Factors controlling discharge of known norepinephrine-containing locus\r\ncoeruleus (NE-LC) neurons were studied in unanesthetized behaving rats, and\r\nthese neurons' efferent impulse conduction properties were examined in\r\nanesthetized rats. Single-unit (SU) and multiple-unit (MU) extracellular\r\nrecordings in unanesthetized preparations demonstrated the following: (1)\r\nTonic discharge co-varied with stages of the sleep-waking cycle (S-WC),\r\nbeing highest during waking (W), lower during slow-wave sleep (SWS), and\r\nvirtually absent during paradoxical sleep (PS). (2) Altered discharge\r\npredictably anticipated S-WC stages as well as phasic cortical activity\r\nsuch as spindles during SWS. (3) Discharge was reduced within active\r\nwaking during grooming and sweet water consumption. (4) Bursts of impulses\r\naccompanied spontaneous or sensory-evoked interruptions of sleep, grooming,\r\nconsumption, or other such ongoing behaviors. (5) Discharge was not linked\r\nto movement per se. (6) Field potentials (FPs) occurred spontaneously in\r\nNE-LC recordings, temporally synchronized with bursts of unit activity from\r\nthe same electrodes during Wand SWS, but at highest rates during PS, when\r\ndischarge was virtually absent. (7) Short-latency (15-50 msec), transient,\r\nbiphasic unit responses and synchronous FPs were predictably evoked by\r\nnon-noxious auditory, visual and somatosensory stimuli; individual\r\nrecordings typically exhibited similar response patterns for each sensory\r\nmodality. (8) The magnitudes of sensory-evoked response varied as a\r\nfunction of vigilance, such that largest responses occurred for stimuli\r\nwhich awakened animals and least responsiveness was exhibited during\r\nuninterrupted sleep. (9) Sensory responsiveness also decreased during\r\ngrooming and sweet water consumption. (10) Transiently reduced discharge\r\noccurred in response to gustatory stimulation accompanying voluntary\r\nconsumption of sweet water. (11) SU and MU recordings throughout the\r\nnucleus yielded remarkably homogeneous results. (12) Robust phasic\r\ndischarge was markedly synchronized among neurons in MU populations.
\r\n\r\nSU recordings of spontaneous and antidromic NE-LC impulse activity in\r\nanesthetized rats indicated the following: (1) Impulse conduction velocity\r\nfluctuated as a function of basal conduction latency, impulse rate, and\r\nnumber of impulses in, a train of activity. (2) Impulse conduction velocity\r\nincreased briefly, then exhibited a more pronounced, gradual decrease\r\nduring the same train of activity. (3) Large increases in conduction\r\nlatency occurred during low-frequency trains of impulse activity. (4)\r\nCalculations indicated that these axons may modulate their own impulse flow\r\nas a result of ion fluxes associated with spike propagation.
\r\n\r\nThese results are interpreted in light of previous data on the\r\npostsynaptic physiology of norepinephrine to indicate that robust activity\r\nin the NE-LC system may participate in terminating CNS and behavioral\r\nprocesses which have minimal value in coping with phasic external events,\r\nand simultaneously enhance activity within systems primarily concerned with\r\nsuch immediate responses. Conversely, low levels of spontaneous or\r\nsensory-evoked NE-LC discharge may enable tonic, endogenously generated\r\nvegetative behaviors to proceed. In this way, the NE-LC system may bias\r\nglobal behavioral orientation between the external and internal\r\nenvironments.
", "doi": "10.7907/rpgq-v891", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:10677", "collection": "thesis", "collection_id": "10677", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:02062018-101121529", "type": "thesis", "title": "Unit Activity in the Hypothalamus and Striatum of the Rat During Learning", "author": [ { "family_name": "Linseman", "given_name": "Mary Ann Monica", "clpid": "Linseman-Mary-Ann-Monica" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Unit activity was recorded from the hypothalamus and striatum\r\nof 80 freely moving rats during an appetitive classical conditioning \r\nsituation. Responses to auditory stimuli were observed from 118\r\nunits before and during a conditioning procedure in which presentation\r\nof food occurred one second after the onset of an auditory stimulus.\r\nA large proportion of units (111) showed changed responses to the CS \r\nduring conditioning. Only 8 of these, however, showed new conditioned \r\nresponses of the very shortest latency measured, 20 msec. after CS \r\nonset. These were interpreted as likely sites of rerouting of the stimulus \r\ninformation within the brain as a result of learning. They \r\nwere located largely near the intersection of hypothalamic and striatal \r\nstructures. A transient increase in rate of background firing over \r\ntrials was recorded following the onset of conditioning among hypo\u00adthalamic \r\nunits, suggesting they may temporarily represent a dynamic trace of the \r\nnew learning. No significant differences were found between areas \r\nstudied in order of appearance over trials of the conditioned responses. \r\nHowever, as a group, the conditioned responses studied here, appeared \r\nsignificantly earlier than a group of cortical neurons studied under \r\nsimilar conditions. There was greater generalization of response \r\nto the CS- by units of the basal ganglia than other areas, suggesting \r\nthey may be of importance in inhibition of response to the CS-.\r\n\r\n", "doi": "10.7907/9BAS-1713", "publication_date": "1973", "thesis_type": "phd", "thesis_year": "1973" }, { "id": "thesis:11184", "collection": "thesis", "collection_id": "11184", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09172018-103619092", "primary_object_url": { "basename": "Segal_M_1973.pdf", "content": "final", "filesize": 63901754, "license": "other", "mime_type": "application/pdf", "url": "/11184/1/Segal_M_1973.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Hippocampus as a Learning Machine", "author": [ { "family_name": "Segal", "given_name": "Menahem", "clpid": "Segal-Menahem" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Bonner", "given_name": "James Frederick", "clpid": "Bonner-J-F" }, { "family_name": "Fender", "given_name": "Derek H.", "clpid": "Fender-D-H" }, { "family_name": "Sperry", "given_name": "Roger Wolcott", "clpid": "Sperry-R-W" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "A series of experiments were conducted with the purposes of\r\ndescribing a functional pathway in the rat hippocampus, characterizing some conditions necessary for activating it, and identifying critical steps in this pathway. In all experiments a classical conditioning paradigm was used and the responses of units in the hippocampus and related forebrain structures to the conditioned stimulus were measured. In the first experiment a few differences between dentate, CA-3, and CA-1, the main fields of the hippocampus, were found. Units in the dentate were first to acquire a conditioned response, CA-3 followed and CA-1 was last. This order fits with the anatomical pathway. However, dentate responses were phasic, that is, did not outlast the CS-US interval, and were not specific to the conditioned stimulus. The responses of CA-3 and CA-1 units, on the other hand, were sustained and specific. The second experiment was devoted to the analysis of conditioned response latencies, in the hippocampus\r\nas well as in septum, subiculum, cingulate, entorhinal, and related structures, all known to be input stages to the hippocampus. In this experiment unconditioned short response latencies were found in the medial septum, one of the afferents of the hippocampus. These were not changed in the process of learning. The shortest conditioned response latencies were found in area CA-3 of the hippocampus. Units in area CA-1 followed, but units in dentate did not precede those of CA-3. Units in entorhinal cortex, the other main afferent to the hippocampus did not seem to precede hippocampal units either. The special relations between the hippocampus and the dentate were demonstrated in another part of this experiment, where dentate units lost their conditioned responses, in the process of extinction, before those of CA-3 and CA-1. It was postulated that septal input triggers CA-3 responses and these\r\nwould be maintained in the presence of reinforcing dentate and\r\nentorhinal inputs.
\r\n\r\nThe relations between the dentate and the hippocampus were\r\nfurther studied in two experiments in which aversive electric shock served as an unconditioned stimulus. In experiment 3 food and shock served as unconditioned stimuli on alternate days. In\r\nexperiment 4 food and shock were presented in the same sessions as unconditioned stimuli to two different CS's. Dentate units had an excitatory conditioned response to a food signal and an inhibitory conditioned response to a shock signal in both experiments. Hippocampal units had excitatory responses to both signals. Acquisition of a conditioned response was not demonstrated within the hippocampus when the conditioned stimulus preceded shock and was slow when food or shock were applied following two different signals in the same session. However, when first trained that a signal precedes food, the conditioned response would be maintained in the hippocampus even if shock is now the US. The dentate is probably involved in the initiation of a conditioned response in the hippocampus but not in the maintenance of it.
\r\n\r\nA sensory-sensory paradigm (experiment 5) has demonstrated\r\nthe presence of unconditioned unhabituated sensory responses in two of the afferents to the hippocampus, that is, the medial septum and the cingulate cortex. It failed to show signs of conditioning in the hippocampus proper. It was proposed that in the absence of an appetitive reward and the activity of the entorhinal-dentate pathway, conditioned responses in hippocampus cannot be established.
\r\n\r\nConditioned entorhinal responses (experiment 6) had long\r\nlatency but also long time constant. Their evoked activity was\r\nmaintained for periods as long as one minute. It was found that\r\nhippocampal responses were larger, if the conditioned stimulus was applied within one minute from the previous trial. Hence, a\r\ncorrelation between hippocampal responses and entorhinal firing\r\nrate was demonstrated. On the basis of these experiments it was\r\nproposed that septal input enters the hippocampus at the CA-3\r\narea, is able to selectively activate these cells only in the\r\npresence of facilitation produced by entorhinal and dentate activity. The facilitatory entorhinal activity is triggered mainly by positive reward.
\r\n", "doi": "10.7907/P1SD-Z263", "publication_date": "1973", "thesis_type": "phd", "thesis_year": "1973" }, { "id": "thesis:3287", "collection": "thesis", "collection_id": "3287", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08302007-114218", "primary_object_url": { "basename": "Hiatt_de_1972.pdf", "content": "final", "filesize": 23527563, "license": "other", "mime_type": "application/pdf", "url": "/3287/1/Hiatt_de_1972.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Investigations of Operant Conditioning of Single Unit Activity in the Rat Brain", "author": [ { "family_name": "Hiatt", "given_name": "David Ellis", "clpid": "Hiatt-David-Ellis" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Unknown", "given_name": "Unknown" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "The aim of these studies was to show that the capacity for operant responses is distributed differentially in the brain and that such capacity is maintained in the absence of feedback from movement in specific parts of the brain. The experimental subjects were rats chronically implanted with microelectrodes for single unit recording from several different brain structures. There were three experimental paradigms. In Experiments I and II positive reinforcement was applied following bursts of activity of an arbitrarily selected unit during periods indicated by a discriminative stimulus. All such units in cerebellum and brain stem displayed significant conditioned rate increases while only about half those in hippocampus, midbrain and superior colliculus did so indicating that operant conditioning is more a property of \"motor\" units. Experiment II was a direct continuation of Experiment I with some of the rats which had conditioned units. The contribution of the bodily movement which seemed inevitably correlated with the conditioned unit response was determined by inducing skeletal muscle paralysis with Flaxedil. Conditioned responses were maintained under paralysis in all 5 rats with an experimental unit in the brain stem but in only one of the 6 rats with an experimental unit in the cerebellum, and none in the other 7 rats with experimental units divided among hippocampus, midbrain and superior colliculus. This indicated that the conditioned responses of most of the units were fed-back from movement which the conditioned activity of the brain stem units probably preceded. A control experiment with non-contingent reinforcement showed that these conditioned responses were probably not entirely due to operant conditioning. This ambiguity was absent in Experiment III which showed clearly operant activity. The rate of units, predominantly in the cerebellum, was increased or decreased depending upon the contingency of reinforcement. However, Experiment III used active animals and tested no units in the brain stem. A final experiment demonstrated clearly operant activity of a brain stem unit under paralysis. Reinforcement was made contingent upon rapid alternation between activity and inactivity of the unit. After acquisition, this behavior was brought under the control of a discriminative stimulus, and then maintained under paralysis, which eliminated the alternation of stereotyped movements that had been correlated with the unit activity.\r\n\r\n(Photographic materials on pages 18, 22, 66, 68, 144, 146, and 148 are essential and will not reproduce clearly on Xerox copies. Photographic copies should be ordered.)", "doi": "10.7907/FQEA-6371", "publication_date": "1972", "thesis_type": "phd", "thesis_year": "1972" }, { "id": "thesis:9694", "collection": "thesis", "collection_id": "9694", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05022016-093643296", "primary_object_url": { "basename": "Kornblith_cl_1972.pdf", "content": "final", "filesize": 21562260, "license": "other", "mime_type": "application/pdf", "url": "/9694/1/Kornblith_cl_1972.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Conditioned Responses in the Reticular Formation", "author": [ { "family_name": "Kornblith", "given_name": "Carol Lee", "clpid": "Kornblith-Carol-Lee" } ], "thesis_advisor": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" } ], "thesis_committee": [ { "family_name": "Olds", "given_name": "James", "clpid": "Olds-J" }, { "family_name": "Owen", "given_name": "Ray David", "clpid": "Owen-R-D" }, { "family_name": "Strumwasser", "given_name": "Felix", "clpid": "Strumwasser-F" }, { "family_name": "Van Harreveld", "given_name": "Anthonie", "clpid": "Van-Harreveld-A" }, { "family_name": "Wiersma", "given_name": "Cornelis A. G.", "clpid": "Wiersma-C-A-G" } ], "local_group": [ { "literal": "div_biol" } ], "abstract": "Unit activity was recorded from the midbrain and pons of 40 freely moving rats in an appetitive classical conditioning situation. Responses to auditory stimuli were observed from 100 units before and during a conditioning procedure in which presentation of food occurred 1 sec after the onset of the auditory stimulus. Conditioned unit responses (i.e., spike rate accelerations or decelerations) were considered to be positive when 1) no similar responses appeared prior to conditioning, and 2) latencies were equal to or less than those of sensory responses derived from the inferior colliculus. Such short latency conditioned unit responses were recorded from 11 probes located in the mid-lateral pert of the ventral region of the brain stem. This region was differentiated from paramedian, far lateral and dorsal parts of the brain stem reticular formation. Conditioned unit responses of considerably longer latencies were recorded from 76 probe located in these other regions. Among the longer latency responses interesting differences appeared in experiments conducted after the first conditioning series was completed. With additional training, units in the \"reticular activating system\" of midbrain and pons tended to yield stabilized responses in the early portion of the\r\nCS-US interval closely related in time to the orientation responses evoked by the CS. In contrast, the responses of units in the limbic midbrain tended to stabilize in the later part of the CS-US interval closely related in time to preparatory responses tied to the US. During extinction when the auditory stimulus was no longer followed by presentation of food, many of the responses were reduced to their pre-conditioning levels. However, there was a tendency for units which had displayed short latency responses on the first conditioning day to be more resistant to extinction than units which had displayed longer latency conditioned responses. The data were interpreted as indicating a local correlate of learning in the reticular formation of midbrain end pons and a separation of the midbrain system into at least two areas: 1) the classical \"reticular activating system\" related to orienting reactions, and 2) the limbic midbrain areas related to drives and rewards. Because the ventral and mid-lateral area with very short latency conditioned responses was not clearly tied to either of these; it was considered as possibly representing a third division.", "doi": "10.7907/J6N6-EV96", "publication_date": "1972", "thesis_type": "phd", "thesis_year": "1972" } ]