribution
What is the primary function of Voltage-gated channels in generating an action potential?
To open and close according to the membrane potential
What is the effect of a hyperpolarizing current on the generation of an action potential?
It makes the inside of the cell less positive
Where are voltage-gated Na+ and K+ channels located in a myelinated axon?
In the nodes of Ranvier
What is the function of myelin in an axon?
To allow for the rapid transmission of action potentials down an axon
What is the effect of a depolarizing current on the generation of an action potential?
It makes the inside of the cell more positive
What is the function of neurotransmitters in synaptic transmission?
To bind to specific receptors in the postsynaptic neuron
What is the primary function of ion channels in cells?
To create passageways through which ions can flow
What is the characteristic of action potentials that makes them all-or-none phenomena?
The amplitude of the action potential does not depend on the size of the triggering depolarization
What is the primary function of the parasympathetic nervous system?
To decrease heart rate and stimulate digestion
What type of glial cell forms myelin in the peripheral nervous system?
Schwann cell
What is the primary neurotransmitter used by the sympathetic nervous system?
Norepinephrine
What is the main component of the central nervous system?
Brain and spinal cord
What is the function of microglial cells in the immune response of the nervous system?
Phagocytosing damaged cells
What is the term for a group of neurons?
Ganglia
What is the main function of the autonomic nervous system?
Controlling the action of smooth muscles, the heart, and various glands
What is the structure composed of layered neurons in each hemisphere?
Cerebral cortex
What is the principle that states that the anatomical organization of the body is reflected in the cortical representation of the body?
Topography
What type of cortex receives and integrates input from multiple sensory modalities?
Association cortex
What is the benefit of minimizing connection lengths in the brain?
Faster signaling over shorter distances
What is the term for the organizational structure that combines short, fast, local connections with a few long-distance connections?
Small-world architecture
What is the effect of increasing brain size on long-distance brain connectivity?
Decreased long-distance connectivity
How do large brains maintain connectivity with increasing size?
By maintaining absolute connectivity
What is the benefit of retaining some long-distance connections in the brain?
Improved communication between distant sites
What is the term for the reduction in interconnectivity with increasing brain size?
Decreased long-distance brain connectivity
Which of the following neurotransmitters is involved in the regulation of social behavior and bonding?
Oxytocin
What is the primary function of electrical synapses?
To pass current directly from one neuron to another
Which of the following is a mechanism of neurotransmitter removal from the synaptic cleft?
Active reuptake
What is the primary function of the hypothalamus in terms of neurotransmission?
To regulate the release of hormones from the pituitary gland
Which of the following is a type of neurotransmitter that is involved in nociception and pain modulation?
Opioid peptides
What is the primary function of synapses in the nervous system?
To transmit information from one neuron to another
Which of the following is a characteristic of chemical synapses?
They release neurotransmitters into the synaptic cleft
What is the primary function of neurohypophyseal hormones?
To regulate blood pressure and osmotic balance
In Diffusion Tensor Imaging, what is the primary application of white matter pathway measurement?
Anatomical connectivity between brain regions
What is the typical time window for the N100 wave in Event-Related Potential analysis?
100-200 ms
What is the primary advantage of Magnetic Resonance Imaging (MRI) over Computed Tomography (CT) in neuroimaging?
Higher spatial resolution
What is the primary application of Magnetoencephalography (MEG) in cognitive neuroscience?
Source localization of neural activity
What is the primary difference between Electroencephalography (EEG) and Electrocorticography (ECoG)?
EEG measures surface EEG, while ECoG measures intracranial EEG
What is the primary application of Event-Related Potential (ERP) analysis in cognitive neuroscience?
Investigating the neural correlates of cognition
What is the primary advantage of Diffusion Tensor Imaging (DTI) in neuroimaging?
Measuring white matter pathways
What is the primary application of Single-Cell Recording in animals?
Investigating neural correlates of behavior
What is the primary difference between Magnetoencephalography (MEG) and Electroencephalography (EEG)?
MEG measures magnetic fields, while EEG measures electrical activity
What is the primary application of Electroencephalography (EEG) in cognitive neuroscience?
Investigating the neural correlates of cognition
What is the primary advantage of using MEG over EEG in cognitive research?
Improved spatial resolution
What is the purpose of averaging EEG signals in ERP analysis?
To reduce noise and increase signal amplitude
What is the primary difference between EEG and ECoG?
EEG is non-invasive, while ECoG is invasive
What is the primary application of event-related potentials (ERPs) in cognitive research?
To investigate neural mechanisms underlying cognitive processes
What is the primary advantage of using EEG in cognitive research?
Greater ease of use and lower cost compared to MEG
What is the primary purpose of using positron emission tomography (PET) in neuroimaging?
To investigate neural activity and function
What is the primary limitation of using EEG in cognitive research?
Poor spatial resolution
What is the primary advantage of using MEG in neuroimaging?
Superior spatial resolution compared to EEG
What is the primary application of electrocorticography (ECoG) in cognitive research?
To study neural activity during epilepsy
What is the primary difference between ERP and EEG?
ERP is time-locked to specific events, while EEG measures spontaneous activity
What is a major drawback of drug studies in perturbing neural function?
Lack of specificity
What is the primary goal of transcranial magnetic stimulation (TMS) research?
To transiently alter local brain physiology
What is the advantage of using genetic manipulations in neuroscientific research?
Ability to explore the consequences of the lack of expression of a specific gene
What is the primary application of transcranial direct current stimulation (tDCS)?
Enhancement of cognitive function
What is the primary advantage of using computed tomography (CT) scans in neuroimaging?
High spatial resolution
What is the primary goal of structural analysis of the brain?
To identify areas of brain damage or abnormality
What is the primary limitation of using drugs to perturb neural function?
Lack of specificity
What is the primary advantage of using transcranial magnetic stimulation (TMS) in neuroscientific research?
Ability to transiently alter local brain physiology
What is the primary goal of genetic manipulations in neuroscientific research?
To explore the consequences of the lack of expression of a specific gene
What is the primary application of transcranial direct current stimulation (tDCS)?
Enhancement of cognitive function
What is the primary purpose of subtractive procedure in functional magnetic resonance imaging (fMRI)?
To identify areas that show changes in metabolic activity
What is the term for the gap between the terminal end of one neuron and the beginning of another in brain graphs?
Edge
What is the primary function of computer models in neuroimaging research?
To simulate neural networks and generate predictions
What is the primary function of Pittsburgh Compound B (PiB) in neuroimaging research?
To bind to beta-amyloid and detect Alzheimer's disease
What is the primary function of functional magnetic resonance imaging (fMRI)?
To use MRI to measure changes in the oxygen content of the blood
What is the primary function of positron emission tomography (PET) in neuroimaging research?
To measure metabolic activity in the brain
What is the primary function of brain graphs in neuroimaging research?
To compare results from experiments using different methods
What is the primary function of retino-topic maps in neuroimaging research?
To represent central vision more inferiorly than peripheral vision
What is the primary function of event-related design in neuroimaging research?
To analyze the neural activity in response to specific stimuli
What is the primary limitation of PET and fMRI in neuroimaging research?
They are limited by their spatial and temporal resolution
What is the primary feature of retinotopic maps in the visual cortex?
They are organized by eccentricity and angular position
What is the functional difference between area V4 and area V5 in the visual cortex?
V4 is sensitive to color information, and V5 is sensitive to motion information
What is the primary advantage of using a flickering pinwheel stimulus in studying the visual cortex?
It allows for the study of temporal resolution limits
What is the primary feature of the visual cortex organization?
It is composed of multiple distinct regions with retinotopic maps
What is the primary difference between the activation profiles of V1, hV4, and VO in response to a flickering pinwheel stimulus?
VO matches the perceptual experience, while V1 and hV4 match the actual stimulus
What is the primary function of the visual areas in the dorsal and ventral regions?
They are involved in processing information from different parts of the visual field
What is the primary characteristic of the visual areas in the visual cortex?
They have functional differences that reflect the types of computations performed by cells within the areas
What is the primary advantage of using functional magnetic resonance imaging (fMRI) to study the visual cortex?
It allows for the study of neural activity with high spatial resolution
What is the characteristic of receptive fields in a cortical module?
They vary based on input source and sensitivity to orientation.
What is the purpose of plotting the preferred orientation of cells as a function of electrode location?
To visualize orientation columns.
What is the term for the organization of cells in the visual cortex, where cells with similar receptive fields are grouped together?
Cortical module.
What is the significance of the polygon formed in the polar graph of a cell's responses?
It represents the cell's optimal stimulus direction.
How do cells within an ocular dominance column differ from each other?
They are sensitive to different input sources.
What is the benefit of the retinotopic organization of the visual cortex?
It allows for efficient processing of visual information.
What is the characteristic of cells in the 'blobs' region of the visual cortex?
They are sensitive to color and finer details.
What is the relationship between orientation columns and ocular dominance columns?
They are complementary and intersect to form a cortical module.
What is the primary function of the primary somatosensory cortex (S1)?
To contain a homunculus of the body, wherein the more sensitive regions encompass relatively larger areas of cortex
What is the characteristic of visual neurons in the visual cortex?
They respond only to stimuli presented in a specific region of space
What is the term for the mapping between spatial location and the neural representation of that dimension in the visual cortex?
Retinotopic map
Which type of visual cortex area is organized into a topographic map, reflecting the spatial organization of the visual field?
V1
What is the primary function of the optic nerve?
To transmit visual information from the retina to the brain
What is the term for the specific region of space that a visual neuron responds to?
Receptive field
Which of the following visual cortex areas is NOT organized into a topographic map?
TEO
What is the primary function of the ganglion cells in the retina?
To form the optic nerve
What is the primary function of the superior colliculus in terms of visual processing?
Spatial orientation
Which area of the brain is associated with the inability to process motion?
V5 (human MT)
What is the result of presenting multisensory information coincidently in time and space?
Enhanced multisensory neural response
What is the characteristic of synesthesia?
Mixing of the senses
What is the result of blindfolding individuals for five days?
Increased activation in the occipital cortex
What is the term for the inability to perceive color?
Achromatopsia
Which brain region is involved in processing information from multiple sensory modalities?
Superior temporal sulci
What is the primary brain region responsible for processing visual information when the target is invisible due to the mask?
V1
What is the result of unilateral lesions to the visual cortex?
Subtle impairment of visual acuity
What is the main difference between the visual perception of individuals with a smaller V1 compared to those with a larger V1?
Individuals with a smaller V1 are more susceptible to visual illusions
What is the region of the brain responsible for color perception that is damaged in individuals with achromatopsia?
V4
What is the term for the process by which an individual is able to perceive visual information in the absence of a visual cortex?
Blindsight
What is the technique used to predict the orientation of the target from fMRI data?
Pattern classifier
What is the term for the areas of the brain that are organized in a specific spatial arrangement to process visual information?
Retinotopic maps
What is the term for the process by which the brain is able to process visual information from multiple sensory modalities?
Multisensory processing
What is the term for the specific areas of the brain that are responsible for processing visual information from a specific part of the visual field?
Receptive fields
What is the major problem with the concept of 'grandmother cells' in object recognition?
It cannot account for how we recognize novel objects
What is the term for the problem faced by patients who can recognize objects but cannot use visual information to guide action?
Optic ataxia
What is the primary function of neurons in the temporal lobe?
To process visual information from the fovea
What is the primary difference between view-dependent and view-invariant recognition?
View-dependent recognition is more robust to changes in lighting
What is the term for the type of recognition that is sensitive to changes in viewpoint?
View-dependent recognition
What is the primary application of studying patients with selective lesions of the ventral pathway?
To understand the neural basis of object recognition
What is the primary problem with the concept of 'ensemble coding' in object recognition?
It cannot account for how we recognize novel objects
What is the primary difference between analytic and holistic processing in object recognition?
Holistic processing is more applicable to face recognition
What is the primary advantage of studying object recognition in novel objects?
It allows for the study of object constancy
What is the primary application of studying patients with category-specific deficits?
To understand the neural basis of object recognition
What is the primary mode of processing involved in face perception?
Holistic processing
Which brain area is specialized for processing information about spatial relations or classifying objects based on spatial properties?
Parahippocampal Place Area (PPA)
What is the primary advantage of mind reading using decoding models?
It can predict the stimulus or mental state based on a physiological response
Which of the following brain areas is involved in the processing of body parts?
Extrastriate Body Area (EBA)
What is the primary difference between view-dependent and view-invariant recognition?
View-dependent recognition requires the viewer to recognize the object from a specific viewpoint
What is the primary advantage of analytic processing over holistic processing?
Analytic processing is more useful for object recognition
What is the primary characteristic of category-specific deficits?
They are specific to a particular category of objects
What is the primary advantage of using statistical pattern recognition in mind reading?
It can predict the stimulus or mental state based on a physiological response
What is the primary application of mind reading in the future?
To communicate with people who are currently unable to speak
What is the primary difference between encoding and decoding models in mind reading?
Encoding models predict the physiological response to a stimulus, whereas decoding models predict the stimulus or mental state based on a physiological response
What is the primary function of the ventral stream, or occipitotemporal pathway?
Object perception and recognition
What is the term for the phenomenon where people perceive an object as a unified whole, not as an entity separated by its color, shape, and details?
Object constancy
What is the characteristic of patients with visual agnosia?
They are unable to recognize objects visually, but can recognize them through touch
What is the primary difference between the dorsal and ventral streams?
The dorsal stream is specialized for spatial perception, while the ventral stream is specialized for object recognition
What is the term for the phenomenon where people recognize objects despite changes in their viewpoint?
View-invariant recognition
What is the characteristic of category-specific deficits?
A deficit in recognizing objects within a specific category, such as animals or tools
What is the primary function of neurons in the parietal lobe?
Spatial perception
What is the term for the type of processing involved in recognizing objects as a whole?
Holistic processing
What is the primary difference between holistic and analytic processing?
Holistic processing is involved in recognizing objects as a whole, while analytic processing is involved in recognizing objects as a collection of features
What is the term for the phenomenon where people recognize faces as a whole, rather than as a collection of features?
Holistic processing
What is object constancy in the context of object recognition?
The ability to recognize objects in various situations despite changes in the physical stimulus
Which of the following is an example of view-invariant recognition?
Recognizing an object from multiple angles
What is an example of a category-specific deficit?
Inability to recognize objects in a specific category, such as animals
What is the term for the inability to recognize faces?
Prosopagnosia
What is the term for the area in the fusiform gyrus of the temporal lobe that is specialized for face recognition?
Fusiform face area (FFA)
What is the term for the processing mode that emphasizes the component parts of an object?
Analytic processing
What is the term for the type of object recognition that occurs when the collective activation of many neurons is involved?
Ensemble theory
What is the term for the ability to recognize objects in various situations despite changes in the physical stimulus, and is achieved through view-invariant recognition?
Object constancy
What is the term for the deficits of object recognition that are restricted to certain classes of objects, such as animals or vehicles?
Category-specific deficits
What is the term for the mode of processing that emphasizes the gestalt or overall shape of an object?
Holistic processing
What is the primary function of the biased competition model in visual attention?
To resolve competition among multiple stimuli for representation in higher-level visual areas
What is the primary difference between reflexive and voluntary spatial attention?
Reflexive attention is exogenous, whereas voluntary attention is endogenous
What is the primary function of cueing tasks in attention research?
To measure the time course of attentional shifts
What is the primary characteristic of limited-capacity stages in attention?
They are involved in the serial processing of single stimuli
What is the primary difference between voluntary and reflexive attention in terms of neural basis?
Voluntary attention is associated with frontal and parietal cortex, whereas reflexive attention is associated with temporal cortex
What is the primary function of the saccade in attention?
To shift attention to a new location
What is the primary characteristic of voluntary spatial attention?
It is driven by internal goals and is voluntary
What is the primary function of the limited-capacity stage in attention?
To filter out irrelevant sensory information
What is the primary function of spatial attention in the processing of visual inputs?
It increases the neural responses to attended stimuli.
What is the effect of reflexive attention on early sensory processing?
It enhances the processing of all stimuli, but only transiently.
What is the effect of highly focused spatial attention on the visual system?
It modulates the activity in the subcortical relay nuclei in the thalamus.
What is the primary difference between reflexive and voluntary spatial attention?
Reflexive attention is automatic, while voluntary attention is controlled.
What is the primary application of cueing tasks in attention research?
To study the effects of attention on perception.
What is the Biased Competition Model of attention?
A model that proposes attention is a competition between multiple stimuli.
What is the primary limitation of the Limited-Capacity Stage model of attention?
It assumes that attention is limited by the processing capacity of the brain.
What is the primary difference between voluntary spatial attention and reflexive spatial attention?
Voluntary attention is controlled, while reflexive attention is automatic.
What is the primary function of the ventral attention network?
Concerned with the nonspatial aspects of attention and alerting
Which brain region is part of the dorsal attention network?
Inferior parietal cortex
What is the term for the network that includes the superior colliculi and the pulvinar of the thalamus?
Subcortical networks
What is the primary function of the dorsal attention network?
Concerned primarily with orienting attention
Which brain region is strongly lateralized to the right hemisphere?
Temporoparietal junction
What is the term for the system that interacts and cooperates with the dorsal attention network?
Ventral attention network
Which brain region is part of the ventral attention network?
Posterior parietal cortex of the temporoparietal junction
What is the primary function of the frontoparietal cortical systems?
Directing different attentional operations
What is the primary function of the inhibition of return in reflexive spatial attention?
To inhibit attention to stimuli that appear at previously attended locations
What type of attention is involved in the selective processing of object features or entire objects?
Selective attention
Which brain regions are specialized for the perceptual processing of color, form, or motion and can be modulated during visual attention?
Extrastriate cortical regions
What is the primary function of the dorsal attention network?
To modulate attention to spatial locations
What is the phenomenon in which attention is directed to a specific location or object without conscious awareness of the cue?
Reflexive spatial attention
What is the primary function of the frontoparietal attention system?
To modulate attention to spatial locations
What is the term for the selective processing of stimuli that are relevant to the current task or goal?
Selective attention
What is the primary function of the biased competition model?
To selectively process stimuli based on their relevance to the current task or goal
What is the main difference between early-selection models and late-selection models of attention?
Early-selection models propose that attention occurs early in the perceptual processing stream, while late-selection models propose that attention occurs late in the perceptual processing stream.
What is the primary function of limited-capacity stages in perceptual processing?
To prevent overload and ensure efficient processing of sensory information
What is the role of reflexive spatial attention in perceptual processing?
To automatically orient attention to a salient stimulus
What is the primary purpose of cueing tasks in the study of attention?
To manipulate the focus of attention in a controlled manner
What is the primary characteristic of voluntary spatial attention?
It is goal-directed and under voluntary control
What is the Biased Competition Model of attention?
A model that proposes that attention is a competitive process between stimuli
What is the primary difference between covert attention and overt attention?
Overt attention involves eye movements, while covert attention does not
What is the primary benefit of attention in perceptual processing?
To prevent overload and ensure efficient processing of sensory information
What is the primary mechanism of memory loss in Short-Term Memory?
Decay
What is the primary function of Encoding in the memory process?
Processing of incoming information
Which type of memory has a duration of minutes to hours?
Working Memory
What is the primary difference between Declarative and Non-Declarative Long-Term Memory?
Type of information stored
What is the primary mechanism of forgetting in Long-Term Memory?
Interference
What is the primary function of Working Memory?
Manipulation and processing of information
Which type of memory has a duration of only a few seconds?
Sensory Memory
What is the primary difference between Short-Term and Working Memory?
Type of information stored
Which type of memory is characterized by a limited capacity?
Short-Term Memory
What is the primary function of Long-Term Memory?
Long-term storage of information
What is the primary function of the sensory systems in the process of memory formation?
To process and interpret sensory information
Which stage of memory formation involves the stabilization of changes in the brain?
Consolidation
What is the term for the loss of the ability to form new memories?
Anterograde amnesia
What is the term for the brief, transient sensory response to stimuli?
Sensory buffer
What is the characteristic of retrograde amnesia in terms of the temporal gradient?
Greatest for the most recent events
Which of the following brain structures is NOT directly involved in the process of memory formation?
Cerebellum
What is the typical performance of patients with retrograde amnesia on digit span tests?
Normal short-term memory
What is the primary function of retrieval in the process of memory?
To access stored information and create a conscious representation
Which type of amnesia is characterized by the loss of memory for events that occurred in the past?
Retrograde amnesia
What is the primary division of long-term memory?
Episodic memory and semantic memory
What is the result of hippocampal memory consolidation?
Quick consolidation
What is the term for the system composed of the hippocampus and surrounding structures?
Medial temporal lobe memory system
What is the primary outcome of the process of learning?
Memory
What is the effect of lesions to the anterior temporal cortex?
Severe retrograde amnesia
Which stage of memory formation involves the processing and interpretation of sensory information?
Acquisition
What is the result of damage to the temporal lobe outside of the hippocampus?
Loss of semantic memory
What is the primary mechanism of the cellular basis of learning and memory?
Changes in the strength of synapses
What is the primary characteristic of long-term potentiation (LTP)?
An increase in the strength of synapses
What is the primary theory of long-term memory consolidation?
Standard consolidation theory
What is the primary characteristic of the CA3 region of the hippocampus?
Cooperativity, requiring multiple inputs to activate
What is the primary deficit associated with anomia?
The inability to find the words to label things in the world
Which part of the brain is especially critical for language production and comprehension?
Left hemisphere
What is the name of the area in the left hemisphere known for its role in language production?
Broca's area
What is the primary characteristic of Broca's aphasia?
Problems with speech production, syntax, and grammar
Which type of aphasia is associated with damage to the connection between Wernicke's and Broca's areas?
Conduction aphasia
What is the primary characteristic of Wernicke's aphasia?
Relatively fluid speech with minimal comprehension
Which area of the brain is involved in processing the prosody of language?
Right hemisphere
What is the term for language disorders resulting from neurological damage?
Aphasia
Which of the following is NOT a characteristic of Broca's aphasia?
Severe comprehension deficits
What is the name of the fasciculus that connects Wernicke's and Broca's areas?
Arcuate fasciculus
What is the term for the smallest unit of language that has meaning?
Morpheme
What is the term for the way in which words in a particular language are organized into grammatically permitted sentences?
Syntax
What is the term for the brain's store of words and concepts?
Mental Lexicon
What is the term for the rhythm and the pitch of the speaker's voice in speech?
Prosody
What is the area of the brain responsible for sound comprehension?
Superior Temporal Cortex
What is the term for the process of understanding spoken language?
Language Comprehension
What is the term for the organization of words in the mental lexicon?
Semantic Networks
What is the term for the smallest unit of sound that makes a difference to meaning?
Phoneme
What is the term for the rules that govern the composition of words, phrases, and sentences in a particular natural language?
Grammar
What is the term for the disorder that results from damage to the language processing areas of the brain?
Conduction Aphasia
Study Notes
Ion Channels and Action Potentials
- Ion channels are formed by transmembrane proteins that create passageways through which ions can flow.
- Ion channels can be either passive (always open) or gated (open only in the presence of electrical, chemical, or physical stimuli).
- Depolarizing current makes the inside of the cell more positive, increasing the likelihood of generating an action potential.
- Hyperpolarizing current makes the inside of the cell less positive, decreasing the likelihood of generating an action potential.
- Action potentials are all-or-none phenomena, meaning the amplitude of the action potential does not depend on the size of the triggering depolarization.
- Voltage-gated channels are crucial in generating an action potential, as they open and close according to the membrane potential.
Action Potential Transmission
- Myelin allows for the rapid transmission of action potentials down an axon.
- Nodes of Ranvier are the spaces between sheaths of myelin where voltage-gated Na+ and K+ channels are located, and action potentials occur.
Synaptic Transmission
- Neurotransmitters are synthesized by and localized within the presynaptic neuron and stored in the presynaptic terminal before release.
- Neurotransmitters are released by the presynaptic neuron when action potentials depolarize the terminal, primarily mediated by Ca2+.
- The postsynaptic neuron contains receptors specific for the neurotransmitter.
- When artificially applied to a postsynaptic cell, the neurotransmitter can bind to its receptors, causing excitatory or inhibitory postsynaptic potentials (EPSPs or IPSPs).
Neurotransmitters
- Classes of neurotransmitters include amino acids, biogenic amines, and neuropeptides.
- Examples of neuropeptides include:
- Tachykinins (brain-gut peptides)
- Neurohypophyseal hormones (e.g., oxytocin and vasopressin)
- Hypothalamic releasing hormones (e.g., corticotropin-releasing hormone)
- Opioid peptides (e.g., endorphins and enkephalins)
- Other neuropeptides (e.g., peptides that do not fit into another category)
Inactivation of Neurotransmitters after Release
- Neurotransmitters must be removed from the receptor after binding.
- Removal can be accomplished by:
- Active reuptake back into the presynaptic terminal
- Enzymatic breakdown of the transmitter in the synaptic cleft
- Diffusion of the neurotransmitter away from the region of the synapse
Electrical Transmission
- Electrical synapses operate by passing current directly from one neuron (presynaptic) to another neuron (postsynaptic) via specialized channels in gap junctions.
- Gap junctions connect the cytoplasm of one cell directly to the other.
Glial Cells
- Astrocytes have an active role in modulating neural activity and help form the blood-brain barrier.
- Glial cells aid in the speed of information transfer by forming myelin around the axons of the neurons.
- Oligodendrocytes are glial cells that form myelin in the central nervous system.
- Schwann cells are glial cells that form myelin in the peripheral nervous system.
- Microglial cells are phagocytic cells that engulf damaged cells as part of the immune response of the nervous system.
The Bigger Picture
- The central nervous system consists of the brain and spinal cord.
- The peripheral nervous system consists of all nerves and neurons outside of the central nervous system.
- The autonomic nervous system is involved in controlling the action of smooth muscles, the heart, and various glands.
- The sympathetic system uses the neurotransmitter norepinephrine, increasing heart rate and preparing the body for fight-or-flight responses.
- The parasympathetic system uses acetylcholine as a neurotransmitter, decreasing heart rate and stimulating digestion.
- Association cortices are regions of cortex that receive and integrate input from multiple sensory modalities.
- The cerebral cortex is a continuous sheet of layered neurons in each hemisphere, with a topographical organization that reflects the anatomical organization of the body.
Functional Magnetic Resonance Imaging (fMRI)
- fMRI measures changes in oxygen content of the blood, assumed to be correlated with local changes in neuronal activity.
- Areas that show increased blood flow when viewing a checkerboard stimulus have higher counts, reflecting increased metabolic activity.
Positron Emission Tomography (PET)
- PET measures metabolic activity in the brain by monitoring the distribution of a radioactive tracer.
- Pittsburgh Compound B (PiB) is a tracer that binds to beta-amyloid and is used as an in vivo assay for Alzheimer's disease.
Brain Graphs
- Brain graphs are a valuable way to compare results from experiments using different methods.
- Nodes in brain graphs act as connectors, providing links to more distant clusters.
Methods for the Study of Neural Function
- Single-cell recording allows neurophysiologists to record from individual neurons in the animal brain to understand how activity correlates with stimulation or behavior.
- Electroencephalography (EEG) measures the electrical activity of the brain, including endogenous changes and changes triggered by specific events.
- Event-related potential (ERP) is a change in electrical activity that is time-locked to specific events, such as the presentation of a stimulus or the onset of a response.
Methods to Perturb Neural Function
- Transcranial magnetic stimulation (TMS) uses magnetic pulses to transiently alter local brain physiology.
- Transcranial direct current stimulation (tDCS) is a non-invasive method to modulate neural activity.
- Genetic manipulations, such as gene knockout technology, allow scientists to explore the consequences of the lack of expression of a specific gene in order to determine its role in behavior.
Structural Analysis of the Brain
- Computed Tomography (CT or CAT) uses X-rays to image the 3-D structure of the brain.
- Magnetic Resonance Imaging (MRI) exploits the magnetic properties of the organic tissue of the brain to image its structure, with superior spatial resolution to CT.
- Diffusion Tensor Imaging (DTI) measures white matter pathways in the brain and offers information about anatomical connectivity between regions.
Senses, Sensation, and Perception
Sensation: Early Perceptual Processing
- Somatosensory receptors respond to touch, pain, and proprioception (position and movement) information
- Primary somatosensory cortex (S1) contains a homunculus of the body, with larger areas of cortex corresponding to more sensitive regions
- Somatosensory representations exhibit plasticity, varying in extent and organization based on individual experience
Vision
Neural Pathways of Vision
- Light activates photoreceptors (rods and cones) in the retina
- Optic nerve forms from ganglion cell axons, some of which decussate at the optic chiasm
- Axons in the optic nerve synapse on the LGN, which becomes the optic radiations sent to V1
- 10% of fibers from the retina innervate non-LGN subcortical structures, including the pulvinar and superior colliculus
Cortical Visual Areas
- Visual neurons respond only to stimuli within a specific region of space (receptive field)
- Visual cells form an orderly mapping between spatial location and neural representation (retinotopic maps)
- Many distinct regions in the visual cortex, each with functional differences and distinct retinotopic maps
- Humans have visual areas that do not correspond to any region in primate relatives
- Areas V4 and V5 are sensitive to color and motion information, respectively
From Sensation to Perception
- Percepts are more closely related to activity in higher visual areas than in primary visual cortex
- Anatomical differences among people in the size of V1 affect the extent of visual illusions
Deficits in Visual Perception
Deficits in Color Perception: Achromatopsia
- Lesions to areas in and around human V4 result in achromatopsia (inability to perceive color)
Deficits in Motion Perception: Akinetopsia
- Lesions to area V5 (human MT) result in akinetopsia (inability to process motion)
Multimodal Perception: I See What You're Sayin'
Multimodal Processing in the Brain
- Some areas of the brain, such as the superior colliculus and superior temporal sulci, process information from multiple senses
- Multisensory neural responses are enhanced when information is presented coincidently in time and space
Errors in Multimodal Processing: Synesthesia
- Synesthesia is a condition where senses are mixed, e.g., colored hearing or graphemes
- Synesthesia is associated with abnormal activation patterns and connectivity in functional and structural imaging studies
Object Recognition
- Object recognition involves the ability to recognize objects as a unified whole, beyond just their individual features.
- This process is closely linked to memory and perception.
Brain Regions Involved in Object Recognition
- The fusiform face area (FFA) is specialized for face perception.
- The parahippocampal place area (PPA) is specialized for processing spatial relations and classifying objects based on spatial properties.
- The extrastriate body area (EBA) and the fusiform body area (FBA) are active when body parts are viewed.
Mind Reading and Brain Signals
- Encoding models predict physiological responses to stimuli, such as the BOLD response.
- Decoding models predict the stimulus or mental state based on physiological responses, such as BOLD activity across voxels.
Principles of Object Recognition
- Object recognition is more than just sensation and perception.
- Our ability to recognize objects remains robust despite changes in visual perspective.
- Memory and perception are tightly linked.
- Patients with visual agnosia are unable to recognize common objects visually, but can recognize them through other senses.
Multiple Pathways for Visual Perception
- The ventral "what" pathway is specialized for object perception and recognition, terminating in the inferotemporal cortex.
- The dorsal "where" pathway is specialized for spatial perception, terminating in the posteroparietal cortex.
Representational Differences Between the Dorsal and Ventral Streams
- The ventral stream focuses on "vision for recognition."
- The dorsal stream focuses on "vision for action."
- Neurons in the parietal lobe have large, nonselective receptive fields.
- Neurons in the temporal lobe have large receptive fields that are much more selective.
Computational Problems in Object Recognition
- Variability in sensory information affects object recognition.
- View-dependent vs. view-invariant recognition theories differ in their assumptions about how objects are recognized.
- Shape encoding is a critical aspect of object recognition.
Grandmother Cells and Ensemble Coding
- Grandmother cells are hypothetical neurons that respond to specific stimuli.
- Ensemble coding theories propose that recognition arises from the collective activation of many neurons.
Failures in Object Recognition
- Object constancy refers to the ability to recognize objects despite variations in the physical stimulus.
- Category-specific deficits are deficits of object recognition restricted to certain classes of objects.
- Prosopagnosia is an inability to recognize faces.
- Acquired alexia is characterized by reading problems after a patient has a stroke or head trauma.
Voluntary Spatial Attention
- Robert Desimone and John Duncan proposed the biased competition model for selective attention, which suggests that attention enhances the processing of relevant stimuli and suppresses the processing of irrelevant stimuli.
- Spatial attention influences the processing of visual inputs, with attended stimuli producing greater neural responses than ignored stimuli in multiple visual cortical areas.
- Voluntary spatial attention can modulate activity in the visual system in the subcortical relay nuclei in the thalamus, providing strong evidence for early-selection models of attention.
Reflexive Spatial Attention
- Reflexive attention is automatic and activated by stimuli that are conspicuous in some way, resulting in changes in early sensory processing.
- A hallmark of reflexive attention is inhibition of return, where the recently reflexively attended location becomes inhibited over time, slowing responses to stimuli occurring there.
- Reflexive attention is transient, with neural responses returning to baseline levels after a short period of time.
Interplay Between Spatial and Feature Attention
- Attention can be directed at spatial locations, object features, or entire objects.
- Feature attention, such as attention to color or motion, can modulate activity in extrastriate cortical regions specialized for the perceptual processing of those features.
Object Attention
- Object attention involves selecting and processing an entire object, rather than just its individual features.
- Object attention can be influenced by top-down expectations and prior knowledge.
Review of Attention and Perceptual Selection Mechanisms
- Attention influences the processing of visual inputs, with attended stimuli producing greater neural responses than ignored stimuli.
- Spatial attention can modulate activity in the visual system in the subcortical relay nuclei in the thalamus, providing strong evidence for early-selection models of attention.
- Reflexive attention is automatic and activated by stimuli that are conspicuous in some way, resulting in changes in early sensory processing.
- Feature attention can modulate activity in extrastriate cortical regions specialized for the perceptual processing of those features.
Attentional Control Networks
- The dorsal attention network (DAN) is a bilateral frontoparietal network involved in spatial attention and orienting.
- The ventral attention network (VAN) is a lateralized network involved in non-spatial aspects of attention and alerting.
- The DAN includes regions such as the superior frontal cortex, inferior parietal cortex, and superior temporal cortex.
- The VAN includes regions such as the temporoparietal junction (TPJ) and ventral frontal cortex (VFC).
Review of Attentional Control Networks
- The dorsal attention network is involved in spatial attention and orienting.
- The ventral attention network is involved in non-spatial aspects of attention and alerting.
- The two networks interact and cooperate to produce normal behavior.
- Subcortical networks, including the superior colliculi and pulvinar of the thalamus, are also involved in attentional control.
Models of Attention
- Hermann von Helmholtz proposed the concept of covert attention, where attention is directed to a stimulus without moving the eyes.
- The cocktail party effect demonstrates how attention can selectively filter out irrelevant stimuli in a noisy environment.
- Early-selection models propose that attention filters out irrelevant information early in the processing stream, while late-selection models propose that attention selects information at a later stage of processing.
- Attention can be quantified by measuring the effect of attention on information processing, such as through cuing tasks.
Types of Memory
- Sensory memory: lasts for milliseconds to seconds
- Short-term memory: lasts for seconds to minutes
- Working memory: a subtype of short-term memory that involves active manipulation of information
- Long-term memory: lasts for hours, days, years, or a lifetime
- Nondeclarative memory: involves skills and habits
- Declarative memory: involves facts and knowledge
Encoding
- The process of processing incoming information to create memory traces
- Consists of two separate steps: acquisition and consolidation
- Acquisition: sensory systems are constantly bombarded by stimuli, but most only produce a brief transient sensory response
- Consolidation: changes in the brain stabilize the information, making it more permanent
Storage
- The result of acquisition and consolidation, representing the permanent record of information
Retrieval
- Involves accessing stored information to create a conscious representation or execute a learned behavior
Anatomy of Memory
- Medial temporal lobe memory system: includes the hippocampus and surrounding rhinal and parahippocampal cortices
- Other areas involved in memory: prefrontal cortex, parietal cortex, and subcortical structures
Memory Deficits: Amnesia
- Anterograde amnesia: the loss of the ability to form new memories
- Retrograde amnesia: the loss of memory for events that happened in the past
- Temporal gradient or Ribot's Law: retrograde amnesia tends to be greatest for the most recent events
Mechanisms of Memory
- Mechanisms of memory involve changes in the strength of synaptic connections between neurons
- Long-term potentiation (LTP) and long-term depression (LTD) are two prominent theories of long-term memory consolidation
Long-Term Forms of Memory
- Verbal memory: involves remembering verbal information
- Spatial memory: involves remembering spatial locations and relationships
Cellular Basis of Learning and Memory
- Most models hold that memory is the result of changes in the strength of synaptic connections between neurons
- Hippocampal memory consolidation is a quick process
The Anatomy of Language
- Anomia is the inability to find the words to label things in the world, and it is not a deficit of knowledge.
- A left-hemisphere network involving the frontal, parietal, and temporal lobes is especially critical for language production and comprehension.
- The right hemisphere has roles in language, especially in processing the prosody of language.
Brain Damage and Language Deficits
Broca's Aphasia
- Caused by damage to Broca's area in the left inferior frontal cortex
- Characterized by problems with speech production, syntax, and grammar, but relatively good comprehension
Wernicke's Aphasia
- Characterized by severe comprehension deficits but relatively fluid speech production
- Originally linked to damage solely in Wernicke's area (posterior superior temporal gyrus), but now also linked to damage outside this area
Conduction Aphasia
- Caused by damage to the connection between Wernicke's and Broca's areas (the arcuate fasciculus)
- Characterized by problems producing spontaneous speech and repeating speech
The Fundamentals of Language in the Human Brain
Words and the Representation of Their Meaning
- The mental lexicon is the brain's store of words and concepts
- A morpheme is the smallest unit of language that has meaning
- A phoneme is the smallest unit of sound that makes a difference to meaning
- Semantic (meaning) relationships between words are an organizational principle of the mental lexicon
Models of the Mental Lexicon
- Syntax refers to the way in which words in a particular language are organized into grammatically permitted sentences
- Grammar refers to the structural rules that govern the composition of words, phrases, and sentences in a particular natural language
Language Comprehension
Perceptual Analyses of the Linguistic Input
- There are no pauses between phonemes in speech that correspond to words
- The prosody of speech is the rhythm and the pitch of the speaker's voice
Spoken Input: Understanding Speech
- Sound comprehension involves the superior temporal cortex
- Damage to this area can result in pure word deafness
Written Input: Reading Words
- Reading is a relatively recent invention (about 5,500 years old)
- Although speech comprehension develops without explicit instruction, reading requires explicit instruction
Learn about ion channels, their types, and how they facilitate electrical signaling in cells. Understand the role of passive and gated channels in generating action potentials.
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