Exam 1 Flashcards
an experiment in which a specific component is added to a system; it is often used to test whether the added component is sufficient for the system to function in a specific context.
Gain-of-function experiment
an experiment in which a specific component is disrupted, often used to determine if the missing component is necessary for the system to function.
loss-of-function experiments
an experiment in which key parameters in a biological system are altered, usually under the experimenter’s control, in order to study the consequences.
perturbation experiments
signaling that uses continuous values to represent information.
Digital signaling: signaling that uses discrete values (0s and 1s) to represent information.
analog signaling
an information processing method; utilizing a large number of units to perform a set of coordinated computations in parallel. It is a key feature of the nervous system.
Massively parallel processing
an information processing method in which processing units are arranged in sequential steps.
Serial processing
(part of the temporal cortex overlying the hippocampus), where maps represent spatial information of the outside world.
Entorhinal cortex
corresponding to movement of specific body parts: nearby neurons in the motor homunculus control the movement of nearby body parts.
Topographic map
a map in the primary somatosensory cortex; it corresponds to sensation of specific body parts. Nearby somatosensory cortical areas represent sensation from nearby surfaces.
Sensory homunculus
a map in the primary motor cortex that corresponds to movement of specific body parts. Nearby areas in the motor cortical areas represent movement control of nearby body parts.
Motor homunculus
which monitors signals originating from changes in blood flow that results from local neuronal activity.
Functional magnetic resonance imaging (fMRI)
is a medical condition characterized by recurrent seizures-strong urges of abnormal electrical activity that affect part or all of the brain.
Epilepsy
the part of the cortex that analyzes auditory signals.
Auditory cortex
-were associated with defects in language.
-Discovered by Carl Wernicke
-Patients have great difficulty understanding language, but they can speak fluently, although often unintelligently and incoherently.
Wernicke’s Area
-is the area in the human left frontal lobe in patients who could not speak.
-Discovered by Paul Broca
-Patients had great difficulty producing language, whether in speech or writing, but their understanding of language is largely intact.
Broca’s Area
majors folds separating the lobes.
Fissures
Each hemisphere of the of the cerebral cortex is divided into four lobes:
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
-a discipline in the 1800s with the goal of mapping the functions of brain areas by studying the shape and size of bumps and ridges on the skull, which were thought to be correlated with an individual’s talents and character traits.
-Developed by Franz Joseph Gall
Phrenology
sends descending output directly and indirectly to spinal cord motor neurons to control muscle contractions, in case we want to move our leg voluntarily (in contrast to the knee-jerk reflex, which is involuntary).
Primary motor cortex
the part of the cerebral cortex that first receives somatosensory input from the body.
Primary somatosensory cortex
the postsynaptic excitatory neuron synapses onto an inhibitory neuron, which synapses back onto the postsynaptic excitatory neuron.
Feedback inhibition
an excitatory neuron synapses onto both an excitatory neuron and an inhibitory neuron, and the inhibition neuron further synapses onto the excitatory postsynaptic neuron.
Feedforward inhibition
neurons that transmit parallel streams of information can also excite each other forming this excitation.
Recurrent (lateral) excitation
when a postsynaptic neuron synapses onto its own presynaptic partner.
Feed-back excitation
propagates information across multiple brain regions, as in the relay of somatosensory stimuli to the primary somatosensory cortex
Feed-forward excitation
refers to a motif wherein a single neuron synapses onto multiple postsynaptic targets via branched axons (axonal branches are also called collaterals).
Divergent excitation
refers to a circuit motif wherein several neurons synapse onto the same postsynaptic neuron.
Convergent excitation
common configurations of neural circuits that allow the connection patterns of individual neurons to execute specific functions.
Circuit motifs
whose axons link different regions of the nervous system.
Projection neurons
a second type of postsynaptic neuron targeted by the sensory axons.
Inhibitory interneurons
referring to axons that project from the CNS to peripheral targets.
Efferents
referring to axons projecting from peripheral tissues to the CNS
Afferents
sensory neurons embed their endings in specialized apparatus.
Muscle spindles
the involuntary forward movement of the lower leg due to contraction of the quadriceps femoris muscle (an extensor) and relaxation of the hamstring muscle (a flexor).
Knee jerk reflex
The simplest circuits in vertebrates, those that mediate the spinal reflexes, comprise as few as two interconnected neurons:
- A sensory neuron that receives external stimuli.
- A motor neuron that controls muscle contraction.
ensembles of interconnected neurons that act together to perform specific functions.
Neural circuits
at chemical synapses, they rely on neurotransmitter release and reception.
Interneuronal communication
is achieved by membrane potential changes in the form of graded potentials and action potentials.
Intraneuronal communication
the process of neurotransmitter release from the presynaptic neuron and neurotransmitter reception by the postsynaptic neuron
Synaptic transmission
How is information transmitted between neurons?
-At electrical synapses, membrane potential changes are directly transmitted from one neuron to another by ion flow across gap junctions.
-At chemical synapses, the arrival of action potentials (or graded potentials in non-spiking neurons) at presynaptic terminals triggers neurotransmitter release.
the site of action potential initiation adjacent to the soma.
Axon initial segment (axon hillock)
