SEARCH · PubMed Health

Results for “Prefrontal Cortex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources

PubMed2004

Enhanced visuomotor associative learning following stimulation of alpha 2A-adrenoceptors in the ventral prefrontal cortex in monkeys.

The present study investigated the effect of locally infused guanfacine, an alpha2A-adrenergic agonist, into the ventral prefrontal cortex (PFv) on visuomotor associative learning. Two monkeys were well trained on a two-problem visuomotor associative task: the monkeys performed movement A if presented with a circle pattern, or movement B if presented with a triangle pattern. For learning of new visuomotor associations, the monkeys were presented with a new set of four patterns in each and every daily session, two of which instructed movement A and the other two movement B. Bilaterally infused guanfacine (2.5 microg/microl; 3 microl on each side) improved the monkeys' ability to learn new visuomotor associations: trials and errors to learning criterion of 90% correct decreased significantly. The monkeys showed an enhanced capability to use win-stay/lose-shift strategy on 'repeat trials' and change-stay/change-shift strategy on 'change trials.' The present results indicate that alpha2A-adrenoceptor in the PFv is involved in regulating visuomotor associative learning.

Adrenergic alpha-2 Receptor Agonists↗

PubMed1996

Functional lateralization of the prefrontal cortex during traditional frontal lobe tasks.

We attempted to identify brain regions functionally lateralized during cognitive tasks traditionally linked to the prefrontal cortex (PFC) by measuring regional cerebral blood flow with H2(15)O positron emission tomography (PET). Fourteen normal subjects were scanned six times while performing six different cognitive conditions comprising three task paradigms putatively sensitive to PFC integrity: the Wisconsin Card Sort (WCS), Delayed Response Alternation (DA), and the Spatial Delayed Response (SDR) Tasks, and three matched sensorimotor control tasks. Multivariate and repeated measures analyses indicated that for all three cognitive paradigms there were no significant hemisphere, hemisphere-by-condition, or hemisphere-by-region effects. However, with more liberal statistical comparison (paired t tests), the superior frontal gyrus showed lateralization during both the WCS and SDR tasks (both R > L). These results suggest that, although some asymmetries may be found using liberal analyses, there is less evidence of lateralized brain function during performance of these tasks of PFC function, than in language and motor systems. Implications for testing PFC function in neuropsychiatric groups are discussed.

Adult↗

PubMed2005

3,4-Methylenedioxymethamphetamine (MDMA) enhances the release of acetylcholine by 5-HT4 and D1 receptor mechanisms in the rat prefrontal cortex.

3,4-Methylenedioxymethamphetamine (MDMA), an amphetamine analog, has been shown recently to increase the release of acetylcholine (ACh) in the prefrontal cortex (PFC). The present study further characterizes the stimulatory effect of MDMA on cortical ACh release and examines the role of serotonin (5-HT) and dopamine (DA) receptors in this response. The extracellular concentration of ACh was increased dose-dependently and similarly by the (+) and (-) enantiomers of MDMA (5 and 20 mg/kg, i.p.). The systemic administration of the 5-HT(4) antagonist SDZ 205,557 (1 mg/kg, i.p.), but not the 5-HT(2A/2B/2C) antagonist LY-53,857 (3 mg/kg, i.p.), significantly decreased cortical ACh release induced by MDMA. The MDMA-induced increase in the extracellular concentration of ACh also was significantly blunted in rats treated with the D(1) receptor antagonist SCH 23390 (0.5 mg/kg, i.p.). The extent to which the coadministration of SDZ 205,557 and SCH 23390 suppressed the MDMA-induced release of ACh in the PFC was no greater than that produced by either antagonist alone. These results suggest that the 5-HT(4) and D(1) receptor subtypes contribute to the mechanism by which MDMA increases ACh release in the PFC.

4-Aminobenzoic Acid↗

PubMedDate not supplied

Dopamine innervation of a subclass of local circuit neurons in monkey prefrontal cortex: ultrastructural analysis of tyrosine hydroxylase and parvalbumin immunoreactive structures.

The ability of dopamine to regulate the cognitive functions of the prefrontal cortex (PFC) involves complex modulatory actions on GABA-containing local circuit neurons in addition to pyramidal cells. However, the subclasses of cortical neurons that receive direct dopamine input are not known. We sought to determine whether dopamine terminals innervate the subclasses of local circuit neurons that contain the calcium-binding protein parvalbumin (PV), namely the wide arbor and chandelier neurons that target pyramidal cell soma and axon initial segments respectively. Sections through area 9 of five monkeys were labeled with immunoperoxidase for tyrosine hydroxylase (TH), to identify dopamine terminals, and with immunogold-silver for PV. Electron microscopic examination of the middle cortical layers (IIIb-IV) revealed that TH-positive terminals were sometimes directly apposed to PV-labeled dendrites, and approximately one-third of these contacts exhibited morphological features that are typically associated with symmetric synapses. In contrast, TH-immunolabeled terminals in the superficial layers (I-IIIa) were less frequently apposed to PV-positive dendrites, and none of these contacts exhibited synapse-like morphology. These findings, in concert with previous studies of GABA- or calretinin-containing local circuit neurons, suggest that dopamine's modulatory action in the PFC involves selective effects on only certain interneuron populations, including those that mediate potent inhibitory actions on pyramidal cells.

Animals↗

PubMed2004

Differential involvement of rat medial prefrontal cortex dopamine receptors in modulation of hypothalamic-pituitary-adrenal axis responses to different stressors.

Recent investigations have implicated the medial prefrontal cortex (mPFC) in modulation of subcortical pathways that contribute to the generation of behavioural, autonomic and endocrine responses to stress. However, little is known of the mechanisms involved. One of the key neurotransmitters involved in mPFC function is dopamine, and we therefore aimed, in this investigation, to examine the role of mPFC dopamine in response to stress in Wistar rats. In this regard, we infused dopamine antagonists SCH23390 or sulpiride into the mPFC via retrodialysis. We then examined changes in numbers of cells expressing the c-fos immediate-early gene protein product, Fos, in subcortical neuronal populations associated with regulation of hypothalamic-pituitary-adrenal (HPA) axis stress responses in response to either of two stressors; systemic injection of interleukin-1 beta, or air puff. The D1 antagonist, SCH23390, and the D2 antagonist, sulpiride, both attenuated expression of Fos in the medial parvocellular hypothalamic paraventricular nucleus (mpPVN) corticotropin-releasing factor cells at the apex of the HPA axis, as well as in most extra-hypothalamic brain regions examined in response to interleukin-1 beta. By contrast, SCH23390 failed to affect Fos expression in response to air puff in any brain region examined, while sulpiride resulted in an attenuation of the air puff-induced response in only the mpPVN and the bed nucleus of the stria terminalis. These results indicate that the mPFC differentially processes the response to different stressors and that the two types of dopamine receptor may have different roles.

Adrenocorticotropic Hormone↗

PubMed2003

Dendritic glutamate-induced bursting in the prefrontal cortex: further characterization and effects of phencyclidine.

To understand the role of N-methyl-d-aspartate (NMDA) receptors in the prefrontal cortex (PFC) and to investigate how the psychotomimetic drug phencyclidine (PCP) may alter PFC function, we made whole-cell recordings from PFC neurons in rat brain slices. Our result showed that most deep layer pyramidal neurons in the PFC were regular spiking cells. They could fire repetitive bursts, however, when activated by glutamate focally applied to the apical dendrite. Application of NMDA to the same dendritic spot also induced bursting, whereas application of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) evoked single spikes only. Coapplication of AMPA with NMDA evoked more single spikes and decreased NMDA-induced bursting. Experiments with NMDA and AMPA antagonists further showed that dendritic glutamate (dGlu)-induced bursting required NMDA receptor activation and was enhanced when AMPA receptors were blocked. At subanesthetic concentrations, PCP decreased dGlu-induced bursting and altered the temporal characteristics of the bursts by decreasing spikes per burst and increasing interspike intervals within bursts. The latter two changes were not observed when AMPA receptors were blocked, suggesting that they are secondary to the increased AMPA receptor contribution to glutamate responses evoked in the presence of PCP. These results suggest that NMDA receptors are essential for PFC pyramidal cells to fire in bursts in response to dGlu input and that PCP suppresses dGlu-induced bursting. Since bursting is necessary for pyramidal cells to activate GABA interneurons, the suppression effect of PCP may further lead to a weakening of the connections from pyramidal cells and GABA interneurons, thereby contributing to PCP's psychotomimetic effects.

Animals↗

PubMed2000

Projections from the rat prefrontal cortex to the ventral tegmental area: target specificity in the synaptic associations with mesoaccumbens and mesocortical neurons.

Excitatory projections from the prefrontal cortex (PFC) to the ventral tegmental area (VTA) play an important role in regulating the activity of VTA neurons and the extracellular levels of dopamine (DA) within forebrain regions. Previous investigations have demonstrated that PFC terminals synapse on the dendrites of DA and non-DA neurons in the VTA. However, the projection targets of these cells are not known. To address whether PFC afferents innervate different populations of VTA neurons that project to the nucleus accumbens (NAc) or to the PFC, a triple labeling method was used that combined peroxidase markers for anterograde and retrograde tract-tracing with pre-embedding immunogold-silver labeling for either tyrosine hydroxylase (TH) or GABA. Within the VTA, PFC terminals formed asymmetric synapses onto dendritic shafts that were immunoreactive for either TH or GABA. PFC terminals also synapsed on VTA dendrites that were retrogradely labeled from the NAc or the PFC. Dendrites retrogradely labeled from the NAc and postsynaptic to PFC afferents were sometimes immunoreactive for GABA but were never TH-labeled. Conversely, dendrites retrogradely labeled from the PFC and postsynaptic to PFC afferents were sometimes immunoreactive for TH but were never GABA-labeled. These results provide the first demonstration of PFC afferents synapsing on identified cell populations in the VTA and indicate a considerable degree of specificity in the targets of the PFC projection. The unexpected finding of selective PFC synaptic input to GABA-containing mesoaccumbens neurons and DA-containing mesocortical neurons suggests novel mechanisms through which the PFC can influence the activity of ascending DA and GABA projections.

Animals↗

PubMed1997

Supranormal stimulation of D1 dopamine receptors in the rodent prefrontal cortex impairs spatial working memory performance.

Although previous research has emphasized the beneficial effects of dopamine (DA) on functions of the prefrontal cortex (PFC), recent studies of animals exposed to mild stress indicate that excessive DA receptor stimulation may be detrimental to the spatial working memory functions of the PFC (Arnsten and Goldman-Rakic, 1990; Murphy et al., 1994, 1996a,b, 1997). In particular, these studies have suggested that supranormal stimulation of D1 receptors may contribute to the detrimental actions of DA in the PFC (Murphy et al., 1994, 1996a). The current study directly tested this hypothesis by examining the effects of infusing a full D1 receptor agonist, SKF 81297, into the PFC of rats performing a spatial working memory task, delayed alternation. SKF 81297 produced a dose-related impairment in delayed-alternation performance. The impairment was reversed by pretreatment with a D1 receptor antagonist, SCH 23390, consistent with drug actions at D1 receptors. SCH 23390 by itself had no effect on performance, although slightly higher doses impaired performance (Murphy et al., 1994, 1996a). There was a significant relationship between infusion location and drug efficacy; animals with cannulae anterior to the PFC were not impaired by SKF 81297 infusions. Taken together, these results demonstrate that supranormal D1 receptor stimulation in the PFC is sufficient to impair PFC working memory function. These cognitive data are consistent with recent electrophysiological studies of D1 receptor mechanisms affecting the PFC (Williams and Goldman-Rakic, 1995; Yang and Seamans, 1996). Increased D1 receptor stimulation during stress may serve to take the PFC "off-line" to allow posterior cortical and subcortical structures to regulate behavior, but may contribute to the vulnerability of the PFC in many neuropsychiatric disorders.

Animals↗

PubMed2005

Involvement of 5-HT1A receptors in prefrontal cortex in the modulation of dopaminergic activity: role in atypical antipsychotic action.

Atypical antipsychotics increase dopamine (DA) release in the medial prefrontal cortex (mPFC), an effect possibly involved in the superior effects of atypical versus classical antipsychotics on cognitive/negative symptoms. We examined the role of 5-HT1A receptors in the mPFC on the modulation of dopaminergic activity and the mesocortical DA release in vivo. The highly selective 5-HT1A agonist BAY x 3702 (BAY; 10-40 microg/kg, i.v.) increased the firing rate and burst firing of DA neurons in the ventral tegmental area (VTA) and DA release in the VTA and mPFC. The increase in DA release in both areas was potentiated by nomifensine coperfusion. The selective 5-HT1A antagonist WAY-100635 reversed the effects of BAY in both areas, and the changes in the VTA were prevented by frontocortical transection. The application of BAY in rat and mouse mPFC by reverse dialysis increased local extracellular DA at a low concentration (3 microM) and reduced it at a higher concentration (30 microM). Both effects disappeared in 5-HT1A knock-out mice. In the presence of bicuculline, BAY reduced DA release at all concentrations. The atypical antipsychotics clozapine, olanzapine, and ziprasidone (but not haloperidol) enhanced DA release in the mPFC of wild-type but not 5-HT1A knock-out mice after systemic and local (clozapine and olanzapine) administration in the mPFC. Likewise, bicuculline coperfusion prevented the elevation of DA release produced by local clozapine or olanzapine application. These results suggest that the activation of mPFC 5-HT1A receptors enhances the activity of VTA DA neurons and mesocortical DA release. This mechanism may be involved in the elevation of extracellular DA produced by atypical antipsychotics.

Animals↗

PubMed1994

The role of D1-dopamine receptor in working memory: local injections of dopamine antagonists into the prefrontal cortex of rhesus monkeys performing an oculomotor delayed-response task.

1. To examine the role of dopamine receptors in the prefrontal cortex (PFC) on working memory, we injected dopamine antagonists (SCH23390, SCH39166, haloperidol, sulpiride, and raclopride) locally into the dorsolateral PFC in two monkeys trained to perform an oculomotor delayed-response (ODR) task. In the ODR task, monkeys fixate a central spot on a cathode ray tube (CRT) monitor while a visual cue is briefly (300 ms) presented in one of several peripheral locations in the visual field. After a delay of 1.5-6 s, the fixation spot is turned off, instructing the monkey to move its eyes to the target location that had been indicated by the visuospatial cue before the delay. Each monkey also performed a control task in which the cue remained on during the delay period. In this task the monkey's response was sensory rather than memory guided. 2. Local intracerebral injection of the selective dopamine antagonists SCH23390 (10-80 micrograms) and SCH39166 (1-5 micrograms) and/or the nonselective dopamine antagonist haloperidol (10-100 micrograms) induced deficits in ODR task performance at a total of 22 sites in the dorsolateral PFC. The deficit was characterized by a decrease in the accuracy of the memory-guided saccade as well as an increase in the latency of the response. The deficit usually appeared within 1-3 min after the injection, reached a peak at 20-40 min, and recovered at 60-90 min. 3. Performance change was restricted to a few specific target locations, which varied with the injection site and were most often contralateral to the injection site. 4. The degree of impairment in the ODR task occasioned by the injection of the dopamine antagonists was sensitive to the duration of delay; longer delays were associated with larger decreases in the accuracy and delayed onset of the memory-guided saccade. 5. The deficit was dose dependent; higher doses induced larger errors and increases in the onset of the memory-guided saccade. 6. Dopamine antagonists did not affect performance on the control task, which required the same eye movements but was sensory guided. Thus, in the same experimental session in which ODR performance was impaired, the accuracy and the latency of the sensory-guided saccades were normal for every target location.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1981

Single cell activity in ventral prefrontal cortex of behaving monkeys.

Single unit activity was recorded extracellularly from ventral prefrontal cortex (VPC) of monkeys during performance of two short-term memory tasks: spatial delayed response and delayed matching to sample. The tasks required perception, retention and recognition of visual cues differing in either color or spatial location. Two separate areas of VPC were explored: a lateral area in the lower prefrontal convexity and a medial area around the medial orbital sulcus. Two categories of unit activity were distinguished on the basis of frequency changes to the cue. One was characterized by non-specific discharge independent upon which cue was presented, the other by discriminative discharge related not only to visual qualities of the cue but to the animal's subsequent use of it. Nearly one-half of all units showed altered firing during the retention (delay) period as compared with intertrial control firing. Eighteen per cent displayed delay activity related to the quality of the preceding cue. The lateral and medial segments of VPC were not distinguished by differences of unit activity in cue or delay periods. Post-trial activity was related to presence or absence of reward. Type I cells showed firing changes following choice reinforcement as well as gratuitous reward; some showed changes in opposite direction following unreinforced choices. They may encode the availability of reward. Type II cells showed changes of activity after unreinforced trials and, in some cases, opposite changes after unexpected reward; they were not affected by the reward of normal correct-choice trials. These cells appear to react to deviations from expectancy of reward. Type III cells exhibited comparable firing changes following reinforced and unreinforced choices. They may encode termination of a trial sequence. Type I was more common in lateral than medial VPC, whereas the opposite was true for type II; type III did not clearly predominant in either area. Ablation studies have shown that the two areas of VPC differ in behavioral functions. This study of their cellular properties revealed topographic differences only during the post-trial period. It is therefore possible that the combination of cue and delay activity (related to exteroceptive input) with post-trial activity (related to interoceptive input) constitutes the neuronal basis for the two areas' differences in behavioral function.

Animals↗

PubMed1994

6-Hydroxydopamine lesion of the rat prefrontal cortex impairs motor initiation but not motor execution.

We examined the effects of bilateral 6-hydroxydopamine (6-OHDA) lesions of the medial prefrontal cortex (PFC) in rats on motor initiation and execution in a simple reaction time task. Reaction times (RT) and movement times (MT) were measured in trained rats on four pre- and postoperative days. Animals with 6-OHDA lesions were selectively impaired on motor initiation as measured by a significant increase in RT on each postoperative day. Motor execution was intact postoperatively, since MT was not altered. Neurochemical analysis revealed a significant depletion of prefrontal dopamine (DA) and noradrenaline (NA) in lesioned animals. It was concluded that DA and, to a lesser extent, NA in the rat PFC were involved in monitoring RT performance.

Animals↗

PubMed1991

Diverse thalamic projections to the prefrontal cortex in the rhesus monkey.

We studied the sources of thalamic projections to prefrontal areas of nine rhesus monkeys with the aid of retrograde tracers (horseradish peroxidase or fluorescent dyes). Our goal was to determine the proportion of labeled neurons contributing to this projection system by the mediodorsal (MD) nucleus compared to those distributed in other thalamic nuclei, and to investigate the relationship of thalamic projections to specific architectonic areas of the prefrontal cortex. We selected areas for study within both the basoventral (areas 11, 12, and ventral 46) and the mediodorsal (areas 32, 14, 46, and 8) prefrontal sectors. This choice was based on our previous studies, which indicate differences in cortical projections to these two distinct architectonic sectors (Barbas, '88; Barbas and Pandya, '89). In addition, for each sector we included areas with different architectonic profiles, which is also relevant to the connectional patterns of the prefrontal cortices. The results showed that MD included a clear majority (over 80%) of all thalamic neurons directed to some prefrontal cortices (areas 11, 46, and 8); it contributed just over half to some others (areas 12 and 32), and less than a third to area 14. Clusters of neurons directed to basoventral and mediodorsal prefrontal areas were largely segregated within MD: the former were found ventrally, the latter dorsally. However, the most striking findings establish a relationship between thalamic origin and laminar definition of the prefrontal target areas. Most thalamic neurons directed to lateral prefrontal cortices, which are characterized by a high degree of laminar definition (areas 46 and 8), originated in the parvicellular and multiform subdivisions of MD, and only a few were found in other nuclei. In contrast, orbital and medial cortices, which have a low degree of laminar differentiation, were targeted by the magnocellular subdivision of MD and by numerous other limbic thalamic nuclei, including the midline and the anterior. Thus topographic specificity in the origin of thalamic projections increased as the laminar definition of the target area increased. Moreover, the rostrocaudal distribution of labeled neurons in MD and the medial pulvinar also differed depending on the degree of the laminar definition of the prefrontal target areas. The rostral parts of MD and the medial pulvinar projected to the eulaminate lateral prefrontal cortices, whereas their caudal parts projected to orbital and medial limbic cortices. Selective destruction of caudal MD is known to disrupt mnemonic processes in both humans and monkeys, suggesting that this thalamic-limbic prefrontal loop may constitute an important pathway for memory.

Animals↗

PubMed1997

Short-term memory for food reward magnitude: the role of the prefrontal cortex.

Memory for magnitude of reinforcement was assessed in rats using a go/no-go short-term memory paradigm. During the task's study phase rats were given a piece of cereal comprised of either 25 or 50% sugar. For all trials, one of the cereal types was designated positive, the other negative. On the ensuing test phase the rat was presented with an object which covered a food well. If a positive food reward was given during the study phase, a second food reward was placed beneath the object. No food reward was placed under the object if the study phase consisted of a negative food reward. Latency to object displacement was used as the measure of performance. Following the establishment of a significant difference between latency to approach the object with reward compared to latency to approach the object without reward, rats were given either agranular insular cortex, anterior cingulate cortex, pre- and infralimbic cortex or control lesions. Agranular insular cortex lesioned animals demonstrated a mild post-surgery impairment. Trials consisting of 10 and 20 s delays between the study and test phases were then introduced. Delays exacerbated the previous deficit of the agranular insular cortex lesion group, but had little effect on the other lesion groups. All animals transferred to a new set of cereals containing 25 and 50% sugar and exhibited taste preferences to sugar solutions of different concentrations. These results indicate that the agranular insular cortex may play an important role in the processing of affect-laden information within a prefrontal cortex short-term or working memory system.

Animals↗

PubMed2006

Prefrontal cortex dysfunction and income: a study in neuroeconomics.

In four samples of adults, individual income was negatively associated with a measure of prefrontal cortex dysfunction even after implementing controls for age, sex, and education. The small association was stronger for men than for women. These results provide support for a neuroeconomic approach to the study of micro-economic variables.

Adult↗

PubMed2000

Relationship among discharges of neighboring neurons in the rat prefrontal cortex during spatial working memory tasks.

The relationship among discharges of neurons that were recorded simultaneously with tetrodes in the rat medial prefrontal cortex was analyzed. Spatial working memory tasks were divided into several distinct stages based on the behavioral correlates of individual neurons, and interneuronal correlation of signal (mean discharge rate at each stage) and noise (trial-to-trial deviation from the signal) was calculated. Behavioral correlates of neighboring neurons were quite heterogeneous and, accordingly, average signal correlation was relatively low ( approximately 0.16). Noise correlation was even lower ( approximately 0.06), but neuronal noise was more correlated among the neurons with similar signals. Spikes underlying the signal and noise correlation among the prefrontal cortical neurons were loosely synchronized over a few hundred milliseconds. These results suggest that neighboring prefrontal cortical neurons process largely independent information and have weakly correlated noise and that precisely synchronized spikes play a relatively minor role in producing the correlated signal and noise among these neurons.

Action Potentials↗

PubMed1998

Relationships between the prefrontal cortex and the basal ganglia in the rat: physiology of the corticosubthalamic circuits.

The prelimbic-medial orbital areas (PL/MO) of the prefrontal cortex are connected to the medial part of the subthalamic nucleus (STN) through a direct projection and an indirect circuit that involves the core of the nucleus accumbens (NAcc) and the ventral pallidum (VP). In the present study, the influence of the PL/MO on the discharge of STN cells has been characterized. The major pattern of the responses observed after stimulation of PL/MO consisted of two excitatory peaks often separated by a brief inhibitory period. The early excitation was most likely to be caused by the activation of direct cortical inputs because its latency matches the conduction time of the prefrontal STN projections. The late excitation resulted from the activation of the indirect PL/MO-STN pathway that operates through a disinhibitory process. Indeed, the late excitation was no longer observed after acute blockade of the glutamatergic corticostriatal transmission by CNQX application into the NAcc. A similar effect was obtained after the blockade of the GABAergic striatopallidal transmission by bicuculline application into the VP. Finally, the brief inhibition that followed the early excitation was likely to result from the activation of a feedback inhibitory loop through VP because this inhibition was no longer observed after the blockade of STN inputs by CNQX application into the VP. This study further indicates the implication of STN in prefrontal basal ganglia circuits and underlines that in addition to a direct excitatory input, medial STN receives an indirect excitatory influence from PL/MO through an NAcc-VP-STN disinhibitory circuit.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed1994

Prefrontal cortex and the relative associability of taste and place cues in rats.

The effects of cutting the corticocortical connections between medial and sulcal prefrontal areas on the conditioning of taste and place cues were examined. In Experiment 1, rats were simultaneously exposed to taste and place cues before injection of 0.15 M LiCl. In controls, a significant conditioned taste aversion (CTA) but no conditioned place aversion (CPA) was observed. In contrast, rats with bilateral knife cuts showed a significant CPA but a weaker CTA. To test whether these results could have been due to the effects of simultaneously exposing the rats to taste and place cues during conditioning, rats were trained independently in either CTA or CPA paradigms in Experiment 2. In the CTA test, rats both in operated and control groups showed a CTA when first tested. Rats with bilateral knife cuts, however, showed a weaker CTA than those in the control group. In the CPA test, rats in the control group did not exhibit a CPA, whereas the knife cut group did. Rats with sham lesions tested in Experiment 2 did not differ from control subjects on either the CPA or the CTA test. Thus, bilateral cuts increased the CPA and decreased the CTA even when tested independently. These results indicate that the relative ease of association of place and taste stimuli may be accounted for in part by the organization of the intrinsic connections of the prefrontal cortex in the rat.

Animals↗