Bone marrow storage and delayed consumption at Middle Pleistocene Qesem Cave, Israel (420 to 200 ka).

Bone marrow and grease constitute an important source of nutrition and have attracted the attention of human groups since prehistoric times. Marrow consumption has been linked to immediate consumption following the procurement and removal of soft tissues. Here, we present the earliest evidence for storage and delayed consumption of bone marrow at Qesem Cave, Israel (~420 to 200 ka). By using experimental series controlling exposure time and environmental parameters, combined with chemical analyses, we evaluated bone marrow preservation. The combination of archaeological and experimental results allowed us to isolate specific marks linked to dry skin removal and determine a low rate of marrow fat degradation of up to 9 weeks of exposure. This is the earliest evidence of such previously unidentified behavior, and it offers insights into the socio-economy of the human groups who lived at Qesem and may mark a threshold to new modes of Palaeolithic human adaptation.

Microfaunal remains at Middle Pleistocene Qesem Cave, Israel: Preliminary results on small vertebrates, environment and biostratigraphy.

Preliminary results of the investigation of the microfauna at the Acheulo-Yabrudian Middle Pleistocene site of Qesem Cave, Israel, are presented. Thus far the assemblage includes ca. 10,000 bone and tooth fragments, of which 50% could be identified to the generic and some hundreds to the species level. Based on the current material, the fauna includes the following squamate reptiles: Laudakia sp., Chamaeleo sp., Gekkonidae indet., Lacertidae indet., Scincidae indet., Pseudopus sp., Varanus sp., Colubroidea indet. (at least three species) and micromammals: Suncus etruscus, Crocidura cf. leucodon, Crocidurinae indet. (large form), Chiroptera indet., Sciurus cf. anomalus, Cricetulus cf. migratorius, Microtus guentheri, Nannospalax ehrenbergi, Dipodillus cf. dasyurus, Meriones cf. tristrami, Gerbillidae indet., Mus cf. musculus, Apodemus cf. flavicollis. These results suggest that the fauna includes only taxa that occur recently in the territory of Israel. The ecological preferences of the nearest living relatives of the recorded taxa allow us to infer a paleoenvironment with a mosaic of open and woodland habitats. However, comparing the lower with the upper levels of the microfauna-bearing profile, a slight shift towards more wooded conditions might be detectable. Biostratigraphical inferences from the recorded micromammal taxa cover a rather wide age range, whereas the radiometric (U-series and preliminary TL) dating enable a provisionally estimated date for the microfauna-bearing levels at 360-300 ka. Detailed morphometric comparisons with material from other sites in the region are necessary and may yet provide further insights.

Flint mining in prehistory recorded by in situ-produced cosmogenic 10Be.

The development of mining to acquire the best raw materials for producing stone tools represents a breakthrough in human technological and intellectual development. We present a new approach to studying the history of flint mining, using in situ-produced cosmogenic 10Be concentrations. We show that the raw material used to manufacture flint artifacts approximately 300,000 years old from Qesem Cave (Israel) was most likely surface-collected or obtained from shallow quarries, whereas artifacts of the same period from Tabun Cave (Israel) were made of flint originating from layers 2 or more meters deep, possibly mined or quarried by humans.

Uranium series dates from Qesem Cave, Israel, and the end of the Lower Palaeolithic.

Israel is part of a geographical 'out of Africa' corridor for human dispersals. An important event in these dispersals was the possible arrival of anatomically modern humans in the Levant during the late Middle Pleistocene. In the Levant the Lower Palaeolithic ends with the Acheulo-Yabrudian complex, characterized by technological developments, including the introduction of technological innovations such as the systematic production of blades and the disappearance of hand-axes. These reflect new human perceptions and capabilities in lithic technology and tool function. Qesem Cave, discovered in 2000, has a rich, well-preserved Acheulo-Yabrudian deposit holding great promise for providing new insights into the period. Here we report the dates of this deposit obtained by uranium isotopic series on associated speleothems and their implications. The results shed light on the temporal range of the Acheulo-Yabrudian and the end of the Lower Palaeolithic, suggesting a long cultural phase between the Lower Palaeolithic Acheulian and the Middle Palaeolithic Mousterian phases, starting before 382 kyr ago and ending at about 200 kyr ago.

Haloperidol- and clozapine-induced enhancement of latent inhibition with extended conditioning: implications for the mechanism of action of neuroleptic drugs.

Latent inhibition (LI) refers to retarded conditioning to a stimulus as a consequence of its nonreinforced preexposure. LI is impaired in acute schizophrenic patients and in rats treated with amphetamine. Neuroleptic drugs enhance LI, and this effect is selective and specific for this class of drugs. The present experiments tested the proposition that neuroleptic-induced enhancement of LI stems from decreased capacity of stimulus-preexposed animals to switch responding according to the new stimulus-reinforcement contingency in the conditioning stage. LI was assessed using an off-baseline conditioned emotional response (CER) procedure in rats licking for water, consisting of three stages: preexposure to the-to-be conditioned stimulus, tone; conditioning, in which the preexposed stimulus was paired with a foot-shock; and test, in which LI was indexed by animals' degree of suppression of licking during tone presentation. Whereas in previous studies that demonstrated LI enhancement by neuroleptics, preexposure consisted of 10 to 40 tones, and conditioning included two tone-shock pairings, the present experiments used 40 tone preexposures, followed by an extended conditioning stage with five tone-shock pairings. It was expected that under these conditions no LI effect would be evident in untreated animals, but that animals treated with a neuroleptic drug, either during the entire LI procedure or only in conditioning, would show LI. Experiments 1 and 2 showed that LI was obtained in rats treated with haloperidol (0.1 mg/kg in experiment 1, 0.03 and 0.2 mg/kg in experiment 2) but not in the untreated controls. Experiment 3 showed that the same outcome was obtained when haloperidol (0.1 mg/kg) administration was confined to the conditioning stage. Experiment 4 showed that clozapine (5 mg/kg)-treated animals showed LI when the drug was confined to conditioning, but not to the preexposure stage. The implications of these results for the mechanism of action of neuroleptic drugs are discussed.