The electron-ion collider: assessing the energy dependence of key measurements.

We provide an assessment of the energy dependence of key measurements within the scope of the machine parameters for a US based electron-ion collider (EIC) outlined in the EIC White Paper. We first examine the importance of the physics underlying these measurements in the context of the outstanding questions in nuclear science. We then demonstrate, through detailed simulations of the measurements, that the likelihood of transformational scientific insights is greatly enhanced by making the energy range and reach of the EIC as large as practically feasible.

Changes of single unit activity in the cat's auditory thalamus and cortex associated to different anesthetic conditions.

Single unit spike trains were recorded in the auditory cortex (n = 78) and in the auditory thalamus (n = 55) of nitrous oxide anesthetized cats. The electrophysiological activity was studied before and during the application of pentobarbital (P, 7 mg/kg), ketamine (K, 12 mg/kg) and a mixture of these anesthetics (KP). The units were characterized during the spontaneous and acoustically driven activity ('white' noise and pure tone bursts). For the majority of cortical (61%) and thalamic (83%) units both drugs tended to decrease the spontaneous firing rate, but affected differently its time structure: P tended to increase the average size of burst discharges, whereas K and KP tended to decrease it. In the cortex the peak firing rate evoked by 'white' noise tended to be decreased, whereas stronger excitatory responses were observed in the thalamus after injection of K or KP. The overall effect of the anesthetics during stimulation by pure tones was an increase in tonal selectivity due to a decrease in the response bandwidth. The response pattern to tones was also sometimes affected by the drugs. The direct evidence reported here for significant alterations of the discharge properties of auditory neurons in the thalamus and cortex resulting from low dose administration of K and/or P emphasizes difficulties in comparing data derived from experiments conducted in various conditions of anesthesia or in the awake state.

Auditory cortical efferent actions upon inferior colliculus unitary activity in the guinea pig.

Differential actions on inferior colliculus central nucleus (ICc) single cells spontaneous activity were observed with both ipsilateral and contralateral auditory cortical electrical stimulation (ACx stimulation). Following ACx stimulation, a firing depression of the spontaneous activity was obtained using contralateral or ipsilateral cortical stimulation, although a greater effect was elicited by the contralateral cortex. In contrast, ipsilateral ACx stimulation elicited more excitation with a shorter latency than contralateral stimulation. In units that failed to show spontaneous firing, the sound-evoked responses and ACx stimulation were studied; approximately 50% of them demonstrated firing depression to ACx stimulation on either side with either clicks or tone-bursts. Thirty percent of the units failed to show changes in response to any cortical stimulation. A temporary disruption of ICc-evoked neuronal discharge was elicited during contralateral cortex stimulation, as previously reported to occur during sleep. The demonstration that auditory cortices may differentially affect the same ICc unit activity, i.e. spontaneous and evoked, suggests that auditory processing may depend on the ongoing spontaneous activity plus the effects exerted from each auditory cortex activation.

Prolactin as a marker of dopaminergic activity at different levels of thyroid function in man.

To investigate the hypothesis of an altered dopaminergic activity in hypothyroidism, seven patients without thyroid tissue were studied by means of three consecutive tests: an iv bolus of TRH (200 micrograms); a continuous iv infusion (5 mg during 30 min) of metoclopramide (MCP); and a second, post-MCP, iv bolus of TRH (200 micrograms). The study was performed three times: (A) without treatment; (B) on the 15th day while on L-T4 (150 micrograms i.d.); and (C) on the 30th day with the same treatment. Each time was a different situation of thyroid function; on the basis of basal serum TSH (P less than 0.001, A vs B vs C). The response of PRL to the first (non-primed) TRH, expressed as the sum of increments in ng/ml (mean +/- SE), was significantly higher in A (659 +/- 155) than in C (185 +/- 61). Individual PRL responses correlated with circulating T3 (P less than 0.02), but not with T4. A significant increase of PRL occurred after MCP in the three situations, but there were no differences among them. Likewise, the responses to the second (MCP-primed) TRH showed no differences. Although there was an expected high correlation (P less than 0.001) between basal TSH and circulating thyroid hormones, the maximal response of TSH to both non-primed and MCP-primed TRH was in B. After MCP, no measurable increase of TSH could be demonstrated at any of the three levels of thyroid function. These results do not support the hypothesis of an altered dopaminergic activity in hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

[Gammagraphic diagnosis of a non-hyperactive suprarenal adenoma]. / Diagnóstico gammagráfico de un adenoma suprarrenal no hiperfuncionante.

It is described the case of a patient with Ovarian Cystadenoma in whom a 3.5 cm nodular lesion was accidentally detected in her left suprarenal gland. She had no signs of hypercortisolism or any other suprarenal pathology and was symptomless. Determinations in the urine of 24 hours of Cortisol, Adrenaline and Noradrenaline, 17-ketosteroids and Tetrahydroaldosterone were normal. Daily rhythm and plasmatic determinations of ACTH, cortisol and 11-deoxycortisol were normal. The Dexamethasone suppression test was also normal. In the suprarenal gammagraphy it appeared an intense captation by left suprarenal without visualization of right gland. A left suprarenalectomy was performed and the anatomopathological analysis showed a clear cell corticoadrenal adenoma. Therefore the only data of the function of suprarenal adenoma was the one coming from gammagraphy. We thought that the adenoma was responsible of practically all the corticoadrenal function without reaching pathological levels, meeting the criteria of "pre-Cushing" syndrome or subclinical Cushing, due to the fact that the contralateral gland was not seen in the gammagraphy. Therefore in the characterization of certain tumors which appear clinically and biochemically as non functional, the suprarenal gammagraphy could be a technique of great usefulness for the diagnosis.

Corticofugal modulation of the information processing in the auditory thalamus of the cat.

Single unit activity of 355 cells was recorded in the auditory thalamus of anesthetized cats before, during, and after the inactivation by cooling of the ipsilateral primary auditory cortex (AI). Most of the units (n = 288) showed similar functional characteristics of firing before and after the cryogenic blockade of AI. The spontaneous firing rate remained unchanged by cooling in 20% of the units and decreased in the majority of them (60%). In some regions, i.e. dorsal division of the medial geniculate body (MGB), lateral part of the posterior group of the thalamus, and auditory sector of the reticular nucleus of the thalamus, the maximum firing rate evoked by white noise bursts was generally affected by cooling in the same direction and to the same extent as the spontaneous activity. Units in the ventral division of MGB showed a characteristic increase of signal-to-noise ratio during cortical cooling. The corticofugal modulation led to the appearance or disappearance of the best frequency of tuning in 51 units and changed it by more than 0.5 octave in 34 units. The bandwidths of different response patterns to pure tones stimulation were used to define a set of functional properties. During cryogenic blockade of AI, two cortically modulated sub-populations of units were usually distinguished that exhibited changes for a given functional property. The complexity and diversity of the effects of cortical inactivation suggest that the corticothalamic projection may be the support for selective operations such as an adaptive filtering of the incoming acoustic signal at the thalamic level adjusted as a function of cortical activity.